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MARINE LIFE

CARLETON RAYand ELGIN CIAMPI

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MARINE

LIFE

BIOLOGICAL
LABORATORY

LIBRARY

WOOK HOLE, MASS.
W. H. 0. L

A. S. BARNES and COMPANY NEW YORK

© 1956 BY A. S. BARNES AND COMPANY, INC.

All rights reserved. No part of this book

may be reproduced in any form, either wholly

or in part, for any use whatsoever, including

radio and television presentation, without the

written permission of the copyright owner,

except by a reviewer who may quote brief passages

in a review printed in a magazine or newspaper.

Manufactured in the United States of America.

PUBLISHED ON THE SAME DAY IN THE DOMINION OF CANADA
BY THE COPP CLARK COMPANY, LTD., TORONTO

LIBRARY OF CONGRESS CATALOG CARD NUMBER 56-5558

ACKNOWLEDGEMENTS

The comprehensi\'eness of this book, by its nature, leaves us greatly in debt to
sexeral authors and publishers for their help and gracious cooperation in grant-
ing permission to reproduce drawings. The figures of plants, chapter 6, were
largely adapted from Marine Algae of the N orthwestern Coast of INorth America
by W. R. Taylor, University of Michigan Press and Marine Algae of the Mon-
terey Peninsula, California by G. M. Smith, Stanford University Press. The
drawings of sharks, chapter 8, were partly reproduced from Part I of Fishes
of the Western North Atlantic by H. B. Bigelow and W. C. Schroeder through
the courtesy of the Sears Foundation for Marine Research, Yale Uni\'ersity,
and from The Plagiostoma by Samuel Garman through the courtesy of
the Museum of Comparative Zoology, Harvard University. Many of the
drawings of fishes, chapter 9, were redrawn from The Fishes of North and
Middle America by D. S. Jordan and B. W. Evermann, a Bulletin of the
United States National Museum. The figures of turdes, chapter 10, were based
on illustrations from The Handbook of Turtles by Archie Carr, Comstock
Publishing Associates. Those of mamm.als were pardy based on illustrations
from The Field Book of North American Mammals by H. E. Anthony,
Putnam's Sons.

All of the photographs except two by John A. Moore of Columbia University
were taken by the authors with the aid of Russell Kinne. It would not have
been possible to procure these photographs without the very kind cooperation
of Jim O'Doherty of Robinson-Hannagan Agency, New York, Don McCarthy
of the Bahamas Development Board, Nassau, and Abercrombie and Fitch Co.,
New York, for the loan of the compressor shown in figure 15.

We also wish to thank Peggy and Dennis Hickman of the Pilot Flouse club,
Nassau, and their surprised guests who were most understanding when they
discovered that we were using their swimming pool as a specimen tank.
Nora Wheatlv and Jean Wilmot were a great help in the typing of manuscript
and the correction of galleys.

The text was improved through the advice of the following: animal behavior,
chapter 2, Dr. Helmut E. Adler and Dr. Evelyn Shaw, both of the American
Museum of Natural History in New York; photography, chapter 3, Peter Stack-
pole of Life Magazine; evolution, chapter 5, Dr. John A. Moore of Columbia
University; plants, chapter 6, Dr. F. G. Lier of Columbia University; reptiles,
chapter 10, Dr. Richard Zweifel of the American Museum of Natural History;
mammals, chapter 10, Dr. H. E. Anthony and Dr. J. C Moore, both of the
American Museum of Natural History.

CONTENTS

INTRODUCTION ix

SECTION I. ^/le .9^

Chapter 1. ZONES OF THE SEA- Where They Live 1

Chapter 2. BIOLOGY OF THE SEA-How They Live 26

Chapter 3. MAN AND THE SEA I-Photography and Equipment 53

Chapter 4. MAN AND THE SEA II-Dangers and Chumming 62

Chapter 5. EVOLUTION, NAMES, AND CLASSIFICATION 68

SECTION II. ^lo^a a^d SSc^t^e^ ^^uuna

Chapter 6. PLANTS OF THE SEA 76

Chapter 7. THE INVERTEBRATE LEGIONS 86

SECTION III. fjd^imii/6 nfil^t ^acA^tte^ : ^te ^f^^^eS^aie^

Chapter 8. THE LOWER FISHES-Lampreys, Sharks, Rays, and

Ratfishes 132

Chapter 9. MASTERS OF THE WATER-Bony Fishes 177

Chapter 10. THE RE-ENTRANTS 303

BIBLIOGRAPHY 323

INDEX 329

vii

INTRODUCTION

The sea for thousands of years has been the least explored part of the earth.
Now, with increased interest in the sea and the development of new and
growing technology for its study and utilization, great esthetic and material
rewards have been made a\'ailable to mankind. The sea has become for many
men a new source of esthetic enrichment because of its primiti\'eness. It is also
a vast reservoir of food and minerals, and this important part of the earth's
resources is becoming more so because of the ever-growing problem of over-
population—a problem which se\'eral atomic scientists have called more serious
than the threat of the atomic bomb. If the sea is to continue to plav its important
role in solving this problem, world-wide and local conservation programs must
be enacted.

Man's relationship with the sea is the same today as that of the early
American pioneers with the undiscoveired wilderness. They believed that the
land had unlimited productivity. But the rapid consumption of land resources
without any thought of conserving the supply has resulted in great decimation
of one-time plentiful forests and wildlife. Even James Audubon did not believe
that the passenger pigeon of our plains, formerlv one of the world's most
numerous birds, could ever become extinct. Flocks of millions once filled the
skies, yet today not one remains. Similar stories of decimation have been repeated
in the cases of the American bison, pronghorn antelope, bighorn sheep, beaver,
many species of ducks, and valuable timber trees such as southern long-leaf pine,
sugar pine and several hardwoods. These examples are onlv a small fragment of
a long list of man's abuse of the land.

We must avoid the careless and tragic exploitation of the sea which we have
not avoided in the case of the land. Behind this exploitation lies one of the
commonest beliefs of modern man— that the sea is inexhaustible. It is absolutelv
vital to realize that the sea, like the land, has its limits and that the exploitation
of the sea beyond its ability to replenish itself can onlv result in the situation
that exists on much of the land. Already there are signs of the exhaustibilitv
of the sea. Whales, thought to be innumerable at one time, were so scarce
before World War II that manv whaling fleets ceased operations. Since the war,
international control has resulted in a slow increase in their numbers. Sea otters,
fur seals, sea turtles, striped bass, salmon, shad, and others all were, or still are,
exceedingly important economically and have all suffered severely from exploi-
tation. Commercial catches of manv important species of schooling fishes are

IX

X INTRODUCTION

smaller todcty than previously in spite of the introduction of scientific fishing
methods.

The sea is also used as a gigantic dumping ground for industrial chemicals,
sewage, garbage, oil, and atomic wastes. There is a widespread feeling that these
things thrown into the sea are safely and completely disposed of. But they
return to plague us in the form of reduced commercial fisheries, exterminated
game fishes, littered beaches, poisonous shellfish, and polluted waters. For
example, several New England rivers at one time had runs of Atlantic salmon
which compared favorably with the runs of Pacific salmon on the west coast,
but now, because of overfishing and pollution, there are few salmon south
of Maine.

These are the abuses that conservationists work to prevent in order to main-
tain the long-term esthetic and economic resources of the earth. Conservationists
are not the wide-eyed dreamers they are frequentlv thought to be, interested
merelv in preserving remnants of rare fauna and flora. Although preservation of
rare species is part of conservation, they are mainly concerned with the
theme first popularly advocated by Theodore Roosevelt— "conser\'ation through
wise use."

There are two basic concepts per\'ading the philosophy of western man that
have been serious barriers to the development of a realistic conservation pro-
gram. The first is the economic conviction that the only possible healthy econ-
omy is one which is constantly expanding— more and more production with
little thought gi\'en to resource limits and replenishment. Second is the primarily
theological dualistic view of the world wherein man and nature are somehow
separated— man rules the world by a sort of egotistical "divine right of kings."
Both of these concepts are in direct contradiction to the known facts that man
and nature are one and that man cannot abuse nature without harming himself
in turn.

I do not see a planet concreted over its land surfaces to provide living and
factory space for an immense human population nourishing itself and sup-
plying all its needs synthetically. Human life is going to depend on plant
life for a long time yet, and in far more ways than its value as an efficient
conversion agent . . . man is still adolescent as a conscious species and
he is faced, again in full consciousness, with the choice of whether he shall
mature into a species loving his world or remain irresponsibly wielding his
new toy of an expanding economy.

F. Fraser Darling

American Scholar, Winter 1956

>(■ H- 1- 1-

Spearfishing and Skin-diving: A Progra)); for the Putiire

Such is oftenest the young man's introduction to the forest, and the most
original part of himself. He goes thither at first as a hunter and fisher, until
at last, if he has the seeds of a better life in him, he distinguishes his proper
objects, as a poet or naturalist it may be, and leaves the gun and fishpole
behind.

H. D. 1 horeau — Walden

INTRODUCTION xi

Wc have noticed a gradual transformation in some divers which invoh'es a
change from a spearfisherman to a naturahst, photographer, or explorer. As the
spearHsherman moves about the reefs looking for his prev, he becomes aware of
the beauty and variety of marine life. It soon becomes unimportant whether or
not he spears anything. His reward is in viewing nature and in gaining an
understanding of it and of himself. He also gains an appreciation and respect
for the order of things in nature and develops a feeling for not wanting to
disturb it.

Uncontrolled spearlishing, on the whole, has the two major disadvantages of
rapidly depleting the number of fishes in an area— even more rapidly than the
net or hook in most cases— and of driving fishes that are not killed into hiding
at the sight of man. It doesn't take lono for a diver to recognize an area where
spearfishermen have been. There is an air of desolation as evidenced by the
empty reefs, and the few large fishes that are present are exceedingly wary. In
sharp contrast, reefs which have not been invaded with spears have yielded
some of our most interesting experiences underwater. Most of the fishes show
little fear and have given endless opportunities for study of their fascinating
behavior and for photography. The same contrast exists between areas where
the over-enthusiastic shell or coral collectdr has been and those reefs which are
untouched and unbroken.

We feel there is a definite need for a program which will maintain and
conserve marine life so that it will not be depleted beyond its ability to replenish
itself. Only through a sound conservation program can skin-diving, either for
esthetic or sporting values, be maintained as an expanding and long-range
acti\'ity. A reef can not be cleaned out of fishes in one summer and be expected
to ha\'e replenished itself the following year. It takes some species many years
to reach maturity and large size and if the sport diver wants to see fish, he can
not take them without any thought of conser\'ing the supply. We suggest the
following program:

1. Underwater Parks

Some of the richest areas should be set aside and protected as are "wilderness "
areas on land. The taking of any marine life, animal or plant, by any means,
should be prohibited. The areas selected should be distributed widely so that
they could act as reproductive centers from which non-protected areas would be
replenished with life. These areas, would be open to skin divers, naturalists,
photographers, and all those who come to enjoy the wonders of nature. The
benefits derived from undersea wilderness areas are as follows:

a) Areas of replenishment. Game and commercial fishes can replenish their
numbers and stock non-protected, surrounding areas, insuring a constant supply.
This guarantees continued and growing interest of sportsmen upon whom large
sporting industries and tourism are dependent.

b) Sanctuary. Common and rare species would be protected from extinction.

c) Esthetic values. The natural, virgin beauty of sea gardens unspoiled by
broken corals or fishes made scarce and wary by spearing is preserved. Interest
in natural beauties of the sea is maintained and expanded and these areas would
become valuable tourist attractions.

xii INTRODUCTION

d) Science and education. Parks serve as natural outdoor laboratories for
accumulating knowledge of the sea, for investigating methods of increasing
fisheries' productivity, for formulation of better conservation policy, and for
basic scientific research.

2. Regulation of Spearfishing

The pressures on fish populations exerted by increasing numbers of spear
fishermen have rendered many areas not worth visiting by the sightseer or
spearfisherman. Controlled spearing, however, will not diminish the population
of an area because it serves to take off some of the individuals that would
normally have died of natural causes.

a) Licensing. Spearfishermen should be licensed in order to maintain control.
Funds derived should be used solely for conservation and enforcement.

b) Regulating catch. Game fishes should be designated and for each of these,
season, bag, and minimum size limits should be established. The spearing of
small, non-game fishes such as angelfishes, butterflv fishes, etc., should be pro-
hibited.

c) Designation of areas. Spearing should be restricted to outlying areas be-
cause, in general, spearfishermen are better divers than sightseers are, and
because any amount of spearing tends to make fishes become warv or drive them
off to deep waters. This would leave easily accessible waters for non-spear-
fishermen such as skin-divers, sightseers, naturalists, and photographers.

Whether our inshore waters remain filled with life and a source of enjoyment
for present and future generations, or, whether they go the way our now com-
paratively barren forests and plains have gone, depends upon the instigation of
a conservation program immediatelv.

How to use this Book

This book is divided into three sections. The first section consists of chapters
on the sea as an environment for life, how life adapts to this environment,
dangers that exist in the sea for man, underwater photography, and evolution.
These chapters are included in order that the reader will better understand
the sea and its life and should be read before attempting to identify species or
groups or to interpret behavior. The last two sections are a guide to the identi-
fication and habits of groups of marine plants, invertebrates, and vertebrates.
Because of the huge numbers of species in the sea (400 basses alone, for in-
stance), each group (family, order, etc.) is represented by only a few of its
commonest species which characterize the group as "types." Therefore, the
reader will not always be able to identify a particular species with this book,
but, by becoming familiar with the characteristics of a group, he can categorize
any species of that group he may come across anywhere in the world. Thus, the
ulua of Hawaii can be identified as a species of jack, the merou of the Medi-
terranean as a grouper, and Japan's tai as a porgy. Identification of groups is
made by characteristics recognizable in the field— silhouette, pattern, mo\'ement,
etc.— and not by laboratory methods such as fin counts or fine anatomy. Though
this book emphasizes groups rather than species, it is important that the reader
refer to a particular species in his observations of behavior.

All of the species given as examples of groups are found in North American

INTRODUCTION xiii

waters chiefly o\'ei" the continental shelf. Many of the species given, however,
range to deep waters and bevond North American seas. Many of the pelagic
species are world-wide in distribution.

Because of the tremendous scope of the subject of the sea, the reader is
asked to refer to the bibliography for detailed information.

There is a great body of unknown facts that only the swimmer can procure
because of his intimate contact with the sea. In 1933, Beebe and Tee-Van
wrote that ". . . not one complete life history of a Bermuda fish is known." That
statement is larpcly true today of marine fishes exervwhere. This guide has been
written in response to the growing interest in the sea and its life in the hope
that better knowledge of the sea and its relationship to man will result.

Carleton Ray and Elgin T. Ciampi
April, 1956

SECTION ONE

CHAPTER /J

ZONES OF THE SEA— Where They Live

The study of mankind— his behavior, his diseases, his. history— could not progress
very far nor be very meaningful if careful attention vere not paid to his
environment— where he grew up and under what circumstances, the climate,
culture, geographical location, and economic conditions. The same is true of
wild life. Whatever aspect we care to study, scientific or aesthetic, a considera-
tion of the environment must enter our minds. If one tries to imagine a plant
or animal without environment, it becomes almost impossible to obtain much
insight into its nature, whether it be a one-celled animal or a complex animal
such as man. For instance, the odd shape of a sargassum fish has little meaning
by itself, but when it is viewed from the perspective of self-preservation in its
habitat of sargasso weed, its meaning as a concealing, protective form becomes
clear.

The study of the relationship between life and its environment is scientific
natural history or ecology. Ecology might be called the crossroads of the life
sciences, where such fields as genetics, paleontology, anatomy, physiology,
embryology, animal behavior, oceanography, evolutionary study, and others find
common ground. But let none assume that ecology is for the scientist only. The
diver who has learned to associate groupers with their homes in coral or rock
has made an ecological observation.

Ecology is the subject of the first two chapters of this book in the hope that
as insight into the sea's environment increases, so will our ability to appreciate
the beauties and wonders of tfte sea increase. In this chapter the main character-
istics of the sea and its zones will be given. The ways and means that life has
adapted to this environment will be discussed in the chapter which follows.

EARTH AND THE SEA

The perspectives and visions of mankind are often not as broad as we would
like to believe. Much of the narrowness of man's particular world is a con-
sequence of the evolutionary place he has come to occupy— that of a giant land

2 UNDERWATER GUIDE TO MARINE LIFE

animal. His size has made it extremely difficult for him to project himself intc
the worlds of the small living things that swarm about him and has restrictec
his vision to include mostly the forms of life that are, like him, giant.

fiis terrestrial point of view has caused him to make a fundamental mistake
in his conception and naming of the planet on which he lives, for this planet is
not one characterized by dry land nearly as much as by the sea. No other
planet, as far as is known, has a sea. Had man been aware of this from earliest
time, he might well have named this planet "Sea" rather than "Earth."

The sea is not only the most unique characteristic of earth, but it clearly
dominates the land in surface area covered. About 70 per cent of the earth's
surface is covered by the sea, an area encompassing about 139 million square
miles. By contrast, all of the lakes and rivers add up to only about one million
square miles. The sea averages about two and one-half miles in depth, whereas
the land rises an average of only slightly more than four-tenths of a mile above
sea level. The volume of sea water is about 334 million cubic miles, a volume
so great that it has been estimated that if all the earth were made level, the
sea would everywhere cover it to a depth of one and one-half miles!

PHYSICAL FACTORS OF THE SEA

Water

The remarkable compound to which all life is responsible and which gives
the sea most of its important characteristics is water.

First, water is most common on earth in its liquid state, and it is fortunate
that the temperature range of most of the earth lies between water's freezing
point and boiling point, that is, between 32° and 212° Fahrenheit (salt water
freezes at about 29°). It is not merely happenstance that the temperature limits
of life lie between the temperature limits of liquid water.

Second, water is one of the few compounds that expands, becoming less
dense, when it changes from the liquid to the solid state. This enables ice to
float, a fact of the greatest significance, for if ice sank, the depths of the sea,
and eventually the whole of polar seas, would freeze solid.

Third, water is the most universal of all solvents, able to dissolve large amounts
of a wide variety of substances that are absolutely necessary for life. In fact,
protoplasm is 50 per cent (flour beetles) to 98 per cent (jellyfish) water.
This liquid virtually bathes every fiber of living bodies, carrying food and
oxygen to cells and carting off metabolic wastes such as carbon dioxide and urea.

Fourth, water has a very high capacity to store heat. The great body of
ocean water is the storehouse of the earth's heat. Without the oceans, the dark
side of our planet would come close to freezing nightly.

Fifth, water is dense and gives support and buovancv to the animals that
live in it. This has the important consequence of solving the problem of support
for marine animals. Strong legs, arms, and skeletons, necessary for support on
land, are lacking in the sea. Instead, the bodies of marine animals are modified
for locomotion and for offense or defense, and not usually for support. Plants
in the sea have no strong supporting stem or trunk. Because of water's buoyancy.

ZONES OF THE SEA-WHERE THEY LIVE 3

many marine animals attain large size. Whales reach measurements that are
impossible on land; if they themselves are beached, they are unable to breathe
because of the great weight of their own bodies.

Dissolved Salts

For all of its remarkable qualities, pure water would not afford much of a
home for living things. The salts are the fertilizers of the seas, and without them
animals and plants could not grow. The seas of the world average about 35
parts per thousand of salt with extremes of 15 parts per thousand at the poles,
where melting ice dilutes the waters, and 46.5 parts per thousand in the Red
Sea, where there is a high evaporation rate and practically no dilution by rivers.
Most of the salts are sodium chloride (table salt), potassium chloride, and
magnesium chloride, but these are not the really vital ones.

Nitrogen is vital in the building of protein. It is rather odd that animals
and plants are not able to utilize atmospheric nitrogen, even though nitrogen
composes about 80 per cent of air. That task falls to the incredibly numerous
nitrifying bacteria in the soil of land, which manufacture salts called "nitrites"
and "nitrates" from the nitrogen of air. These are then used by plants to build
protein. Eventually, however, many of these nitrites and nitrates find their
way into the sea by way of river systems. Allee, and others (1950) estimate
that the Mississippi River alone brings 792,000 tons of nitrate into the Gulf
of Mexico each year. This is the principal but not the only way that nitrogen
reaches the sea. Some nitrifying bacteria exist in shallow sea waters, but how
much they contribute is not known.

Once in the sea, nitrites and nitrates are used by plants in the so-called
shallow-water "zone of nitrogen utilization." Animals eat the plants, and nitrogen
in the form of protein is distributed in the tissues of living things of the sea.
When these things die, they sink to the depths. Bacteria cause decay, and
nitrogen compounds are released in a deep-water "zone of nitrogen regeneration."
Nitrites and nitrates accumulate in the depths until they are swept to the surface
by currents in places where upwelling occurs. On the surface this rich fertilizer
once again becomes available to plant life. So we see that nitrogen in the sea,
is subject to an endless cycle, a cycle intimately connected to that of life and
death.

The story of that other important fertilizer, phosphorus, is similar to that of
nitrogen. Once again, it is brought from the land to the sea by rivers, and again
it is used bv plants in a zone of phosphorus utilization. The plants are eaten by
animals. These living things sink to the deep sea when they die. Decay releases
phosphates in a zone of phosphorus regeneration and upwelling of deep waters
brings them to the surface.

Immense as are the amounts of nitrogen and phosphorus compounds in the
sea, we must not think that they are inexhaustible. Just like any other fertilizers,
they can be used up. Every summer, as the sea warms and the plankton turns
the sea into a living soup, these fertilizers become progressively scarcer as the
abundant life uses them up. In some places the amount of such fertilizers limits
the amount of life that can grow in the water. When cold weather returns,
much of this life dies and the fertilizer returns to the depths. So the cycle of

4 UNDERWATER GUIDE TO MARINE LIFE

nitrogen and phosphorus is one of the seasons as well as of life and death.

Calcium is an important substance in the life of the sea but for a different
reason than was the case for nitrogen and phosphorus. It is also brought to the
sea by fresh water, existing in sea water as calcium sulfate largely, but it does
not build tissues. Instead, it builds skeletons. About 1.6 per cent of the salts of
the sea are calcium compounds. Many groups of animals, notably corals, sponges,
crustaceans, worms, molluscs, foraminifers, and some coralline plants are able
to precipitate soluble calcium compounds into relatively insoluble calcium
carbonate to build their skeletons. Since this reaction proceeds fastest at about
75° to 80° Fahrenheit, a common temperature range for tropical waters, it is
no surprise that coral reefs and the largest shelled animals are found in the
tropics.

Silicon is similar to calcium. It is a skeleton builder, but it is used by only
a few groups, notably radiolarians, diatoms, and sponges. It exists in the sea
in the form of silicates. Silicates are the principal component of common glass,
and most siliceous skeletons have a decidedly glassy look.

Nitrogen, phosphorus, calcium, and silicon are the four biologically most
important elements that are present in the sea in the form of dissolved salts.
There are other elements of lesser importance, such as iron and magnesium,
with similar case histories.

Aside from their importance to life, salts have two important effects on
water. One is that they depress the freezing point of salt water from 32°
Fahrenheit to about 29°. The other is that salts cause water to be more dense.
Various salt concentrations are partly responsible for varying water densities.

Every year about 660 million tons of earth are washed into the sea, and with
this dirt come great quantities of nitrogen, phosphorus, calcium, and silicon.
Therefore, it would seem that the sea is constantlv growing more and more
salty. Some scientists have assumed that the sea was originallv fresh water
and have even tried to compute the age of the sea by dividing the total tonnage
of salts in the sea by the yearlv deposition rate, but they have arrived bv this
method at very low figures for the age of the sea. The reason for this is that
deposition of these salts in the sea occurs at a varying rate, and salts are often
deposited permanently on the bottom. As salts are added by rivers, so they are
taken out of the water by various means. In fact, the sea has probably remained
about as it was with respect to salt content for the last billion years.

There is some correlation between river deposits of salts and abundance of life.
The Atlantic and Arctic receive most of the North American river drainage and
have continental shelves to hold the deposits. Less river water flows into the
Pacific, it has no shelf to speak of. The comparative richness of life in the
Atlantic is due to this fact. The richness of some Pacific areas is due to another
factor, upwelling.

Dissolved Gases

Oxygen enters the sea primarily by being dissolved at the water's surface and
is distributed by water currents. Disturbed surfaces dissolve oxygen best simply
because more surface is exposed and because rough water acts as a good mixing
agent.

ZONES OF THE SEA-WHERE THEY LIVE 5

Plants also furnish oxygen to the sea by the process of photosynthesis. This
reaction requires light, however, so it occurs only in approximately the first
250 feet of water. As the light diminishes with depth, plants become oxygen
users, not producers. At about 100 feet, plants use about as much oxygen as
they release, and below that depth the few plants that exist become dependent
upon oxygen, releasing very little. The 100-foot depth is called the "compensa-
tion level," and it xaries with light conditions, latitude, time of day, and water
claa'ity.

Oxygen is extracted from water by the respiration of all forms of life and
bv oxidation and decay of dead bodies through the agency of bacteria. Allee,
and others (1950) state that bacteria probably use more of the sea's oxygen
than all other forms of life combined.

The concentration of oxygen in the sea is highest at the surface, where
solution and photosynthesis take place and where the water may even become
supersaturated. This is particularly true of brightly lit surface waters in mid-
afternoon when photosynthesis is at its peak. At a depth of about 1,500 feet,
oxygen falls to its lowest level because it is not produced there, yet enough life
is present to use what there is rapidly. Oxygen increases below the 1,500-foot
level because it is carried downward by sinking cold vvaters from polar seas.

In the comparatively few deep spots where overturn of water cannot occur
and where sinking cold water cannot reach bottom, the water may become
stagnant. All of its oxygen is used, and the poisonous gas hydrogen sulfide
accumulates from the decay of dead bodies that sink there. The Black Sea is
the most famous body of water that accumulates hydrogen sulfide. Practically
no life at all occurs there from a depth of 600 to 6,000 feet. The Bay of Naples
and several deep fiords of northwestern Europe also tend toward stagnancy.

Carbon dioxide is the third major gas in the sea. It is a fertilizer similar to
the salts of nitrogen and phosphorus. It is released into the sea by the respiration
of all animals and by plants deprived of light. It is dissolved by surface waters in
the same way that oxygen is dissolved from the atmosphere. It is also released
at the bottom of the sea by decomposition of dead bodies and, like nitrogen
and phosphorus compounds, accumulates in deep waters. Upwelling brings
this carbon dioxide to the surface.

Carbon dioxide is used in two very important ways. First, it is used by plants
in photosynthesis to build carbohydrates (sugars and starches). Second, it is
used in the converted form of carbonates and in combination with calcium to
build the limy skeletons of many invertebrates.

Pressure and Depth

Next to the yvetness of water itself, the most noticeable effect of water on
the diver is that of increased pressure as he descends. The pressure of air at
sea level is one atmosphere or about 15 pounds per square inch. For every 33
feet of descent into the sea, the pressure increases one atmosphere. At the
deepest part of the ocean, animals are subject to about 1,000 atmospheres of
pressure or 15,000 pounds per square inch. This immense pressure would be
quite disastrous if applied unevenly to a body, but it has no effect when it is
exerted in all directions inside the body and out. To illustrate: each square inch

6 UNDERWATER GUIDE TO MARINE LIFE

of our body is subject to 1 5 pounds of pressure at sea level. Yet we feel nothing.
The pressure outside us is balanced by pressure in our tissues. However, if
the pressure were exerted unevenly, there would be a startling difference. The
area of the palm of a hand is about 10 square inches. Very few of us could
move our hands if they were held down by 150 pounds of weight. At a depth
of 100 feet this weight would become 600 pounds. But, as many aqua-lung
divers know, there is little difference in swimming at 100 feet or near the surface
because the pressure is equal in all directions inside the body and out. This is
not to say, however, that dives to 100 feet are as simple as those at the surface.

Pressure at any depth is due to the weight of water in a column above that
depth. As is well known, added weight on a body will tend to compress it, but
water is not very compressible. If water were incompressible, the surface of the
ocean would rise about 100 feet, but 100 feet in an average depth of two and
a half miles is a very small fraction. This comparative incompressibility of water
has the effect of keeping buoyancy about the same at all depths, so that incom-
pressible objects sink in the sea at an even rate all the way to the bottom. Com-
pressible objects, such as fishes with a swim bladder, would tend to sink faster
and faster with increased depth since added pressure reduces their volume
which, in turn, decreases buoyancy. To combat this, fishes increase the pressure
in their swim bladder to keep their body volume constant and to equalize
buoyancy at all levels where they swim. The depth to which any fish can safely
descend might depend in part on its ability to increase pressure in its swim
bladder to match water pressure. Hesse, Allee, and Schmidt (1951) state that
surface fishes with empty swim bladders can stand pressures of 100 atmospheres
without harm.

Plankton is similar to fishes in being able to withstand rather drastic pressure
changes. By day, much plankton lives just at the edge of the lighted sea, at a
depth of 1,200 to 1,500 feet. By night, this plankton rises to the surface, a
change of 30 to 40 atmospheres of pressure, without harm.

Though very little is known about pressure relations in the deep sea, one
thing seems fairly certain. The pressure itself plays a relatively minor part in
determining what forms of life live there. More important are temperature,
which is near the freezing point in the deep sea, lack of light, and relative
scarcity of oxygen and food. But pressure does have special effects to which
animals must adapt. The swim bladder problem is one that deep-sea fishes
must solve. Pressure also causes colloid gels (such as protoplasm) to take on
more water, and for this reason deep-sea animals are more gelatinous in texture
than shallow-water ones.

Light

Light is important to life in several ways. First and foremost, it supplies the
energy necessary for plant photosynthesis. Second, it is necessary for sight,
without which the behavior of many forms of life would be radically changed.
Third, it is responsible for color itself and for the adaptive coloration of animals
and plants.

The nature of light and color are vitallv important concepts to grasp if we

ZONES OF THE SEA-WHERE THEY LIVE 7

are to understand the way animals and plants live. Light as we see it is actually
composed of a mixture of colors: red, orange, yellow, green, blue, indigo, and
violet. These spectral colors have been seen by anyone who has seen a rainbow
or looked at sunlight refracted through a prism. These colors take the form of
waves of varying length. As the length of the waves varies, so does the color
of the light vary. The longest visible wave lengths are red and the shortest
are \iolet. Light waves that are invisible to our eyes exist, and these are called
"infrared" (longer than red) or heat waves, and "ultraviolet" (shorter than
violet) or burning rays.

Light has two important characteristics that are important to the photographer
(Chapter 3) and to the life of the sea. These must be distincdy separated in the
mind as two factors which may act either separately or together. They are
interisity and quality.

Intcnsitv simply means brightness. Any wave length or combination of wave
lengths can exist over a wide range of intensities. As progress into the depth
of the sea is made, intensity of light decreases. Some animals have photoreceptors
that react solelv or chiefly to light intensity. Intensity regulates the behavior
of a great number of animals. Some plankton rises to the surface by night.
Squirrel fish, conchfish, coral polyps, and big-eyes become active at dusk. Plants
cannot photosvnthesize below a certain light intensity.

Quality of light, or color, depends chiefly on differences in wave length from
red to violet. The color of an object depends on differential absorption of some
wave lengths of light and the reflection of others. For example, the squirrel
fish appears red because it absorbs all wave lengths of light except red, which
it reflects. Quality of light has important consequences for life. The different
groups of algae photosynthesize in response to different wave lengths. Adaptive
coloration of many animals is a response to light quality.

It is now possible to descend from the surface to the abyssal depths of the
sea and to see what happens to light as progress is made downward. The most
immediate effect of sea water on light is reflection from the surface. In calm
waters about 3 to 4 per cent of light is reflected and never enters the sea, in
average waters 15 per cent, and in rough waters about 30 per cent.

From the surface to depths, the quantity of light diminishes constantly due
to the opacity of water. It is possible to divide the sea into three zones on the
basis of light intensity alone.

1. Euphotic or Well-Lit Zone. This is the shallow-water zone with a depth
range of about zero to 250 feet. It is rich in plankton, especially the
photosvnthetic types, and in herbivorous or plant-eating animals. Photo-
synthetic plankton is abundant to 150 feet and almost disappears at the
deepest part of this zone. The depth of this zone is largely determined
by the water's clarity. The Sargasso Sea is probably the clearest sea water
found anywhere. Sea water is generally more transparent than fresh water.

2. Dysphotic or Dimly Lit Zone. From 250 feet to the level at which all
light disappears, the life of the sea is adapted to dim light. The level at
which all light disappears varies from 600 feet to about 5,600 feet depend-

8 UNDERWATER GUIDE TO MARINE LIFE

ing on water clarity and the angle of incident light. The extent of this
zone is not as deep near the poles as near the equator. Animals of this
zone frequently have large eyes in order to be able to see in weak light.
Animals with bioluminescence, that is, possession of organs that can
emit light, become common. Herbivores, or plant-eating animals, become
scarce or absent. In clear water, the intensity of light at 3,000 feet is one
three-millionth of its intensity at 3 feet.
3. Aphotic or Lightless Zone. Below the dysphotic zone, no light at all exists.
Many, if not most, animals possess luminescent organs, either for food-
finding or defense. Eyes may be totally lacking or reduced in size.
Herbivores are completely lacking, and only detritus eaters (those who
eat debris) or carnivores are left.

Quality of light is also affected by water, but there are no zone names to
describe this. In clear waters, the long waves or reds are absorbed first and the
short waves or violets are absorbed last (Chapter 3). Silty or plankton-filled
waters reflect red and yellow and therefore appear greenish. By the use of
colored photographic plates exposed for long periods, it has been determined
that all wave lengths are still present in clear water at 300 feet, but the reds
are exceedingly weak. At 1,500 feet red and green are gone completely.
William Beebe, in his dives in the bathysphere, observed that a strangely bright,
blue light could be perceived by his eye up to about 1,800 feet. After that he
saw no light at all. Blue light not visible to the human eye persists quite a
distance below this depth, however.

The colors of animals and plants vary in response to these changes in light
quality. It is not nearly as difficult to correlate the color changes in plants with
depth (Chapter 6) as it is to correlate these changes in animals. For instance,
it is well known that many nocturnal animals are red (squirrel fish, big-eye,
etc.) and that animals of the dvsphotic zone where red is lacking tend also
to be red (especially fishes and crustaceans). At those depths these animals
must appear black since there is no red left to reflect. Red animals give way
to brown, black, or transparent animals in the aphotic zone. So it would appear
that red coloration is an adaptation to dim light or to waters where red wave
lengths are lacking and that it acts as protective coloring for these animals of
nocturnal habits or dimly lit zones. Many people have wondered why so
many animals are red at depths where red supposedly cannot be seen. The
assumption is made that animals see as humans do. But many animals that live
in waters of low light level have the capacity to see objects that humans
cannot see. To these animals, red objects are protectively colored.

Temperature

Temperature determines to a very important extent where and how animals
live. Sea water varies from 27° to 108° Fahrenheit depending on latitude and
depth. The temperature of surface water varies the most, but deep water of
over 1,000 feet in depth in all latitudes is extremely uniform at about 35°
Fahrenheit. Temperature variation is not nearly as great anywhere in the sea

ZONES OF THE SEA-WHERE THEY LIVE 9

as it commonly is on land. Rarely does the sea vary more than 70° Fahrenheit
at any one place. By contrast, land temperatures at Fairbanks, Alaska, vary from
60° below zero in winter to 105° in summer.

If a di\'er were to progress downward through the water, even in warm seas,
he would reach, at a depth of 150 to 500 feet, a level where the water
suddenly became much colder. This place is called the "thermocline" and marks
the strong stratification between warm surface waters and cold deep waters.

Temperature has several effects on water and on animals which are purely
physical. Cold waters are denser and have a greater viscosity than warm water.
Cold waters, therefore, sink below warm waters, and the temperature differences
become partly responsible for water movements in the ocean. Increased viscosity
of cold water means that planktonic animals sink more slowly in cold waters
than in warm. This may be part of the explanation for the huge concentrations
of plankton, particularly crustaceans, pteropods, and protozoans, in arctic or
subarctic waters or in deeper waters of warmer seas. These planktonic animals
are relatively scarce in shallow, warm waters.

Features of the Sea

It is easy to imagine the sea as a sort of featureless bowl, but since the
advent of sonic soundings about fifty years ago, it is now known that the
seas show all the features of the land— mountain ranges, canyons, valleys, vol-
canoes, etc. There are differences between the features of the sea and those
of land, however. The former are on a much grander scale but are barren and
comparati\'elv immutable. The gigantic deformities in the suboceanic crust of
the earth for the most part lurk in dark, silent, plantless depths, where erosion
is almost at a standstill.

Geologically speaking, the ocean may be divided into three regions Cfig. i):

1. Continental Shelf. This is a gradually sloping extension of the land under
water. It is formed by the deposition of river sediments as they are brought
from the land. As the ocean's water level rises and falls, the shelf is
alternatelv part of the underwater sea and part of the land. In some places,
such as the West Coast of North America, no continental shelf to speak
of is present, but the edges of most continents have shelves extending
outward from shore as little as. 10 or as much as 800 miles. The edge of

the shelf is usually at a depth of 600 feet. The shelf fauna and flora is
the most varied in the sea.

2. Continental Slopes. At the edge of the continental shelf the downward
pitch of the ocean bottom increases rapidly so that the water gets rapidly
deeper. These clifflike slopes and escarpments form intermediate depths
of the sea where protozoan oozes cover most of the bottom (Chapter 7).
The size of these escarpments so dwarfs anvthing of similar form on
earth that it is hard to comprehend them. They may descend from 600
to 18,000 feet, taking 100 miles of downward slope to do so. This repre-
sents a maximum size, but in some places the escarpments are even more
spectacular, being not as long but much steeper.

10

UNDERWATER GUIDE TO MARINE LIFE

3. The Deep-Sea Bottom. This lies below the great majority of the sea's
area. It is here that the most spectacular canyons on earth sink and the
greatest mountains on earth rise.

OCEANIC PROVINCE

OCCANIC TRENCH

Fig. I. Veatures and zones of the sea.

In the western United States are many well-known mountains, one of
which is Pike's Peak. It rises to 9,000 feet from a plateau of 5,000 feet high,
a total of 14,000 feet. Mt. St. Elias in Alaska is one of the very largest of
mountains on earth, rising from sea level to 18,000 feet, twice the height
of Pike's Peak. Mt. Everest rises to over 29,000 feet, but its base is very high,
so it actually is not as large in sheer volume as is St. Elias. By contrast,
Mauna Kea of Hawaii rises a total of 31,000 feet directly from the sea
bottom (almost 14,000 feet from sea level) and is so huge that it forms the
greater part of the largest of the Hawaiian Islands. There are many huge
mountains under the sea at least as large as Pike's Peak that never even reach
the surface.

Mountain ranges of the sea are no less spectacular. By far the longest range
on earth is undramatically called the "Mid- Atlantic Ridge," which is 10,000
miles long. It begins off the coast of southern Africa and runs unbroken to
Iceland, showing a few times above the surface in such islands as the Azores
and Ascension.

Perhaps the most spectacular and mysterious of the deep-sea features are
the trenches, steep canyons usually found close to shore lines and continental
shelves, which plummet to depths of up to 35,000 feet (Mariana Trench).
The deepest North American trench is the Puerto Rican Trench with a
depth of 30,246 feet. Trenches are usually deeply filled with layers of sediment
a mile or more in thickness. Without these, the trenches would be even deeper.

The bottom of the deep sea is usually covered with a monotonous layer
of red clay where a few hardy animals make their homes. Hesse, and others

ZONES OF THE SEA- WHERE THEY LIVE H

(1951) give the following percentages for the distribution of the depths of
the seas over the earth.

15.6 per cent of the sea bottom is 0-5,900 feet deep

19.3 " " " " " " " 5,900-11,800 " "

58.4 " " " " " " " 11,800-17,750 " "
6.5 " " " " " " " 17,750-35,600 " "

The Movements of Water

This is a complex subject which concerns waves, tides, horizontal water
currents such as the Gulf Stream and vertical currents such as upwelling. It
is very difficult to clearly separate these factors. All of them cause a mixing of
ocean water in complex patterns and are thus vital to the life of the sea,
particularly in distributing animals and plants and in fertilizing surface waters
from below.

Waves constitute the least massive of the various types of water movement.
They are surface phenomena, rarely having any effect on waters greater than
300 feet (or a maximum of 600 feet) deep.

Winds provide the energv necessary to create a wave. The size of a wave
depends mainly on four factors of winds: (1) velocity— the stronger the wind
the higher the wave, (2) duration— the longer the wind blows, the higher
waves will become, (3) fetch— the longer the distance over water that the
wind can blow without obstruction, the larger the waves, and (4) direction—
the longer the wind blows in an unchanging direction, the bigger the waves
will be. These four factors interplay and vary greatly to produce waves of
a few inches high to a probable maximum of 40 feet in height. Barnett (1954)
states that it would take a 60-mile gale blowing steadily in one direction for
a distance of 900 miles to produce a 40-foot wave, and since such conditions
are not often met, such waves are rare. The very high velocity of gusty winds
does not produce high waves because it literally blows the waves' tops off.

The water itself moves very little in the horizontal direction of the wave.
It merely rises and falls in a circular fashion as the wave form passes through
it. To prove this, all one has to do is to place a floating object on the water's
surface and notice that it bobs up and down in a circular pattern with the
waves, but does not move forward with them. When a wave reaches shallow
water, the circular pattern of the water movement becomes flattened because
of the proximity of the bottom. This causes the forward edge of the wave
to become steeper and steeper until it falls over on top of itself and breaks
Cfig. 2). The force of a breaking wave can be tremendous. It is enough to
carve holes in rocks or to lift large stones and even throw them through the
air. It has been calculated that some huge waves strike with a force of up to
3 tons per square foot, ample warning that swimming in large breakers near
shore can be very dangerous business.

Tides are very different from waves, in that they are of cosmic origin. The
gravitational pulls of the sun and the moon provide the energy of the tides.
When the sun and moon are both lined up with the earth and with each other,

12

UNDERWATER GUIDE TO MARINE LIFE

their pulls are complementary and the highest tides, called "spring tides,"
occur. This happens during the new and full moons. When the sun and moon
form a right angle with the earth as the center, their gravitational pulls partly
cancel each other and the lowest or "neap tides" occur. This happens during
the first and third quarters of the moon.

WIND AND WAVC DIRECTION

Fig. 2. The breaking of a wave on a sloping shore.

Tides are erratic in occurrence and in height. In general they are lowest
at the equator and highest toward the poles. In most places high tides occur
twice a day, but in some places they occur only once. The highest tides in
the world occur in Nova Scotia's Bay of Fundy, followed closely by several
spots such as the Turnagain Arm near Anchorage, Alaska. In both of these
places, tides must travel up narrow channels in a short period of time. This
causes a tidal-wavelike rush of water called a "bore" to form. It is not known
exactly why extremely high tides form in some places and not in others. Pre-
sumably it has to do with the configuration of the ocean bottom. If the bottom
forms a trough, so that water can oscillate back and forth in it like water in a
bathtub, and is the right size, so that the period of this rocking vacillation
matches the period of the movements of the sun and the moon, water will
rock back and forth in the trough to give very high tides of up to 50 feet.
Bores will occur when the trough has a constricted end, up which tidal water
may rush.

The currents in the sea have a more complex origin and are of greater
importance than waves and tides, even though they are usually not as
spectacular to look at. Horizontal currents traveling over the ocean's surface are
motivated primarily by prevailing winds, and their direction is influenced by
the rotation of the earth. The prevailing winds in both hemispheres blow from
the east along the equator, the trade- winds, and from the west along the horse
latitudes (30° north and south), the westerlies. The rotation of the earth
causes a deflection of these winds so that their paths become circular— clockwise
above the equator and counterclockwise below. In general, ocean currents
follow this wind pattern (/ig. 3), but are compficated by the conformation
of coasts and the ocean bottom. In the center of these great, rotating bodies
of water are eddies where the water just turns around and around and never
goes anywhere. One such eddy is the Sargasso Sea.

Vertical currents are caused bv density diff^erences of water, that is, by
varying temperature and salinity. As water is heated near the equator, it becomes

ZONES OF THE SEA-WHERE THEY LIVE

13

less dense, rises to the surface, and flows northward. At the polar regions, it
cools, sinks and flows very slowly back to the equator at the rate of a mile a
day. In warm seas, water evaporates rapidly and becomes denser due to in-
creased salinity. In ihe Sargasso Sea, for instance, water sinks due to increased
salinity. Tropical rains have an eflfect in diluting water and making it less dense.
These interplaying factors vary so as to produce quite complex results, but
temperature has generally the greatest effect in the oceans. Thus, circulation
is mostly toward the poles on the surface and toward the equator in deep water.
UpwelHng is a special and very important vertical movement caused mosdy by
winds. The principal areas of upwelling in North America are off the coast
of Newfoundland and widely along the southwest coasts of the United States
and northern Mexico. On the lee coasts of prevailing winds, water is blown
away from the shore and must be replaced by upwelling water, floating up

Fig. 3. Currents of North American seas. The names of the curreyits are indicated
on the map.

from the depths. Conversely, windward coasts accumulate surface water which
sinks. This is reflected biologically by the abundant coral forests in the Caribbean
where warm water accumulates, and the comparatively depauperate coral fauna
of western Mexico where cool water wells up from below. However, these
upwelling seas compensate for lack of coral by possessing a great abundance
of plant and animal plankton, and very rich oceanic fisheries, largely com-
posed of schooling fishes, become established as a result. In fact, areas of
upwelling show the greatest abundance of life to be found anywhere on earth.
The champion of all upwelling areas seems to be off the coast of Peru and
northern Chile.

There are other causes of upwelling besides winds. These are storms, tides,
and the passing of two currents of unequal density (when this occurs, one sinks

14 UNDERWATER GUIDE TO MARINE LIFE

and the other rises). But these causes are probably minor in comparison to the
effect of winds.

The net result of all these massive water movements is the production of
rather stable, but exceedingly complex water masses in the seas, which may be
identified by characteristics of temperature and salinity. The complexities of
their movement are introduced largely by the lay of the land, that is, con-
formation of the ocean bottom and of the land masses. For instance, the best
known of the horizontally moving water masses, the Gulf Stream, is a distinct,
blue river of water, 1,200 times the size of the Mississippi, which pours out
of the warm Gulf of Mexico through the Florida Strait at a speed of up to
6 mph. It proceeds north to Cape Hatteras, where it is deflected out to sea,
runs into the cold Labrador Current near Nova Scotia, and breaks up into four
separate currents before reaching England. Water returns to the Gulf of Mexico
by the Caribbean Current to the south. Similarlv, the movements of vertical
water masses are influenced by the conformation of the bottom. Most of the
cold bottom water of the mid-Atlantic is supplied from the antarctic because
those of the arctic are blocked by underwater barriers. Local rain, river influx
into the sea, melting ice, and sun also have effects on densitv which greatly
complicate the picture.

In summary, the movements of water have, no doubt, a greater effect on
the abundance and distribution of marine life than any other physical factor.
The oscillating surface factors of waves and tides are mainly responsible for
mixing oxygen and carbon dioxide at the surface. In shallow water, they buffet
the living and nonliving alike, either building or eroding shore lines and forcing
the sessile, or sedentary, animals and plants that live under the impact of their
blows to become either massive and thick like corals and sea shells, or flexible
and resilient like seaweeds and gorgonians. The nonoscillating water movements
are composed of an interplay between two rotating systems, one which is
horizontal and caused by winds and one which is vertical and caused by winds
and varying water densities. These produce circulating water masses and serve
to mix dissolved salts and gases and to distribute animals, particularly planktonic
ones, throughout the seas of the world.

ZOOGEOGRAPHY: Communities of Marine Life

It is almost too obvious to point out that the sea is not evervvvhere the same,
but simple statements are often the most important ones. The studv of the
various environmental differences and similarities that exist in the sea or on
the land and the precise recognition of their characteristics allows the recognition
of definite zones, that is, fairly sharplv delimited areas where a certain set of
physical features prevail— certain temperature limits, water movements, depths,
light, etc. One such type of zone is the tidal, characterized by movements of
waves and tides. Another type is the eu photic or lighted zone, discussed in the
section on light. Another is the temperate, delimited bv certain temperature
extremes.

Any zone will have living in it a group of animals and plants that have
become specialized to meet the physical and biological requirements of its zone
in order to live more efficiently there. All of these forms of life are grouped

ZONES OF THE SEA-WHERE THEY LIVE

15

tooether as a connmmity. It is usually possible to apply the same names to
communities as to zones, and so there are, for example, tidal, temperate, and
euphotic communities.

Provinces are divisions of the sea similar to zones but larger in scope. The
whole of the deep sea, excepting the very bottom, is spoken of as the oceanic
province, for instance.

The communities and zones of land are separated on the basis of plant
associations. In the sea, temperature and the nature of the substrate are used.
The zones defined bv hght intensitv have already been described. Temperature
zonation is simplest and will be considered first.

Temperature Zones

The temperature zones are three in number: tropical, temperate, and arctic.
(The temperature zones of North America are given in figure 4.)

Fig. 4. The tetnperature zones of North America.

THE TROPICS

The temperature of truly tropical waters almost never falls below 68°
Fahrenheit. Near shore, most tropical waters are 75° to 80° all year long. Some
subtropical waters fall to a minimum of 61° but are not as different from the
tropics as are the temperate zones. The tropical seas represent the most ideal

16 UNDERWATER GUIDE TO MARINE LIFE

environment for life found on earth so it is not surprising that the greatest
diversity of hfe lives there. The tropics are characterized largely by endemism,
that is, a great many groups live there and nowhere else. All phyla of the animal
kingdom are represented. High temperature is the basic reason for this, but other
factors enter in. For instance, there is an abundant supply of food in the tropics
so nourishment is not usually a major problem.

Not only are the tropics characterized by endemism, but animal groups seem
to be more diverse there than anywhere else. The most bizarre shapes and habits
and the greatest variation in behavior within any group are usually present in
tropical members of that group. A review of the fishes adequately reveals this fact.

The tropics are further distinguished by the presence of the lowest tides
and the clearest water of all seas. They are the home of the coral reefs and
dazzling white coral sands.

Tropical seas are divided into these three regions: the Indo-Pacific, the
Adantic, and the East Pacific, in order of their richness of species and size.
Many animals and plants such as the hammerhead shark, all the sea turtles,
and many bony fishes are found in all three, that is, they are circumtropical.

Atlantic Tropics. These waters extend north to southern Florida and thence
to Bermuda. The whole of the Gulf of Mexico is included. The warm Caribbean
and Gulf currents characterize this region. There is good coral growth here,
probably richest in the Bahamas, but these are neither generally as lush nor as
extensive as those of the Indo-Pacific. The sub-tropics of the Atlantic extend
up the eastern coast of Florida to Cape Hatteras. There is very little coral
growth here because of low temperatures and the lack of the hard bottom to
which coral must anchor (Ekman, 1953).

East Pacific Tropics. Tropical waters reach north to the lower tip of Baja
California on the west side of that peninsula, and the whole of the Gulf of Cali-
fornia on the east is tropical. The subtropics reach north to San Diego. Upwelling
of deep bottom water cools almost the whole of this zone rather drastically at
times, and the warm waters are rather shallow in extent. Even in the tropics,
water of 54° Fahrenheit lies only 600 feet down. The lower limit of the tropical
water is a shallow 300 feet.

This is a distinct zone which bears a few resemblances to the Atlantic tropics,
but which, because of the isolation forced on it by the barrier of the Isthmus of
Panama and the depauperate central Pacific, has many endemic groups and
lacks several tropical groups completely. Ekman (1953) lists the kelp basses,
Paralahrax, as endemic and says that porgies have only one species, butterfly
fishes two species, while parrot fishes, common eels, and manatees are completely
lacking.

TEMPERATE SEAS

These are the waters of the greatest temperature variation. Temperatures do
not generally rise above 70° Fahrenheit, but they do sometimes reach as
much as 80°. However, these zones, being subject to wide seasonal variation,
may have temperatures only a little above freezing to the north in winter.

The temperate zones show a wide variety of bottom types from rocky to
sandy or muddy. The shores are often covered with dense beds of brown algae,
which are scarce in the tropics.

ZONES OF THE SEA-WHERE THEY LIVE 17

Atlantic Temperate. Atlantic temperate waters lie from Cape Hatteras north
to Cape Cod where the Labrador Current ends its southward flow. At Cape Cod
the mean annual temperature is 46" Fahrenheit and the extremes are 37° in
winter to 66° in summer.

Above Cape Cod is a zone reaching to Labrador that may be called cold
temperate, boreal, or subarctic. This is the home of the sculpins, halibuts,
rock eels, and of huge schools of cod and herring among others.

East Pacific Temperate. The temperate Pacific lies from San Diego to the
Gulf of Alaska. This is a very uniform zone, both in temperature and in flora
and fauna, throughout its whole length. Ekman (1953) lists the following
August temperatures for this zone: San Diego 64°, San Francisco 55° to 61°,
Seatde 61°, and the Gulf of Alaska 57°. The reason for this uniformity is that
upwelling cools the southern part and warm currents warm the northern part.
The winter temperatures show much greater variation, however, being much
colder to the north.

This region has a verv large per cent of endemics. Ekman (1953) lists the
surf perches, greenlings, and rockfishes QSehastodes^, and there are many
others. Starfishes are more greatly varied in this region than anywhere else in
the world. There are 92 species of them, of which 60 per cent are endemic.
The sun star, Pycnopodia, is the largest of all starfishes.

The boreal or subarctic Pacific is similar to that of the Adantic with its cod,
halibuts, rock eels and sculpins. It extends from the Aleutian Islands north to
the Bering Strait.

Boreal waters in general contain the greatest schools of fishes in the seas.
Colder waters have fewer kinds of animals and plants than warmer waters,
but this does not prevent those few species from reaching immense numbers
in the summer when light is strong, days are long, and surface waters are still
cool and viscous enough to support plankton. These constitute ideal conditions
for plankton and when they are combined with the upwelling near the
Labrador coast, which brings nourishment in the form of dissolved salts to
the surface, it is not too hard to see why life is so abundant there. Boreal seas
are further characterized by immense beds of algae, rocky shores, and the world's
highest tides.

ARCTIC SEAS

Waters of the arctic zone never get warmer than 41° to 45° in summer and
reach these heights only for short periods. Ice is an ever-present characteristic
whether in floe or iceberg form. These waters are present north of the Bering
Strait and Labrador. In general, the boreal animals and plants are also found
here, and among them are sculpins, blennies, sea snails, and dense beds of
brown algae. Tides are high and shores are rocky in this zone.

Substrate Zones

On land, the word "substrate" usually refers to the ground under our feet,
since it forms the support of most terrestrial animals and plants. But in the
sea, "substrate" may refer either to the ocean bottom or to the water itself since
both are dense enough to support life. (In subsequent chapters, "substrate" is

18 UNDERWATER GUIDE TO MARINE LIFE

used in general in the former sense.) Therefore, the substrate of the sea, in
which anu over which the life of the sea hves, is three-dimensional in contrast
to the two-dimensional substrate of the terrestrial world. Flying animals, such
as birds, insects, and bats, like fishes, live in a three-dimensional substrate, air.

The ocean is divided into two large provinces, the neritic, over the continental
shelf, and the oceanic, over the deep sea. Both of these are subdivided into two
subprovinces, the henthic, or sea bottom, and the pelagic, or open water. (The
divisions of the provinces of the sea are given in figure 1.)

Since "pelagic" simply means "living in the open sea," it usually refers to
animals of several types, subdivided according to swimming ability. "Planktonic"
(from flanktos, meaning "wandering") refers to animals whose swimming
powers are not great enough to combat water movements. These usually small
or microscopic organisms, about 60 per cent of which are diatoms, are the most
important life of the sea. The word "nektonic" is applied to animals that move
freely through the water. The highest development of free movement is found
in fishes and the re-entrants. The use of these terms is rather simple. For instance,
the tuna is largely oceanic-pelagic-nektonic. A snail or a scorpion fish is neritic-
benthic. Some animals overlap in zones. A bottle-nose porpoise is pelagic-nektonic
but is both oceanic and neritic. Some groups are exclusively pelagic, such as
diatoms, radiolarians, jellyfishes, arrow worms, pteropods, and some prochordates.
In order of abundance among animal pelagic forms, Hesse and others (1951)
list copepod crustaceans, pteropods, siphonophores, arrow worms, octopuses, and
squids, then fishes. Diatoms are more numerous than any of these.

Exclusively henthic groups include sponges, sea squirts, brachiopods and
bryozoans. Most echinoderms, worms, clams and oysters, and snails are also
henthic.

THE OCEANIC PROVINCE

The water beyond the continental shelf is divided into zones according to
light. For practical purposes, it is best to consider two major zones to be present
rather than three previously set up in the section on light. Thus, there is a
lighted (euphotic) zone and a dark or abyssal (aphotic) zone. The dysphotic
or dimly lit zone is a transitional zone between these two.

The Lighted Oceanic-Pelagic Zone. This zone is, of course, not well-defined
from the lightless zone and varies greatly in depth. In general, it is never more
than 600 feet deep. All nektonic-pelagic animals, whether they are oceanic or
neritic, must be alert or protectively colored or both because of a complete
absence of hiding places. In keeping with this, it is here that are found the
swiftest swimmers. Coloration is usually countershaded or obliterative (Chapter
2) and is composed of blues or greens above and white or silvers below. The
mackerels and tunas are perfect examples of this.

The fishes, squids, and mammals are the dominant nektonic-pelagic animals
since their powers of swimming are best. There are no large plants and there is
no organic debris (detritus) in this zone, so all of the nektonic species depend
upon plankton or plankton-eaters either directly or indirectly for food
(Chapter 2).

The nektonic species are slightly heavier than sea water and must swim
slowly but constantly to keep from sinking. The swim bladder of the fishes

ZONES OF THE SEA-WHERE THEY LIVE 19

helps keep them near the surface, but oddly enough some pelagic fishes such
as mackerels have no swim bladder. Oil and fat help the mammals rise to the
surface, but even they almost never cease moving during the whole of
their lives.

Plankton, on the other hand, is largely dependent upon currents. Most plank-
tonic animals and all planktonic plants are microscopic or small, like crustaceans,
pelagic tunicates, various larvae, arrow worms, protozoans, pteropods, and
diatoms, but some are very large, such as the giant lion's-mane jellyfish, Cyanea,
the basking shark, and the ocean sunfish (Hesse, and others, 1951). These
large planktonic animals are good swimmers, but they usually just drift with
the currents. All of the small plankton depend heavily on flotation mechanisms
to keep from sinking. The specific gravity of sea water is 1.02 to 1.03 and that
of living matter is 1.02 to 1.06. The flotation mechanisms that compensate for
this slight overweight are several. Most protozoa, many larvae, and many
crustaceans have extensions of their body or skeletons so that they off^er great
resistance to water. These extensions work best in water of rather high viscosity
and are found only on very small animals.

Other animals and plants reduce their specific gravity by various means, such
as reducing the weight of their skeletons (pteropods, protozoa, and crustaceans),
taking on extra body water (jellyfish), storing oil droplets (fish eggs, basking
shark, penguins, whales, ocean sunfish), or by storing gases (Portuguese man-
of-war, bony fishes with an air bladder, chambered nautilus).

The Ahyssal-Pelagic Zone. The animals of this zone depend entirely upon the
rain of dead plankton falling from above or on other members of their community
for food. There are no herbivores, and there is usually a direct relationship
between the abundance of plankton at the surface and the abundance of life
in this zone. Fishes and cephalopods predominate, and these are usually small
although exceptions to this rule occur. For instance, the giant squid is the
largest of cephalopods. Some protozoa are larger at depths, but this is related
to increased viscosity of deep cold waters.

This is a very stable and uniform zone where changes in light and temperature
and the movement of water are very slight. Since there is very little water motion,
animals with fragile bodies, such as the oarfish (ribbonfish), are common. Many
of the fishes are elongate in shape (the chimaera and the frilled shark). Low
temperatures in this zone as well as high pressures prevent the efficient formation
of lime (calcium carbonate) so skeletons and shells are weak. Pressure also
causes protoplasm to take up more water so tissues are gelatinous. Archaic
animals are common because of a comparative lack of competition probably.

All over the world, the abyssal zones are rather uniform resulting in the
wide distribution of the deep-sea animals.

The Abyssal-Benthic Zone. This is perhaps the least well-known zone of the
sea where cold, lightless, almost motionless waters exist. In a few places, a rock
bottom is found, but most of the bottom is covered with clay or ooze, the latter
being composed of the countless skeletons of planktonic animals and plants.
In shallower places, the protozoan oozes cover huge portions of ocean bottom
(Chapter 7). This is particularly true of the North Atlantic where the protozoan
Glohigerina, holds forth. A red clay bottom is typical of much of the Pacific and
is a very sterile medium for life.

20 UNDERWATER GUIDE TO MARINE LIFE

Support and anchorage are big problems in such gooey substrata. Sea spiders
(pycnogcnids) creep about on long legs. Crinoids and glass sponges have long
stalks on which they are supported, and some crabs have hairy feet. Brittle stars
are abundant and support themselves on their long arms. The largest known
crustacean is the Japanese spider crab with legs that may span 1 5 feet, lives here.

THE NERITIC PROVINCE

This is the realm of the underwater swimmer. Whereas oceanic diving has
been done and will be important in the future, the shallow waters near shore
offer greater variety of life and less harsh conditions; almost anyone is able
to enjoy these waters. The boundaries of this zone are the shore line and the
outer limit of the continental shelf (if it is present) at a depth of about 600
feet. Therefore, the majority of the neritic province is euphotic or well lighted.
This province is variable in almost every respect, including nature of bottom,
temperature, animals and plants, and water movements.

The Neritic-Pelagic Zone. There is an overlap between the oceanic-pelagic
and the neritic-pelagic. Most of what has been said about the oceanic-pelagic
also applies to this zone. However, many of the animals of this zone are
dependent on the bottom during some time of their life. Pelagic invertebrate
larvae usually settle to transform to sessile, benthic adults, and many of these
pelagic animals at least feed on or near the bottom. Actuallv, onlv a few
habitually neritic animals and plants are free of the bottom throughout the whole
of their lives, and these are mostly planktonic ones, small species such as diatoms
or some crustaceans.

The life of this zone includes planktonic larvae, jellyfish, fish eggs, crustaceans,
pteropods, squids, the great majority of sharks and rays, and most bony fishes.
Most of these cannot survive if they stray into the oceanic province.

The IN eritic-Benthic or Littoral Zone. Of all the zones of the sea, this one
shows the greatest diversity of life, especially in a special subdivision of this
zone, the coral reef, which will be considered presently.

It is rather difficult to decide how to subdivide this area. From the point of
view of water movement, there is said to be an eulittoral or tidal zone, which
is bounded by the high- and low-water marks of the highest spring tides and
which varies in extent with the geographical location, and a sublittoral or non-
tidal zone, which extends from low-water to the edge of the continental shelf.
Within each of these are several zones which define the all-important
communities of the neritic province.

Some nektonic species such as small fishes are so intimately connected to the
benthic region that they may be spoken of as being nekto-benthic. Among these,
the reef fishes are notable examples. But mostly, the zones of these benthic
regions are characterized by algae or sessile, plantlike animals or other
invertebrates.

THE EULITTORAL OR TIDAL SUBZONE

This is the harshest environment of the sea, and the only one that can be
thought of as having weather as we know it on land. As the tides cover and

ZONES OF THE SEA-WHERE THEY LIVE 21

uncover this zone, great changes in wetness, temperature, salinity, light,
and friction produced by the harsh buffeting of waves are experienced. On top
of all this, food is rather scarce, being present for most animals only when
water covers them. This means that the animals and plants of this zone have
to be the hardiest in the sea. It also means that from the low-water mark to
the high-water mark, conditions become harsher and harsher and more and more
like conditions on land, and that life becomes more and more impoverished.
Therefore, it is not surprising to find that many eulittoral animals and plants,
such as periwinkle snails, blennies, and gobies, show tendencies toward
terrestrialism.

This zone is subdivided according to the nature of the bottom into rocky,
sandy, and muddy shores. Rocky shores are characteristic of eroding coast lines.
This solid substratum forms an anchorage for sessile forms of life such as rock-
weed (Fmcms), barnacles, mussels, snails of various sorts. Here life piles on life.
As soon as one animal or plant anchors itself to the rock, another may anchor
next to it or attach itself to the original resident. Great numbers of small
animals live almost exclusively attached to seaweeds or shells. Most of the ani-
mals either bore into rock for protection or have heavy shells themselves. The
plants are tough and resilient so as to be able to vvithstand the beating of
the waves.

Tidepools are little rock communities in themselves. A great variety of life
that can stand wide ranges in salinity, high temperature, and quiet water lives
here, including small fishes such as gobies and killifish, bryozoans, hydroids,
seaweeds, tunicates, worms, sponges, anemones, barnacles, and mussels.

Sandy and muddy tidal shores are typical of depositing coasts. Marsh grasses
such as Spartina are invaders from the land and are not bona fide marine plants.
The invertebrate fauna is dominated by burrowing forms such as clams, whelks,
sand bugs CJ^ippa), and worms. In places where there are no aquatic plants
but where marsh grass is found, a great variety of snails, crustaceans, starfishes,
crabs, and others are added. Soft bottoms of a mixture of sand and mud are richer
than either sand or mud alone. This illustrates the general principle that mix-
tures of habitats usually produce richer fauna than either habitat does when
pure.

THE SUBLITTORAL OR SUBTIDAL SUBZONE

The types of animals and plants of the tidal zone are also usually typical of
the nontidal zone, except that the species are richer and more varied here. Once
again, there is a division into rocky, sandy, and muddy shores.

The rocky shores bear extremely rich faunas which have at their base great
forests of plants or plantlike animals, such as kelp or corals. As in the tidal
zone, life builds on life, but fishes are dominant. Animals here usually have
heavy protective shells (abalone), spines (sea urchin), or protective coloration
(octopus). Every phylum of the animal kingdom is represented, with the
notable exception of the exclusively pelagic arrow worms.

The loose substrata of sand and mud are like those of the tidal zone except
that they are richer, containing flatfishes, rays, stargazers, anglers, squids,
prochordates such as Amfhioxus, and a greater variety of crustaceans, worms

22 UNDERWATER GUIDE TO MARINE LIFE

and molluscs. Furthermore, the sublittoral soft bottoms are frequently covered
with lush growths of eelgrass or one of the marine algae which, though rootless,
can obtain a foothold in sand or mud. This adds another batch of animals such
as sea urchins, starfishes, sea horses, pipefishes, eels, killifishes, and even more
worms, molluscs, and crustaceans. The presence of plants markedly increases
not only the diversity, but also the abundance of life due to the added oxygen
and debris which they bring. Here also, a sand-mud mixture supports the
greatest amount of life. As might be expected, coarse sand or gravel supports
the least. The forms that live in pure mud are very delicate and usually of
fairly deep water, since fine mud particles do not come to rest on the bottom
until quiet seas are reached near the outer "mud-line" of the continental shelf.

Special Zones

Three zones, all of them littoral and tropical, must be given special attention
because of their unique characteristics. They are (1) a special type of muddy
shore, the mangrove zone, (2) a special type of plant community, the Sargasso
Sea, and (3) a special type of rocky zone, the coral reef.

THE MANGROVE ZONE

World-wide in muddy, estuarine flats of the tropics grow mangrove trees,
especially the red mangrove, Rhizofhora mangle, whose branching and support-
ing aerial and stiltlike roots form a swampy tangle in which the fauna of the
sea meets that of the land. Crabs, tree oysters, snails, small tropical fishes,
snappers, tarpon, and other brackish-water species meet raccoons, land snails,
land crabs, and even some fresh-water fishes. Actually the beginning of man-
groves usually means the end of the shallow sea for in the roots of the plants,
debris and coral, sand or mud are trapped and a land-building process is begun.
In fact, as the debris gets thicker and drier, the mangroves themselves die out.

THE SARGASSO SEA

In the great eddy of central Atlantic waters from Berm.uda to the south and
west toward the Bahamas, Sargassnm, or sargasso weed, the only floating
brown alga, is found in fairly large quantities to form a distinctive community
of its own. This weed breaks off from its anchorage on rocks in the Caribbean,
especially during hurricanes, and is carried to this sea by ocean currents such
as the Gulf Stream. There it lives and grows, but it probably does not repro-
duce there, until it dies and disintegrates. The total mass of this algae has been
greatly overestimated. Clumps of it do become quite large, according to how
much gets tangled up together, but it is not a threat to navigation as is some-
times stated. Actually, the area of the Sargasso Sea would be quite sterile of
life were it not for this weed, for, though this is the area where the world's
clearest waters are found, it is also an area of sinking water where nutrients
are rather sparse.

Sargasso weed is brown and leafy (Chapter 5) so most of the animals that
live in it are brown and bear leaflike appendages as concealing coloration and
form. The weed forms a substrate, a sort of pseudobenthos, for a rather restricted

ZONES OF THE SEA-WHERE THEY LIVE 23

fauna. A comprehensive list of the fauna given by Hesse, and others (1951),
and Ekman (1953) includes a few crustaceans, several hydroids, a few worms,
brvozoans, two barnacles, a tunicate, some snails, a sea spider, a pipefish, and
the extraordinarv sargassum fish. All of these live directly on the weed most or
all of their lives. Sargassum also forms a nesting place for flying fishes. The
young of many tropical fish use the weed as a place of protection.

THE CORAL REEF

Most of us, if given free choice of places to dive, would pick the coral reef
for several reasons. It possesses by far the gaudiest, most varied, and most
luxurious fauna of any place where life is found on the earth. In its never-
ending nooks and crannies, innumerable animals make their homes, animals
which quite frequently have extraordinary habits.

Coral reefs owe their existence to groups of animals and plants which deposit
calcium around themselves as a protective skeleton. This building of lime
progresses best in tropical waters for two reasons: (1) the chemical reaction
which forms calcium carbonate is fastest at temperatures of 68° Fahrenheit
and above, and (2) calcium is more soluble, and hence more abundant, in
warm waters than in cold.

Though the name "coral reef" is given to a limy reef built largely by stony
or madreporite coral, these little colonial animals are not the only reef builders.
On almost all reefs the stinging, hydroid millepores, called "fire corals," are
very common and, to go farther afield, foraminiferans, calcareous algae such as
Halhneda, and calcareous bryozoans play a dominant part. In fact, the madre-
porite corals sometimes even take third place behind foraminiferans and algae
in the building of some reefs. Still, the tropical madrepores are the dominant
and most spectacular builders of reefs.

Temperature is important; a minimum of 68° Fahrenheit is necessary for
the building of coral reefs. The temperature also determines the abundance and
variety of corals, for at the marginal temperature of 68°, coral becomes rather
depauperate. It takes higher temperatures of about a minimum of 74° to
introduce large branching corals to a reef. Borderline waters of 68° such as
those off Bermuda, have a noticeably depauperate coral fauna. Hesse, and
others (1951), compare Bermuda's 12 coral species to the Red Sea's 125. On
the other hand, coral can stand very high temperatures of up to 132° Fahren-
heit when uncovered by low tides for short periods. Stony corals do exist in
cool temperate waters, incidentally, but reefs are never formed.

Temperature is not the only limiting factor for the growth of coral reefs.
Moving water must be present, and it must move at the right speed, not so
fast as to break the coral or to prevent the coral larvae from gaining a foothold
and not so slow as to prevent the distribution of enough planktonic food and
oxygen to keep the coral animals alive.

Coral must have firm substrate to which to attach itself. It is poor or lacking
if hard bottom is scarce. Such is the case on the otherwise adequate southeastern
coast of Florida.

Coral is usually poor in areas of cold upwelling waters. The eastern Pacific
has a poor coral fauna for that reason.

24 UNDERWATER GUIDE TO MARINE LIFE

The depth of water influences coral growth. Because of the symbiotic,
photosynthetic, oxygen-supplying flagellate protozoans (Chapter 7) that live in
coral polyps, growing reefs are not found in waters deeper than about 150 or
perhaps 200 feet. Clarity of water has a great deal to do with successful coral
growth. In fact, silting can kill coral by cutting down light or by smothering the
coral animals.

Lowered salinity will eliminate corals. The mouths of rivers never have
coral growths and heavy tropical rains are a reef -destroying factor.

With all these things taken into consideration, it is almost a wonder that
reefs are formed at all. Nevertheless, reefs are one of the most common char-
acteristics of all tropical seas, being common between 30° north latitude and
30° south latitude. The Gulf Stream pushes the northern limit up to Bermuda
at 32° north latitude. Probably the finest and most extensive coral formations of
the North American continent are those of the Bahama Islands.

Coral grows at varying rates depending on the local conditions. A usual average
of one inch a year is given by Hesse, and others (1951). The growth of branched
coral is sometimes marked by yearly ridges. The American Museum of Natural
History in New York has a fine specimen of antler coral from the Bahamas
showing these ridges a good two to three inches apart. This is adequately
rapid to make nautical charts worth very little after a few years. In places like
the Red Sea, whole port towns have had to be abandoned because coral growth
made their harbors inaccessible.

The heavy stone corals and brain corals are the foundation stones of reefs.
The branched Acro-pora shows great variety of form, being more delicate in
deep or quiet waters. All of these look like they are of a permanent nature,
rugged and durable, but the story of a reef is not one of mere construction. It
is also one of destruction, as is the whole cycle of life. Coral polyps die eventually.
Single coral colonies may live and grow over a period of a couple of hundred
years, but this process comes to a halt, and if the dead coral is not quickly
built upon by new colonizers, its lime will be etched by the waves and turned
to sand or redissolved in the sea. Waves are the greatest of the physical factors
which destroy reefs. Two more of these are winds and rains. But probably the
greatest overall destroyers are boring animals such as worms, sponges, clams,
crustaceans and others. Fishes which gnaw on coral, such as the common
parrot fishes, also add their bit in destroying coral formations. All of these
forces help reduce coral to sand, which sometimes becomes compacted into
coral limestone such as that seen on shores near many coral seas. The best
reefs to visit are those in which the forces of construction overbalance those of
destruction. The practiced eye soon learns to recognize the difference between
dying and flourishing reefs, which are sometimes close together.

Three types of reefs are known (/ig. 5). These are (1) the fringing reefs
which closely follow coasts near shore, (2) the barrier reef which is separated
from shore by a lagoon, and (3) the coral atoll which is a ringlike island
formed by the sinking of a volcanic island at sea. The longest construction
ever built by living animals, including man, is Australia's Great Barrier Reef,
1,250 miles of coral formations. The deepest constructions of life are also of
coral origin. At Eniwetok Atoll in the Pacific, a boring of 4,000 feet was made
through limestone before striking a volcanic rock bottom (Barnett, 1955).

ZONES OF THE SEA-WHERE THEY LIVE

25

As has been pointed out, the coral reef is the most gaudy and varied realm of
life on earth. The animals live so close to each other spatially that they often
develop symbiotic dependencies on one another. The pearlfish and the sea
cucumber, the conchfish and the conch, and the zooxanthellae and the coral
polyps are only a few examples of this.

Coral itself "blooms" at night, the polyps mostly keeping to their limestone
chambers by day. In fact, the whole reef teems with nocturnal animals, such
as big-eyes, squirrel fish, and others that are more active at night than by day.
But even by day the coral reef is a bustling community. So ideal is the protection
offered among coral branches and caves that many animals never leave the reefs.
This protection also seems to allow them to be more brilliantly colored than
elsewhere, but it must be admitted that the reason for the exceptionally gaudy
colors of reef animals is not known. Possibly, the colors of the animals have
evolved to match the brightness of the lisht and the clearness of the waters. Com-

o O

petition for space on the reef is keen and is probably another reason for the
diversity of life, since the animals attempt to adapt to new situations quickly
(Chapter 5).

Most of the life of the reef is benthic or nekto-benthic since almost all of the
species, including the large groupers, make their homes in reefs or feed near
the bottom. The great majority of benthic groups are represented on reefs
as are the great majority of animal phyla. About the only group which is not
well represented on reefs is the large algae, chicflv the brown algae (phylum
Phaeophyta). Reefs are largely an animal realm and, indeed, very little matter
of nonanimal origin is found there.

FRINGING REEF

BARRIER REEF

ATOLL

Fig. 5. The three kinds of reefs Qadapted from Darwin^. The top row of diagrams
represents cross-sectional views of reefs; the bottom row, views from, above. Each type
of reef may he exposed at low tide and may even form, the foundation for land
formation. Since a reef grows fastest at its outer, seaward border, land masses which
are sinking will draw the coral downward. The coral will grow to reach the surface
only at its seaward edge and a lagoon will be formed.

CHAPTER ^

BIOLOGY OF THE SEA— How They Live

In this chapter the ways of life of animals of the zones of the sea will be
examined under the broad headings of adaptation to habitat, distribution and
dispersal, food and food chains, symbiosis, adaptive coloration, animal behavior,
and ecology and evolution. Each of these is a huge and complex topic so we
can do little more than whet the reader's appetite with general principles here.
Furthermore, these few topics by no means exhaust the subject of "how they
live." Methods of locomotion, methods of defense, and breeding patterns are
three more aspects, for instance (Chapters 7 to 10). It is hoped that the diver will
be able to see each animal he encounters under water in the light of the prin-
ciples that are given so that he will be better able to appreciate the evolution
and adaptation of the system of animate nature and also so that he may be able
to increase the depth of his experience in the sea. Most of the principles that
are discussed, incidentally, are not peculiar to the sea, but apply to all life,
including mankind.

ECOLOGY AND EVOLUTION

The nature of the sea and its immutability compared to land— its relative
homogeneity and lack of sharp environmental contrasts— has been discussed.
In this chapter, we shall see how animals adapt to meet this environment.

Several billion years ago, probably about 4.5 billion, the earth was formed
as an immensely hot conglomeration of condensed gases. Over the next few
billion years, this mass cooled to the .temperature of water in its liquid state;
below 212° Fahrenheit. By this time, the earth had become enclosed in a hard,
wrinkled crust several miles thick, and this crust had trapped water vapor within
it which began to be disgorged from volcanoes in great jets of steam. Huge
clouds were formed, and a deluge of rain began to fall, which did not let up
until the amount of water equivalent to about one-fifth of all the water in the sea
had filled the ocean basins. Cloud formation and rains continued with diminish-
ing intensity until, about a billion years ago, the waters in the seas had reached
approximately their present level. It was in the shallow, warm waters of this
sea that life arose by a chemical reaction involving combination of chemicals

26

BIOLOGY OF THE SEA-HOW THEY LIVE 27

drawn from the sea's organic "soup." Before the beginnings of the Cambrian
Period, about a half a bilhon years ago, all the major animal phyla had
evolved, the history of which still remains largely a matter of mystery. All of
these phvla carry remnants of their place of origin in the sea because there is a
liquid (plasma) bathing the tissues of all animals which is very much like sea
water in its composition. The similarity of sea water and plasma indicates that
the seas of a billion years ago, when life arose, were very similar in chemical
composition to what they are today.

Only one-fifth of all the total number of species of animals (including
insects) are found in the sea, whereas four-fifths live on land. This is in spite of
the fact that the sea's area is over twice that of land. It is also in spite of the fact
that of the sixty classes of animals, only four are not found in the sea, whereas
twenty-five are exclusively marine (Hesse, and others, 1951). Therefore the
sea has a greater diversity of groups since most groups originated there, but it
has a much smaller number of species than the land. This apparent paradox
can be explained by the fact that land, where barriers between habitats are
much more difficult to cross, which results in isolation, is a much harsher and
more variable environment than the sea. Only the most adaptable animals
are able to live on land at all, and these are subject to large and constant
en\'ironmental changes, with which they must keep step by evolving to meet
new conditions quickly. It is isolation, enforced bv barriers, and environmental
xariabilitv that lead to increased numbers of species. Land animals have evolved
to a higher psychological order in response to a relatively complex and harsh
environment.

Competition is another factor that affects the rate of evolution. Evolution
is fastest in areas of most strenuous competition on land or sea. The greatest
competition in the sea occurs in the tropical reef areas, where a great number
of species are jammed close together in an optimum environment subject to
little variation. Consequently the most advanced and highly evolved species
of marine animals are generally found about tropical reefs. Toward the deep
sea or toward colder waters, environments become harsher, resulting in elimina-
tion of species that cannot adapt to these conditions. Thus, fewer species are
found in deep and cold waters than in the tropics, and these are subject to
lessened competition. This permits some archaic animals to survive in deep
or cold waters, whereas they could not survive in tropical, shallow waters. This
is the reason that primitive fish, such as isopondyls (herringlike fishes) are
mainly found in temperate or arctic zones, in the deep sea, or in fresh waters.
The cold and deep waters are harsh enough to reduce the number of species
and to reduce competition but, unlike land environments, are not variable
enough and have few barriers to impose isolation. The numbers of individuals
is great in northern and deep waters, but the number of species is small.

Evolution is not over. Environments constantly change, and all life, including
man, must adapt to meet change, or else perish.

ADAPTATION TO HABITAT

Adaptation refers to adjustment between a living animal and the parts of its
environment. This is a phenomenon that is exhibited by every living thing

28 UNDERWATER GUIDE TO MARINE LIFE

including man and is a direct result of evolution (Chapter 5). Adaptation
is exceedingly complex and can never be measured by a single factor such as
adaptive coloration, food-getting mechanisms, or breeding habits for the simple
reason that adaptation is an adjustment of all the activities of an animal or
plant. Because adaptation is so complex, it is never perfect. It is inconceivable
that any living thing could perfecdy adapt in every way to meet the ever-
changing requirements of the environment. This is not to say that adaptation is
not very successful, however. The adaptations for speed of movement are not
absolutely perfect in the mackerels, tunas, and spearfishes, but these fishes are
certainly not inadequate in meeting the demands of their predatory ways.

Adaptation cannot be studied without reference to the question. Adaptation
for what? It is not specific enough to say that an animal is adapted for its
general environment. We must define what part of its environment, what
specific way of life, that animal has evolved to meet. In other words, where in
the community does that animal fit in? We know, for instance, that barbers,
bakers, and candlestick makers all have their particular adaptive skills in a
human community. It is no less obvious that groupers, parrot fishes, and sponges
have their separate places in a coral community as well. The adaptive place
of every animal is called its niche, and in order to define it, the community
must be re-examined.

The various zones of the sea have been defined under the section on zoo-
geography in the last chapter. These zones were shown to be different in their
general physical characteristics of temperature, substrate, salinity, etc. In other
words, zones are defined by a set of physical characteristics. All the animals
of a zone were lumped together in a community, each species of which is
subject to similar physical characteristics. Different communities may difi^er in
many ways, but all communities are alike in one respect: Elton (1935) says
that the basic ground plan of all communities is dictated by food chains and
that the niche any animal occupies is largely determined by its place in the food
chain, that is, what it eats and what eats it.

For instance, the herring is a plankton-eater and is eaten by a large number
of predatory fishes, such as tunas, swordfishes, etc. Therefore, it is best to
define "niche," as Elton points out, by an animal's relation both to its food and
to its enemies.

"Niche" is an important concept and the discovery of its niche is vital in
understanding any animal. But, of course, the description of a niche cannot tell
us all there is to know about an animal. The ways it breeds, moves, is colored,
and behaves are all vital aspects that do not derive from a study of food patterns
alone.

One point that must be emphasized is that animals are not continually
engrossed in one long struggle for existence throughout the whole of their
lives. As Elton (1935) emphasizes, animals are not always doing something.
It is true that all animals are adapted to a particular mode of life which revolves
around feeding, but it is not true that everything animals do or that every
anatomical characteristic they possess are of adaptive significance. Some actions
or characteristics may have little or no significance. If the diver is to interpret
adaptation correctly, he must learn to distinguish between significant and insig-
nificant traits and actions.

BIOLOGY OF THE SEA-HOW THEY LIVE 29

Youth, Maturity, Old Age, and Death

"The interaction out of which the organism develops ... is between the
organism and environment! And the organism is different at each different
stage of its development." (Lehrman, 1953.)

It is rather obvious to us the way environments change through the years
or with the seasons. It is also obvious that animals grow, but it is not very
widely appreciated what a drastic effect on the life of an animal growth has.
Animals start out life as a helpless egg, which soon hatches or develops into only
a slightly less helpless hatchling or newborn. This tiny creature goes through
a growth period in which increase in size is rather rapid through juvenile
and subadult stages. At the onset of sexual maturity, the growth rate levels off,
that is, becomes slower and, though growth continues past the onset of maturity,
it tends to be slower and slower as time goes on or even to stop. As old age is
reached, vigor is decreased, breeding stops, and some animals (man, for instance)
even shrink a little in size. Rarely, in nature, do animals die by "natural causes."
Predators, parasites, or disease usually spell the end.

There are several fascinating questions that may be raised concerning this
cycle of life which every living thing goes through. Some forms of life such
as fishes seem never to stop growing. In most animals, aging does not begin
until growth ceases and no one seems to know how long fishes could live if
it were not for predators, parasites, and disease. Some fishes live one hundred
vears or more, but it is not known when they begin to grow old. But these
questions are not the main interest here. What is of the greatest significance
is that this cycle means that as an animal grows and matures, it must pass
through a series of stages, each one of which is different from the others. In
general, animals are most vulnerable in the beginning of the cycle when they
are small, and therefore the process of elimination of the individuals with the
greatest negative selective value is strongest in the young before maturity is
reached, a fact of evolutionary significance. Those individuals that do survive
do so only because they have been able to find food and elude enemies through-
out all stages of their life, and in this rather simple statement, we believe, lies
the greatest proof of the great delicacy and complexity of adaptation. For instance,
the jewfish is a huge, powerful, carnivorous animal when it is mature. But each
jewfish starts life as a tiny egg which hatches into a small hatchling. When the
voung fish starts to feed, it is a fraction of an inch long and must have all
the adaptive behavior necessary to allow it to live the life of a tiny, secretive,
invertebrate-eating carnivore. Soon it grows to a deep-bodied, little reef fish with
many of the habits of other small, spiny-rayed fishes that live alert, watchful
lives in rocks and reefs. As it grows, its prey and enemies and ways of life
continually change, and, at maturity, breeding behavior adds another facet to
its life.

Therefore, every animal may be thought of as passing through a series of very
different stages each one of which must be finely adapted to the environment.
The greater the animal's difference in size between youth and maturity, the
greater and more significant will be its adaptive changes through life. This is
the reason why so many fishes have young that are different in so many respects
from their parents and are sometimes mistakenly listed as separate species.

30

UNDERWATER GUIDE TO MARINE LIFE

DISTRIBUTION AND DISPERSAL

In any community, a number of species is found, each of which has its own
distribution Cfig. 6). Some species might be found in only one community— the
parrot fish in the coral reef— and some might be found over a wide range of
habitats— the common eel, ranging from the Sargasso Sea to fresh-water streams
at different stages of its life.

U.S. COAST
H SPECICS OR 1.3%

TROPICAL, SUB-TROPICAL
AND TfMPERATE AMERICA
5 SPf CIES OR 0.9 %

WCST INDIES AND
TROPICAL PACIFIC
8 SPECieS OR 2.5%

TROPICAL AND SUB-TROPICAL
AMERICA-2IO SPECIES OR 6b%

PELAGIC -v3 9 Spec IE S OR (2.3%

WORLD WIDE NEAR SHORE
IH SPECIES OR 'i.'i%

WEST INDIES ,
EAST ATLANTIC AMD EUROPE
8 SPECIES OR 2.5%

SARGASSUM-4SPeCIES OR l-SX

Fig. 6. An example of geographical distrihtition— species of Bermuda shore fishes
(^adapted from Beehe and Tee-Van, 1933^.

The distributions of the species of a community are far from static, and the
numbers of individuals of any one species in a community are subject to con-
stant variation. Some communities are even compound, that is, there may be
several animal communities present in any one zone. For instance, the coral reef
has strikingly different day and night communities, and the temperate zones
have very different seasonal communities. It even sometimes happens that the
fluctuation in numbers of one form of life basic to a community mav change
the whole complexion of the environment. This is what has happened in con-
nection with the decrease in eelgrass in the 1940's.

Fluctuations like these have a great deal to do with factors aff^ecting distribu-
tion and dispersal— the questions of why animals are found where they are and
how they get there. Such fluctuations complicate the studv of communities
greatly, because one is never sure just which species are community members
and which are not.

The answer to why animals are found in one place and not in another, lies
in understanding the principle of ecological valence. Briefly, valence describes
a range of tolerance which an animal can stand in relation to any factor of
the environment. The valence of coral reef formation with respect to temperature
ranges from a low of 68° Fahrenheit to well over 100°. The valence of whales
in relation to food depends upon the supply of the planktonic crustaceans on
which they feed. Both of these valences are small and limiting in value, but
valences can be large. For example, the valence of killifishes with relation to
salinity ranges all the way from pure fresh water to pure sea water. The valence

BIOLOGY OF THE SEA-HOW THEY LIVE 31

of the sperm whale with relation to temperature allows this species to live in
all oceans.

Every species of animal has a valence for each of the many factors that de-
termine its distribution. There are valence values for food, temperature, salinity,
water clarity, light, pressure, enemies, breeding behavior, shelter, other animals
of the communitv, and all the other myriad factors that affect that animal at
any stage of its life. The distribution of any animal is usually not limited by
all of these factors but by only one or two. Figure 7 illustrates the law of the
miniviwn; an animal's distribution is limited by the factors to which the animal
shows the least tolerance.

There are several clues to the discovery of limits to distribution. First, limiting
factors are often biotic, that is, have to do with the animals' relation to other
animals in the community, and these are sometimes very complex. Second,
limiting factors work on all stages of the life of an animal and animals are
limited at the stage where they show the greatest sensitivity to environment.
For instance, oysters grow in some brackish waters where they are seeded by
oyster farmers, but low salinity prevents their breeding there. Third, sometimes
the limiting factor is not deadly or even harmful in itself, but affects distribution

I I

J L

^ LIGHT
OXYGEN
DEPTH

I

-|— I TEMPER/^TVBE

H SALINITY

j I WATETR CLARITY

I I
-) 1 1 FOOD

I I

LOWER LIMIT I THE I UPPER LIMIT

OF TOLERANCE I f^lNinUM' ^'^ TOLERANCS

I I

Fig. 7. Ecological valence and the law of the minimum. Each har represents a
valence value for one of the important factors in the life of an animal. Distribution
in this hypothetical case is limited hy low temperature tolerance and hy the high end
of salinity tolerance; this animal coidd not live in waters lower than a certain tem-
perature or of above a certain salinity. An animal's distribution is limited hy the
factors to which the animal shows the least tolerance.

only indirectly. For instance, light in itself is not harmful to most nocturnal
animals, but these animals avoid light for protection against other animals
(Elton, 1935). Fourth, limits may often be discovered by noticing a decrease
in the numbers of animals near limiting conditions. Animals are most common
in optimum conditions or away from limiting conditions. Again, coral is a good
example. There are few corals in Bermuda where the lower limiting temperature
is reached and many in the Red Sea's optimum habitat. Fifth, rarely does any
one species of animal approach its physiological limits. Animals find suitable
habitats psychologically and travel the path of least resistance away from mar-
ginal conditions, unless they are forced there.

32 UNDERWATER GUIDE TO MARINE LIFE

The limits of distribution are complicated greatly by the factors of vagility,
or the relative power of dispersal of an animal. Sea turdes swim actively and
so are found in all tropical seas— they have high vagility. However, many of the
groups common to the coral reef communities of the Indo-Pacific are rare or
lacking in the east Pacific because their powers of vagility are not great enough
to allow them to cross the huge and rather barren central Pacific. Many sessile
animals, such as coral and sponges, have pelagic larvae which increase the
vagility of the species. Mackerels migrate and have high vagility. Many sedentary
fishes or fishes of coral reefs have pelagic eggs or young which serve to spread
them to new habitats. In fact, it is relatively common to find young reef fishes
far from their parental homes, but rare to find adults of these species far from
the tropics. Many Caribbean reef fishes have their distributions listed "north
to Cape Cod." This northern extention of range is due mainly to wandering
young in the Gulf Stream. Of course, pelagic eggs and wandering young
represent wasteful methods of dispersal because many never find suitable habitat
and die. For instance, many Caribbean fishes and corals are not found in
Bermuda because the wandering young do not live long enough to cross the
wide expanse of open sea between these two places. Other methods of dispersal
are adventitious (incidentally acquired), for example, sessile animals on ships
and driftwood or whale barnacles attached to whales. In summary, the greater
the vagility of a species, especially when vagilitv is bv swimming free of the
influence of currents (nektonic animals) the more widespread a species is liable
to be.

An important factor influencing distribution and dispersal concerns barriers.
Barriers are like fences which keep animals from moving out of an area. Bar-
riers are rather obvious on land and consist of rivers, mountains, plains, or
deserts that a species can not cross. But barriers in the sea are harder to see
and much more variable. Barriers in the sea are also usually of a less severe
nature than on land so that most marine animals have wider distributions than
are common for terrestrial animals. The most obvious barrier is a land mass.
For instance, the isthmus of Panama prevents most Caribbean species from
reaching the east Pacific. Land masses separate the major divisions of the sca-
the oceans. Other barriers are salinity, temperature, and oceanic currents. How
severe a barrier is depends a great deal on the vagility and tolerance of the
animal. For instance, powerful swimmers like tuna can skirt around such bar-
riers as land masses, a feat a blenny could not accomplish. Therefore, tunas
have wide ranges and blennies small ones.

Barriers seem to the human eye to be of a rather permanent nature, but this
is not true. Barriers vary widely in geologic time. The earth's temperature is
an example. Not too many million years ago Panama lay beneath the ocean's
surface. Because of this impermanence of barriers, distribution is influenced by
a third factor besides valence and vagility. This is the geologic age of a group.
A family of fishes that has existed for 75 million years has obviouslv had more
time to spread itself throughout the seas than a family that has existed for 10
million years. This is why the squirrel fishes, derived from relativelv ancient
stock, are found in all tropical seas, whereas the grunts of the genus Haemnlon,
relative Johnnies-come-latclv, arc found onlv in the New World.

Two more factors concerning distribution must be understood. First, when
the range for the green turtle is given as "cosmopolitan in tropical seas," this

BIOLOGY OF THE SEA-HOW THEY LIVE 33

docs not mean literally that the green turtle is to be found all over the tropics.
What it does mean is that this turtle will be found only in the particular habitat
of the tropics to which it is adapted, namely shallow beds of marine plants near
rocks and coral. Second, the number of individuals of a species to be found in
suitable habitats varies greatly with food preference, size, enemies, disease,
reproductive capacity, and a number of other factors. Basically, however, density
comes down to carrying capacity, a measure of the limit of the numbers of
individuals the en\'ironment can support, which is dependent mainly on food
supply.

There are certain psychological checks that prevent carrying capacity from
being exceeded. Territoriality is the chief of these. This means that a breeding
pair of a species sets up and defends a certain area where other members of
the species are not tolerated. If breeding space is all taken, individuals that
do not find adequate territory do not breed. In species that do not set up
territories, carrving capacity is limited chiefly by food.

Carrving capacitv is not static. For instance, in summer in north boreal seas,
long davlight hours and cool viscous waters support huge amounts of plankton
so that the carrying capacity for whales and fishes greatly increases at that
time. Therefore, the number of a species found in any area depends upon
the carrving capacitv for the species in that area at a particular time and is
regulated largely by food and the psychological factors.

FOOD AND FOOD CHAINS

Since the adaptive niche of animals is largely defined by their place in the
food chain, it is important that this subject be understood if the life of the
sea is to be appreciated. Elton (1935) is mainly responsible for focusing attention
on this subject.

There would be no food in the sea and no life on earth were it not for
chlorophvll and the reaction of photosynthesis. Chlorophyll is present in the
great majoritv of plants and in some plantlike animals such as flagellates, and
is a catalyst in utilizing the sun's light energy in the following reaction:

Light energy + carbon dioxide + water ^ ^ sugars and starches + oxygen

Basically, the food chain involves the following relationship which is common
to all communities (with the possible exception of the deep sea, to be discussed
later in this section) :

r ^1 photosynthesis i eaten by i ^ ^- • i l i,-

energy of the sun 1 > plants ^ plant-eatmg animals or rierbivores

I eaten by

flesh-eating animals or carnivores

This is an oversimplified diagram, of course. For instance, the omnivores, which
eat both plants and flesh, are not included. Neither are the detritus- or debris-
eaters which eat dead organic matter from the bottom. Furthermore, there are
many grades of carnivores, from the plankton feeders (whales, mackerels) to

34 UNDERWATER GUIDE TO MARINE LIFE

the large species which eat large carnivores themselves (killer whale, white
shark). Rarely does an animal have a diet that is restricted to only one food
species. The dependency of the sperm whale on giant squid, the blue whales
on krill, or the sea slug on seaweed are three of the few examples of such
dependency. It is much more common to find that an animal will eat a variety
of things depending on its food-getting mechanisms and the availability of
food species. Probably the animals with the most catholic tastes are the omnivores
which eat just about anything they can catch and swallow (some sharks, many
crabs, catfishes, etc.).

The importance of size on choice of food is easily illustrated. For instance,
the killer whale and the blenny are probably equally voracious feeders, but they
are forced to eat very dissimilar things because of a vast difference in size.
There are exceptions to the size rule that the biggest animals eat the biggest
objects. Puffers and killer whales gang up on prey to increase their effective
size. Poison, as a food-getting mechanism, increases effective size. On the other
hand, the largest of all cartilaginous fishes and mammals (basking sharks,
whale sharks, manta rays, and baleen whales) eat tiny planktonic animals.

One primitive mechanism of food getting is filter-feeding and is extremely
widespread in the animals of the sea. It alwavs involves the straining of plankton-
bearing water. The larger plankton-eaters feed by a filtering process. Such
fishes as whale sharks, mackerels, and herrings, filter with gill rakers, and
whales filter with baleen. Many groups of invertebrates also filter-feed. Among
these are clams, oysters, sea squirts, sponges, crustaceans, corals, many worms,
and salpas. Some of these, such as crustaceans and salpas, are planktonic and
form a vital link between small, single-celled planktonic plants or protozoans
and the large fish or mammal plankton-feeders. The other groups are sedentary
and depend on small plankton brought to them by water currents.

A food chain may be drawn for any animal in the sea. Examples of food
chains follow. (The arrow points from the food or energy source to recipient.)

Oceanic, plankton-eating, carnivore food chain (whale):

sun ^planktonic plant >- krill ^baleen whale

Coral reef, omnivore food chain (angelfish) :

sun galeae ^anoclfish

planktonic pla

Small invertebrates

— ^ angcU
lant /

Inshore, carnivore food chain (striped bass):

sun ^.planktonic plant ^planktonic animal

striped bass -^ small fishes^

BIOLOGY OF THE SEA-HOW THEY LIVE 35

Each of these examples is somewhat simpHfied. The striped bass, for instance,
does not eat only small fishes, but may also eat crabs, but in spite of this, food
chains are short. The shortest consists of three steps and concerns herbivores
as follows:

sun >• algae or turtlegrass >■ green turtle

The longest are of the large, voracious carnivores, but these are lengthened
only because of a step-by-step increase in the size of the carnivores involved:

sun ^planktonic plant ►•planktonic animal

Killer whale -^ seal -< herring

It is often stated that parasitism and mud-eating are examples of simplified
food chains. This is not really so. For instance, the mullet is a mud-eater, but
its food chain is not the following:

mud ^mullet

Instead this food chain is quite complex as follows:

sun >planktonic plant ^planktonic animal

plants (/ ^ plankton-eaters

debris and mud
planktonic plant 1

X

small mud-dwellers

illet

Therefore, the mullet's diet of mud consists of three separate food chains,
all of at least four steps. Similarly, the parasite's food chain is not simple but
is exactly like that of a carnivore in that it involves flesh-eating.

One food chain deserves to be somewhat set apart from the rest. This is the
food chain of the deep sea. It is a popular opinion that life decreases from
the surface to the bottom, but several scientists, including Beebe, Barton, and
Jacques Cousteau (Cousteau, 1954), have remarked that life decreases to the
dimly lit or dysphotic zone and then increases downward. Deep plankton
forms the DSL (deep scattering layer) which can be detected on echo-sounding
devices. Direct observations made from the bathyscaphe, a remarkable undersea
boat which uses the principles of an aerial balloon, indicated an increased
abundance of life with depth and that the DSL is the top layer of this abundance.
This has led Cousteau and others to suspect that some unknown link in the
food chain is responsible.

36

UNDERWATER GUIDE TO MARINE LIFE

While it may be true that httle is known of the deep sea, we do not beheve
that an unknown hnk in the food chain is necessary to explain the abundance
of life in the depths. The sun is still the source of energy, although indirectly,
but two food chains, which are linked together, are really involved, one at the
surface and one in the depths (fxg. 8). Life in the depths is connected to the
fundamental reaction of photosynthesis at the surface and is not self-sustaining,
but the basic form of life in the depths is not photosynthetic; it is bacteria
which cause decay and nitrification. Bacteria is a sort of "plankton of the depths"
with respect to food chains there, and since bacteria is most abundant at the
bottom, so are the animals that feed on bacteria.

SUN

X ^

PLANT PLANKTON ^HERBIVORES ^CARNIVORES

TO PLANT PLANKTON

DrcAY ^ORGANIC

BACTERIA MATTER

\

AMMONIA ^-NITRIFYING BACTERIA-

-NITRITES AND NITRATES

Fig. 8. Deef sea food chains. Animals of the deef scattering layer (DSIS) and deep
sea are dependent wpon two sources for their hasic food: I) the constant rain of dead
animals from the surface and 2) the deep water plankton consisting of various
bacteria and simple plants. Both of these sources are dependent upon the sun, directly
or indirectly, for energy. Since surface life is most abundant in the first 250 feet of
water and bottom life is most abundant in the deep sea, a graphic representation of
the numbers of animals at various depths takes the form of an hourglass as shown on
the left.

So far, we have dealt only with food chains involving a few animals. When
a whole community is considered, the food chains of all the species must be
added up to form a food cycle. Figure 9 shows a greatly simplified cycle of the
coral reef.

Food chains have a great effect on animal numbers. Carnivores, for instance,
could never become more numerous than the herbivores they eat. It is estimated
that for every planktonic animal there are seven planktonic plants. The numbers
of planktonic animals per baleen whale is almost inconceivable. Figure 10
shows a pyramid of numbers in which the most numerous forms of life are
shown to be the photosynthetic plankton and the least numerous are the large
carnivores. This concept explains the relative rarity of the extremely large,
voracious predators like the killer whale and the white shark.

BIOLOGY OF THE SEA-HOW THEY LIVE

37

THIRD LtVEl -"'

(secondary consumfrs)--^

SECOND LEVEL / ANIMAL PLANKTON

(PRIMARY CONSUriERS) / (e ,. protozoa, pferopod.
and c«-t*^tttccans)

SWIMMING PREDATORS
bony (i%h, s«a twr-H^s, 3*A snak«

SUN

DISSOLVED WUTRIENTS
{ *o.l1-s and qosea )

SUN

Fig. 9. A simplified food cycle of the coral reef arranged in order of energy Qfood')
source levels. This is a representation of the total of all the food chains in the com-
munity using animals from the coral reef as examples. The first level is photosyn-
thetic, the second level herbivorous, and the third level carnivorous. However, any
one animal may helong to more than one level— the omnivore which eats both animal
and plant matter. Bacteria may he said to constitute a fourth level since they live on
decaying matter. In general, the higher the level the less is the dependence upon the
level immediately preceding for food and the more efficient the iise of the food supply.
Conversely, the higher the level the greater the energy loss through respiration, a
fact related to the increased activity in the animals of the higher over those of the
lower levels. (^Adapted from Allee and others, 19S0.')

LARGE PREDATORS
MEDIUM-SIZrO PRfOATORS
SMALL PREOATORS

I KILLER WHALE i WH\1
I I SEALS » BLUEFISHJI

\TE SHARK
ILARCC BASS; JACK
HERRING ) WRASSE J GOBICS

ANIMAL PLANKTON

PLANT PLANKTON

Vig. 10. The pyramid of numbers; the higher the energy level Qfg. 9) or the farther
out on the food chain an animal is, the less numerous it is. The rectangular areas
represent relative numbers of animals. Examples are given opposite each rectangle.

SYMBIOSIS

The word "symbiosis" is derived from syn, meaning "together" and hios,
meaning "hfe" and means nothing more or less than "hving together." An
animal that lives with another is called a "symbiont." There are various ways,
however, in which animals and plants do this, ranging from nothing more than

38 UNDERWATER GUIDE TO MARINE LIFE

an occasional meeting in a community to the exceedingly delicate adjustment
required by parasitism or mutualism.

From the purely chance meetings of species to the most delicately adjusted
symbiotic relationship, all shades of gray exist. Therefore, in order to identify
the three main categories of symbiosis— commensalism, mutualism, and parasitism
—the diver will often find himself in the position of having to make value
judgments as to just what the advantages or disadvantages of a relationship
might be.

The evolution of symbiosis is bound to progress from the disjunctive (no
constant bodily contact) to the conjunctive (constant bodily contact), but from
there the paths of evolution diverge. Perhaps the most ideal relationship is one
in which both symbionts are benefited (mutualism). Commensalism evolves
into parasitism, and parasitism often evolves into mutualism.

Commensalism

This is a relationship in which the symbionts share the benefits unequally, one
receiving advantage and the other not affected except, perhaps, in a minor way.
Therefore, the symbiont receiving advantage is active and the other is passive.
The active member may benefit by obtaining shelter, support, locomotion, or
food (exclusive of the tissues of the passive member).

Commensalism is the least involved of the three special types of symbiosis
discussed here. It is most often disjunctive, but approaches being conjunctive
in some cases and is either social or nutritive. If nutritive, however, the relation-
ship is not antagonistic.

Well-known examples are the pearlfish, which uses the cloaca of the sea
cucumber for retreat, the conchfish, which uses the conch for the same reason,
and the many bony fishes which live in seaweed or under the bells of jellyfishes.
In the case of the man-of-war fish, commensalism is very near to being con-
junctive since this fish is rarely seen out of the company of the Portuguese
man-of-war and even feeds on some of the food that the jellyfish captures. A
truly obligatory conjunctive commensalism is found in the whale barnacles
which can only live on whales, the benefit of the association being all theirs.

Mutualism

In this symbiosis, both symbionts share the benefits of the relationship. Both
species need not benefit in the same way; in fact, they usually do not. One
may receive shelter or transport and the other food. The fine adjustments
necessary for two animals to live and benefit together are sometimes very
extraordinary.

Usually mutualism is conjunctive, though it may be disjunctive. It is either
social or nutritive and is always non-antagonistic. As in commensalism, examples
from the sea are common and striking. The zooxanthellae of corals is one. Crabs
show mutualistic relations with anemones in which the crab carries the anemone
about on its back; the crab is protected by the stinging tentacles of the anemone,
and the anemone receives transport and support. Some crabs even hold anemones
in their claws and use these as weapons or food-getting devices. Other hermit

BIOLOGY OF THE SEA-HOW THEY LIVE 39

crabs become clothed in a sponge, which gives the crab a home and the sponge
transport. These are conjunctive examples. Disjunctive examples are found
among butterfly fishes, which relieve large predators such as snappers of throat
and body parasites with satisfaction to both parties.

Parasitism

In parasitism, which will not concern us very much in this book because most
parasites live within the bodies of other animals and cannot be seen, the relation-
ship is either conjunctive or disjunctive and is always antagonistically nutritive.
One of the svmbionts is small and benefits by partaking of the tissues of a
larger host. The host is always harmed to a greater or lesser degree. Parasitism is
derived from a predator-prey relationship, in which the parasite has become
adapted to feed on only one host (see lampreys. Chapter 8). In any case, the
ideal parasitic relationship is not one in. which the parasite kills its host, for in
so doing it destrovs its own home and its source of food.

Parasites include various groups of worms, crustaceans, and protozoans among
others. Manv of the phyla of the animal kingdom have parasitic members.

Certain worms and the remarkable deep-sea angler fish, Photocoryniis, have
males which are parasitic on the females. The male angler, for instance, attaches
himself at an earlv stage of growth to the body of the female. He is a true parasite,
receiving all food from the female, and degenerating to a small animal con-
taining reproductive organs only.

ADAPTIVE COLORATION

Whether the colors of an animal are changeable or not, the colors it exhibits
at anv one time are verv often adaptive in nature, that is, are of some benefit
to the animal in its environment. Color adaptation can take several forms-
concealment or warning, for instance— but in every case it is important to
view the colors of animals with careful reference to the animal's environment,
its behavior there, and the characteristics of the visual receptors of other
members of its community. Otherwise, colors lose their meaning. Furthermore,
it is necessary to realize that not all colors and color patterns are adaptive. Some
colors have no adaptive significance. Thus, the tasks that are faced when
studying colors are, first, to determine if the coloration is adaptive at all and,
second, to determine what purpose the adaption serves. Sometimes the adaptions
are obscure, and the diver must be very careful in his interpretation.

Animals change color with response either to environment or to stimuli
associated with courtship or fear. The colors of fighting sailfish become notice-
ably more intense; the octopus shows a nearly white color phase when it is
frightened or alarmed; blennies and gobies change color with sexual excitement
during breeding.

Adaptive coloration has been reviewed by Cott (1940) in a brilliant book
on the subject. Cott begins his book by pointing out the very important fact
that vision rests upon a three-fold basis. First, the physics of light is responsible
for the intensity and quality of rays that emit from an object. Second, the
physiology of the eye and nervous system gives a picture of that object to the

40 UNDERWATER GUIDE TO MARINE LIFE

brain. Third, and most significant, the brain interprets that picture. The eye
picks up a picture, but the brain does the interpretive "seeing," and, in general,
the brain sees only what it knows. This means that past experience has a
great deal to do with what is seen. The whole point of adaptive coloration is
a play on the interpretive part of vision.

Concealment — Cryptic Coloration

In the case of concealment, adaptive coloration serves the purpose of making
the adaptively colored animal harder for its enemies to detect or harder for its prey
to notice. In other words, the clues by which detection of an object is made are
rendered inconspicuous. Methods of concealment are four in number:

1. Color Resemblance. The most common method of concealment involves
colors and color patterns that match the background. The flatfishes Qcolor
photograph'), round sting rays (fig. 76) and the cowfish (/ig. 12) show this
admirably in their resemblance to substrate. The octopus is another notable
example of an animal that matches its surroundings. The red colors of
moderately deep-water or nocturnal animals might be adaptive, making
these species appear black. Several deep-sea animals and the larvae of eels,
tarpon, bonefish and ladyfish are almost completely transparent, which is a
protective lack of coloration that imitates the transparency of ocean water.

Some animals change colors throughout life to match their changing
environments. Cott gives the examples of the flying fishes, which are brown
when young in sargasso weed and blue when adult in the open sea, and
the sea slug, Aplysia Qcolor photograph), which changes from red when
it lives on red algae when young to olive-brown when it lives on brown
algae as an adult. Great numbers of bonv fishes and a few sharks are able
to change color, being, in general, of lighter coloration in open water over
a light bottom or near the water's surface and of darker coloration over a
dark bottom or near dark places.

2. Obliterative Coloration. This adaption is encountered mostly in open-water
species and is explained by figure 11. It involves countershading, in which
the animal is darker above than below. This, in combination with
illumination from above, makes the animal look flat and inconspicuous.
Mackerels are excellent examples of this. The diver who has seen the
barracuda swim toward him like a ghost has seen another good example
of obliterative coloration. Countershaded fishes appear dark when seen
from above, and when seen from below appear light against the surface.
Most fishes are countershaded in addition to their other coloration
adaptations.

3. Disruptive Coloration. In most cases, matching colors alone are not
enough to conceal an animal. Methods which break form and outline,
the greatest of all clues to identification, are very often employed. Stripes
or bars are effective in breaking outline as shown by figure 12.

The jaw outline of many bottom-living predators is concealed by the
presence of fleshy, protectively colored tabs. Such is the case with toadfish,
anglers, stargazers, sculpins, and scorpion fishes.

BIOLOGY OF THE SEA-HOW THEY LIVE

41

TOP -LIGHTING

&

MO COUMTERSHADING

COUNTERSHADING

&

UNIFORM ILLUniMATION

TOP- LIGHTING

&

COUNTERSHADING

Fig. 1 1 . An example of ohliterative coloration— the mako shark. The top figure
shows the shark as it would appear if it were uniformly colored and lifted from
above— a shadow is thrown on the lower side and the animal is conspicuous. The
center figure shows the shark uniformly illuminated, hut colored darker on its hack
(as the mako shark actually is')— still conspicuous. The bottom figure shows the shark
as it actually appears in the water with a combination of top-lighting and counter-
shading— flat and inconspicuous. (^Adapted from Cott, 1940.)

The eye of many animals, being an especially noticeable part of the
body, is frequently concealed by a stripe or disguised as those of butterfly
fishes Ccolor photograph) and the porkfish QColor Plate 5). The eye also
may be included in the pattern of the rest of the body, as seen in anglers,
some groupers, and the scorpion fish, by extending body pattern and color
onto the eyeball.

Shadow Elimination. Animals are very often not betrayed by their own
bodies but by the shadows that they cast. Shadows frame animals
conspicuously, and the elimination of shadows is a valuable aid in avoiding
detection. This method of concealment is common in bottom fishes.
Depressed species such as rays, flatfishes, and batfishes cast little or no
shadow.

Rarely is only one of these four methods of concealment used by an animal.
The mackerel shows ohliterative coloration, but its blue to blue-green ground

42

UNDERWATER GUIDE TO MARINE LIFE

-a-a!^

Fig. 12. Four examples of disruptive coloration in tropical reef fishes. Upper left:
the rihhonfish, Eques species, is vertically striped on its head and horizontally
striped on its hody, which serves to break the fish into two major parts. Upper right:
a midget bass, the harlequin serranid, Prionodes tigrinus, breaks its body into seg-
ments with vertical bars and puts a stripe through the eye to mask it. Lower left: the
Nassaii grouper, Epinephelus striatus, breaks the outline of its massive jaws by con-
tinuing the pattern of stripes from the snout onto the lower jaw (note the con-
spicuous tuning fork pattern on the forehead, a good identifying characteristic^.
Lower right: the cowfish, Lactophrys tricornis, shows a disruptive coloration as well
as color resemblance and protective habits, all of which cause the fish to look like
a rock Qa large stone coral is at the right in this picture^.

ri

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SflB^^vjBHI

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BIOLOGY OF THE SEA-HOW THEY LIVE 43

color matches the open water, showing color resemblance as well. The sergeant
major has bars for disruptive coloration, color phases which match environment,
and countershading. The octopus is one of the few animals that shows only
one method, color resemblance, though even in this case, its sometimes
noticeable blotchings could perhaps be interpreted as disruptive coloration.
The round ray is both protectively colored and flat to eliminate shadow. These
examples should serve to illustrate the point. Do not look for one simple answer
to concealment; it is most often a combination of interplaying factors. Conceal-
ment of one part of the body may even be combined with advertisement of
another part. For example, the four-eyed butterfly Hsh conceals its real eye and
advertises a posterior false eye.

Advertisement — A posemotic Coloration

Diametrically opposed to concealment is advertisement. Some animals are
conspicuously colored either to serve as a warning or as an aid for food-getting.
Bright colors and striking patterns by themselves do not reveal to us whether
an animal will be conspicuous or not. Rather, how the animal looks to the other
members of its community is again the important criterion. Animals that
advertise are frequently sluggish and stand their ground, especially when they
are protected by having poisonous spines or flesh. They are sometimes gregarious,
so that their conspicuousness is reinforced by their numbers, and they usually
display themselves freely.

There are two aspects to advertisement, action and color pattern. Sometimes
these work alone, but they usually go hand in hand. Animals that are conspic-
uous-looking in their environment also act in a conspicuous way.

1. Warning Colors. Conspicuous colors are sometimes taken on by animals
to advertise the fact of their ill-tasting flesh, poisonous flesh, poison spines,
or anything else about them that is definitely distasteful or dangerous.
These animals travel more or less with impunity and with little fear of
attack. This, of course, involves learning on the part of the predators
which avoid attacking these animals. By advertising themselves, recognition
is made easier, and there is reinforcement of dangerous qualities by striking
appearance. Many sea slugs (nudibranchs) are very brightlv colored to
advertise their distastefulness iColor Plate 10^.

Warning display goes hand in hand with warning colors. The porcupine
fish inflates not only in order to appear larger, but also as a warning of its
dangerous spines and poisonous flesh. The sculpins erect their preopercular
spines when molested. The squids and octopuses cause waves of color
to pass over their bodies, causing hesitation on the part of predators.
Toadfishes utter a grunt probably as a warning to advertise the power of
their jaws.

Some warning colors are adventitious and the result of symbiosis. Thus,
the man-of-war fish achieves protection due to the warning colors or form
of the Portuguese man-of-war's tentacles. Some Indo-Pacific demoiselles
live in the protection of stinging anemones. One crab uses a live anemone,
held in its claws, as a warning to predators.

44 UNDERWATER GUIDE TO MARINE LIFE

2. Conspicuous Localized Characters. In some cases, it is not the whole
animal that is advertised but some specific part of it. Lumped in this
category are a wide variety of fascinating examples, most of which involve
some sort of misrepresentation or deception and which can almost be
thought of as being a sort of concealment-advertisement combination, for
in making one part of a body conspicuous, the other parts are made much
less so.

The one sort of exception to this general rule is exhibited by animals
which conspicuously advertise a particularly dangerous part of their bodies.
No deception is involved here. The sharp, preopercular spine of angelfishes
is usually a bright yellow. The poisonous spiny dorsal fin of the European
weaver, Trachinus, is a conspicuous black. The lancetlike white spine on
the caudal peduncle of the blue tang contrasts with its otherwise blue
body. Electric rays frequently have ocellar spots on their backs as warning
marks.

The other purposes of conspicuous localized characters are several and
involve misrepresentation as stated above. First, conspicuous contrasting
colors may serve to startle predators. This is a protective device involving
bluff. The batfishes spread their pectoral fins to show a startling black and
white banded pattern when threatened. Sailfishes are known to erect
their huge dorsal fins when fighting or excited, and they may thus alarm
aggressors.

Second, conspicuous colors may serve to lure prey to the most dangerous
part of an animal. The angler fishes use their first dorsal spine as a lure
to attract prey, and the stargazers have a similar lure inside their mouths.
In both of these cases, the lures are wiggled to make them even more
conspicuous. Anemones have attractively colored stinging tentacles which
lure small fishes to their deaths.

Third, conspicuous characters may serve to distract attention awav from
the most dangerous part of an animal. The cuttlefish, Sepia, and probably
other squids as well, exhibits rapid waves of color on the posterior part
of its body, which draw attention away from the tentacles. When the
cuttlefish draws close to its prey, these relatively inconspicuous tentacles
are shot out, and the capture is made.

Fourth, colors and conspicuous marks are often used to misrepresent
the posture or position of an animal or to direct attack to less vulnerable
parts of the body. The combination of an eye stripe and an eyelike spot
near the tail of the four-eyed butterfly fish creates the impression that
this fish is swimming backwards. Longitudinal stripes through the bodies
of such fishes as shark-suckers, cobia, and the rainbow runner make these
animals appear to stand still while they are actually moving speedily
forward. Squids, octopuses, and some sea slugs QAflysia^ emit clouds of
inky fluid when annoyed, which confuse an enemy and mask their
retreat. Some animals leave parts of their own bodies behind to confuse
enemies. This habit is called "autotomy" and is well known in the cases
of many lizards, including the glass "snake," which can discard its tail at
a moment's notice, then grow a new one later. In the sea, the crustaceans
are the best-known practitioners of autotomy. Many of them have a special
autotomous joint where a limb may be broken off. This limb then wiggles

BIOLOGY OF THE SEA-HOW THEY LIVE 45

furiously for a minute or two, distracting the enemy, and allowing the
crustacean a chance to slip away unnoticed. The discarded limb may be
eaten, but this doesn't bother the crustacean which simply grows another
as good as the one lost.

Disguise

Disguise is like concealment, but in the case of disguise the resemblance to
objects is real and not abstract. That is, animals are adapted not just to become
inconspicuous by destroying parts of their own identity, but by resembling
objects about them. Cott (1940) calls these animals "posers." Concealingly
colored animals are "self-effacers." Disguise is put on either for protection or
ambush as is the case with concealment.

The sargasso weed community shows several good examples of disguise. The
sargassum fish QColor Plate 10^ and some crustaceans that live in this weed
are not only colored like the weed, but they bear fleshy, weed-resembling
protruberances on their bodies.

Se\'eral sea horses and pipefishes bear extensions of their bodies to make
them look weedy. The angler, Lophins, is colored a'nd roughened to look like
a flat rock. Scorpion fishes look like weedy pieces of coral rock. Filefishes
imitate floating seaweed. The decorator crab, Stenorhynchiis, clothes itself with
seaweed as an adventitious disguise. Several other crabs become clothed with
sponges or anemones in a symbiotic relationship.

Disguise is particularly interesting because it demands not only that an animal
look like some foreign object, but also that it act like that object. The trumpet
fish is brown and slender like a eoreonian stalk, but this eff^ect would be lost if
this fish remained horizontal. Therefore, trumpet fishes assume a vertical
position (usually near gorgonians) when alarmed and let the water currents
sway them so that the illusion is complete. Similarlv, the angler fish stays
motionless like a rock and the sargassum fish moves very little in sargasso weed
in order to accentuate their disouises.

Mimicry

Mimicrv involves a resemblance even stronger than in disguise for it involves
strong imitation of one living organism by another in both habits and appearance.
The purpose of mimicry is restricted to warning and false warning.

Two types of mimicry are known. First, if a relatively scarce, palatable, or
nondangerous species mimics a relatively abundant, distasteful, or dangerous
species, Batesian mimicry is said to exist. This mimicry involves learning by
predators of the pattern of color and form of the distasteful species which is
not eaten. Animals which imitate this distasteful species then are presumably
also not eaten. However, the mimic can never become abundant or the learning
of the warning pattern is weakened. For instance, the tasty viceroy butterfly
mimics the distasteful monarch, but viceroy butterflies are much less plentiful
than monarchs and are generally shunned by predators. Examples of Batesian
couples in the sea are rare. Cott states that the English sole, Solea inilgaris, has
a dark spot on its side which mimics the black, poisonous dorsal spines of the
European weaver fish, Trachinns.

46 UNDERWATER GUIDE TO MARINE LIFE

Second, if a number of species, all of which possess the same distasteful
or dangerous attributes, come to resemble each other, the association of dangerous
qualities with their appearance is made simpler for the predator, that is, learning
is reinforced. Perhaps this is why the distasteful sea slugs (nudibranchs) look
so much alike and are so brightly colored.

ANIMAL BEHAVIOR

The purpose of this section is to give some understanding of the principles
involved in activities of marine animals as they adjust to their environments.
The stories of fish behavior told by fishermen and others who come in contact
with the sea are often interesting and fascinating, but for the most part they
have been greatly misinterpreted. Often human qualities have been attributed
to fishes and superficial conclusions drawn from only bits of behavior. To the
diver who has to deal with the aggressive fishes in their environment this can
be dangerous. A more rewarding approach can be taken by careful scrutiny
of the evidence available. This involves looking into the physical and mental
equipment possessed by marine animals, into the kind of behavior one can
expect with a particular type of nervous system possessed by an animal, and
into the part that sense receptors (visual, olfactory, etc.) play in their total
behavioral adjustment to their environment.

It may become apparent to the underwater naturalist as he studies the marine
animals and their environment that these animals do not perceive their
environment as the diver does. Many of these animals are deaf (the starfish,
worms and snails, and probably some fishes). Many are blind, others have poor
vision (sharks and rays), and some have excellent vision (some bony fishes,
squids, octopuses). It is suspected that some fishes can hear sounds of higher
frequencies than humans. Most fishes, such as the bottom feeders, have a
highly developed sense of smell and are able to detect very weak chemical
concentration. It becomes clear that the underwater world as seen by the diver
appears different to each species, and what sometimes appears to be bizarre
coloration, shape, or behavior in a fish to the diver can be explained as a method
of survival adapted to the sensory and motor abilities of the animal that feeds
on it. The diver perceives the underwater world mainly through vision. Man's
vision underwater is far superior to that of fishes. He is very sensitive to color,
he can focus over a wide range of distances with excellent visual acuity, and he
is a good judge of distance because of binocular vision. But he is limited when
compared to most fishes, for their behavior depends upon smell and lateral line
receptors for contact with the environrnent. Man cannot smell underwater nor
can he detect vibration as fishes can over great distances. This makes man
primarily a day animal in the sea, for at night, unless he brings a light source
with him, he loses his visual superiority and becomes as helpless as a fish out
of water.

Marine Invertebrates

The behavior of marine invertebrates is for the most part dependent upon the
type of structural equipment (action equipment, sensory receptors, nervous

BIOLOGY OF THE SEA-HOW THEY LIVE 47

system) that a given species has and upon the environment in which it is able
to live. It is able to live in a particular environment only if the environment
continues to provide the stimulus (light, food, temperature, etc.) to which its
receptors are capable of responding. The higher vertebrate animals (mammals)
have advanced structural equipment (well-developed nervous system, sensory
receptors, and action equipment) which, in contrast to invertebrates, is well
integrated, making possible complex behavior patterns and modifications of
behavior by learning from previous experience.

Behavior of invertebrates varies, depending upon the efficiency of their sense
organs, the type of nervous system, the kind of action equipment possessed,
and it is also dependent upon the animal's past experience and inherited instincts.
The intelligence of a species is determined by the degree to which sensory
receptors cooperate with one another in governing the nature of behavior.

The marine sponge, Sycon (phylum Porifera), is one of the lowest of
invertebrates. After its free-swimming larva stage, it attaches itself to the bottom
and becomes immobile, filtering its food from the surrounding water. There is
no nervous system. There is only protoplasmic transmission of impulses from
one cell to a neighboring cell, each cell serving the combined functions of action
equipment and receptor. Pore cells are stimulated by water currents and
chemicals, which start the beating of flagellated cells found lining the body
walls. This animal has no other sensory receptor and its stationary existence
makes it completely dependent on its environment.

The sea anemone (phylum Coelenterata), more highly organized, shows an
advance in sensitivity to its environment far greater than that of the sponge.
It is able to move if the food supply becomes scarce, and it grasps its food by
its tentacles and passes it to the mouth. These tentacles have contact sense and
chemical sensitivity. The anemone also shows a reaction to light. The actions
of coelenterates are integrated by the most primitive tvpe of nervous system
known, the nerve net (/rg. 13^.

The brittle starfish is part of a group called "echinoderms," which include the
starfishes and sea urchins (phvlum Echinodermata). They are slightly higher
in psychological position than the sea anemone because of their more efficient
type of nervous system involving a nerve ring Qfig. 13^. The nerve ring is not
a controlling center like a true brain but is a more efficient transmitter of
impulses than the nerve net. This nerve ring is used mostly for controlling
locomotion, and cooperation between parts is slightly better than in the coelen-
terates. These advances, although the echinoderms have radial symmetry,
usually allow whatever area is more strongly stimulated to take the lead in
locomotion. Brittle stars are sensitive to light, moving about at night capturing
their food. The light-sensitive cells are found at the ends of the arms. The sea
urchin has light-sensitive pigmented spots on the body. Chemical-sensitive buds
are found on the tentacles, tube feet, and the mouth area of brittle stars. The
whole body is somewhat chemically sensitive with the ventral side slightly
more so. Contact sensitivity is well developed and is important for locomotion.
Contact receptor cells have hairlike projections found on the tube feet and
tentacles. The sea urchin relies on the spines for its contact responses. Most
starfish move about with the action of the tube feet. The britde star moves
by the action of its arms, which are powered by large muscles. The sea urchin,
when excited, moves by the spines. Otherwise it uses its tube feet.

48

UNDERWATER GUIDE TO MARINE LIFE

The worms (phylum AnneHda) have a definite advantage over the starfishes
and sea urchins in that the head end of the body is well supplied with sense
organs, there being progressively less sensitivity toward the posterior end. This
permits the head to take the lead in behavior and makes possible a more complex

SAN OUORM, Nereis,
NCRV0U5 SXSTEM

CRUSTACEAN
NERVOUS SYSTEMS

STARFISH
MCRVC RING

pr.»

SQUID
NERVOUS S'ySTEM

FISH
HtRVOOS 5YSTCM

OUFAtTORY
3ENSE

Fig. 1 3 . Nervous systems and sense organs.

adjustment to environment. The sandworm, Nereis, is an example of this group.
It burrows into sand and has its chemoreceptors (smell, taste) mainly on the
head end of the body, allowing a more directed food-locating behavior than is
present in echinoderms. One other factor important in this group for adaptive
orientation is the development of a centralized nervous system involving a brain
Cfig- 13). These improvements of nervous structure with concentration on the
head end integrate the body processes in a better way than the lower animals
previously discussed. The marine worms have paired ocelli (simple eyes) which
are sensitive to light, and the worms react by hiding by day. Chemical sensitivity
is mainly located on the tentacles on the head end although there is some
sensitivity on the tail and body appendages. There is strong sensitivity to
vibration from the substrate.

Some members of the phylum Mollusca (snails, octopuses, and squids, but
not clams and oysters) have a much better-developed head end, and this anterior
part of the body exercises greater control over other parts of the body than that
found in the worms. This superiority is also evident in improved sense receptors
and nerve conduction. The groups of this phylum have a great variety of
behavior, which ranges from the permanently attached oyster and the slow-
moving clam to the fast-moving octopus and the squid. Chemical sensitivity is
present in the tentacles of the snail and scallop and in the sucking discs of the

BIOLOGY OF THE SEA-HOW THEY LIVE 49

octopus and the squid. The snail has hght-sensitive receptors at the end of
the tentacles. The octopus and the squid have eyes that are almost as highly
developed as those of the mammals. This has been one of the chief reasons for
attributing a high intelligence to these animals. These highly developed receptors
and a well-developed nervous system (fig. 13^ place the octopus and the squid
among the highest in intelligence among invertebrates, but their apparent lack
of sensory and motor integration does not warrant placing them higher than
fishes in psychological standing. The scallops have a row of light-sensitive
receptors on the mantle edge near the base of the tentacles. Clams have light-
sensitive cells on the inner surface of the siphon. An elongated muscular foot
in clams provides locomotion. Sea slugs and snails have a gliding movement
caused by waves of muscular contractions on the foot. The octopuses move on
the ground by using their tentacles and in open water by jet action of expelled
water.

The phylum Arthropoda is a very diverse group composed of almost a
half-million species, of which crabs, shrimps, and lobsters are part of a group
called "crustaceans." This group lies above the Mollusca in psychological
standing because of the existence of a brain and the ladder-type nervous system,
which has a pair of ganglia in each body segment. This results in better integra-
tion of the parts of the body than is found in molluscs. The head with the
specialized sense receptors plays an important part in the animal's orientation.
The crustaceans have chemoreceptors in the antennules, or small antennae.
These receptors are used to locate food by picking up juices diffusing in water
from some distance away. They are also used to detect food by contact. Substrate
vibrations are picked up with legs and body. Most of the crustaceans have
compound eyes, which are especially well adapted for picking out moving
objects.

Fishes

Much of the behavior of the invertebrates is closely related to the extent
of the development of their nervous system. In the vertebrate fishes, as well as
in the invertebrates, the nervous system is principally a bridge between the
sense organs and action equipment, but it is distinguished from the invertebrate
system by having a spinal cord, which runs along the back, associated with a
much better brain (/ig. i3). This tubular conductor permits a unification of
the action equipment not possible in the invertebrate ladder-type system.
Although fishes have this advanced tubular system, they still retain a form
of segmental system, which acts like a ladder-type system (not, however,
evolutionarily related to the ladder system) and which accounts for some of
the stereotyped behavior found in fishes. This segmental system is retained in
part by all higher vertebrate animals.

SENSE RECEPTORS OF FISHES IN GENERAL

VISUAL

The eyes have a flattened cornea with a fixed-focus lens. Vision is usually
20-30 per cent binocular because of the position of the eyes on the sides of the

50 UNDERWATER GUIDE TO MARINE LIFE

head and each eye is able to move independently. The eyes are able to focus
only on near objects. Distance focusing is limited. Fishes have a wide-angle field
of vision. Careful experiments have shown fishes to have color vision, but it
seems weak. Verrier (1928) found that the structure of the retina does not
permit good visual acuity. Acuity seems to be similar to the peripheral regions
of the human eye. It allows good vision of movements of objects, but perception
of form seems defective. The eyes are used by all fishes to some degree except
for a few nocturnal species.

OLFACTORY

Ciliated cells in sacs, which have an opening to the exterior nostrils are able
to detect the presence of weak concentrations of chemicals in the water
Cfig- 13). These receptors are used for locating food at a distance as well as for
detecting chemical gradients in water. Smell is used to some degree bv about
half of all fishes.

TASTE

There are many grouped cells with hairlike projections in and around the
mouth, on barbels (when present), on growths which hang from the lips, or
often covering the body surface. These receptors detect chemicals emanating
from food close to the body. The contact taste receptors in the mouth cavitv
are used for the selection of food and rejection of foreign objects. Some fishes,
mainly those that feed by sight, swallow objects without much attention to
selection, and often strange objects are found in their stomachs. Taste seems
to function in all fishes.

THE LATERAL LINE

Lateral line receptors are composed of ciliated cells clustered at intervals
along a lateral line on the sides of the body from head to tail and on some
fishes branching on the head (fig. 13^. These receptors are sensitive to the
intermediate vibrations between those perceived by the ear and those perceived
by the body surface. While the auditory sense can detect vibrations of high
frequency, lateral line receptors can detect only low frequency water movements.
Skin contact receptors are sensitive only to solids, water pressure, and very
slow vibrations.

Lateral line receptors are used to locate prey, to avoid predators, and to
localize obstructions by detecting direct and reflected water movements. In some
fishes at night, these organs become the dominant sensory receptors. They are
also sensitive to relative water pressure as well as to direction and rate of flow
of water.

ALIDITORY

The auditory sense in fishes is poorly developed. However, there is evidence
that some fishes can hear sound frequencies of up to 8,000 cycles per second
or more. Some fishes are not able to hear at all. The ears of fishes are not visible
on the body surface and are used mainly for equilibrium and orientation. It is
possible that some fishes use vibrations reflected from the surface, the shore,
and the bottom as aids to orientation.

COMMON EEL-

SPOTTED MORAV

HOUN DFI SH

^jjyeyiMHHH»GWiiU»Mi«-:

PIPEFISH

MORTHERNJ
SEAHOFtSE

SHORT-WIN&ED FL.YIfslO FISH

COLOR PLATE i

COLOR FLAl E 1

BIOLOGY OF THE SEA-HOW THEY LIVE 51

THE ROLE OF SENSE RECEPTORS IN THE BEHAVIOR OF FISHES

When the environment of fishes is compared with that of land animals
it is found that the sea is much less variable than land. The chemical content
and temperature of the sea vary little, food is easier to get, and there is no
weather as we know it on land (except near shores). This stability of environ-
ment requires a smaller repertory of adjustable activities, which accounts for
the lack in sea animals (except for the re-entrants) of the advanced psychological
organization that is found in the higher land animals.

In spite of the fact that fishes live in a comparatively constant environment,
there are a great many types of habitats in the sea— coral reefs, seashores, open
sea, and the great depths. Physiological factors such as weak vision, a good
olfactory sense, possession of a swim bladder, and well-developed action equip-
ment determine in which of these environments a species will live and a
species' environment determines to a great extent its type of behavior.

In the environment of a particular species, the pattern of behavior is to a
certain degree determined by the sense receptors it possesses. This close relation-
ship between sense receptors and characteristic behavior is clearly evident in
the feeding habits of the rays. These animals have weak eyesight and a well-
developed sense of smell and touch; they are for the most part bottom-feeding
animals (except the devil fish and the manta), which use their smell and touch
organs to locate crustaceans and molluscs in the sand. The jacks are an example
of fishes with excellent eyesight, which obtain their food by darting at or
hunting down small schooling fishes at the surface.

The important place of sensory equipment in the activities of fishes is pointed
out by Jarmer (1928), whose studies show that when a fish is exposed to a visual
or olfactory stimulus (depending upon which is its main operating sense), it
automatically bites. This is characteristic behavior of fishes in general, resulting
from the possession of a primitive type of vertebrate nervous system. In the
higher vertebrates, as in the mammals, when one sensory system makes contact
with a prey, the animal becomes alerted and other sensory systems are brought
into play for a better orientation before striking. These animals have the ability
to delay their responses to a stimulus because of their advanced nervous system,
whereas in fishes the stimulus brings on a direct and automatic response. An
example of this type of behavior is given in the case of the diver who dove into
the water within a few feet of a barracuda, a visual feeder. The fish turned
instantly and struck the swimmer at the moment of the splash. Approached
underwater, the same barracuda would probably do no more than show
curiosity. The diver's splash and movement resembled the splash and movement
of the prey of this fish, that is, he resembled the characteristic visual feeding
stimulus, the splashing at the surface of a wounded fish or of schooling fish.

The stereotyped visual feeding behavior of the barracuda was demonstrated
when the authors placed freshly killed fish on the bottom near a barracuda,
resulting in no feeding response. But moments later when a moving, wounded
fish was presented, the barracuda swiftly struck. A shark with weak eyes and a
strong sense of smell, on the other hand, would have reacted readily to the smell
of the dead fish on the bottom and also to the wounded, moving fish. Conse-
quently, an excellent method for understanding fishes' behavior is to group
them according to the way they secure their food. They generally fall into two

52 UNDERWATER GUIDE TO MARINE LIFE

groups— the visual feeders and the chemical feeders (mainly through sense of
smell)— with one system dominating consistently.

1. Chemical Feeders. The chemical feeders, such as the mullets, rays, and
most sharks, among others, usually have poor eyesight, but they have a
well-developed olfactory sense supported by touch and taste organs, and
these are used to locate bottom life and carrion, and to sift organic matter
from the bottom.

The olfactory system is a general "exciter," which increases searching
activity around the area where the scent is detected, and as the fish gets
nearer to the source of the scent, the paired olfactory organs direct the fish
to the food. Vision and the contact sense probably come into play in the
immediate vicinity of the food.

2. Visual Feeders. Many species of fishes respond more to the visual stimula-
tion of a moving object than they do to chemical stimuli (barracuda,
bluefish, tuna, cod, blennies, etc.). These are the fishes that pursue their
prey, and vision is the dominant sense used in making contact with their
environment.

These fishes, upon immediate sighting of a moving prey or preylike
object across their fields of vision, respond with a compulsive and direct
strike. This response appears only when the prey lies within the field
of visual acuity of a given species, an acuity which in fishes is generally
limited to short distances. The eyes and body move simultaneously, as if
sighting and striking were one movement, so powerful is the role of vision
in these species. The voracious bluefish is a good example and is well
known among fishermen for striking at any object that falls within its
visual field. The eyes have a rather powerful, direct and stereotyped
influence on behavior in the visual group, almost always producing the
biting response, whereas in the chemically dominated group, olfaction
plays the part of a general exciter and accounts for less stereotyped
behavior.

The other sensory systems generally support the dominant systems, but they
may take the place of chemical or visual senses as the dominant sense under
some conditions; for instance, at night or in murky waters the lateral line
receptors often become the dominant sense. These exteroceptive systems in fishes
generally work independently with little intersensory integration.

In the behavior of the higher vertebrates, such as some amphibians, reptiles,
birds, and mammals, no one sensory system dominates consistently in the way
that fishes' behavior is dominated by vision or olfaction. One sensory system,
when stimulated, brings another system into action with overall integration of
activities. Bringing other sensory systems into play requires more time, gives a
better orientation to the stimulus, and allows greater flexibility in responding,
enabling the animal to make a better and wider adjustment to its environment.

CHAPTER *|

MAN AND THE SEA, I— Photography and Equipment

UNDERWATER PHOTOGRAPHY

This section has been written to help the underwater swimmer to explore,
document, and enjoy underwater life. With photography as a tool, the swimmer
can better identify the different species that swim about him as well as make
possible contributions to science.

The aesthetic aspect of the underwater world has been one of its greatest
attractions, an attraction that is hard to describe. Only through photography
can it be brought to the surface. One has only to see coral, which takes endlessly
exciting formations, and the angelfishes, which are the colorful ballerinas of
the underwater world, to realize the possibilities for taking artistic photographs.
The graceful movements of schools of fishes as they swim about the reefs, the
birdlike flying of the rays, and the sleek beauty of sharks as they move through
the water— all make fascinating pictures.

There are startling nature photographs to be taken: the gigantic whale shark
standing on its tail feeding on plankton, the manta ray leaping out of the water
as it drops a newborn in midair and heralds the birth with a thundering slap
as it hits the water, the parrot fish standing on its tail with its mouth open
while little wrasse clean its teeth and face by eating the food particles left
there. There are hundreds of similarly interesting instances in the lives of sea
animals yet to be recorded on film.

Effects of Sea Water on Light

Underwater photography is mainly for clear waters. Ideal locations are
tropical waters such as those surrounding the Bahamas, where visibility is
sometimes better than 100 feet. Excellent photographs can be taken, however,
in waters with visibility of 15 feet or better. Water conditions which allow
visibility less than 15 feet limit picture taking to close-ups.

Penetration of sunlight into the sea is limited by the roughness of the
surface, the density of water, and the turbidity caused by the presence of
organic (planktonic) and inorganic (silt) particles. These particles cause an
effect called "scattering," which tends to make pictures taken under water at

53

54 UNDERWATER GUIDE TO MARINE LIFE

a distance lack contrast and three-dimensional effect. This is similar to shooting
pictures in a fog. Because of scattering, the camera should be as close to the
subject as possible in order to obtain sharp contrast.

Sea water also has the effect of absorbing colors differentially, the red end
of the spectrum suffering the greatest loss. The deeper sunlight penetrates, the
greater the loss of colors. The deterioration of color from the surface to the depths
in clear water is as follows (for photographic purposes): At about 3 to 4 feet
from the surface, red begins to disappear noticeably; at 15 feet so little remains
that photographs taken without filters show no red. Orange goes out at about
30 feet, yellow at about 65 feet. Below 65 feet only green and blue remain, until
at approximately 1,800 feet all light visible to the human eye disappears. These
figures are approximate and dependent upon water conditions. (Chapter 1.)

Exposure Under Water

Exposures under water depend upon surface conditions, the type of bottom,
and the turbidity of the water. Because of turbidity, light-meter readings are
more accurate the closer the subject is to the meter; the greater the distance,
the less reliable the reading. In shallow water with only one kind of bottom
(e.g., sand) generally one reading is sufficient for all exposures as long as the
surface conditions remain the same. Clouds and water currents that stir up
particles are factors that change lighting conditions.

In calm water only about 3 to 4 per cent of the incident light is lost because
of reflection, but choppy water results in a 20 to 30 per cent loss in intensity
at 2 or 3 feet below surface. On bright calm days in clear waters, exposures at
about 5 feet below surface are almost the same as above the surface. To 30 feet,
use a meter or increase the lens opening one more stop. A direct-reading light
meter (Weston) can be mounted in an underwater housing in line with the
lens for constant readings.

Shutter speeds under water are generally the same as above water. A general
working shutter speed is 1/50 to 1/100; for static subjects (e.g., coral) 1/25 may
be used for increased depth of field, provided the camera is not in motion. The
success of increased shutter speeds for taking fast-moving objects is somewhat
limited by the low light-level conditions.

Camera

Under certain conditions any type of camera can be used to take underwater
pictures, but the most successful underwater pictures are taken with the
camera arrangement which reduces mechanical handling to a minimum. This
allows the photographer to take advantage of opportunities and to concentrate
on safety and subject. These are important considerations when one remembers
the equipment the swimmer has to carry, the constant motion, the attention that
must be paid to safety, and the time element involved in use of the aqua-lung.
Also, if an exciting specimen swims by, the swimmer with an ordinary camera
could not take more than one picture if he had to struggle with setting the
shutter speed and lens opening, cocking the shutter, and advancing the film.
Another factor operating to complicate picture taking is that the reaction time

MAN AND THE SEA, I

55

Fig. 14. Underwater 'photographic equipment, (a) Plastic housing for Dejur
Spectator 8nim. inovie camera and ^Aleston Direct Reading exposure m.eter. (b) In-
expensive Voit plastic camera hag for beginners, (c) Praktina 35mm. single-lens
reflex camera with rapid sequence spring motor, (d) Plastic housing for a 35mm.
single-lens reflex camera vAth a Weston Master exposure meter, (e) Cast metal
housing for Robot 35m,m,. rapid-sequence camera. The plastic cases were assembled
by plastics dealer and the controls added by the authors at a total cost of less than
twenty-five dollars for each case.

56 UNDERWATER GUIDE TO MARINE LIFE

of fishes and most marine animals (about one twenty-fifth of a second) is faster
than that of humans. This means that if a photographer and a fish sight each
other at the same time, the fish could be at least halfway turned around and
headed away before the photographer raised his camera.

The 35mm. camera is widely accepted as the camera best suited to underwater
work. Both camera and case are small and easy to handle. It takes a thirty-six-
exposure roll of film, enabling the photographer to take fewer trips to the surface
to reload. Some 35mm. cameras have bulk loading attachments which take up
to four hundred frames. There are 35mm. cameras available which have a
spring mechanism that transports the film and cocks the shutter, leaving only
the trigger release to be pressed for rapid sequence exposures. The Praktina
Cfig. 14} and Robot meet all these requirements.

Movie Cameras — For Underwater Use

When selecting an 8mm. movie camera, one should:

1. Select a camera with an f/1.9 normal and f/2.5 wide-angle lens.

2. Select a camera which has the longest film run possible on one winding
(e.g., 10 feet). Long scenes are effective, short scenes are meaningless.
A long film run cuts control manipulations and allows concentration on
the subject. A good example of such a camera is De Jur (/ig. J4).

3. Select a camera you know won't jam in the middle of an important scene
necessitating a trip back to the boat to clear a jam. Jamming is time-
consuming, troublesome, expensive, and results in the loss of previously
exposed film.

The factors which determine the selection of a good 8mm. camera for underwater
work also apply to the 16mm. camera. The 16mm. camera should load the
largest footage possible; short footage cameras mean many trips to the surface
and loss of opportunities. Many of the professional photographers use motors
attached to their 1 6mm. cameras to eliminate hand winding.

The Use of Wide-Angle Lenses Under Water

With both motion-picture and still cameras, a wide-angle lens is necessary
when one wishes to encompass larger subjects without having to shoot at great
distances.

Because of the refraction of light through glass, air, and water, objects under
water appear one-third larger or underwater distances appear one-fourth less.
This affects the goggled eye as well as the camera, making it necessary for
the photographer to back off farther to fill the picture frame and to set the
focusing scale at 75 per cent of the actual distance. The wide-angle lens helps
overcome this by permitting the camera to be taken closer to the subject. The
lens offers another advantage in that it has a larger depth of field, which means
one can shoot almost without chanoing focus. This is highly desirable, consider-
ing that most underwater pictures are taken at a low light level which calls for

MAN AND THE SEA, I 57

wide apertures— resulting in lower depth of field. It is important when selecting
a wide-angle lens for scientific work that there be no distortion at the edges
and corners— the type of distortion found with some extreme wide-angle lenses.
This distortion is acceptable for amateur work.

The Normal Lens and Underwater Close-up Photography

There are all forms of interesting life— coral, crabs, small reef fishes, plandike
animals, etc.— that require close-up photography. Most camera range finders
are useless under water, but single-lens reflex viewers for critical focus give a
large enough image to be useful.

The depth of field at short camera-to-subject distances is slight (even with
small apertures) and a miscalculation of only an inch or two is enough to cause
out-of -focus pictures. (A workable rule for determining depth of field for any
aperture is one third the distance in front of the subject facing the camera and
two thirds behind.) The wide-angle lens is desirable for photographing large
marine subjects, but it necessitates that one get close to the subject in order
to fill the negative. This lens is not effective when working close to small
moving subjects; small reef fishes are generally -skitterish when approached
closely, within a few feet, and swim off or become hyperactive. The use of a
reflex camera equipped with a normal lens set for distances of 18 inches to 3
feet gives a slight telephoto effect allowing the photographer to back off so as
not to disturb the subject yet fill the negative. This is contrary to the general
belief that only wide-angle lenses are suitable for underwater work.

With nonreflex cameras a measured stick is useful to determine distances
when photographing static life, but drives off the active life. Since most small
fishes are constandy moving about a small area around the reef, a ruled stick
can be used to determine probable distances where the subjects have a good
possibility of appearing. This involves studying subject behavior before shooting,
but it can be very rewarding. Keep in mind that the yardstick appears one third
longer under water.

Color-Correcting Filters

Color correction filters will function to a depth of approximately 50 feet.
Beyond this depth in most waters not enough of the remaining red, orange, and
yellow light is left (because of the effect of selective absorption, scattering of
light, and lack of intensity) to make filtering practical. Some source of arti-
ficial light is necessary to restore color below this depth. There are shallow-water
photographers who feel that filters are unnecessary and that the blue-green effect
is desirable and truly representative. This is a matter of individual preference.
The authors feel that the complete elimination of the blue-green effect results
in the loss of the unique color tones of the underwater world and prefer the use
of filters which do not completely eliminate this effect.

For waters that tend toward blue with litde green use a CCR series (color-
correcting red) filter. If the water tends toward yellow, that is, has a definite
green tinge, use a CCM series (color- correcting magenta) filter. For a clear tropical

58 UNDERWATER GUIDE TO MARINE LIFE

waters like the Bahamas the authors prefer CCM :^20 or #30. These filters
will give an overall balance of color with a slight blue-green effect without
introducing a large filter factor. Be sure to include the filter factor along with
the exposure meter reading to get your camera exposure setting. For instance, the
filter factor for a CCR #30 filter is 1.8.

Black and white pictures show increased contrast if a filter of the series
CCY (color-correcting yellow) is used. A CCY #10 or #20 is adequate for
most waters. All these filters are available in gelatin sheets at low cost, and they
may be cut and mounted on the back or front of still or movie lenses, or pasted
on the inside of the camera case in front of the lens. When using filters and a
meter it is possible to put the same filter over the meter to eliminate exposure
computation involving filter factors.

Film

Films for underwater photography are the same as used above water. Consider-
ing that most underwater lighting conditions are of a low light level, the best
color films are the faster speed Anscochrome and Ektachrome. Ektachrome gives
good results, but Anscochrome gives better color rendition under water. The
exposure latitude is one stop under and over ideal exposure for good color
rendition.

Black and white films have a wide exposure latitude with three stops above
and below ideal exposure giving a workable negative. The best films are
Panchromatics with an ASA 50 emulsion speed or better. For caves and poor
lighting conditions found near reefs, take advantage of the faster speed films.
However, increased speed of film usually results in increased graininess which
cuts usability when enlarging.

Any color film like Anscochrome 16mm. reversal movie film that has an
ASA 32 rating and gives excellent color rendition at low light levels is well
adapted for underwater use. This film allows the underwater photographer to
use smaller lens openings and to shoot under conditions which formerly did
not allow color. Anscochrome reversal film allows a latitude of one stop over
and one stop under ideal exposures.

Thin emulsion black and white films have extremely high resolving power,
very fine grain, and fair contrast which make them good for underwater work.
The exposure latitude of thin emulsion films is about the same as ASA 32
color films.

Film manufacturing is undergoing great changes to which the underwater
photographer should be alert.

Artificial Lighting

There are tremendous photographic opportunities in waters shallower than
about 60 feet for the amateur and the professional. Below 60 feet, in caves, and
where poor lighting is found, artificial lighting units such as flash attachment
and strobe light units that can be converted to underwater should be used.
These units can bring light and color to the blue-green depths. It would

MAN AND THE SEA, I 59

take many pages of technical information to go into the techniques of artificial
lighting in deep waters. There are excellent books devoted to the subject. (See
Bibliography.)

Underwater Camera Techniques

A good technique to ensure not missing any opportunities when exploring
is to take along two cameras, one in hand and the other hanging from a neck
strap. Each camera might be set for special work: one set at IV2 feet to 3 feet
for close-up work and the other set for distance shots; one with color film
and the other black and white; one a still camera and the other a motion-
picture camera. It is a frustrating experience to have a camera loaded with black
and white film when a good color situation presents itself

Whenever possible, avoid shooting into open water, but try to frame sub-
jects with a reef, coral, or a school of fish. Pictures of fishes with people in the
background are also interesting and show relative size. Special effects are
obtained when subjects are shot against the surface or with back lighting.
Generally the best results are obtained with side lighting. Get as close to the
subject as possible to avoid pictures without conttast. Underexposing slightly
and overdeveloping negatives will increase negative contrast and permit the
use of a smaller lens opening for increased depth of field. Sunshiny days are
best for color, and then around middav. Avoid fogging and light streaks in
the film by reloading in the shade or, if in an open boat, under a canvas
or towel.

The lack of gravity experienced under water permits all sorts of special
camera effects equal to the most expensive studio setups. For example, by
using the feet for propulsion and handholding a movie camera, one can get a
dolly effect as well as all sorts of angle shots.

For an exciting experience as well as a method that affords wonderful photo-
graphic opportunities, put on an aqua-lung with extra weight, and sit on the
bottom in an area where there is much life. As soon as the fishes come to
see you as an unthreatening part of their environment, they will swarm around
you with curiosity or completely ignore you, allowing you to study and photo-
graph them in their natural state.

Underwater photographic technique is by no means standardized. There is
much that the photographer can still do toward evolving new techniques.

Underwater Housings

In order to take pictures under water, it is necessary to have a watertight
case for your camera. If you own one of the more popular cameras, such as
the Robot, Ditto, Leica, Argus, Rolleiflex, Contax, Nikkon, or Canon, there
are manufactured cases available. (Write the manufacturer of your particular
camera for information.) Inexpensive camera arrangements for the beginner
are shown in figure 14. Many photographers build their own cases because
of the expense of manufactured models and because many cameras do not have
cases designed for them.

60

UNDERWATER GUIDE TO MARINE LIFE

Fig. ]5. Some diving gear for snorkeling and self-contained diving. Snorkel tubes,
mask, emergency air pack, and flippers are in the foreground. Aqtia-lungs and air
coinpressor for filling tanks are shown in the rear.

DIVING GEAR

Basic Equipment

The basic equipment necessary to start underwater exploring includes swim
fins, mask, and snorkel. The mask or goggles is a must, for the eyes see every-
thing out of focus without it. One must constantly keep in mind that the mask
makes objects appear one third larger or distances one fourth smaller. The
mask should fit comfortably, allow maximum vision, and not leak water. The
flippers, or swim fins, will greatly increase swimming ability and speed as well as
free the hands for photography and safety. They wall also give better balance
and maneuverability. The fins should feel comfortable— if too tight they will

MAN AND THE SEA, I 61

impede circulation, leading to cramps. An allowance of an extra size should be
made if one plans to use a full rubber suit that covers the feet.

The snorkel tube Cfg- ^5) is usually made of plastic, rubber, or metal. It
allows the swimmer to breathe surface air with the head under water and the
eyes out of the sun. One of its important features is that it permits the bodv
to float just a few inches below the surface at the point the body would normally
be in a dead man's float. Consequently, little energy is expended in keeping
afloat as compared to treading water without a snorkel. Thus, the swimmer
can swim great distances without tiring. The snorkel is a very simple device
to use. The valveless tube is used by the experienced swimmer and the ball-valve
type by beginners. A good technique for almost doubling your breath-holding
time under water is to take many quick, deep breaths before taking the last
one for the plunge; this rapid breathing before diving builds up oxvgen in the
blood.

Safety under water, as in all other activities, works best when it is an attitude
rather than a set of rules, for trouble can come from unexpected directions.
Keep on the alert for the unexpected.

The diver should carry at all times a very sharp, double-edged, pointed knife
for emergencies. He should also carry an emergency air pack (underwater
parachute), which, responding to a squeeze, will inflate, take the diver to the
surface, and keep him afloat.

The Aqua-Lung or Scuba

This self-contained underwater breathing apparatus gives the swimmer almost
all the freedom that a fish experiences. It allows the diver to go into deeper
water with litde effort, without the need to surface for air. It is useful to the
naturalist and especially useful to the photographer, for he can sit and wait
for opportunities. (Figure 131, the "kissing" grunts, was taken after one of
the authors remained still on the bottom at 35 feet for almost three quarters
of an hour.) The experience of using the aqua-lung in clear waters, abundant
with marine life, can be one of the most memorable in one's life. It can also
be the last. It is such a simple device to start using that the novice can easily
get himself into trouble. The authors recommend strongly that no one attempt
to use any self-contained underwater breathing apparatus without at least six
hours' training under competent instruction. Besides instruction on how to use
the lung, a portion of the six hours should be devoted to the part water pressure
plays in the aqua-lung's operation and to the eff^ect of pressure on the body. A
beginner would be wise to start with the snorkel, which will make him conscious
of his breathing, then move to the aqua-lung.

BASIC SAFETY RULES

1. Never dive alone; use the "buddy" system, and keep within sight of each
other.

2. Plan in advance what is to be done in an emergency. Be sure all members
of a diving party know the technique for executing the back pressure-arm
lift method of artificial respiration.

CHAPTER

4

MAN AND THE SEA, II— Dangers and Chumming

DANGERS OF THE SEA

When one thinks of dangers of the sea, sharks, barracuda, moray eels, and
other large, predatory animals immediately come to mind. These animals can
be dangerous, but they are not usually every man's greatest danger in the sea.
Dangers come from two sources primarily, from within the diver and from the
sea. By far the most potent of these dangers are those that derive from within,
for the diver can carry within himself the attitudes and knowledge that make
the sea, like an automobile, either a safe or dangerous place.

The diver must develop an attitude of safety and respect for the sea which
involves thorough knowledge of equipment (Chapter 3) and a resolve never
to dive alone or out of sight of other divers. The diver should take every
precaution that his equipment gives him every bit of advantage possible.

The diver must have a knowledge of his own physical limitations which
involves the general principles of diving physiology (bends, nitrogen intoxica-
tion, squeeze, lung collapse) and the peculiarities of his own body. This knowl-
edge will keep him from the overconfidence which would lead him into
situations beyond his ability to handle.

The diver must equip himself with a knowledge of the sea's inhabitants,
their identification, habits, and adaptations to their environment. This, of course,
implies to a certain extent that the diver is often free from possible injury from
the life of the sea to the extent that he is skilled in biology. One of the diver's
most common errors is attaching such anthropomorphic qualities as cowardice
to animals of the sea. This is a fundamental and even dangerous mistake in
trying to understand behavior patterns and mentalities very different from our
own. One of the important dangers that comes from within is fear, which
leads to panic or even immobilization of the diver. This fear usually arises from
misinformation and lack of understanding of the sea and its life. Consequently,
the way to eliminate fear is to know and understand the sea, in which environ-
ment the diver is a misfit, able to exist only in a highly organized state. Even
with his technology, the diver moves under water with disadvantages and fears
similar to those which primitive man experienced in the Stone Age, being
subject to similar dangers from the elements and from wildlife. Man's real

62

MAN AND THE SEA, II 63

superiority in the sea, an environment which for him is foreign, is not physical,
but is psychological and intellectual, for the physical elements of this environ-
ment prohibit man from being as effective in the sea as he is on land.

It is not the authors' intention to review the life of the sea minutely for
dangerous species. This would require a book in itself (see Bibliography).
Instead, the following is a review of the ways in which animals and plants
are dangerous, with examples of each. The usefulness of this review depends
a great deal on the common sense of the diver. For example, a complete
list -of all fishes with sharp spines, sharp gill rakers or heavy teeth would
include most of the fishes in the sea. The diver must use his own judgment
when handling these fishes.

Details of the dangers of the species mentioned are described in Chapters
7 to 10.

Passive Dangers

STINGING, IRRITATING, BITING, AND SPINY ANIMALS

Most dangers in the sea are passive ones, such as fire coral and the poisonous
spines of some fishes, which become dangerous Only through the actions of
the diver. It is a good rule never to touch any 'plant or animal which cannot
he properly identified. Wear gloves. The dangers from stingers, poisonous spines,
etc., exist in a very great number of species. Usually, such mechanisms are used
as modes of defense by these creatures, though in some cases they are also
food-getting mechanisms, such as the tentacles of the Portuguese man-of-war
or those of anemones. But in all cases, man plays the aggressor, and therefore
he can almost completely control this aspect of danger merelv bv knowing where
the dangers lie. A good example of this is the case of the diver who, having
caught an octopus, slung it over his shoulder and was bitten on the back as
he carried the octopus up the beach. He died from the poisonous bite in a short
while. He was the victim of the now popular belief that octopuses are harmless.

There is a huge array of species spread throughout most of the phvla of the
animal kingdom that can sting or injure with spines and claws. Some of these
species advertise their harmful parts, but some do not. On the whole, spines
and stings are defensive in purpose and do not cause serious injury, but a
few are very dangerous. For this reason the very dangerous species are listed
separately.

Dangerous examples:

Portuguese Man-of-War; Lion's-mane jellyfish; Sting ravs; Eagle rays;
Chimaera; Scorpion fishes; Sea snakes; Octopuses; Squids.

Less dangerous examples:

Red tide protozoan; Fire sponge; Poison-bun sponge; Manv sponges with
sharp spicules; Many coelenterates with large nematocysts, including some
hydroids, anemones, and fire corals; Parasitic flukes which cause "swimmer's
itch"; Bristle worms of several species; Biting worms such as Nereis; Cone
snails; Sea urchins; Crabs and lobsters with strong spines or claws; Spiny

64 UNDERWATER GUIDE TO MARINE LIFE

dogfish; Bony fishes with strong teeth such as the toadfishes; Bony fishes
with fin spines such as catfishes; Bony fishes with opercular spines such
as the squirrel fishes and the angelfishes.

This list covers almost all the species that can be dangerous to the diver.
However, judgment and common sense are the best guides for handling most
animals with spines, claws, or teeth. Many fishes have spiny gill rakers inside
their gills which can inflict cuts when handled.

ENTANGLEMENT AND ABRASION

In extensive beds of algae, particularly kelps, it is fairly easy to get dangerously
entangled in these long, tough plants. Several corals are very sharp and can
inflict cuts that are painful, liable to infection, and slow to heal. The reason
for the slow healing and extra pain of coral cuts is not known. Any cut that
bleeds freely should be attended to at once because of the danger of infection.
A diver, simply for safety's sake, should not remain in the water if bleeding
because of the danger of sharks. The diver must use his own judgment in this
area, staying away from kelp and branching coral or rocks in rough water.

POISONOUS FLESH

Almost all animals of the sea are good to eat, but the flesh of some can produce
results varying from an upset stomach to death. The maki-maki or "deadly
death" is a Polynesian species of puffer fish with extremely virulent flesh.
Fortunately, North America is relatively free of species with poisonous flesh.
The poisonous parts may either be the muscles or some other organ of the
viscera such as the liver, gall bladder, or reproductive organs. It is sometimes
rather difficult to trace down what organs of an animal are poisonous or under
what conditions a normally nonpoisonous species may become poisonous. For
instance, some species, such as the yellow-fin grouper, barracuda, and various
jacks among others, have poisoned people, but very little is known of the causes
responsible for this. It is suspected that these fish sometimes eat the flesh or
eggs of poisonous fishes. This is a subject about which very little is known.
Because more and more animals of the sea are being used for food, this subject
is becoming very important.

Some well-known examples of poisonous animals:

Many filter-feeding clams and oysters (they become poisonous in the warm
months due to accumulation of toxic plankton in their digestive tracts);
Six-oilled shark; Chimaera; Escolar; Some triggerfishes; Some filefishes;
Most puffers (Chapter 9— Plectognaths); All porcupine fishes and boxfishes.

Active Dangers

THE AGGRESSIVE SPECIES

These are few in number, and each of these is considered in detail individually
in later chapters. All predators are aggressive for food and will attack only if
the diver falls into their feeding patterns, which usually he does not. Many of
these animals can be driven off by taking the psychological advantage and
swimming toward them (with the exception of the killer whale).

MAN AND THE SEA, II 65

Anything the diver does that resembles the normal prey oF these predators
might cause them to bite. For example, blood in the water stimulates sharks
into a nervous frenzy called the "feeding mood" so that they will bite at any-
thing in and around the area scented with blood. The smell of blood leads
them to the prev, and when the victim or any object comes into range of their
poor evesight thev will almost always bite. This is a normal feeding pattern of
most sharks, which have a highly developed olfactory sense. For that
reason, carrying dead or wounded fish on a belt while swimming can also be
dangerous.

Many fishes feed mainly by sight, and those dangerous to man are usually
the faster-moving fishes such as the barracuda. They usually hunt down their
prey with quick, darting strikes. Any splashing about the surface, especially in
water with poor visibility, may resemble a school of frightened fish or a
wounded fish, causing barracudas or other fishes to strike blindly. This is
almost like a reflex with them (Chapter 2). Such fishes as wahoo or tarpon
might possibly become dangerous in the same fashion.

Bright, shiny objects such as rings or belt buckles look like the bright side
of some fish and attract predators. When fishes are hurt they often show their
light undersides. Having objects or clothing that flutter as the diver moves
through the water can be dangerous for the same reason.

Diving at night or in water with poor visibility can be extremely dangerous
because many fishes such as sharks and fishes that would not normally attack
man do so under these conditions (barracuda, Chapter 9, and sharks. Chapter 8).
Here again, the diver enters the feeding pattern of fishes, for many fishes locate
prey at night by picking up vibrations of swimming movements with their
lateral line receptors (Chapter 2). These fishes pick up the vibrations of prey
moving through the water and strike in the direction from which they are
emitted.

Some fishes have chemoreceptors on the skin of the body, and it is possible
a touch by a diver will emit a biting response in the direction of the touch.

Of course, almost all animals on land or sea when cornered or wounded will
fight with every ounce of their strength. When a diver reaches into a hole for
a lobster there is a chance that he will be bitten by a moray eel. The eel sees this
move as an aggressive action and bites to defend itself. Toadfishes and wolf
eels can also be provoked into biting in this way.

The killer whale, being an intelligent mammal, must be viewed apart. It is
particularly dangerous because of its liking for larger warm-blooded prey.
Luckily, it is rarely seen out of cold northern waters. Almost nothing is known
of its reaction to man under water.

Aggressive animals dangerous to man:

Some sharks; Large moray eels (when molested); Barracuda; Killer whale.

Other large predatory animals which might be dangerous if man enters their
feeding pattern:

Sawfish; Tarpon; Spearfishes; Giant jewfishes; Wahoo; Some other large
predators.

66 UNDERWATER GUIDE TO MARINE LIFE

LARGE SPECIES

The size and power of some marine animals should be a deterrent to handling
them or being careless in their presence. Since the sea is an environment to
which they, not the diver, are adapted, all animals of large size must be
respected. The best defense upon meeting large animals under water is to let
these animals see you as part of the environment and to move slowly and
without alarm. Here, as in aggressive species, taking the psychological advantage
and swimming toward them will usually drive them off.

Possibly dangerous large animals:

Large squids; Large octopuses; Whale shark; Basking shark; Manta ray;
Other large sharks and rays; Tarpon; Tuna; Spearfishes; Large groupers;
Jewfishes; Sea turtles; Seals; Sea lions; Porpoises; Whales.

CHUMMING— ATTRACTING ANIMALS

In most places, the majority of the animals of the sea are remarkably unafraid
of the diver because, until recently, he has left them comparatively unmolested.
In areas where spearing is done, fishes have become wary and difficult to
approach. For purposes of photography and observation, chumming is extremely
useful in attracting the wary and tame alike. Eventually, with periodic feeding,
quite quickly in fact, fishes and other more intelligent animals learn to recognize
their benefactors. It is a great thrill to be able to establish harmony with the
animals of the sea by chumming them.

Very little is known about chumming. New techniques, methods, and subjects
should constantly be tried. It would be just as well not to try to chum sharks,
manta rays, huge jewfishes, or barracuda by feeding methods, but almost all
others, including sting rays, which have been known to be able to recognize
their feeders in captivity, might be tried. Chumming of very small fishes such
as wrasse, blennies, and gobies is very rewarding. Three general methods of
chumming may be used:

1. Feeding. Good chum may be prepared from a mixture of sand, bread, and
shrimp. In place of shrimp, various other sea foods may be used, but red
meat is not successful because it bleaches out in water. Natural foods such
as broken sea urchins, shellfish, and large crustaceans are also successful.
The first step is to get fishes to eat in the presence of the diver— chum-
ming the area. If the diver is to be associated with the food, it is important
that the time between presentation of food and eating be as short as
possible and also that presentation of food be made often. Eventually, the
subject will be following the diver about, waiting for more offerings.
Groupers are particularly good subjects of this method. Morays are some-
what less "friendly" subjects, food placed near holes in reefs usually pro-
ducing one or more of them. Great masses of smaller fishes such as wrasse
never fail to accept food vigorously.

2. Sounds. This is a subject about which very little is known and about
which critical experimentation is yet to be done. Mullets are known to
be attracted by bells. Croakers and grunts might respond to an imitation

MAN AND THE SEA, II 67

of the noises they make. Porpoises communicate by sounds under water
and could probably be attracted by imitating them.

Movements. Smooth, regular movements will attract very little attention
under water, but jerky, splashy movements are known to scare most fishes
away and to attract such large predators as barracudas and sharks. The
clever use of body movements can serve to attract some fishes. The authors
used retreating movements to attract barracudas for photographic purposes.
The same have been known to elicit the curiosity of groupers. Small fishes
such as blennies and demoiselles are often attracted by wiggling fingers.
Movement is another area about which little is known.

CHAPTER /^

EVOLUTION, NAMES, AND CLASSIFICATION

As the swimmer explores the underwater world, he soon becomes aware of the
diversity of shapes, forms, and habits of marine life. The bizarre shape of the
sargassum fish, the sleek beauty of the tuna, and the plantlike form of gorgonians
lead him to wonder what their relationships are, both to the environment and
to each other. The adaptation of each of these to their environment depends
upon the many small hereditary changes which, if advantageous, allow them
to find food more easily, breed more successfully, or live longer. This adaptation
involves evolution.

EVOLUTION

Figure 16 gives in "tree" form an outline of evolution of fishes for the last
400 million years, the period of time that their evolution is known through
paleontological studies. No more than the barest summary of the evolutionary
process from which the tree took root and grew can be given here. (The
excellent books noted in the Bibliography, especially Simpson's Meaning of
Evohition, should be consulted for further information.)

The basic unit in evolution is a 'population, all members of which have free
access to all other members without spatial, ecologic, social, or any other barriers.
Take, for example, a hypothetical isolated coral reef, over and around which
swim several individuals of a certain species of butterfly fish. These individuals
compose a single population; all of them could breed freely together if they
so chose. This population may be thought of as possessing a number of char-
acters, hereditarily controlled by genes, in common. That is, the population
represents a common gene pool. Because all members of the population breed
tooether and share genetic features in common, thev would not be likelv to
diff"er from each other significantlv, perhaps only varying slightly in size or
intensity of coloration, etc.— differences due to the possession of slightly different
assortments of genes from individual to individual. Butterfly fishes, for example,
show variations which are due to different gene assortments. For instance,
members of a single population may have eye stripes of varying widths and

68

EVOLUTION, NAMES, AND CLASSIFICATION

69

Fig. 16. The evolution of pshes. The stippled areas are approximately proportional
in size to the numbers of species in each group. Notice that the more advanced groups
tend to replace more primitive groups with time. Adapted from Romer (1945) and
Young O950').

70 UNDERWATER GUIDE TO MARINE LIFE

lengths. However, no single individual can have all widths or all lengths of
eye stripe. Instead, there are individuals with long, wide stripes, short, wide
stripes, long, narrow stripes, and short, narrow stripes.

A species may consist of one population, but it is usually composed of several
populations which are more or less independent, but do have some gene flow
between them. That is, some members of neighboring populations do breed, so
that these populations also have genes in common, though the species gene
pool is less restricted in scope than is the population gene pool. Within the
species, gene flow may be restricted enough between some populations to allow
them to differ recognizably from others. In such cases, these are called suhs-pecies.
In humans the four races, Caucasoid, Negroid, Mongoloid, and Australoid, could
be biologically classified as recognizable subspecies. Each has its own charac-
teristics and, until recently, had its own geographical location. With increased
gene flow between these races, the result in time will probably be a breakdown
of race distinctions.

Evolution would probably not progress very far, however, if it depended solely
on differing assortments of genes that are already present. Somehow new build-
ing blocks must be found, and these are produced by mutations. The nature of a
mutation is only partially understood. Presumably, it is a structural change in
a gene or even a rearrangement of genes on a chromosome which causes that
gene to have a different effect than formerly.

Most mutations are small changes. Drastic changes are rarely tolerated in
nature, and in the great majority of cases of large changes due to mutation,
the result is early death. Mutations are usually deleterious in effect, since
mutations are purely random changes, not dictated by the environment or the
needs of the organism. Purely random changes do not usually benefit an or-
ganism which has evolved over a period of thousands of years in response to
its environment. But, of course, beneficial mutations do occur occasionally.

Mutations are rather common. Any one gene may mutate once in several
thousand individuals. Evolution is the process by which the fate of these rather
common, mostly small, sometimes beneficial mutations is determined. The
assortment of genes also plays an important role since certain assortments of
genes are more or less beneficial than others. The environment determines the
fate of genes in evolution. Every gene or combination of genes can be assigned
a selective value in its environment. If the gene is beneficial, the selective value
is plus; if deleterious, the value is minus; if it has no effect, the value is zero.
The environment determines this value since a gene, and an animal possessing
genes, does not exist in a vacuum but in a definite place at a definite time.
What may be beneficial in one place may not be so beneficial in another. By
the process of natural selection, the beneficial genes are selected for and the
deleterious ones selected against. Since the genetic change is not usuallv drastic,
neither is the selection drastic. It usually expresses itself in a differential breeding
rate between the individuals possessing beneficial and deleterious genes. Those
individuals possessing beneficial genes find adjustment to their environment
easier and produce on an average more offspring than those possessing deleterious
genes. This results in time in a marked shift in the whole population toward
the beneficial change within an environment which is presumed to be stable.
Environmental change usually results in a change in direction of evolution.

EVOLUTION, NAMES, AND CLASSIFICATION 71

Let us return to the butterfly fish population on the isolated reef which was
previously mentioned. Suppose that these fish were at one time plainly colored,
small yellow fish without a vertical stripe through the large black eye. Suppose
that one individual was the result of a mutation which caused a narrow stripe
to appear through its eye. This stripe would be an advantage in camouflaging
the otherwise very noticeable eye (Chapter 9), and the gene controlling
the stripe could be said to have a plus selective value. It would aid this fish to
avoid its predators a little better, give it a little more time to eat, and allow it a
slightly longer life in which it could produce more off^spring, some or most of
which would also have this camouflaging eye stripe. Eventually, stripeless in-
dividuals would be rare or lacking. More mutations might also occur to strengthen
this trend toward a stripe through the eye in butterfly fishes. Such a trend is, in
fact, very evident in these fishes.

But evolution cannot be concerned merely with the change within one
population. Somehow there must arise. a situation whereby two types are pro-
duced from one, a splitting by which new species, families, and higher categories
may arise out of the old. This can only occur if somehow the population is
broken into two parts which cannot interbreed with one another. Suppose one
segment of the butterfly fish population was swept away or wandered away
to another distant reef. There would now be two populations on two different
reefs. These populations would have slightly different mutations, and the reefs
would represent slightly different environments. The results of the evolution
in these populations would thus be different, and, given time, two new species
would evolve which, even though rejoined, might have become so different that
breeding would not occur between them. With expansion of this process of
splitting, new families, orders, and higher groups may come into being. It is
not too difficult to imagine how, by this process, certain fishes in shallow waters
became amphibians adapted to spend part of their lives on land by selection
in favor of supporting limbs, how certain amphibians became reptiles adapted
to spend all their lives on land by selection in favor of an impervious dry skin,
how certain reptiles became mammals adapted for active life by selection in
favor of warm-bloodedness, and how certain apes became men adapted for con-
templative life by selection in favor of high-mindedness. In each case, some of
the descendants of the groups which gave rise to higher categories remained
behind, so we see that evolution is a process that creates new forms and builds
on itself. The nineteenth-century biologist Thomas Huxley likened evolution
in filling the available living space on earth to the filling of a barrel. First, the
barrel may be filled with apples. Then pebbles may be put into the spaces
between the apples. Sand fills the spaces between the pebbles and finally water
may be poured in to fill the barrel. Simpson (1949) adds that the barrel itself
expands as the new forms of life create new ways of life bv their verv presence.
For instance, without birds, there would be no bird lice, without insects no
insect-pollinated flowers, and without whales, no whale barnacles.

Evolution is studied from three aspects chiefly. First, the history of evolution
is given in fossil form— paleontology. Second, the mechanics of evolution are
revealed by genetics. Third, the all-important environmental effect is examined
by ecology, commonly known under the name of natural history. We have
briefly explained the first two. This book mainly concerns ecology, and three

72 UNDERWATER GUIDE TO MARINE LIFE

phenomena observed by ecologists and paleoecologists studying evolution are so
instructive that they must be mentioned.

First, there is the phenomenon of convergence. Unrelated animals living in
similar environments or having similar habits are under similar environmental
stress and frequendy come to look alike. Porpoises, for instance, are adapted
for a swift-moving, fish-eating existence on the open sea. Before mammals
became dominant, when the reptiles reigned, a group of reptiles called
"ichthyosaurs" with porpoiselike habits were remarkably like porpoises in body
form. The whales and whale sharks are remarkably alike and have similar
habits. There are many eel-shaped fishes all adapted for secretive predacious
lives, yet derived from widely different groups of fishes. These are all examples
of convergence of body form in response to similar habits and habitat.

The second phenomenon is faralleUsni, which differs from convergence but
little. Again it concerns evolution of animals in response to similar conditions,
but, unlike convergence, the groups were not widely divergent to start with
and have merely followed parallel courses in evolution. The demoiselles and
the butterfly fishes are very similar in habits, size, and form and were derived
from fairly closely related suborders of fishes. There are several predacious
species of bottom-dwelling fishes such as toadfish, scorpion fish, stargazers, etc.,
which have developed from closely related stock.

The third is adaptive radiation. All groups of animals will tend to evolve
in all ways that are open to them within the limits of their own anatomies.
Thus the reptiles and mammals have both had swimming, running, flying
species. The fishes have radiated into almost every conceivable niche from the
surface to the deep sea, from plankton and plant-eaters to voracious carnivores,
and from life on rocks and reefs to sandy beaches. Even smaller groups of fishes
show their own radiation patterns. One has only to examine the varied mackerel-
like fishes— swift predators, plankton feeders, eellike forms, etc.— to see radiation
at work.

Evolution is a dynamic, continuing process. It is going on today even in the
human species. Rarely does it come to a halt in any group. When such a halt
occurs, the result is usually extinction— especially when environmental change
occurs— but occasionally a seemingly changeless "living fossil" is left behind: the
oyster, the horseshoe crab, the sturgeon, Lingula. Evolution is a peculiar combi-
nation of the randomness of mutation and the orientation of natural selection.
It is natural selection imposed by the environment that keeps species within
bounds. Without it, deleterious genes could accumulate, and the result would
almost certainly be genetic pandemonium, which could only result in environ-
mental maladjustment and extinction.

Evolution is highly opportunistic. New situations are quickly met by organisms
that seize new opportunities, but such meeting is largely due to the chance
that the animals are present to meet these opportunities and the chance that
mutations of plus selective value occur. Islands or isolated coral reefs, for in-
stance, have notably depauperate faunas simply because many groups of animals
have not found their way there.

Evolution seems slow to humans who measure time in minutes, hours, and
years. Geologic time is not so reckoned. To the human eye, the world is a
static place, but this eye sees only one frame of a moving picture. We should

EVOLUTION, NAMES, AND CLASSIFICATION 73

not forget that the human Hfe is too short to see evolution in action and that
the human animal has been on earth only one thousandth of the time that life
has existed here. The age we live in is, in fact, an extraordinarily dramatic
one typified by the harsh climatic conditions of an ice age, by fluctuating
currents and water levels of the sea, and by the geologic upheaval of whole
great mountain ranges such as the Pacific Coast range. But our lives are too
short for us to notice most of these changes.

Evolution has no goal, but it does have method and a reason. The necessity
of life to adapt to an ever-changing and complex environment is its reason.
The sensitive man will contemplate and study these things as he swims among
the wonders of the sea that lie about him.

NAMES

It is of utmost practical necessity that names be given to the species of marine
life about us. For common everyday purposes, common everyday names are
used. These are sometimes adequate. Mostly they are not. When you eat a
sardine, do you spread a small herring or a pilchard or a Spanish sardine on
your bread? These are three different fishes, all -called "sardine." Different
languages have different words for the same fish; for example, "ronco" (Spanish)
and "grunt." "Langouste" (French), "crayfish," and "spiny lobster" are all names
referring to the same animal. Examples are virtually endless of the confusion,
multiplicity, and overlap of common names that are given to marine animals
and plants.

Common names are given by just about every method imaginable. The
margate fish was named for the sailors from the English port of Margate. The
yellow grunt was named for its color. The pompano was named for its shape.
Gill's mojarra was named after a man. No one knows how or why the ridley
turtle got its name.

Obviously, some way had to be found out of this imbroglio of terms. In the
mid-eighteenth century, a Swedish scientist named Linnaeus founded the system
of scientific nomenclature which we use today. There is no need to be con-
founded or overimpressed with scientific names. They are only names, after all,
which may be a little foreign to most of us but which offer us some stability in
the confusion of names, especially when we are not familiar with the local
terminology.

CLASSIFICATION

Linnaeus's system for naming animals is built around binomial nomenclature.
That is, every species is given two names, a first, capitalized, generic name, and
a second, uncapitalized, species name. The genus of the spotted moray is
Gyninothorax; the species is moringa. The complete name is Gymnothorax
moringa. The subspecies name, if any, adds a third name.

The Linnaean system was originated in a time before the acceptance of the
validity of evolution. Linnaeus himself was a special creationist. Nowadays his
system has been adapted into an evolutionary scheme and supposedly reflects
the tree of evolution as it is revealed to us by the study of fossils. But since the

74 UNDERWATER GUIDE TO MARINE LIFE

fossil record is far from complete and since the interpretation of it is subject
to human frailty and differences of opinion, there are several systems of classifi-
cation which involve duplications and overlaps of the same type that occur in
common names. Are the triggerfishes, trunkfishes, and puffers three separate sub-
orders, or are they three parts of one suborder? Opinions differ and names are
invented to express the differences. Luckily, there is little difference of opinion
regarding families, and they can be given the strongest reliance. This is due to
the fact that the families of animals and plants form fairly distinct groups. For
some reason, the transitional species that unite families are short-lived and
usually do not stay around long enough to give scientists a chance to examine
them or their fossil remains. This is probably because families share the char-
acteristics of an adaptive type which is established quickly in evolution, so
quickly that there are few intermediates. Basically, the classificatory system of
living things is built as follows:

Kingdom: only two in number— animal and plant.

Phylum: the largest subdivision, e.g., Chordata, including protovertebrates
and vertebrates.

Class: a major phylum subdivision, e.g., Osteichthyes, including all bony fishes.

Order: a prominent assemblage of families, e.g., Apodes, including all true eels.

Family: the basic "adaptive type" grouping, e.g., Muraenidae, including all
moray eels.

Genus: a distinct morphological tvpe; e.g., Gymnothorax, including an as-
semblage of very similar species.

S'pecies: the unit of interbreeding individuals, e.g., Gymnothorax moringa,
the spotted moray eel.

It will be noticed that there are seven subdivisions in this svstem. As we
progress down from kingdom to species, the evolutionary relationship between
comparable groups becomes closer and closer Cfig. 17^. Most often, however,
seven subdivisions are not enough to express the numerous branchings of the
evolutionary tree, so the prefixes "sub," "super," or "infra" mav be added to the
seven primary divisions or new categories such as cohort or tribe may be added.
The basic system between class and genus may thus be expanded:

Cohort

Superorder

Order

Suborder

Infraorder

Superfamily

Family

Subfamily

Tribe

Just as evolution is complex and increases in complexity as we learn more
about it, so the classificatory system increases in complexity in an attempt to
reflect evolutionary patterns. There is some effort to stabilize this system. This

EVOLUTION, NAMES, AND CLASSIFICATION

75

takes the form of rules set up by an international committee on nomenclature
(Schenk and McMasters, 1948). Family names end in "idae," subfamilies in
"inae"; modern taxonomists end orders in "iformes," suborders in "oidei," and
superfamilies in "oidea."

In the following pages an attempt is made to use the simplest classification
possible. Classification is no idle business. The whole point of it is to simplify,
and the underwater swimmer will find it to his benefit to try to think in terms
.of a classificatory system in which each species has its position in a family which,
in turn, has its place in an evolutionary system. An effort should be made to have
in mind a hypothetical family image which gives the species of the family their
major characteristics. This book is built around the convenience of having such
family images, and a "type" system has been used here (Introduction).

Fig. 17. The relationship between the evolutionary tree and classification.

SECTION TWO

CHAPTER

6

PLANTS OF THE SEA

With the notable exception of eelgrass, 7:ostera, and turtle grass, Thalassia,
flowering plants, most of the marine flora is made up of algae. The word "algae"
is a catchall for several very distinct groups. Their variation in size is immense,
ranging from microscopic to 200 feet in length. The variation in color is no less
striking, ranging from blue-greens and greens to reds, violets, and browns. All
of them, however, possess the pigment chlorophyll, which is without doubt
the single most important plant compound known. Without it, plants would
not be able to utilize the sun's light energy to manufacture carbohydrates (and,
by addition of minerals, proteins) from carbon dioxide and water. This process
is known as "photosynthesis" and is responsible for all life on earth since it is
at the very base of the food chain. Chlorophyll absorbs light at the blue and
red ends of the spectrum and reflects green, the color it appears to our eyes.
The blue and especially the red light that is absorbed provides the energy used
in photosynthesis. Since sea water absorbs light difl^erentially, eliminating the
reds and then the yellows until, at over 65 feet, very little but green and blue
are left, the quality of light available at various depths influences the distribution
of the variously colored algae. This subject will be considered as each group is
discussed.

The smallest algae as well as the most important in the sea's economv are
the planktonic ones, which are single-celled, usually enclosed in a skeleton,
and which float or swim near the ocean's surface in immense numbers. There
they form the grass of the sea, a vast and nourishing pastureland. The larger
algae are mostly confined to shore, shoal, rocky, and reef waters, where they are
anchored to rocks, shells, wharves, or even other algae (in which case they are
said to be "epiphytes"— epi, meaning "on," fhyte, meaning "plant." These tvpes
are most dense on shores sheltered from beating surf and, for that reason, Long
Island Sound and Monterey Bay have particularly dense and varied floras. The
large algae are easily separated from all other plants bv their lack of true roots,
stems, or leaves, although thev have basal holdfasts which look superficially
like roots and an upright, usually branched structure that looks like a stem and
bears flat, leaflike extensions.

76

PLANTS OF THE SEA

77

The one place where no photosynthetic plant can exist, of course, is in very
dim light or darkness. Because photosynthesis is impossible in such places, one
would not expect to find photosynthetic algae below a depth of about 200 feet.
Algae become rare below 100 feet. These figures vary according to the nature of
the water.

One group of single-celled animals (Protozoa) is commonly referred to as
being more closely related to plants than to animals. This is the zoologists'
Flagellata or Mastigophora or the botanists' Euglenophyta. Flagellates are con-
sidered by many scientists to be a perfect link between animals and plants
since they achieve mobility by means of flagella as do many animals, yet are able
to manufacture food by photosynthesis as are most plants. Obviously, according
to evolutionary theory, before there were true animals or plants, there must
have been some group that gave rise to both and thus possessed the potential
attributes of both. Such a group is Flagellata, a group which is considered in
the chapter on invertebrates simply because its members look and act more
like animals than plants. Flagellates, like small one-celled true plants, are plank-
tonic and form a basic food of the sea. Many algae have sexual stages, notablv
the male sex cells, that closely resemble protozoan cells.

Bacteria are very minute and simple plants. They are not true algae. Their
very simple order of construction sets them aside from all other plants. They are
well known as the causal agents of many diseases and are probably the most
common of all living things. They will not be included here, but it must be
remembered that they form a basic food for many of the small one-celled animals.
Some of them are unique among living things in their ability to use inorganic
compounds (nitrates, nitrites, and sulphur compounds) as a source of energy.
This method involves no photosynthetic process and indicates the primitive
nature of bacteria (deep sea food chains, Chapter 2).

Many plants of the sea, like garden plants, are known only by their scientific
names. Most of the genera described and figured here have several species
widely distributed on both coasts.

DIATOMS: Phylum Ghrysophyta— F/^wr^ 18

Diatoms are microscopic one-celled algae that live in immense numbers near
the surface of the sea, being the most common planktonic plant. They are
enclosed in a siliceous shell of great variation and beauty. The shells may be

,^3«Wj%_

Fig. IS. Diatoms. The diatoms are shown much enlarged, the circular one being
only about one-fiftieth of an inch in diameter natural size. Drawn from microphoto-
graphs hy the authors.

78 UNDERWATER GUIDE TO MARINE LIFE

rectangular, round, ovoid, or oddly club-shaped but are almost always marked
by regular lines or pores, which may be, in some instances, so fine and regular
that they are used to test the resolving power of the finest microscopes. The
accumulated shells are deposited as diatomaceous earth, which has a number
of extremely important commercial uses, such as insulating furnaces, preventing
afterglow in matches, filtering oil and beer, acting as an abrasive in silver and
car polishes, purifying water, and clarifying antibiotics. The accessory pigment
fucoxanthin is present as in the brown algae, and its role will be discussed
under that group.

BLUE-GREEN ALGAE: Phylum Cyanophyta

The dark, blue-green color of most of these most primitive algae is a com-
bination of the blue of phycocyanin and the green of chlorophyll. Some of them
also have a red pigment. Trichodesniiiini is one of these algae and is sometimes
present in such quantities that it gives the sea a reddish color. The Red Sea is
said to have been named because of the occasional presence of this alga. Blue-
green algae are small, inconspicuous, slimy algae found most typically in
fresh-water ponds as scum and in the sea adhering to mud, rocks, or wharves.
Their small size frequently requires microscopic examination for identification.
Mermaid's hair is found adhering to rocks, mud, and wharves of both coasts.
Like other blue-green algae, it forms a dark, fuzzy, somewhat slimy mat on the
surface to which it is attached.

The pigment phycocyanin absorbs orange and red very efficiently and passes
on the energy so acquired to chlorophyll, which uses it for photosvnthesis.
Almost no blue light is absorbed by these algae so they must live in very shallow
water, although Marshall (1954) reports the presence of blue-green algae in the
deep sea. They must live on decaying organic matter, somewhat like fungi,
there.

GREEN ALGAE: Phylum Ghlorophyta— F/^wr^ 19

The vivid green color of these plants is due to chlorophyll, which identifies
them. They are very numerous and are the most diversified and complex of
algal groups, having 5,700 species the world over. They are especially familiar
as pond scum, on rocks in streams, or on the bark of trees CProtococciis^ . In
the sea, the green algae are mostly small and of temperate to tropical distribu-
tion, being more varied to the south. Thev are not as conspicuous as red and
brown algae. The marine green algae varv from flagellated, planktonic, micro-
scopic, colonial, or single-celled forms, Dunaliella, to the small, branched,
filamentous forms found attached to rocks in the intertidal zone, Clado-phora,
and the showy, large sea lettuce, Lllva, which is usuallv found attached to rocks,
other algae, or wharves just below the low tide mark. Sea lettuce reaches 3 to 4
feet in length and has a very wide distribution from the subarctic to the sub-
tropics. It is fragile and is frequently broken by wave action and thrown up on
beaches. Enteroiuorpha, sometimes called "grass," is a genus of manv species,
most of which are very small. Some, however, reach 2 feet or more in length.
The plant is either single or branched, and the blades are usuallv round and
tubular and are always hollow. Most of the species are of the temperate zone.
Sea moss, Bryopsis, is a lovelv, plumose plant which grows to 8 inches high.

PLANTS OF THE SEA

79

merman's shaving

BRUSH- P«-»»<c»llus
Vo 5 in-

Fig. 19. Green algae. Adapted from Smith Q1944^ and Taylor ^1937^.

80 UNDERWATER GUIDE TO MARINE LIFE

It may grow in sand, or mud, in tidepools, or on wharves and rocks. It is tem-
perate and tropical in distribution. The sponge seaweed, Codium, has a
spongy texture and is branching. It is very common in the warm waters of both
coasts. It grows to a height of about 8 inches. A few green algae are calcified
as are many red algae. Halimeda is a tropical reef-building calcareous alga. One
of the oddest of green algae is the tropical merman's shaving brush, Penicillus
Cfig. 43^. It grows to 5 inches high, and the name perfectly describes its shape.

The green algae are probably the ancestors of all later plants. They show
strong similarity to higher plants in their pigment chlorophyll, which is carried
in typical bodies in the plant cells called "chloroplasts." Chlorophyll is green,
so it absorbs all colors of the spectrum except green, which it reflects. Therefore,
the chief light rays used in photosynthesis are of the red and blue ends of the
spectrum. Because there is very little red left in water below 15 to 20 feet,
the green algae cannot photosynthesize efficiently there and are rarely found
in this greenish water. Surprisingly enough, some green algae live deeper than
any other photosynthetic plants. Some are found at depths of 200 feet where
they use the dim blue light that is available.

BROWN ALGAE: Phylum Phaeophyta— F/^wrt'^ 20 and 21

This is an almost exclusively marine group of over a thousand species and
includes the largest and most conspicuous of all algae, the kelps. The color is
brown to olivaceous and is caused by the presence of fucoxanthin, an accessory
pigment which increases absorption of green light. Fucoxanthin passes the
energy it absorbs on to chlorophyll for utilization. Chlorophyll itself absorbs
reds and blues for photosynthesis. Thus, brown algae are the most successful
utilizers among algae of a wide range of the colors of the spectrum and are,
therefore, the most conspicuous and most varied algae of the sea, both in form
and habitat.

The brown algae are typical of rocky shores from the tidal zone to depths
of 50 or 100 feet or more. The deeper ones are long, however, and are able to
reach up into shallower waters for light. The temperate to arctic zones see
the greatest variety and abundance of them, though they are present in tropical
seas also.

There is a great variety of form among these algae. Most of the following are
of temperate to arctic distribution and are found on both coasts. Ectocar^us
grows to 12 inches and is filamentous and branched. It frequently grows on
other algae, that is, is an epiphyte. Fiicus, rockweed, is very common on rocky
shores in the tidal zone. This is the alga that makes whole shores look brown.
It has little buoying bladders along the stem, which, when dry, make a popping
noise as they are burst underfoot. Rockweed is not found in tropical waters
but is the most common seaweed north of Cape Hatteras and central California.
Ascofhylhim is like rockweed but reaches tropical waters. It grows in the same
places as rockweed, but there is no midrib on its stem as there is on Fucus.
Desmarestia is a large genus of bushy, branched algae which grow on rocks
and is abundant only in the warmer months. The branching identifies them,
being pinnate, that is, branches extend from the main stem on both sides of the
central stem, which is not itself branched. Most Desmarestia species are small,
but some reach 6 feet in length. Sargasso weed, Sargasswn, was discovered by

PLANTS OF THE SEA

81

Fig. 20. Brown algae— 'plate 1. Adapted from Smith Cl^'^'^^ i^^d Taylor CWBV).

82

UNDERWATER GUIDE TO MARINE LIFE

VINE KEUP
Matrocvstis

Fig. 21. Brown algae— plate 2. Adapted from Smith (^1944) and Taylor (i937).

BUEN NV

SCORPION PlSl

COLOR PLATE 3

GRAYSBV

COLOR HLATF. 4

PLANTS OF THE SEA 83

Columbus in 1492. It lives and breeds on shores in the Caribbean, but breaks off
during storms, becomes pelagic, floating in clumps, and is carried to the Sargasso
Sea between the Bahamas and Bermuda by the Gulf Stream where it propagates
by fragmentation. It forms the basis of a fauna all its own (Chapter 1). The
mermaid's fishline. Chorda, is well named for its ropelike, unbranched strands,
which reach 15 feet in length. Beds of this alga are sometimes very extensive
especially on the East Coast. Chorda is an annual, growing each spring.

The various kelps are the largest of algae and among the largest of all plants.
The immense beds of kelp are especially well known on the West Coast. They
can be dangerous to swim in, the long, very tough tendrils easily snagging the
swimmer or his equipment. They harbor a great number of fishes as well as
the famous and rare sea otter. Some kelps, however, are small and live in tidal
zones. The tvpical kelps or devil's aprons belong to the genus Latninaria. They
reach 15 to 20 feet in length but are usually seen much smaller. The wide, flat
blades are typical. In the common species, these blades are single, but other
species may have several blades rising out of a single stipe (stem). Other kelps
are the bladder kelp, Nereocystis, which is found in waters up to 100 feet deep
and grows best on shoals or rocks near active waves or currents; the sea colander,
Agariim, a seedy-looking plant with a perforated blade, which grows up to 5 feet
long in the north temperate Atlantic; the sea pumpkin, Pelagoj)hyciis, which
is a large kelp found from Santa Barbara to Baja California; the vine kelp,
Macrocystis, which is the longest of all algae, with a length of up to 200 feet.

Lessionopsis is a verv bushy brown alga which reaches 6 feet in length. It
grows on rocks exposed to surf and is found only on the West Coast from
Alaska to Carmel, California. Alaria is large, sometimes up to 15 feet or more in
length. It has a prominent midrib and a group of small blades near the base of the
stipe. It is found on both coasts, mainly in colder waters. The sea palm, Postelsia,
is a very odd alga which grows on the West Coast in shallow waters where it is
exposed to the full force of the waves. Padina, the peacock tail, is a leathery,
funguslike form found in the tropics. It grows to a few inches in height.

Some brown algae are of considerable economic importance. Gelatin and the
filler used in cheap ice creams come from them. They are widely used as food,
especially in the Orient.

RED ALGAE: Phylum Rhodophyta— F/^wr^ 22

It is often stated that red algae are adapted better than other algae for life in
deep waters. It would be perhaps better to substitute "intermediate" for "deep,"
for these algae are able to utilize not the light of shortest wave length, the blues,
which most deeply penetrates the water, but rather the light of intermediate
wave lengths, the greens. Red algae possess the accessory pigment phycoeryth-
rin, which imparts a red to deep purplish color to the plant. Sometimes the
color may be orange or olivaceous. Phycoerythrin absorbs the light which is
almost exactly complementary to that absorbed by green algae. The greens of
the spectrum are most efficiently used by red algae, while reds and blues are
not of much use. Therefore, red algae tend to replace green algae in water
over a few feet deep and are found in waters to 100 feet or more in depth.
They are most common, and most efficiently photosynthetic, at 15 to 50 feet,
the depth where green light predominates and red light is weak.

84

UNDERWATER GUIDE TO MARINE LIFE

SE/\ f->OS5
Ave. 'I i

IRISH MOSS
Chondrvs

AqoLftlhteiUK

CALCAREOUS ALCA

Ccr&flino.
+0 b in.

Fig. 22. Re^ algae. Adapted from Smith C1944') and Taylor Cl937^.

PLANTS OF THE SEA 85

Most red algae are small and filamentous or branched. For that reason they are
frequently called "sea mosses." Many genera are much alike and frequently
hard to identify. Red algae are most common in temperate to tropical seas. There
are 2,500 species the world over.

Laver, Porphyra, looks like sea lettuce and is frequently epiphytic— found
growing on other plants. Like sea lettuce, it is fragile and washes up on beaches
or into shallow water. It is found from the subarctic to the tropics and is orange
or red to purple in color. It reaches 3 feet in length. Gymnogongrus is a beautiful
and striking dark purple alga which looks like a small rockweed. It frequently
grows among tropical coral but is also found in the temperate zone. It has a
firm or even horny texture. Gigartina has a wide range of habitats from quiet
sandy shores to rugged rocks where it must withstand the pounding of a heavy
surf. It may be olive to purple or rose-red in color, and the surface is roughened
by little outgrowths. The texture is leathery, and the plant may be branched,
single, or spatulate in shape. Polysiphonia is very mossy in texture and finely
branched. It is commonly only a couple of inches in length but may reach 3
feet. The color is a dark purple to brown or black, or even olivaceous. The many
species are found from the arctic to the tropics of both coasts, and they grow
anchored to rock, wharves, or other plants from the tidal zone to moderately
deep water. The Irish moss, Chondrns, is very common, growing on rocks in
shallow water. The various species are quite variable, but all are bushy and not
over a foot tall, most being only a few inches. The color is a rose- to purple-red,
or even with a green tinge, and the distribution temperate. It is a source of
industrial chemicals. The dulse, Rhodymenia, gets into fairly deep water and
is also found in the tidal zone. It looks like rockweed or Gymnogongrus in its
branching and is a pretty, bright purplish red in color. It is of temperate
distribution, keeping to deeper waters to the south of its range. Very often
species of this genus have little bladelets at the tips of the main blades. Several
species reach a length of a foot, but most are smaller. Agardhiella is a treelike,
small, branched red alga which is very common on temperate coasts. It is
frequently heavily burdened with crustaceans and other animals that live in
its branches.

Several red algae deposit calcium carbonate or lime around themselves. Some
of these aid in the building of reefs. CoralUna ranges from the tropical to the
temperate zones of both coasts. It is a dull purple or red in color and reaches
a height of 6 inches. Bossea is a West Coast coralline alga, which grows on
rocks in shallow water. It reaches a little over 6 inches but is mostly much
smaller.

SEED PLANTS: Phylum Tracheophyta

The eelgrass, Zostera, and turtle grass, Thalassia (^g. 43^, and their close
relatives are alone among the truly marine seed plants. They live in sandy,
or muddy, quiet shallow waters. The leaves are slender and reach up to 4 feet
in length. These plants send out long runners to propagate and bear small
flowers and seeds. Many animals such as sea horses and green turtles depend
upon these grasses for homes or food. It is unfortunate that because of pollution
and parasitic infestation eelgrass has disappeared from much of its former
territory. These plants range from the arctic to the tropics of both coasts.

CHAPTER

7

THE INVERTEBRATE LEGIONS

The diverse series of phyla that compose the invertebrates is so complex that the
subject will be treated here on the level of the largest groups— classes and orders.
This task in itself can be more complex than it would first appear to be, since
95 per cent of all of the species of animals are invertebrates.

So huge is the invertebrate group, that no living man can say that he
thoroughly comprehends even a majority of their vast array. Thus, the study
of them is divided into a great number of subsciences— entomology for insects,
protozoology for protozoans, conchology for molluscs, and so on. Nevertheless,
comprehension of the types of invertebrates on at least a phylum and class level
is possible, and we believe that such a treatment is vital in understanding the life
of the sea. (More thorough treatments are available as listed in the Bibliography.)

The study of invertebrates can be a fascinating thing. Because their ways of
life are so far removed from the realm of man, one cannot help but be
constantly struck by a sense of the bizarre. Most invertebrates possess very
limited brain power and do not vary their habits as much as do vertebrates, but
within the limited behavioral pattern of each lie constant surprises. The colors
and the beauty of form and motion of many of them are often breath-taking, and
their odd habits are constant sources of wonder.

The invertebrates are united by the possession of no single characteristic,
but rather by the lack of one. None of them has vertebrae or a backbone.
Formerly, Aristotle separated invertebrates and vertebrates on the basis that
vertebrates possessed blood and the invertebrates supposedlv lacked it. His word
on this matter was accepted until only 150 years ago when invertebrates were
shown to possess blood, though it is frequently colorless.

In the following pages, the major habitat and ways of life of each group
are given, together with brief descriptions of a few representative species.

NONGELLULAR ANIMALS: Phylum Protozoa {first animal)

A noncellular animal is one whose body is not di\ided into cells. Therefore,
within the single cell of most protozoans, all the functions of digestion,

86

THE INVERTEBRATE LEGIONS 87

respiration, locomotion, and so on are carried out. It is true that some protozoans
are colonial— several living together as a single group— but none of these has a
division of labor among cells in which the cells are united into organs for
special purposes.

This phylum is the most variable one in either the animal or plant kingdom.
No one body plan, form, or type of symmetry typifies all protozoans. Some
species, like Amoeba, are even able to change their form as they move about,
but most species have one form that typifies them throughout their lives.
Protozoans are among the largest of phyla, existing practically everywhere— in
sea water at all depths, in fresh water, on land, and broadcast through air as
spores. Some are parasitic, causing such diseases as amoebic dysentery, malaria,
and African sleeping sickness.

Protozoans are all small. A microscope is required for seeing their details of
structure, though many can be seen with the naked eye. They range in size from
a few thousandths of a millimeter (1/25 of an inch is equivalent to 1 mm.)
to an extreme of over ¥i of an inch for some fossil, amoebalike protozoans with
skeletons. Protozoans reproduce by fission, a simple splitting of a cell in two,
a method which allows them to increase their numbers rapidly when the right
conditions prevail. Just when and where these conditions prevail is the key to
understanding protozoans, for they are all extremely sensitive to environmental
modifications. Under the proper conditions of salinitv, temperature, viscositv,
pressure, light, food, etc., the numbers of a certain species may become
incomprehensibly immense. If these conditions change only a little, the species
will often die off and produce dormant stages, such as resistant spores which
will become active again only when conditions once more become adequate.
But so great are the numbers of species of protozoans that almost any conditions
are adequate for at least one or two species. Rarely, if ever, are any waters
free of them.

Protozoan behavior never varies much within a species. Some species are
light-sensitive, moving toward or away from it. All react to mechanical shock
and temperature change, and most can sense food, moving toward it.

Most of the protozoans with which we shall be concerned are planktonic
and occupy a vital place at the very base of the food chain, either deriving their
body-building energy directly from the sun or from bacteria or other minute
particles which they eat.

Flagellates: Class Flagellata or Mastigophora — Figure 23

This group, which forms a link between true animals and true plants (algae),
occupies an extremely important place in evolution. Some of them contain
chlorophyll and are photosynthetic, looking very much like some single-celled
green algae (Dunaliella, fig. 19'). Others eat food such as bacteria or decayed
substances as do animals. The photosynthetic species have a light-sensitive eve
and move toward light. They are extremely important in the sea as basic
converters of light energy to carbohydrates.

All of the flagellates have one or several flagella, or whiplike filaments, which
move the animal. Some flagellates are colonial with several cells living together
as a unit, and these bear a remarkable similarity to the sponges in that there is a

UNDERWATER GUIDE TO MARINE LIFE

subordination of the single cell to the life of the whole colony, a prerequisite
for a many-celled animal.

This group forms the greatest of all linking groups in evolution. Not only does
it unite animals with plants and protozoans with sponges, but the other groups
of protozoans, as well as higher animals, were probably derived from flagellates.

NootiltA.CQ.

.. / -

5jllCeou.s CKry^omonacl

Cryp+on^onad "x V

Radiolaricxrx

Fig. 23. Protozoans. Adapted from several authors.

The chrysomonads form a group of predominately photosynthetic planktonic
flagellates. They very often have a siliceous or calcareous skeleton and almost
always have two large, conspicuous yellow or brown bodies (chloroplasts)
within them which contain chlorophyll.

The cryptomonads are oval-shaped and have a large gullet in which two
flagella arise. Some are photosynthetic and others ingest organic matter through
the gullet. None of these has a hard skeleton.

The dinoflagellates are the largest and most numerous of the marine, plank-
tonic, photosynthetic protozoans and are of enormous importance in the economy
of the sea. The body is most often encased in plates made of cellulose, and there
are two flagella, one of which rests in a groove which circles the body. Ceratinni
is a common form in which long spines are developed as a flotation mechanism.
The red tide organism, Gyimiodiniuvi hrevis, occurs sporadically in tremendous
numbers along the coast of the Gulf of Mexico and in other warm seas. When
it appears, sea water is turned into a muddv, reddish color and svrupv consistencv,
causing a high mortality of marine life. If the temperature is high, it produces
a vapor that is very irritating to eyes, nose, and throat. No one knows what
causes sudden outbreaks of red tide. Gonyaulax causes similar damaging out-
breaks of "red water" in Southern California. Noctiltica is luminescent and non-
photosynthetic. It is large, to 1/25 of an inch in diameter, and when it is
disturbed by a wave, a boat, or a swimmer, will emit a sudden light. The com-
bined light of countless millions of them causes a beautiful, sparkling glow on
the water's surface. The natural color of NoctiJiica is pale pink and bv day a
pinkish tint may be given to the sea by them.

All of the three groups of flagellates mentioned have some species which

THE INVERTEBRATE LEGIONS 89

live in symbiotic relationship in the tissues of a wide variety of invertebrates,
especially in corals, jellyfishes, and radiolarians. These species are known
collectively as "zooxanthellae" and are small, degenerate, photosynthetic animals
which live and multiply in the tissues of their host. They are able to live free
of the host, but rarely do so. Zooxanthellae use the carbon dioxide, phosphorus,
and nitrogen wastes of the hosts in order to synthesize food. They yield oxygen
to the host and may even be digested by the host when the latter is hungry
(Hyman, 1940). The brownish or yellowish color of corals and radiolarians
is due to the presence of zooxanthellae. Some coral animals are greenish, and
this is due to the presence of zoochlorellae, small, single-celled green algae that
live in the hosts' tissues in the same way as do zooxanthellae.

Amoebalike Protozoans: Class Sarcodina or Rhizopoda — Figure 23

Among the most delicate and beautiful objects of the sea as well as the
largest protozoans belong to this group. All of the species have extensions of
their bodies called "pseudopodia " ("false feet") by which they move and
capture food. Pseudopodia are neither constant in form nor number, but are
best thought of as being tentaclelike extensions which may appear or disappear
at any place on the body. How pseudopodia are formed by the protozoan is
not known.

The foraminiferans ("hole bearers") are a group of amoebalike protozoans
that build calcareous skeletons which are perforated by many minute holes
through which the slender pseudopodia extend. The animal starts life with a
small shell of one chamber. New chambers of ever-increasing size are added,
usually in a spiral fashion (like the growth of snails) until the time of death.
Foraminiferans are found in immense numbers from surface waters to the
abyssal zone. Their skeletons have accumulated in huge quantities in oozes
on the sea bottom. One form, Glohigerina, has covered 30 per cent of the
forty million square miles of ocean floor with its shells (Buchsbaum, 1948).
The chalk of England's Dover cliffs, a thousand feet thick, is composed largely
of foraminiferan shells. If one considers that upwards of fifty million shells may
occur in one pound of bottom ooze, the number of shells on the sea bottom
becomes inconceivably great.

Radiolarians are like foraminiferans, but have siliceous skeletons. They have
yellow-brown zooxanthellae in them, which probably contribute to their
nutrition. The delicate and frequently very beautiful skeletons, as well as oil
or fat droplets in the body, and the fine pseudopodia aid these animals in floating
at the surface of the ocean. In the very deep parts of the ocean (over 15,000
feet), radiolarian oozes are formed of the skeletons of these animals. Somewhat
less than 5 per cent of the ocean floor is carpeted by this ooze. At these depths,
the calcareous skeletons of foraminiferans dissolve, leaving onlv the relatively
insoluble siliceous skeletons of radiolarians.

Giliates: Class Ciliata — Figure 23

Ciliates are named and distinguished from all other protozoans by the
possession of little hairlike processes called "cilia" which cover their bodies.
Most are free-swimming, but some live attached to substrate or are colonial.

90 UNDERWATER GUIDE TO MARINE LIFE

There are a "reat number of marine species, none of which has a skeleton. They
are not common as oceanic plankton, but they are very numerous inshore in
shallow water or as parasites. The species of ciliates live wholly by hunting
down prey or by filtering sea water by means of currents set up around their
"mouths" by the cilia. Because of these active modes of feeding, ciliates are
the most active of protozoans and show more response to environment than do
other protozoans.

One group of ciliate derivatives called "suctorians" has lost cilia and has
acquired long tentacles by which prey is captured and sucked dry. Prey usually
consists of other protozoans or small larvae of invertebrates and may be several
times the size of its captor. Suctorians are very common attached to substrate
or to other animals in shallow waters.

SPONGES: Phylum Porifera {"pore-bearer")

Colonial animals are those in which several individuals have banded together
to form one functional unit. Multicellular animals are those in which the
different cells have become associated into different organs for the performance
of different jobs. Sponges sit on the fence between being colonial and multi-
cellular. They probably arose from flagellate protozoans because they are
composed of aggregates of flagellated cells, but these cells are not gathered
together to form organs. There are several types of cells, some wandering and
amoebalike, and there is a supporting skeleton. Therefore, sponges, though
they are not on the direct evolutionary line toward multicellular animals, do
show how multicellular animals might have arisen through associations or
colonies of single cells.

The partial independence of the cells of sponges is demonstrated by the
sponges' powers of regeneration. Sponges are a bit like the magical broom
of "The Sorcerer's Apprentice." If a sponge is cut into many pieces, each piece
is capable of producing a new sponge. It is even possible to separate the cells
of a sponge by squeezing it through a fine cloth. These cells, if they are still
living, will group together again and grow into a new sponge.

Sponges are very plantlike and, in fact, were not known to be true animals
until the nineteenth century. Basically, a sponge is a hollow vase perforated
by holes (hence the name "pore-bearer"). There are many small holes by which
water enters the vase and one larger hole, or a few larger holes, bv which water
leaves. The latter are large enough to be easily seen by the naked eye. Currents
of water through the vase are caused by the beating of the flagella of the cells
on the inside and bring microscopic, planktonic food to the cells of the sponge.
In most cases, sponges are not merely simple vases, however, but have become
much infolded and complicated in form, so that the internal surface area
of the sponge is greatly increased without involving much of an increase in size.

Sponges have skeletons composed of calcium carbonate, silica compounds,
or spongin fibers. The first two are brittle and in the form of delicate, ncedlelikc,
branching spicules which are enmeshed together to form the sponge's supporting
structure. Spongin is resilient and is the substance known to us all as the fibers
of the bath sponge, Eiispongia. It is largely on the basis of their skeletons that
sponges are classified.

THE INVERTEBRATE LEGIONS

91

Sponges exist in a wide variety of shapes. Some are small and even parasitic.
Others, such as the Pacific Neptune's cup, Poterion, are big enough to sit in.
In general, sponges are like plants in growth pattern. For instance, a tree has
a pattern of growth by which it may be recognized, but there is no set number
of branches it must have. The same is true of sponges in that there are branching,
erect, encrusting, or vaselike patterns of form, but each species shows consider-
able variation within that form.

The great majority of sponges are marine, there being only one small
fresh-water group. Sponges are largest and most varied in shallow, tropical
waters. Almost everywhere that they are found, a host of other animals, mostly
worms and crustaceans, are associated with them, living in the cavities for
protection. The most notable of the sponge symbiotic relationships exist
between several species of hermit crabs and a few species of a family of horny
sponges. The sponge grows on the shell occupied by a crab and eventually
grows to cover the entire shell. Then the sponge dissolves the shell away and
itself forms the home of the hermit crab. This is a case of mutualism in which
the crab is protected from predators by the bad taste of the sponge and the
sponge benefits by receiving transportation. Although most sponges taste and
smell badly and are protected by their sharp spicules, two groups of animals,
the nudibranch molluscs or sea slugs and the sea spiders, have some species that
eat sponges. The sea slugs frequently imitate sponges in shape and color. The
sea spiders suck the juices of sponges.

Calcareous Sponges : Class Calcarea — Figure 24

These are the simplest sponges, small and vaselike, either single or grouped
in colonies, yellowish to whitish or muddy in color, and with spicules of lime.

VENUS FLOWER BASKET
Euplec+ella-lOin.

BREAD-CRUMB SPOMGE
Halichror,dr,o.-(nficih+4in-

BATH SPONGE
Eu-sponc^ia- 8in.

Fig. 24. Sfonges. Drawn from life.

92

UNDERWATER GUIDE TO MARINE LIFE

Almost all of these sponges are found in shallow temperate waters on pilings
or rocks or in tidepools. Leucoselenia is one of the most common of the colonial
or branched forms, and Grantia is an "urn sponge." Both of these rarely reach
over an inch or two in height. The distribution of these sponges is world-wide.

Fig. 25. Top. This colonial vase sponge, three inches high, has large holes called
excurrent openings through which water, taken in through many minute holes in the
sides, leaves the animal. Bottotn. The basket sponge, Hircina, anchored on a small
coral outcrop and almost large enough to sit in, is the largest species of sponge in
North American waters.

THE INVERTEBRATE LEGIONS 93

Glass Sponges: Class Hexactinellida — Figure 24

These are mostly vaselike sponges of deep water. The skeleton is formed
entirely of six-rayed spicules of silicon compounds. Since most of them must
anchor in the mud of deep water, there is commonly a rooting tuft of elongated
spicules at the base of the sponge. The skeletons are frequently extremely
beautiful glassy objects like that of the Venus flower basket, Eii-plectella. This
group is found in deep water of all seas but is most common in the tropics.

Horny Sponges: Class Demospongiae — Figure 24

The great majority of sponges belong here, and most sponges encountered by
the diver will be of this class. The skeleton is largely formed of spongin fibers,
which gives a breadlike texture to most of them. Some of them, however, have
siliceous spicules (never six-rayed as- in glass sponges), and a few have no
spongin but only have siliceous spicules. Some of the species have echinating
spicules, that is, the spicules are sharp and break off in whatever object they
touch. The fire sponge, Tedania, and the poison-bun sponge, FihiiUa, are two
of these. The fire sponge is shaped like the red sponge Ccolor photograph'), but it
is usually a much more brilliant reddish orange in color. The poison-bun
sponge is breadlike in texture, brownish in color, and grows in rounded clumps
like many common sponges. Both of these are West Indian and capable of
producing more or less severe burning stings. Because of the irregular shape
of many sponges, it is hard to recognize some of the species, so it is a good
precaution to wear heavy gloves when handling them.

The colors of horny sponges vary widely from the yellow bread-crumb sponge
to the brilliant red of the fire sponge and the red-beard sponge, the purplish red
of the red sponge, the green of some boring sponges and vase sponges, and the
drab brown or black of bath sponges and basket sponges. The form of horny
sponges is even more variable. The bread-crumb sponge, Halichondria, and
boring sponges, Cliona, which can bore into the shells of molluscs or into rocks,
are encrusting; the red-beard, Microciona, and the finger sponge, Chalina, are
erect and branching; many are like vases and are colonial (/ig. 25 and color
■photograph); the bath sponges, Euspongia, are rounded; the basket sponge,
Hircina (/xg. 25) is cup-shaped and almost large enough to sit in. Almost all
of these types have extremely wide distribution, but horny sponges are most
varied and are largest in the tropics. The area of the Bahama Islands is
especially rich with them.

POLYPS AND MEDUSAS: Phylum Coelenterata

These are the jelly animals— jellyfishes, hydrozoans, gorgonians, corals,
anemones— so named because of the presence of a jellvlike substance, consisting
of about 98 per cent water, which is found between their outer (ectoderm)
and inner (endoderm) layer of cells. These are the lowest members of the animal
kingdom which have cells organized into organs— digestive, muscular, nervous,
reproductive— and they also show, for the first time, a nervous system. This is
a very primitive system with no brain and consists only of a network of nerve

94 UNDERWATER GUIDE TO MARINE LIFE

fibers, but it does allow coordinated muscular action so that these animals can
perform simple coordinated movement, such as contraction of the animal as a
whole or movement of tentacles.

Basically, there are two types of body form in this group, the sessile polyp
and the free-swimming medusa. Actually, these two are merelv two forms of
the same thing, the polyp being long of body with the mouth up and the medusa
being short and turned over with the mouth down (fig. 26). The primitive
species have both of these forms present in an alternation of generations, a name
given for the extraordinary breeding method in which the polyp reproduces
asexually by budding to produce medusas and the male and female medusas
reproduce sexually by union of egg and sperm to produce more polyps. The
whole phylum is divided into classes on the basis of which one of these
generations, the polyp or the medusa stage, has become dominant. Because
medusas are active and free-swimming, they show greater responsiveness to
environment than do polyps.

All of the species of coelenterates are united by the possession of two charac-
teristic features. First, they are radially symmetrical; in other words, the top of
the body differs from the bottom, but all the sides are the same. Second, most
have unique stinging structures called "nematocysts" (_fig. 26), which, in
response to a touch on a trigger (cnidocil), are able to shoot out a piercing
barbed thread, injecting poison into the object with which it comes into
contact. The poisonous thread acts like a fish line, holding the prey to the
tentacle. One nematocyst by itself would not be very potent in either poisoning
or holding prey, but as the prey struggles, it becomes more and more enmeshed
in nematocysts and is subdued shortly. Some nematocysts are large and powerful
enough to cause serious poisoning to man, particularly those of the Portuguese
man-of-war and the lion's-mane jellvfish. These cells are the organs of offense
and defense of coelenterates.

Coelenterates are found in great numbers all over the world in shallow to
deep waters. Some eat fishes, some feed by filtering plankton, and some have
food manufactured for them by other organisms living in them (symbiotic
zooxanthellae or zoochlorellae). Some of them are verv striking because of the
beauty of their skeletons, as in corals, or the beauty of the iridescent blues,
yellows, and reds of their bodies, as in anemones and jellyfishes. As unattractive
as jellyfishes may be lying dead on a beach, in the water they are very beautiful
as they move by gentle, rhythmic pulsation of their translucent bells, their
tentacles streaming gracefully behind. But the diver should not be too carried
away by the beauties he finds in this phylum. While most are harmless, many
can produce painful stings.

Hydrozoans: Class Hydrozoa — Figure 27

This is a group of great variation, having species that show alternation of
generations between polyp and medusa stages and those that are exclusively
polyps or medusas with no alternation of generations. There are twenty-seven
hundred species of hydrozoans in all waters of the world.

The hydroids are the most typical of the hydrozoans, showing typical
alternation of generations. Most of them arc small, colonial, plantlike, branching,
and have a skeleton of a stiff, horny material (though some are without

THE INVERTEBRATE LEGIONS

95

budd

barbed, poisonous +Kr£Q.d

eicloderm

POLYP
(asexual)

MEDUSA
(sexual)

AFTER
DISCHARGE

Fig. 26. The alternation of generations of a typical hydrozoayi coelenterate is shown
on the left. The asextial polyp and sexual medusa exhibit the same general hody plan
except that the medusa is greatly shortened, inverted, and has much more jelly than
the polyp. Coelenterate nematocysts, on the right, fire a poisonoiis thread into prey or
enemies on contact.

skeleton). These are among the most common of seashore animals, but they
usually go unnoticed because of their small size. Among the many genera of
small hydroids is Ohelia, which shows, among its branches, two kinds of polyp
animals, a feeding one with tentacles and a reproductive one which produces
the sexual medusas by budding. At some times of year these little hydroid
medusas are very plentiful.

There are many species of small hydroids like Ohelia. One of these is
Hydractinia, which is commonly found on the shells of hermit crabs (fig. 38^,
a case of mutualism in which the crab receives protection from enemies because
of the presence of the stinging hydroid tentacles and Hydractinia gets free
transportation. Most hydroids are too small to sting man, but a few have very
large nematocysts which are painful to touch. Phillips and Brady (1953)
list Lytocarpus of the eastern coast of Florida and southward as one of these.
This is a small colonial species like Ohelia and grows on rocks and pilings
among seaweeds. Treatment for the sting consists of thorough washing with
soap, followed by application of ammonia or calamine lotion to soothe the burn.

Tuhularia, of temperate waters, is a beautiful reddish-pink hydroid that grows
unbranched out of a mat and reaches a height of almost 6 inches. The most
common small hydroid of the West Indies is Pennaria Cfig. 29), which looks
like a small Christmas tree. Not all hydroids are small, however. One gigantic,
noncolonial polyp, Branchiocerianthiis, reaches 6 feet in length and lives in the
ocean depths.

The stinging coral, or fire coral, Millepora Qfig. 28 and fig. 144^, is not a true
coral, but is a hydrozoan related to hydroids. It grows in a great variety of
forms— branching, erect and bladelike, massive, or encrusting (often on sea fans).
They have dense, limy skeletons with very small pores through which the polyps
project. Stinging corals are major contributors to the formation of reefs in all
tropical seas. The sting of the West Indian species is only moderately painful
and the effects usually wear off in a few hours. Indo-Pacific fire coral can
produce more painful stings.

96

UNDERWATER GUIDE TO MARINE LIFE

HYDROZOAN JELLYFISH
GonionemiJ-S - ■§■ in.

STAR CORAL
As4ran<^.a-3,n.

SETA FETATMLR
liPennatula- fo i.

Fig. 27. Polyps and medusas. Adapted from Mayer (7970) and drawn from life.
See Color Plate 10.

THE INVERTEBRATE LEGIONS

97

Trachyline hydrozoans are all medusas and look like true jellyfish. (One
species, Geryonia, is shown in Color Plate 10.) They have no polyp stage,
contrary to most hydrozoans, and are small to moderate in size, not reaching more
than 4 inches across the bell. They may be distinguished from true jellyfish by
the presence of a shelf called the "velum," projecting inward from the lower
bell margin Cfigs- 26 and 27).

Fig. 28. Stinging coral, Millepora, takes on a number of forms including that of
these foot-high hlades, hut it is most easily recognized hy its mustard-yellow color and
knohhy textiire. In the background is a large hush gorgonian.

98

UNDERWATER GUIDE TO MARINE LIFE

Fig. 29. Top. Pennaria, a form of colonial hydrozoan, is only an inch high and looks
like a Christmas tree. Each of the white knobs is the head of a single animal. The
tentacles are too slender to he seen. Bottom. Sea whip gorgonians, unlike most
anthozoans, "bloom" by day to capture their planktonic food. Each animal is barely
one-fourth of an inch in diameter.

THE INVERTEBRATE LEGIONS 99

The last of the hydrozoan groups is that of the Portuguese man-of-war, order
Siphonophora. These are not single animals as is commonly supposed, but are
floating colonies consisting of several kinds of medusas and polyps living together.
One medusa forms the bell or float of the colony. Other medusas form swimming
bells, which move the colony through the water. The polyp members of the
community contribute the feeding individuals, tasting or feeling individuals,
stinging individuals with nematocysts, and reproductive individuals. Thus, a
siphonophore is actually a complex colony of manv kinds of individuals all
specialized for diff^erent functions. Not all kinds of individuals may be present
in a colony. For instance, the Portuguese man-of-war, Physalia QColor Plate 10^,
lacks medusoid swimming bells and depends solely on the wind for distribution.

All of these colonial siphonophores are pelagic. Most are small and delicate,
but the purple sail, Velella, and the Portuguese man-of-war are rather large.
Of these, the latter is famous for the power of its large nematocysts. Bad stings
can cause cramps, nausea, difficulty in breathing, or, very rarely, death. One of
the authors received the stings of only two nematocysts in his heel. In very
short time, the poison had traveled to the region of the groin, making walking
painful. Bad stings should receive immediate medical attention. The man-of-war
reaches a size of a foot across the float and with tentacles over 30 feet long.
It is thus able to catch a fish the size of a mackerel.

True Jellyfishes: Class Scyphozoa — Figure 27

This is a rather small, compact group of only two hundred species. No true
jellyfish has a velum as do the hydrozoan jellyfishes. Most have polyp generations
of small size, which produce medusas by a type of budding (strobilation) during
the warm months. 1 hese are the common, large medusas and are found in all
seas, particularly those of temperate and cold zones. They are common objects
cast up on beaches. (A typical species, Pelagia, is shown in Color Plate 10.)

The true jellyfish common in warm or tropical seas are the cubomedusans,
which are named for the high, squarish or cuboidal shape of the bell. At each
corner of the bell is a single tentacle or group of tentacles. Caryhdea is a common
example. It is an inshore jellyfish, a strong swimmer, a fish-eater mainlv, and has
a strong sting. Most cubomedusans are only 1 to 2 inches across, but some reach
10 inches. Their sting has given them the name of "sea wasps."

The discomedusans are the typical jellyfishes which are most common in
temperate and cold waters. They have round, hemispherical bells and are the
largest of all coelenterates. One species, the lion's-mane jellyfish, Cyanea, reaches
a diameter of 8 feet or more with tentacles 200 feet long. Huge shoals of this
animal are common in arctic or boreal seas, but, luckily, large ones do not range
far south. They possess a dangerous sting because of their large size. The blue
jellyfish, Aiirelia, is the most common jellyfish of the Atlantic and Pacific. This
genus reaches a foot across the bell and can produce an irritating sting. Pelagia
and Dactylometra, the speckled jellyfish, are two very beautiful and delicate
discomedusans of temperate to tropical waters. Both can produce painful stings.
The former is only a couple of inches across, but the latter reaches up to a foot
in width.

The rhizostomes are jellyfishes without tentacles and are common in shallow

100 UNDERWATER GUIDE TO MARINE LIFE

tropical waters. One in particular, Cassiopeia, is common in the West Indies.
It has no true single mouth and cannot sting, but it possesses a much-divided
and lobed digestive system which contains symbiotic algae. This jellyfish is often
seen lying lazily upside down in shallow water, exposing the algae to sunlight.
The algae, therefore, produce some of the food for this jellyfish by photo-
synthesis. All rhizostomes have the many-lobed digestive system like Cassiofeia,
but most have no algae in them and therefore must live by catching plankton
or small fishes.

The young of many fishes use jellyfishes for protection, escaping the tentacles
by alertness. Sometimes, however, they fall prey to their jellyfish protectors.

Gorgonians, Anemones, and Corals: Class Anthozoa — Figure 27

There is no medusa stage at all in this group. Instead, the polyp has become
complex and either secretes a home around itself and is colonial or is large in size
and solitary. There are over six thousand species of anthozoans found in all seas,
but they are far more common and larger in tropical seas than elsewhere. The
colors found in this group are often very beautiful and caused partially by
pigment and partially by the presence of organisms, zooxanthellae and zoo-
chlorellae, that live in the tissues of the polyp. Hard corals are most often
brownish, but they may be green, blue, or, in the case of the Mediterranean
precious coral. Cor allium, a gorgeous red. The sea pen is red and phosphorescent.
Gorgonians are brownish. The browns, yellows, and greens are the colors caused
by symbiotic animals and plants. Most coral skeletons are white like coral sand.

All of the members of this group are carnivorous, but the size of the prey
varies greatly, and in many, the oxygen supply is augmented by the presence
of zoochlorellae or zooxanthellae. The small, colonial anthozoans eat planktonic
food, and the largest polyps, the anemones, catch fish or whatever else they
can trap in their stinging tentacles. All are sedentary, though anemones can
creep very slowly on their bases, and must wait for food to come their way.
They either feed by passively filtering sea water or by attracting fishes with their
flowerlike body form and colors. Some anemones even have little fishes living
symbiotically in the protection of their tentacles, and these may serve to attract
other fishes near enough to be caught. In any case, food is not acquired
actively by the tentacles as in the case of the octopus. A fish must bump into
a tentacle through its own carelessness to be captured.

Many of the anthozoans, notably the corals, are nocturnal. With the coming
of dusk, the coral colony blooms as thousands of tiny polyps emerge from their
calcareous homes. This seems to be somewhat a contradiction of the fact that
light is needed by the zooxanthellae that produce oxygen for the coral, but
enough light is probably able to reach the retracted polyp to allow photosynthesis
to occur.

Very few members of this group possess nematocysts large enough to do
damage to humans. Only one large anemone of the Indo-Pacific is really
dangerous. Others may produce a barely perceptible burning when touched.
Corals, however, may inflict cuts that are slow to heal and become easily infected.
This is known as "coral poisoning" and is not very prevalent in North America.
Ergophine ointment is said to be of use in alleviating the irritation of coral cuts.

THE INVERTEBRATE LEGIONS

101

Fig. 30. Top. Sea fans, Gorgonia, over a foot in diameter, often anchor to feden-
cidate coral in fairly calm water. Several small corals may he seen to the left, includ-
ing a hliie coral Qtof left^. Bottom. Eusmilia is one of the most heautiful corals. The
colony is not large, hut each coral polyp is of good size, up to three-fourths of an inch
in diameter.

102

UNDERWATER GUIDE TO MARINE LIFE

Among the several groups of non-stony corals, the gorgonians are the most
prominent. These are the bushy sea whips C/igs. 28, 29, 97 , 144^ and sea plumes
C/xgs. 97, J48) and sea fans Gorgonia Qfig. 30~). Sea whips and sea plumes have
a resilient skeleton composed almost entirely of a horny material called
"gorgonin" and because of their toughness often form dense beds in places
where wave action would break stiff, stony corals. The beautiful iridescent,
purplish sea fans add a considerable amount of lime to the skeleton. Being less
.resihent, they more often grow attached to stony corals in calmer waters. The
precious red coral, Coralliiim, of the Mediterranean is a member of this group
whose skeleton is composed almost entirely of lime of a bright red color.

Fig. 3]. Top. Brain coral, Meandra. Female hlue-head wrasse often cluster around
the tops of large corals like this very large and almost perfectly symmetrical specimen.
Bottom. Staghorn coral, Acropora cervicornis, forms extensive thickets where m.any
fishes make their homes.

THE INVERTEBRATE LEGIONS 103

Gorgonians are secondary reef builders and are largely tropical in distribution.
Several animals live in their bushy branches. Among these are the basket star,
Gorgoncephahis, hydroids, oysters, and some others.

Dead man's fingers, Alcyonium, is representative of a group of anthozoans
called "soft corals." It is usuallv found in rather deep water, but it reaches up
to the low-tide mark. It has a flabby, mushroomlike texture supported by
calcareous spicules. Soft corals vary in shape from squat, spongy masses to erect,
treelike, branching forms and are found in all seas, but they tend to keep to
fairly deep water.

The pennatulaceans include the very beautiful sea pansies, ReniUa, and sea
feathers, Pennatula. Both of these have a long single polyp that forms the axis
of the colony and which serves to anchor the colony in soft substratum. This
axis can move the colony slowly or withdraw the colony into the bottom when
it is disturbed. These are the most active of the anthozoans. On both sides
of the axis, there are extensions that carry the small feeding polyps. Most species
are beautiful shades of yellow, red, or purple and inhabit shallow, tropical, and
subtropical waters of all seas. Many of them are luminescent and will give off
light when disturbed.

The anemones form a fairly compact group of anthozoans. They are devoid
of a skeleton and are noncolonial and flowerlike. Their distribution is world-wide
in all seas, and they are almost always found attached to hard, rocky, or coral
reef bottoms, where they sit waiting for prey to blunder into their tentacles.
The size range is from less than an inch to 2 feet in diameter. Anemones usually
avoid bright light and can move slowly on their bases more or less like a snail.
They like to attach themselves in crevices, with only the tentacles exposed. Their
colors are often extremely beautiful, ranging from bright green to white or dark
brown with delicate blues and reds. Anemones are able to contract greatly
in size, and when they do so the tentacles are drawn inside, which makes them
difficult to spot. (The common West Indian anemone is shown in a color
photogra'ph.^ Metridiuin is the most common temperate Atlantic species. The
west coast green anemone, Crihina, owes its color to the presence of zoochlorel-
lae. Adainsia (/tg. 38) is a remarkable anemone that lives in a mutualistic
relationship on the shells of hermit crabs, giving the crab protection by means
of its nematocysts and even patching holes in the shell the crab occupies
(Hyman, 1940). The anemone benefits by receiving food and transportation.
Several other anemones live in similar mutualistic svmbiosis with crabs.

The true or madreporite corals are like small anemones but are colonial and
secrete calcium carbonate (lime) around their bodies for protection. (Their
environmental requirements are discussed in Ghapter 2 under coral reefs.)
Gorals are found north to temperate waters, but form reefs only in the tropics.
Star coral, Astrangia, is one that is found north to Cape God. Gorals show a
great variety in form. Some are small like star coral, some are massive like several
kinds of stone coral Qcolor photograph'), and the brain coral, Meandra Qfig. 31
and color photograph), some are stump-shaped like pedunculate corals Cf^g.
30), and some are branching like the staghorn coral, Acropora cervicornis
Cfig- 31), or the antler coral, Acropora palmata Ccolor photograph). There are
many species of small decorative corals. One is Eusmilia (fig. 30), an extremely
beautiful coral, which has large polyps even though the colonies are quite small.

104

UNDERWATER GUIDE TO MARINE LIFE

Fig. 32. Comb jellies. Adapted from Mayer (I9i2).

On the West Coast is found the sohtary coral Balenofhylla, which reaches a
half-inch in diameter.

COMB JELLIES: Phylum Gtenophora {"comb-bearer")— Figure 32

There are only a few species of these exceedingly beautiful animals, but
these often occur in tremendous numbers and are common in all seas. Their
transparent bodies shimmer with delicate colors of glassy, iridescent beauty
and bear eight comblike rows of cilia which move the animal through the water
and have given these animals their name.

Ctenophores are exclusively pelagic, predatory animals. They catch planktonic
prey or small fish by means of two long retractile tentacles that extend from
the sides of the body and which bear sticky "lasso cells." Some have no tentacles
and filter plankton from the sea.

Almost all the species have very wide distribution. The little sea gooseberry,
Pleurohranchia, is found in all the seas of the world. The sea walnut, Mnemiop-
sis, is like the sea gooseberry, but it is larger and is luminescent. If a boat is
driven through a swarm of them, the disturbance causes each one to emit a
bright, sudden flash of light. The Venus girdle, CesUis, is very different from
these, being elongate and like a ribbon. It reaches a length of 3 feet occasionally
but is usually seen much smaller.

FLATWORMS: Phylum Platyhelminthes— F/^wr^ 33

Flatworms are not common or prominent in the sea, but are very well known
as parasites— the flukes and tapeworms. One group of small flukes, the schisto-
somes or blood flukes, has a larva that normally infects sea birds. It is also able
to burrow partially into human skin, where it forms an extremely itchy swelling
known as "swimmer's itch" or "seabather's eruption." These larvae die soon
after entering the swimmer's skin, so do not produce parasitic infection in man.
Phillips and Brady (1953) suggest immediate fresh-water bathing plus applica-
tion of dilute ammonia or antihistamines for relief of the itching.

Not all flatworms are parasitic. The turbellarians are flattened, frequently
leaflike worms that creep about among plants or over the bodies of marine
animals such as crustaceans. They possess amazing powers of regeneration. If the
head of a turbellarian is cut off, the headless body grows a new head, and

THE INVERTEBRATE LEGIONS

105

the bodyless head grows a new body— result: two worms. If the head is cut
longitudinally in two the result is the regeneration of two heads.

Almost all free-living flatworms have two eyes on the head which are turned in,
making the animal appear cross-eyed. These eyes do not form an image, but
inform the worm of the presence of light or dark. In general, flatworms avoid
light. They feed on organic matter of all sorts, which they locate by means of
chemical reception. Flatworms either glide on their bellies by means of cilia or
swim by body undulations.

The acoel flatworms have no digestive system and range up to a half-inch
in length. The red Polychoerus is found in the tidal zones of both coasts.
Convohita is a green acoel that derives its color from zoochlorellae in its body.
This animal may feed when young, but when it becomes adult, it lives entirely
by digesting the zoochlorellae, which results in the death of the worm, an
example of poorly balanced mutualism (Buchsbaum, 1948).

Rhabdocoel flatworms have a straight intestine and are very common on
muddy and sandy shores or seaweeds. The triclads have three-branched intestines,
are of dark color, and are most common on stony bottoms of northern seas. Both
rhabdocoels and triclads rarely reach a half-inch in length. Bdelloura is a triclad
common on the gills of the king crab, Lhnidus.

The polvclads have many-branched intestines and reach a length of a half-foot
or more. The tropical ones are frequently very beautiful, matching their sur-
roundings in color. Some polyclads are pelagic. They swim by means of wavelike
motions of the sides of the body.

All of the flatworm groups mentioned show tendencies toward commensalism,
suggesting that the parasitism so common in other flatworm groups, such as
flukes and tapeworms, evolved first from commensalism. The end product of
parasitism is often mutualism which, however, is not present in flukes and
tapeworms.

proboscis wi+k s+yle+

V

SCHISTOSOME LARVA

POLYCLAD
Pie ucloceros-tii.

Rhabdocoel triclad

Plo-qios-fortiarn-rrii Bdelloui-a --t in

ARROW WORM PHORONID
^a<)i + U- Jj-.n Phoroni5-^i-i

Fig. 33. Unsegmented wonns. Adapted from several authors and drawn from
life.

106 UNDERWATER GUIDE TO MARINE LIFE

RIBBON WORMS: Phylum Nemertea— F/^wr^ 33

These are the lowest members of the animal kingdom to have a circulatory
system through which blood flows and a digestive system with a separate mouth
and anus. Both of these characters are of immense importance, allowing animals
to be more independent in their environment. The presence of blood, by which
food and oxygen are distributed throughout the body, and an anus, which frees
the mouth of the task of egesting undigested food, gives greater freedom of
action to an animal by increasing general body efficiency.

The seas contain 550 species of nemerteans, which range from an inch to
100 feet long. The long ones, however, are not much thicker than a piece of
ordinary string. On the head end is a sheath bearing a long noselike proboscis.
At the tip of the proboscis a sharp stylet which resembles the nematocysts of
jellyfishes is usually present. The proboscis is shot out at prey hke an entangling
lasso, and those nemerteans which have a stylet use it to poison the prey.
Worms, fishes, or crustaceans may be captured and are swallowed whole. The
proboscis may also be used for defense and for burrowing.

Nemerteans are found all over the world from the arctic to tropic seas. The
largest in North America is the flesh-colored Cerehratulns of the temperate east
coast. It reaches a length of 20 feet and burrows in sandy or muddy shores by
day, but it may swim about at night near the bottom. It is very common and is
often dug up by clam diggers. Other nemerteans are as numerous as Cerehra-
ttihis, and some are very beautifully colored with bright red or green stripes and
bars. A few species are pelagic.

ARROW WORMS: Phylum Chaetognatha
("bristle- jawed") — Figure 33

These are swift-swimming, predatory, planktonic worms which reach the small
size of only about % of an inch and are extremely common in cold temperate
and arctic waters. They capture small planktonic animals in their bristly,
hooked jaws. There are about thirty-five species. Sagitta is the most common
genus. Their evolutionary position is not known.

ROTIFERS: Phylum Rotifera ("wheel-bearer")— Figure 34

These little animals are extremely interesting to watch, but unfortunately a
microscope is needed since their size is about that of a large protozoan. Some
rotifers have the most extraordinary shapes and are very common attached to
objects in shallow water. Some are pelagic.

MOSS ANIMALS: Phylum Bryozoa ("moss animal")— Figure 34

Some of these little plantlike animals are so similar to the hydroid coelen-
terates that the two groups can only be distinguished by an expert with a
microscope. As their name implies, they look mossy. They are colonial. Some
are erect and branching, and others are flat and encrusting in form. All are
enclosed in an external skeleton, which gix'es the colony support and may be

THE INVERTEBRATE LEGIONS

107

ROT ITER
Qrea+ly enlarged

Bird's hcad bkyozoam

8u.<^u.la.- 2. in

ENCRUSTING BRYOZOflN
£Q.ch OLniroal - li^ in.

Ffg. 34. Rotifer and hryozoans. Adapted from several authors.

either hornv and flexible or heavily calcified and stiff. Bryozoans feed by filter-
ing plankton out of sea water by means of a crown of tentacles called a
"lophophore."

The bird's head bryozoan, Biigula, is a common and very widespread form
found in most waters of the world. It looks like a small brownish tuft of moss,
is 2 to 3 inches high, and grows anchored to almost any hard bottom in shallow
water. Some individuals of the colony are reduced in size and look very much
like the head and beak of a bird. These are called "avicularia" and constantly
move from side to side snapping at any object that lands on the colony, keeping
the colony free of foreign matter. Living BuguJa seen under a microscope show
these amusing little individuals very well.

An amazing habit of manv moss animals is the formation of the brown bodv.
Periodically, the tentacles and anterior digestive system of a single animal
degenerate into a brown clump which is ejected through the anus. Then a new
set of internal organs is regenerated. No reason for this is known. The brvozoa
lack a circulatorv svstem, and their evolutionary position in the animal kingdom
is not known.

PHORONID WORMS: Phylum Phoronida— F/^wr^ 33

The genus Phoronis with a very few species comprises almost all of this
phylum. These worms are small, usually about a half-inch in length, and are
like moss animals in habits and appearance except that they are adapted to live
in straight tubes in shallow mud or sand flats rather than attached to hard
substrate. Also, they are not colonial, although they are frequently found grouped
together. They have a tentacle tuft (lophophore) and filter plankton from sea
water as do moss animals. While they are not common on the east coast, thev
are fairly abundant on the west coast.

SEGMENTED WORMS: Phylum Annelida

The worms whose bodies are divided into segments are called "annelida"
which means "ringed." In some of these worms, like the sandworm. Nereis,
the rings, or segments, are obvious, but in others they are less so. This is a
huge group of several thousands of species. Segmented worms are evolutionarilv

108

UNDERWATER GUIDE TO MARINE LIFE

very important as the group which gave rise to the arthropods, the largest of all
phyla, which include insects and crustaceans.

This phylum is divided into three major classes— earthworms, leeches, and
marine worms. Only the last of these will concern us, the marine worms or
Polychaeta. Two other small classes, the echiurids and sipunculids, are tacked
onto this phylum because they seem to have been derived from segmented worms.

In habits, this group varies greatly, from errant (wandering), predaceous
worms to tube-dwelling, sessile plankton-feeding types, but the important thing
about segmented worms is that they have a well-developed nervous system and
a segmented muscular system so that rather refined movements are possible.
This is an important advance over the nonsegmented animals that we have
dealt with so far.

Sexaal +a.il

PALOLO WORM
Eu„,ce- 10 in.

lft+rover+ «&, BUDDING, SEKUAL WORM

Syllis-ea.ch

PARCHMEMT WORM

BRISTLE WORM
Hermoc(ice-U+.

Fig. 35. Segmented worms. Adapted from the Reports of H.M.S. Challenger

Cl 873-76^ and drawn from. life.

Marine Worms: Class Polychaeta — Figure 35

The marine worms are obviously segmented, and most of them are provided
with appendages on each segment called "parapodia," which bear bristles.
Parapodia represent the initial effort made by invertebrates to develop limbs.
They function as limbs, as gills, or in food-getting.

THE INVERTEBRATE LEGIONS 109

The species of this class are extremely common in all seas. They may be
rather neatly divided into three groups on the basis of habits— errant or wander-
ing species, burrowing species, and tube-dwelling species.

1. Errant Polvchaetes. These marine worms are the most common. They are
the most active worms and are armed with a jaw-bearing pharynx which
can extend and retract for the capture of living prey. Some of them can
swim, but most are found secreted under stones, among weeds, and other-
wise hidden from their many enemies which relish their soft bodies for
food. The breeding habits of some errant polychaetes are amazing. Most
famous is the palolo worm, Eunice, one species of which is found in the
South Pacific and another in the West Indies. During the last quarter
of the October-November moon in the South Pacific or the third quarter
of the June-July moon in the West Indies, the bottom-living palolo
breaks off its tail (Borradaile and Potts, 1935). The tail, ripe with either
eggs or sperm, then swims to the surface of the water, where thick swarms
of these reproductive tail ends occur. When eggs or sperm are released,
the tail, now an empty bag, dies and sinks to the bottom. Meanwhile, the
original head end of the worm on the bottom regenerates a new tail which
becomes reproductively ripe the following year.

Swarming of breeding individuals at the water's surface is common in
errant polychaetes. It insures fertilization of a maximum number of eggs
since many worms are grouped closely together. Some swarming worms emit
a light so that the females and males can more easily find each other. Others
have the remarkable ability to bud off new individuals from the posterior
end of the bodv- Each of these individuals can breed but cannot feed since
it has no mouth parts. Sometimes a long chain of budding worms may be
found at the water's surface during the breeding season. Two of these
budding types are Syllis and Autolytus, both of wide distribution and
growing about an inch in length.

The sandworm. Nereis, is perhaps the most familiar of errant polvchaetes.
There are great numbers of worms found the world over that look like
this worm. Some are well over a foot in length, and the larger ones can
give a painful bite with their strong jaws.

The sea mouse. Aphrodite, is a mud-dwelling, stout-bodied, very beautiful
species with long, silky, iridescerit bristles. It reaches 4 inches in length. The
scale worm, Lefidonotus, reaches 2 inches and is common under stones
near shore. These are both stout worms of wide distribution which stay
near the bottom.

One family of errant polychaetes deserves special mention because of
the stinging powers of its bristles. This is the Amphinomidae, or the silky
bristle worms. There are several species, all of which have long, detachable
bristles that easily penetrate skin and cause a burning sensation. These
bristles are hard to remove. Phillips and Brady (1953) suggest removing
the bristles with adhesive tape. The most common bristle worm is Henno-
dice of tropical waters. It often reaches a foot in length and is warningly
colored with red marks on the sides. The white bristles tipped with

110

UNDERWATER GUIDE TO MARINE LIFE

Fig. 36. Tof. The arrow crab, Stenorhynchus, three inches long and named for its
long nose, moves slowly and depends on its concealing shape for protection. Bottom.
These strange mounds, over a foot in diameter, failed to reveal their builders when
the authors dug into them. They are probably biiilt by burrowing polychaete
worms.

red are erected when the worm is annoyed. Eiirythoe is a west coast
bristle worm of pink color and snow-white bristles.
2. Burrowing Polychaetes. These worms have reduced parapodia and head
and frequently look very much like earthworms. Most of these worms

THE INVERTEBRATE LEGIONS 111

travel in soft or loose bottom. The lugworm, Arenicola, is common in
temperate seas and reaches about a half-foot or more in length.
3. Tube-dwelling Polychaetes. The beautiful fan worms of the family
Sabellidae, plankton-feeding worms with a delicate crown of plumes at
the head end CcoJor photooraph^, belong to this group. They are found
in all seas but are largest in the tropics, where their flowerlike tentacles
are often seen protruding from tubes in massive corals. When disturbed,
they quicklv retract into their tubes.

The tubes, which are secreted by these worms, may be hard and calcified,
as they usuallv are when in exposed places, but some of these worms
live in U-shaped, parchmentlike tubes in soft bottoms. One of these is the
parchment worm, Chaetopterns, of temperate seas. It is among the most
luminescent of animals and is extremelv delicate. It circulates water through
its tube bv flapping delicate appendages in order to filter-feed on plankton.

Sipunculids: Class Sipunciilida — Figure 35

These are large, sand- or mud-dwelling, burrowing worms of most seas. There
is no segmentation to the muscular body. Thev live- in burrows and have at
the head end a retractile, tentacle-bearing, muscular "introvert" with which
they grasp and swallow mud and sand. Thev are, therefore, much like earth-
worms in habits.

Echiurids: Class Echiurida — Figure 35

These worms are very much like sipunculids, but instead of an introvert, they
have a trunklike extension for feeding. Echmrius is a stout-bodied species which
lives in a U-shaped tube in mud.

The larvae of the European echiurid, BoiielUa, have an unusual method of
establishing which sex they will be. The larvae are free-swimming. If they land
on the trunk of an adult female, they develop into small, parasitic males on
that female. If they do not land on a female, they grow into solitary females.

The trunk of echiurids serves both for locomotion and for food-getting.
Some species live in soft bottoms and some in clefts in rock, and they frequently
move from place to place, not staying in one cleft or tube. They do not eat
sand or mud, as do sipunculids, but eat animal and plant matter, probably
mostly debris.

ARTHROPODS: Phylum Arthropoda ("joint-legged")

Four-fifths of all species of animals on earth are arthropods (insects, crusta-
ceans, spiders, etc.). They literally abound everywhere, in every imaginable
habitat, occupying more different kinds of habitats than any other phylum. For
these reasons, arthropods are undoubtedly the most successful animals on earth.

Arthropods are named for their many-jointed appendages. In the primitive
species, there is a pair of appendages present on every segment of the body,
but in the advanced species, these appendages look very different in different
parts of the body, being modified into antennas, various mouth parts such as

112 UNDERWATER GUIDE TO MARINE LIFE

mandibles, maxillae, or maxillipeds, claw-bearing "arms," walking legs, swim-
merets, and tail "fins" on the abdomen. It is the character and number of the
appendages that form the basis of classification of arthropods.

The skeleton of arthropods is well developed and typically formed of a
complex substance called "chitin," which sometimes is strongly calcified (crabs
and lobsters).

Unlike the skeletons of vertebrates, however, the skeleton of arthropods
covers the body rather than forming an internal structure. Also unlike vertebrate
skeletons, the external skeleton does not grow but must be periodically shed as
the animal grows inside, the new skeleton always being a little larger than
the old.

The nervous system and the eyes of arthropods are well developed, allowing
interesting and complex behavior. The eyes are compound, that is, are composed
of several individual small eyes grouped together yet acting as a unit. They are
especially well suited for detecting movement since an object produces an
image first on one facet of the eye, then another in succession as it moves
across the field of vision.

For the first time in the review of invertebrate phyla, a separate respiratory
system is present. This may take several forms— either gills, book "lungs," or
tubelike tracheids— but whatever the form, it allows a more efficient respiration
than that of previous phyla, which picked up their oxygen through absorption
through the surface of the animal. This advance, in turn, allows larger size,
higher metabolism, and increased activity.

For all these reasons the arthropods are well-protected, active animals which
have complex behavior. The crustaceans form the most numerous group of
arthropods in the sea.

Crustaceans: Class Crustacea— Figures 37 and 38

All crustaceans have three rather definite parts of the body— head, thorax or
trunk, and abdomen. Sometimes the head and thorax are united into a single
unit, as they are in crabs and lobsters, and covered by a single "shell" called
the "carapace." Crustaceans have a larval stage called a "nauplius" Qfig. 3i7^,
which is common in plankton and is often an extremely bizarre little animal.
It is by means of larvae that many crustaceans are distributed through the seas.

The primitive crustaceans are filter-feeders which sift plankton from sea water.
More advanced species are carnivores or scavengers. In fact, the crabs and lobsters
are the vultures of the sea, eating literally any organic material, living or dead,
that they can lay a claw on.

Some crustaceans have good powers of defense in their very strong claws.
Others are protectively colored or shaped to mimic rocks or seaweeds. Still others
can change color so as to match the lightness or darkness of the bottom. Many
of the highly developed crustaceans have a remarkable defense involving
intentional loss of a limb or autotomy. If a limb is seized bv an enemv, the
crustacean snaps it off, then retreats, later growing another limb.

This class occupies a vital place in the economy of the sea. Many of its
species form the major food source of m.any animals. Notable among the many
examples is the dependence of the baleen whales on the Euphausian decapods

THE INVERTEBRATE LEGIONS

IB

called "krill." Man, when he speaks of possible future food from the sea in
terms of "plankton cakes," usually means the small planktonic crustaceans which
are extremely abundant in polar and boreal seas in the warm months.
The several groups of crustaceans are briefly reviewed below.

WATER FLEAS: Order Cladocera

Water fleas are enclosed in a large, round, bivalve carapace, which does not,
however, cover the head, and have two large antennas which are organs of
locomotion. Daphnia is a fresh-water form commonly sold in pet shops as a
living fish food. Some water fleas are verv oddly shaped, and all are small,
scarcely the size of the head of a pin. Their distribution is world-wide. They
are planktonic, very numerous, and an important food for plankton-eating fishes.

OSTRACODS: Order Ostracoda

Like water fleas, ostracods are planktonic, small, swim with the antennas,
and are enclosed in a bivalve shell. But ostracods look just like little swimming
clams. The study of ostracods is especially important to oil prospectors because
certain fossil ostracods are found associated with oil deposits.

NAUPLIUS LJ\RVA

MENTIS SHRIMP

1

Scjuilla-l-ol ft.

SHORe SLATER

u,,,.- 1 ,„.

Fig. 37. Lower crustaceans. Adapted from various authors including the Reports of
H.M.S. Challenger Ql 873-7 6') and drawn from life.

114

UNDERWATER GUIDE TO MARINE LIFE

SNAPPING SHRIMP

Cro-nqon- i m

PELAGIC SHRIMP
Lencifer - 4- ■".

PHYLLOJQIvifl LARVft

. SPINY LOBSTER

Pig. 38. Advanced crustaceans. Adapted from the Reports of H.M.S. Challenger
Ql 873-76") and drawn from life.

REV SNAPPER

MARGATE SRUMT \. 1 "^^-^^^

COLOR PLATE %

YELUOWTAIL DEMOISELLE

REEF FISH

BAN O EP
BUTTERFLY FISH

FOUR- EYED
BUTTERFLY FISH

COLOR PLATE 6

THE INVERTEBRATE LEGIONS 115

COPEPODS: Order Copepoda

This is the third and last of the small, planktonic crustacean groups. Again,
movement is accomplished by means of two large antennas. Usually there is
a single large eye in the center of the head, which has given one fresh-water
form the name of Cyclops, after the Homeric giant. The body is usuallv pear-
shaped, and the females are often seen carrving two little sacs of eggs attached
to their abdomens. Calaniis is one especiallv abundant, cosmopolitan copepod
which is eaten by fishes and baleen whales. Some copepods are parasitic
(fish lice).

BARNACLES: Order Cirripedia

Barnacles have been described as crustaceans that lie on their backs surrounded
by a shell, kicking food into their mouths with their feet. These "feet" are
actually long appendages that form a sievelike net for the trapping of plankton
as thev are rapidly thrust in and out of the shell in a grasping motion. Barnacles
are the only sessile crustaceans and are hermaphroditic (both sexes in one
animal). Hermaphroditism is present in many sessile animals, doubling the num-
ber of voung produced as the result of one copulation. Sessile animals must
produce high numbers of voung at a breeding because they can not move from
place to place and are thus restricted in acquiring mates. In the case of barnacles
the usefulness of hermaphroditism is particularly well illustrated. Unlike many
sessile animals which merely shed their eggs and sperm into the sea, barnacles
have internal fertilization in which the very long penis of one barnacle deposits
sperm directly in the body of a neighboring barnacle. But the barnacle is
limited in its mating by the length of the penis, and isolated barnacles out of
reach of other barnacles can not mate, although it is possible that these indi-
viduals fertilize themselves. The barnacle thus compensates for being sessile by
doubling up, each individual being both fertilizer and fertilized, with twice
the number of larvae being produced.

The goose barnacles, Lepas, attach themselves to substratum by means of a
long, muscular stalk. Goose barnacles most often attach to floating objects in
the sea, the bottom of ships or to seaweeds. One species attaches to jellyfishes.
The acorn barnacle, Balanus, is an extremely common animal of the tidal zones
of all oceans.

Barnacles frequently attach to living animals such as molluscs, crabs, or
lobsters, and one barnacle, the whale barnacle, lives exclusively on whales.
Barnacles do not harm the animals on which they attach except by slightly
hindering movement, but some specialized barnacles have become parasitic.
The most remarkable of these is SacctiUna (^g. 37^, a parasite on crabs. The
Sacczdina lar\'a bores through the shell of a crab and pours its cells into the
blood of the crab. These cells conglomerate on the underside of the intestine,
and then the whole cell mass grows into a rootlike system which permeates the
crab's whole body. The part of the Sacculina containing the reproductive organs
protrudes from the underside of the crab's abdomen. SacciiUna lives on the body
of the crab, but it does not kill the crab, only causing parasitic castration.
Eventually, the Sacculina drops off, and the crab regenerates its sex organs.

116 UNDERWATER GUIDE TO MARINE LIFE

MALACOSTRACANS: Order Malacostraca

The rest of the crustaceans, including crabs, lobsters, sand fleas, shrimp,
prawns and others, are included here. In all of them, the appendages on difi^er-
ent parts of the body are sharply marked off from each other. The largest
appendages are those of the trunk, which are used for locomotion and food-
getting and very often bear claws. There are almost always stalked eyes on
the head. A carapace covers the head and at least part of the trunk.

All members of this group may be referred in general body plan to a
central type, that of the shrimp or prawn, in which the body is adapted mainly
for swimming. The species that depart from this general body plan do so as a
result of a change of habits to burrowing or crawling, which causes a modification
of the limbs on which heavy claws may be developed.

ISJehalia, a little crustacean common all over the world on shallow rocky or
weedy shores (especially near foul water), is the most primitive of this group.
It reaches only a half-inch in length.

The amphipods are elongated and compressed little crustaceans without a
true carapace. These are the beach fleas or sand fleas, and there are great num-
bers of them found literally all over the world, living either semiterrestrially on
moist beaches or in shallow water. Gammarus is one common genus. The
amphipods can swim, walk, and jump. They rarely reach an inch in length,
but sometimes they grow larger. The coloration of amphipods often matches
that of their background. Except for their movement, they are often difficult to
see. Amphipods form a major item of diet for many fishes. One interesting
amphipod, the skeleton shrimp, CapreUa, is about a half-inch long and is often
seen clinging to seaweeds, especially AgardhieUa, or other suitable substrate
by means of its small, posteriorly placed legs. It captures small prey with clawed
legs near the mouth in a comical-looking, lurching motion of the whole body.
Its acrobatics as it clambers over seaweeds are very amusing to watch.

The isopods are small crustaceans that are depressed in body form. The
terrestrial sow bugs and pill bugs are examples. Isopods are found on land,
in fresh water, over almost all of the sea, and are even sometimes parasitic.
Therefore, they qualify as the most widespread of all crustacean groups. Most
species are small and found creeping over rocks, in seaweed, or over sand.

The mantis shrimps, Squilla, are similar to isopods in being flattened, but
they live in burrows in soft bottoms and bear large, raptorial claws, like those
of the insect praying mantis, with which they capture prey. Some mantis
shrimp reach the large size of almost a foot, but most species are under a third
of that size. They are found all over the world.

The rest of the malacostracans are grouped under Eucarida, which includes
all the crustaceans in which the carapace covers the whole head and trunk
and forms a single unit called the "cephalothorax." Krill, or euphausians, are
pelagic, small eucaridans that occur in huge swarms in cold seas and form a
basic item of the baleen whale's diet.

The largest of the eucaridans are the decapods, or species with ten legs,
which include the crabs, lobsters, shrimps, and prawn. Some decapods are
armed with large claws and some are not. Among those that do not have
claws is the sand bug, Hifpa, which lives a rough and tumble life in sandy
shores, where it constantly has to battle the force of the breaking surf. The

THE INVERTEBRATE LEGIONS 117

sand bug filters plankton brought to it by the waves by means of its feathery
antennas. The spiny lobster, PamiUnis, has no claws, but can inflict cuts with
the spines that cover its bodv and antennas. It makes a rasping noise when it is
seized by rubbing a knob at the base of the antenna on a rough groove on the
face below the eyes.

Very few of the shrimps and prawns have claws. They eat plankton and
smaller bits of organic matter. Very often, these animals travel in large schools,
and most of them swim actively, whereas the crabs and lobsters walk on the
bottom and swim very little. Perhaps the most famous shrimp is the snapping
shrimp, Crangon, which possesses one huge claw. This claw is used to make a
snapping or crackling noise that is well known to divers and which became
famous during the last war when it was picked up on underwater sound
devices. Schools of snapping shrimp are found in shallow, calm water the
world over. The marine shrimp, Stenopus, is a very beautiful, clawed shrimp
with a white bodv crossed with blue and red iridescent bands and long,
filamentous antennas.

One of the largest and probably the most famous of all crustaceans is the
Atlantic lobster Homarus. It grows to edible size of 1 to 3 pounds in about five
years, but lobsters may reach very old age, a weight of up to 35 pounds and
2 feet in length. Homarus is probably the finest-tasting lobster found anywhere.

Some crabs have somewhat reduced the abdomen and must hide this fleshy,
poorly protected part in a snail shell which is carried about like a house. These
are the hermit crabs, which have some remarkable symbiotic relationships with
sponges, hydroids, and anemones.

The true crabs reduce the abdomen to a little tab that folds under the
cephalothorax. They form a large and complex group found the world over.
Some true crabs have even taken to terrestrial life in the tropics. Crabs are the
scavengers of the sea and will eat any organism they can catch or find dead.
Their habits are not as varied as might be supposed. They all have large claws
which are used for defense and offense or for manipulating objects. The claws
of some are to be a\'oided since they can quite easily crush a finger or a toe.
Most crabs display their claws in a threatening gesture whenever they are
approached. Some crabs are exceedingly well camouflaged and will not threaten
with their claws since they depend on concealment for defense.

Crabs are pugnacious and active animals. Some of the most amusing experi-
ences under water can result from watching their antics, their battles with one
another, and their rapid, sidewise scuttlings about for food. One crab that is
often seen about coral reefs is the spiderlike arrow crab, Stenorhynchus (/ig.
36). This bizarre and gangling little fellow makes a humorous picture as it
reaches out for food with its blue claws and brings the food to a mouth that is
far under its long snout.

Arachnids: Class Arachnida — Figure 39

This class is mainly a terrestrial one and includes the economically beneficial,
but not well-loved spiders, centipedes, and millipedes. The rightfully disliked
ticks are also arachnids. Arachnids were among the largest in size and most
dominant of marine animals in the Cambrian Period from 400 to 500 million

118

UNDERWATER GUIDE TO MARINE LIFE

SEA STRIDER.
HQloborHes--§-i»i.

HORSESHOE CRAB
Limu.lixs- l&in.

SEA SPIDE
Nymphon-3in.

Fig. 39. Arachnids and insects. Adapted from the Picports of H.M.S. Challenger
(^1873—76^ and drawn from life.

years ago, before the age of fishes. In Silurian times, 350 million years ago,
some scorpionlike arachnids became the first animals to venture onto land.
Now, marine arachnids are restricted to a few animals which are either hold-
overs from the past or have very specialized habits.

The body of arachnids is sharply divided into a cephalothorax (head-body)
and an abdomen. There are no antennas and no true mouth parts that could
be called jaws, the mouth parts always being of the sucking variety (except for
the horseshoe crab).

There are only two arachnid groups in the sea. The first of these contains
the living fossil, the horseshoe crab, Limuhis, which has existed on earth
virtually unchanged for almost 200 million years. It is found on sandy shores
over much of the earth, especially in the temperate seas of North America and
in the western Pacific. Horseshoe crabs are harmless, but the feet of swimmers
have accidentally been pierced by the long tail spine. Very large horseshoe crabs
may be over IV2 feet long. They crawl slowly over the bottom, grasping in-
vertebrates with their clawed feet. Prey is "chewed" by means of the hard
bases of the legs near the mouth. They burrow in soft bottoms and can swim
weakly by paddling with their feet. Under the abdomen of the horseshoe
crab are a series of leaflike plates. These are the book gills which furnish these
animals with oxygen from the water. Commensal flatworms are often found on
the leaves of these gills.

The sea spiders or pycnogonids are among the most incredible animals found
in nature. They are very often of red coloration since several species li\c in
rather deep water. They range in size from less than an inch in leg span to
over 4 or 5 inches. The body is small, and the abdomen almost nonexistent,
but the legs are extremely long and contain branches of the stomach which
ordinarily would be in the abdomen if the abdomen were large enough. The
mouth parts are of a sucking type; sea spiders live by sucking the juices from

THE INVERTEBRATE LEGIONS 119

such plantlike animals as anemones, sponges, hydroids, and sea squirts, in
the same way that some insects such as plant lice (aphids) live bv sucking
plant juices. Sea spiders are common in all seas, but they are so well camouflaged
by their shape and remain so still that they are not very often seen.

Insects : Class Insecta — Figure 39

Onlv one group of insects has invaded the sea, the water striders, familiar
bugs which shuttle across calm waters of wooded ponds, lakes, or streams.
Oceanic water striders, Halohates, are small and tropical in distribution.
They are predacious bugs with sucking mouths. They never enter the water
but live bv walking on it as a land animal walks on the ground. Just how these
little insects have adapted to live on the open expanse of ocean where there
is no shelter from waves and weather is not well known. They probablv feed on
small flying insects such as midges that fall on the open sea from the air. Thev
also may eat diatoms.

MOLLUSCS: Phylum Mollusca

The name "Mollusca" refers to the fact that these are soft-bodied animals.
Molluscs are nonsegmented, but thev have a head with tentacles and usually
with eyes. Thev usually move by crawling about on a foot, a broad flattened
area on the ventral surface. In the case of bivalves (clams and oysters) and
tooth shells, the foot acts as a digging organ and in the case of cephalopods
(squids and octopuses), it is formed into tentacles. The mollusc's outer body
covering is called the "mantle" and usually secretes a shell which protects the
soft body of the inhabitant.

The molluscs form a gigantic group with about eightv thousand or more
species. However, this great arrav falls rather neatlv into five major groups,
each of which forms a rather compact unit, both as to form and general habits.
In general, molluscs are rather slow-moving, sluggish animals. The exception
to this rule occurs in the octopuses and squids, in which the nervous system is
among the best developed of all invertebrates.

Chitons: Class Amphineura — Figure 40

These are the most primitive of molluscs. The bodv is shaped like an oval
disc and always bears eight hard plates on the back for protection. There are
no tentacles. Some rather rare or deep-water chitons are wormlike in shape,
but the great majority adhere closely to the body plan described. They are all
animals of shallow, rocky shores where they adhere with their muscular foot,
often so tightly that they cannot be removed without breaking them. Chitons
browse on algae, using their tongues, which bear hard rasping teeth called a
"radula," to scrape their food from rocks. Bv day, chitons prefer to rest in
shady crannies or dark places on the undersides of rocks, but they wander about
freely at night. Chitons defend themselves by rolling into a ball like an
armadillo or pill bug.

Chitons are found in all waters in the world. Thev are mostly under 3 inches

UNDERWATER GUIDE TO MARINE LIFE

SPINDLE SHELL

bubble: shcll jooth shCll

Bu.lloL- 1 in. DentaiKMH-Sln.

Fig. 40. Chitons, snails, and tooth shells. Drawn from life.
See also Color Plate 10.

THE INVERTEBRATE LEGIONS 121

in length, but the Pacific Cryptochiton reaches almost a foot. There are many
species off the Pacific Coast of North America. Chitons are less numerous in
the Atlantic.

Snails: Class Gastropoda — Figure 40

This is the largest class of molluscs by far. The body is short and is usually
covered by a single, spiral shell. Locomotion is accomplished by means of the
flat, muscular foot upon which the animal glides. Some conchs use the foot
to make short jumps rather than as a glider, and the small, planktonic pteropods
have 2 winglike feet for swimming at the surface of the sea.

All snails have tentacles bearing chemoreceptors and eyes. None of them
move rapidly. The mouth has a tongue with a radula. The beautiful shells of
snails have caught the attention of collectors.

The most primitive of gastropods are the flattened limpets, keyhole limpets,
and abalones. These are all animals of tidal or subtidal rocky shores. All scrape
algae from rocks with their many-toothed radula or eat dead organic matter,
and all are more active by night than by day. The limpets and keyhole limpets
are the smallest, never reaching over 4 inches and averaging much smaller.
The abalones, however, reach a foot in length and are delicious as food. They
are found only in the Pacific and are treated as game animals protected by law
on the Pacific Coast of the United States. The limpet, in spite of the primitive
nature of its nervous system, shows a remarkable homing behavior. Each
limpet has a definite place on a rock to which it adheres when it is uncovered
at low tide. It wears a depression in the rock which conforms to the shape
of its shell. When covered by water at high tide, the limpet moves away as
much as three feet from its rock, "scar" home to browse, returning again at
low tide. It finds its way back by remembering the topography of its home
rock and always fits itself into the scar.

The rachiglossans are snails that have only three large teeth in the radula.
These are used to bore through the shells of clams and oysters or other molluscs
or perhaps other animals. All of them are carnivorous. The well-known whelk
(scungill), Biisycon, is a large species which lays eggs that look like a string
of flattened beads. The oyster drills, Urosalpinx, are pests in oyster beds. Murex
CColor Plate 10^ is a widespread tropical genus which has a shell that is dis-
tinctly laminated and often very spiny at the places where the lamellae overlap.
Nassa is a small species that eats other molluscs but also scavenges; it is very
common on mud bottom.

The taenioglossans make up the great majority of snails. They include
carnivorous species such as the moon shell, Natica, which feeds on shellfish
and lays eggs in sand collars, common objects cast up on beaches. The slipper
shells, Crefidula, and periwinkles, Littorina, are common tidal or subtidal
vegetarians of rocky shores. The queen conch, Strombus gigas QColor Plate 10^,
forms a home for the little conchfish and is among the largest of snails, often
weighing over 5 pounds. It progresses by jumping and is a scavenger. The
cowries, Cyffaea CColor Plate JO), are among the most beautiful and most
sought after of shells. They are most common in the tropics and not very
abundant in North America. The helmet shells. Cassis, include the king conch

122 UNDERWATER GUIDE TO MARINE LIFE

or king helmet CColor Plate JO). Helmets prey chiefly on bivalve molluscs and
reach a size almost as large as that of the queen conch.

The toxoglossans include the poisonous cone shells, Conns (^Color Plate 10^,
which have the radula reduced to two long, sharp lancets attached to a poison
gland. The cone shells are not known to be dangerous in North America, but
some of the South Pacific species are deadly. They should not be handled.
Treatment of the poisoning is just like that for snakebite (consisting of lancing
the wound in order to encourage bleeding, followed by immediate attention
by a physician). Cone shells can always be recognized by their conical shape.

The remaining groups of snails all tend to reduce the shell. Pteropods are
seldom more than Vi of an inch long, have transparent, papery shells, and
are planktonic. Their foot is divided into two large "wings" for purposes of
swimming. They are common enough in some places to form bottom oozes from
their cast-off shells. The large sea slug or sea hare, Aplysia QcoJor photograph^,
reaches almost the size of a football, feeds on algae, and ejects a harmless, inky
fluid when it is molested. The smaller plumed sea slugs or nudibranchs CColor
Plate W) are probably the most beautifully colored of all invertebrates. Their
soft but iridescent colors and flowing movement are extremely beautiful. They
grow to a maximum of about 4 inches. Most plumed sea slugs are of cold-water
distribution, but some species are also found in the tropics. They are carni\'orous,
and some are almost unique in that they eat sponges which are avoided by all
other animals but sea spiders. Other species eat anemones or bite the heads
off^ hydroids for food. (The hydroids do not seem to be bothered much by
this since they quickly grow a new head.) The plumes on the backs of sea
slugs are used as respiratory gills and have given these animals the name of
"nudibranch" which means "naked gills." One nudibranch, Eolis CColor Plate
lOX has extensions of its digestive tract reaching up into its dorsal plumes.
The nematocysts of the coelenterates, which it eats, are stored in these exten-
sions and are used by Eolis for defense— a completely unique use of the
defensive mechanism of one animal by another. Eolis's plumes are brightly and
warningly colored, and Eolis is avoided by fishes.

Tooth Shells: Class Scaphopoda — Figure 40

These litde animals have a long hollow shell, a radula like the snails, and a
burrowing foot like the clams. They never are more than about a half-foot long
and are usually half that length. They burrow into sandy or muddy bottoms
and feed on microscopic organisms. They are chiefly of cold or deep waters
offshore.

Bivalves: Class Pelecypoda — Figure 41

These are compressed animals with no head and with two shells or valves
united by a hinge. The hinge is elastic, and when the shells are closed by
muscles, the hinge is compressed. When the muscles are released, the hinge
causes the shells to open. Thus, these animals must exert muscular force to
keep their shells closed but exert no force to open them. A starfish is able to tire
a bivalve merely by a continued pulling force. When the much stronger bivahe
relaxes its muscles out of exhaustion, the starfish is able to eat it.

THE INVERTEBRATE LEGIONS

123

PTEROPODS

CKallenqer-'if in

BOB-TAILED SQUID
Roisia- 4 in.

ARGONAUT
ESe CASE -"t in.

Fig. 41. Clams, peropods, cephalopods and hrachiopods. Adapted from the Reports
of H.M.S. Challenger (1873-76) and McGoxvan (J 954) and draivn from life.

124 UNDERWATER GUIDE TO MARINE LIFE

Bivalves are adapted mainly for protection. Their thick shells are so effective
in this respect that this ancient group has evolved very little during the many
million years of its existence. It is true that about all they do is feed and
breed and secrete a shell. In general, they move only a little, their major
response to disturbing stimuli being a closing of the shells.

Almost all bivalves are filter-feeders. They have incurrent and excurrent
siphons through which sea water enters and leaves the bodv. This water brings
oxygen and microscopic, planktonic nutrients to the bivalve. The bivalves form
a very compact group. Some, such as the mussel, Mytihis, are sessile and
attach themselves to hard substrate by means of tough threads called a "byssus."
The jingle shells, Anoniia, have fragile shells and are common in all seas at-
tached to all sorts of solid objects in shallow water. The ark shells. Area, have
heavy shells, and one species, the bloody clam. Area fexata, is the only mollusc
with red blood. Oysters, Ostrea, are also attached to solid substrate. They have
the capability of changing from one sex to the other alternately. A few species
of oysters form commercially valuable pearls. Pen shells, Pinna, are common,
thin-shelled, tropical species which have a sharply triangular shape. They
frequently are seen partly buried, pointed end down, in sand. The upper end is
very sharp and can inflict deep cuts.

Among the nonattached and motile pelecypods are the quahog or cherrystone
clams, Venus, which are typical of the many burrowing clams of sandy or
gravelly beaches. The soft-shelled clams, Mya, have a thinner shell than the
quahog and prefer softer bottoms like soft sand or mud. The same is true of
the angel-wing clam, Barnea, and the razor clam, Ensis, which also have
fairly delicate shells. Clams with thin shells have, in general, longer svphons
and bury themselves deeper than do the harder-shelled species. Thev are also
more active and faster diggers than the hard-shells.

One species of pelecypods has left the general protectively shelled pattern of
adaptation described in previous species. The shipworm, Teredo, is actually
an almost naked clam that uses its reduced shell to bore through wood. Like
termites, shipworms utilize wood for food.

The scallops, Peeten, are actively swimming pelecypods. Thev clap their
shells vigorously together to force water out of the body cavity and thus move
by a sort of jerky jet propulsion. Scallops have photoreceptors around the edge
of the mantle and also have long, sensitive tactile and chemoreceptive tentacles
attached to the mantle's edges.

All clams and oysters are edible, and some are delicious, but because of their
filter-feeding habits, they may at certain times of the year and in some waters
become poisonous. Obviously, pelecypods from foul or polluted waters should
be avoided. In the summer, toxic bacteria and protozoans mav become plentiful
enough in some waters to cause pelecypods, with these microorganisms in their
digestive tracts, to become poisonous. It is also said that during the breeding
season some clams and oysters are toxic due to the accumulation of sex products
in them. At any time of year, these animals spoil quicklv. They should be eaten
only when absolutely fresh. It is generally a good rule to eat pelecypods only
during months which have an "r" in them; the cooler months, September
through April.

THE INVERTEBRATE LEGIONS 125

Squids and Octopuses: Class Cephalopoda {"head foot") — Figure 41

In this group, there is a definite tendency to lose the shell and to become
active and predatory. Some cuttle fishes, Sefia, still have a shell known as
"cuttlebone," but it is entirely internal. The common squids, Loligo, have a
fragile pen-shaped shell buried in their flesh and the octopuses are without
shells. In all cephalopods the foot is developed into a circlet of tentacles around
the mouth. The mouth has a parrotlike beak, and the bites of cephalopods
are poisonous, sometimes dangerously so. Although these animals are not often
inclined to bite, their means of defense centered elsewhere, they should be
handled only with care. While the tentacles are not dangerous, the bites from
octopuses have been known to result in death.

Defense consists of protective coloration coupled, in the case of octopuses,
with secretive habits or, in the case of squids, with speed of swimming. When
molested, all cephalopods have the habit of emitting a smoke screen of dark
inky fluid and then making a hastv retreat. In some deep sea squids, the ink
is luminescent.

Cephalopods are the largest, speediest, and most active of invertebrates. The
giant squid, Architeuthis, is a favorite food of the sperm whale, lives in the deep
sea, and reaches a length of about 50 feet including the long tentacles. Some
octopuses have an armspread of over 12 feet. Octopuses are shy animals, but
large ones are less shy than small ones.

The nervous system of cephalopods is extremely well developed. Their giant
nerve fibers conduct nervous impulses at a very rapid rate. Their eyes are very
much like mammalian eyes, and these animals see very well. These features
provide cephalopods with the extremely fast reflexes necessary for active
predatory animals, but they do not necessarily imply intelligence, for which
integration of senses and actions is needed (Chapter 2). In fact, the intelligence
of these animals, like their ferocity, is often overestimated.

Cephalopods are the original inventors of jet propulsion. They draw water
into the mantle cavity and forcibly eject it from a siphon. They can change
direction by moving the siphon, but they usually swim backwards.

The color changes of cephalopods are the most rapid and striking to be seen
in the entire animal kingdom. By means of rapidly redistributing pigments in
their pigment-bearing cells or chromatophores, they can cause complete change
of color or even waves of color to pass over their bodies in a matter of seconds.
Most cephalopods match background by means of color change. They also
change colors when feeding or in response to stimuli leading to fear.

The tentacles of cephalopods are organs used for food-catching, movement
(octopuses crawl), and reproduction. These tentacles bear suckers, the power
of which is remarkable. Even a small octopus of only a few feet in tentacle
spread can hold onto a rock so as to be almost immovable. Care should be taken
by the diver not to let an octopus grasp him and a rock at the same time. This
the octopus will not do as an aggressive action, but only if it is first molested.

During copulation, sperm is transferred to female cephalopods with one
specialized tentacle which usually has the suckers reduced in number and size.
In some octopuses, namely the paper argonaut, Argonauta, and Philonexis, the

126 UNDERWATER GUIDE TO MARINE LIFE

sperm-bearing arm is actually detached from the male and placed in the mantle
cavity of the female. This arm was originally thought to be a separate animal, a
worm, and was named Hectocotylus. Most octopuses do not lose their sexual
arms during copulation, however.

Cephalopods can be divided into two groups on the basis of how many arms
they have. The squids have ten arms, two of which are much longer than the
rest. These are very swift-swimming animals which are common near shore or
at sea the world over. They eat fishes and invertebrates. The common squid,
Loligo, is a common shore form and reaches a length of Wi feet. Sepiotenthis
(^color fhotograph^ is found in the West Indies and is very beautifully colored.
Both of these show preference for traveling in schools in precise military
formation. Sometimes as many as several dozen may be seen lined up swimming
together.

The octopuses have eight tentacles, usually all of equal length, and are of
bottom-living habits, eating other invertebrates such as molluscs and crustaceans
mostly. Some are small and pelagic and fairly good swimmers. Others are
extremely flattened and sluggish, spending most of their time attached to rocks.
But most are shy and nocturnal, though active, bottom animals. Klingel (1944)
gives a sympathetic account of the common octopus, Octofiis (Color Plate 10^
He says that the best way to spot the home of one of these shy animals is to take
note of the presence of a pile of shells and stones which the octopus accumulates
near its home. After feeding, the octopus has the peculiar habit of drawing hard
objects to its body.

Octopuses show fear by means of a livid white color phase, but they also
have color phases composed of virtually every shade or pattern imaginable. Ink
is used both for a defensive smoke screen and for recognition of one octopus
by another at night. The paper argonaut, Argonmita, is an octopus, the female
of which forms a beautiful papery shell as an egg case. The argonaut is an animal
of rather deep tropical waters, but it appears at the surface when it is breeding.

BRAGHIOPODS: Phylum Brachiopoda— Figure 41

This phylum is mentioned chiefly because one species holds the geological
longevity record for all animals; Lingiila has been in existence for 400 million
years. Brachiopods are not now very varied, but were among the most common of
animals many million years ago. They look like bivalve molluscs since they
have two shells and filter-feed on plankton, but they are actually quite diff^erent
anatomically. The lamp shells are brachiopods that grow attached to rocks by a
stalk. Brachiopods are fairly common in deep water offshore, but a few are
found in shallow waters.

ECHINODERMS: Phylum Echinodermata ("spiny-skinned")

The starfishes and their allies form an important group evolutionarily
speaking since they have a larva that looks very much like the larva of some
prochordates. Therefore, the chordates (including vertebrates) and the echino-
derms are thought to have common ancestry.

Adult echinoderms are characterized by the tube feet by means of which

THE INVERTEBRATE LEGIONS 127

thev move. These are little tubes that have suction discs at their ends and
w^hich operate by means of an internal bulb that pumps water into the muscular
foot, causing it to expand, and that sucks water from the foot, causing it to
contract. The strength of several hundred feet working together is considerable.
There are five groups of these spiny-skinned animals.

Starfishes: Class Asterida — Figure 42

As the name implies, these are star-shaped animals. They are especially
diverse on the west coast of North America where the sun star, with a diameter
of up to 2^2 feet, is the largest starfish known. All starfishes are carnivorous on
bivalve molluscs. They setde over a bivalve and exert a steady pull on the
bivalve's shells. Eventuallv, the bivalve tires, and the starfish then extends its
stomach into the bivalve and digests the bivalve right in its shell. Starfishes are
not very variable in form. (The very common large West Indian star, Oreaster,
is shown in figure 43.) Some starfishes are blue, and others are red, brown, or
even bright yellow. All can regenerate arms if these are lost.

Brittle Stars: Class Ophiurida — Figure 42

These are the most acti\'e of the echinoderms, able to move quite rapidly
with their long serpentlike arms. In fact, they are often called "serpent stars."
They are fragile and may even purposefully break arms off when they are
handled, a defense mechanism that occupies the predator's attention while the
brittle star makes its escape. In the middle of the underside of the body is a
mouth with serrate, toothlike edges. These are used to sift out and chew the
small pieces of organic matter on which these animals feed. Most species are
nocturnal, and some are very common in deep water. (A typical brittle star
is shown in Color Plate 10.)

The basket star or Gorgon's head, Gorgoncephalus, is an extraordinary and
very sluggish brittle star that has finely branched arms. It is common in the
tropics and reaches a width of 2 feet, but because of its sedentary habits and
protective seaweedlike shape, it often goes unnoticed. It may be found adhering
to corals or clumped in the branches of sea plume gorgonians, where it catches
small, planktonic animals with its tentaclelike arms.

Sea Urchins and Sand Dollars: Class Echinida — Figure 42

The bodies of these animals are rounded and spinv in the case of sea urchins
and flattened and smooth in the case of sand dollars. There is a shell formed
of calcareous plates and on the underside is a five-toothed chewing apparatus
called "Aristotle's lantern" with which these animals scrape their algae food
from hard surfaces or chew organic matter. These animals move slowly by
means of tube feet and depend on their spines or hard shells for protection, for
their meat is tasty, forming an excellent chum for fishes. Sea urchins and sand
dollars range in all waters of the world over all types of bottom. The long spines
of the needle-spined sea urchins, Diadeina, common in all warm seas, are very
sharp and brittle and easily pierce flesh, gloves, or even shoes. The spines break

UNDERWATER GUIDE TO MARINE LIFE

BASKET 5TAR
&GorqoncephaluS- Vo 2 f i-

Fig. 42. Echinoderms. Drawn from life.

THE INVERTEBRATE LEGIONS

129

^4 / /

Fig. 43. Top. The heche-de-mer, Holothuria, averaging about eight inches, is an
extremely sluggish mud-eater. The pearlpsh uses the heche-de-mer' s cloaca for a home
Cphotograph courtesy John A. Moore^. Bottom. The West Indian star, Oreaster, is
commonly found on sandy, weedy hottom among plants like turtle grass, Thalassia,
and the alga, the merman's shaving brush, Penicillus.

-^'/

off in the flesh and Hberate a puipHsh fluid which stains the wound. The sensa-
tion is painful, but the effects are not generally long-lasting. The bits of spine
that cannot be pulled out soon dissolve in the flesh. Most sea urchins do not
bear such sharp, long spines, but sharp-spined species should not be handled
barehanded. Some that have short spines have poison glands associated with these
spines. These are the flexible urchins, one of which, Aerosovia, has a sting
reported by Phillips and Brady (1953) to be as painful as that of the Portuguese
man-of-war. Luckily, this urchin keeps to rather deep water.

130 UNDERWATER GUIDE TO MARINE LIFE

Sea Lilies: Class Crinida — Figure 42

These are almost exclusively deep-water animals and are among the most
common of animals found there. Deep-water sea lilies are stalked and very
plantlike. There are a few sea lilies that break off their stalks and swim by
waving their arms. One of these is the sea feather or feather star, Antedon, and
it sometimes ranges to waters only about 100 feet deep. It is of temperate
distribution.

Sea Cucumbers: Class Holothurida — Figure 42

The onlv echinoderms that have lost their spinv or hard skin are the sea
cucumbers, which have an appearance exactly like their name. They exist in
shallow and deep waters all over the world and may be either chunky and
muscular or elongate and delicate. A ring of tentacles encircles the mouth.
The tentacles are tactile and chemoreceptive organs. Tentacles also serve to
shovel mud and sand, the sea cucumber's source of food, into the mouth.
Some sea cucumbers have the defense mechanism of eviscerating themselves
through the mouth by means of a violent contraction of the body when they
are disturbed. The sea cucumber soon regenerates the internal organs. The
beche-de-mer, Holothnria (/ig. 43), is a common form found in tropical seas
the world over. (Its commensal relationship with the pearlfish is described in
Chapter 10 under that fish.)

INVERTEBRATE CHORDATES: Phylum Chordata

This is the phylum to which the vertebrates belong, but there are some
invertebrate members of this phylum. These invertebrates are the species that
have no backbone, hence are truly invertebrates. But they do have other internal,
anatomical characters that vertebrates have (including a dorsal, tubular nervous
system), and these place the invertebrate chordates or prochordates in the same
phylum as vertebrates. All of the prochordates are filter-feeders, and most of
them are small.

Cephalochordates : Class Cephalochordata — Figure 44

These are the lowest forms of fishlike animals. Avifhioxus and its close allies
are small, up to 3 inches or so, and are common buried in clean, sandy shores
of much of the world. They lie in the sand with the mouth protruding, filtering
plankton from sea water by means of a large basketlike pharynx.

Hemichordates : Class Hemichordata — Figure 44

The acorn worms, Balanoglossus, and others, live in holes in soft-bottomed
shores and feed, as do other prochordates, by filtering sea water. The acornlike
"head," which is used both in burrowing and feeding, separates them from other
wormlike animals. Some members of this class are small, sessile, and colonial.
They live on the sea bottom and are not likely to be encountered by the diver.

THE INVERTEBRATE LEGIONS

131

Tunicates: Class Tunicata — Figure 44

The sea squirts are the most common prochordates and are most hkely to be
encountered. They are Httle, round, or elongate, vaselike animals that have two
openings, an incurrent opening for taking in water, and an excurrent one for
passing water out. Thus, they resemble clams in this respect and filter-feed
exactly as clams do. Ciona and Molgula are two common, shallow-water sea
squirts that live attached in groups to rocks or pilings in shallow water. The
name "sea squirt" is derived from the habit that these animals have of squirting
water when they are handled.

There are several almost transparent members of this class that might be
mistaken for comb jellyfish. Like comb jellyfish, they are pelagic and swarm
on the open sea. Some of them are solitary and others are colonial and all are
filter feeders. Salpa is one solitary form of fairly large size. Pyrosoma lives in the
tropics, is colonial, and has living in it a luminescent bacteria. Large masses
of Pyrosoma, when stimulated, emit light strong enough to read by. Young
(1950) reports that this light may be a protective device since fishes that seize
these animals drop them when their lights go on.

Avv\pVi ioxuS-2 in.

<nolc)u.lci-1 in.

C \ ov-\aL- o >r>

Fig. 44. Prochordates. Drawn from life.

SALPIO

SECTION THREE

CHAPTER

8

THE LOWER FISHES— Lampreys, Sharks, Rays,

and Ratfishes

The vertebrates— fishes, amphibians, reptiles, birds, and mammals— compose the
dominant and most advanced of the chordates (Chapter 7). This is an extremely
diverse group, united by the possession of at least traces of a backbone composed
of separate vertebrae. They also possess a cranium which encloses and protects
the specialized anterior end of the central nerve chord, the brain. It is
through the specialization of the brain and the allied sense organs (eves, nose,
ears, etc.) that the advanced vertebrates are able to respond more delicately
to subtle modifications of their environment than any other animals. Thus
they have become the dominant living organisms on the earth and in the sea.
It is not at all clear where the vertebrates came from. Probably some of the
prochordates had common ancestors with some vertebrates, but this occurred
so long ago (at least 500 million years) that the story is not preserved in fossil
form for us to interpret today.

THE JAWLESS VERTEBRATES: Glass Agnatha {"imthout jaws")

This group, widespread in the temperate zones of both hemispheres, includes
descendants of a once prominent array of fishes called "ostracoderms" which lived
over 300 million years ago. The ancient forms were mud-eating, bottom-living
marine animals which looked more conventionally fishlike than their eellike
descendants, the lampreys and hagfishes of today. These have survived probably
because they took up a very specialized mode of life— parasitism. It is a matter
of definition whether to call the lampreys and hagfishes "parasites," "carnivores,"
or "scavengers." Theoretically, the parasitic habit begins with a stage in which
an animal merely partakes of part of the living host's tissues but lives a
largely independent life. The mosquito is an example. Gradually, as evolution
progresses, the dependence on the host increases until the parasite is virtually
completely dependent on the host. Such is the case with the tapeworm.
Lampreys and hagfishes are a borderline case. They are specialized in feeding

B2

THE LOWER FISHES 133

methods but are not so host-dependent as to have become nearly as anatomically
altered as the tapeworm. Some biologists prefer that they be called "specialized
carnivores," but since they feed on living prey, the term "parasite" is better.
As is so often the case with parasites, the body form has tended to become
simple and degenerate, in this case elongate and with a poorly developed
skeleton of cartilage. The hagfishes tend to be scavengers, too, since they feed
on dead or dying prey.

The Agnatha are distinct from all succeeding vertebrates because of their lack
of paired fins and jaws. In the modern forms the mouth is merely a round
disc with a hole in the middle containing a rasping tongue. This mouth acts
as a powerful sucking mechanism. Hence, these forms are sometimes called
the "Cyclostomata" ("round mouth"). With this mouth they are able to do
such things as grasp and bore into their fish prey, build a nest of stones, anchor
themselves to rocks, pilings, or even boats, and grasp their mates while breeding.

Because of the lack of paired fins, they are not very good swimmers. Though
they can dash for prey at considerable speed, their steering is not as good as
that of fish with more fins and shorter bodies. One does not see them swimming
about nearly as much as one sees them attached to some item of substrate
waiting to strike, almost snakelike, at some unlucky fish that happens to pass
their way.

The two groups of agnathans are distinct, and each attacks its prey in a quite
different way.

LAMPREYS: Family Petromyzontidae

There are usually seven gill openings on each side, and there are no barbels
on the snout. The eves are large, and the dorsal fin is discontinuous. Lampreys
swim vigorously but not too efficiently, and are active, voracious animals. They
attach themselves to fishes, preferably at the softer throat, side, and belly
regions, and scrape away the skin with the rasping tongue in order to suck
the blood and eat some of the flesh. Their saliva is an anticoagulant. Very often
this either kills the prey outright or so weakens it as to cause delayed death.
Larger fishes do recover. They prefer the soft-scaled fishes. Hard scales seem
to be protection against attack.

Not much is known of lampreys in the sea, though they spend most of their
lives there. They are most commonly observed in streams in the spring, where
they go to breed after a certain unknown number of maturing years in the sea.
In this respect, they are like salmon and are said to be anadromous. During their
journeys up rivers, they perform remarkable acrobatics in climbing rapids and
low falls with the aid of their sucking mouths. In the riffles, a nest is scooped
out of gravel and large numbers of small eggs are laid. These hatch into
Ammocoetes larvae which are nonparasitic but look much like the adults. After
spending three to five years in fresh water, having attained a 6-inch length,
the Ammocoetes go to the sea to mature, and the breeding cycle begins again.

Lampreys may become landlocked as they have in the Great Lakes, where
they have all but destroyed the lake trout and whitefish industries. In spite of a
repulsive appearance, they are edible and quite tasty. Formerly they were a
popular food in New England and in Europe.

Lampreys are found in all temperate seas.

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UNDERWATER GUIDE TO MARINE LIFE

Fig. 45. Sea lamprey.

SEA lamprey: Petromyzon marinus

Size: Up to 3 feet.

Weight: Up to 3 pounds.

Distribution: The North Atlantic of Europe and the United States south to
Chesapeake Bay and rarely to Florida.

Identification: Same as for the family.

Habits: This lamprey is known to attack members of the cod and mackerel
families. Probably it also preys on other soft-scaled fish. Fish are sometimes
caught by fishermen which bear the scars of such attack. They have not been
recorded attacking warm-blooded prey such as man, but if one does attach to
an arm or a leg, so strong is the grip, it cannot be pulled off. However, raising
the animal out of the water will cause it to release its hold.

Similar Species: The Pacific lamprey, Entospheniis tridentatiis, is common
from Alaska to southern California. It is landlocked in Goose and Clear Lakes
in California. Its prey mainly consists of salmon and steelhead trout. This species
is very similar to the East Coast form.

SLIME EELS OR HAGFISHES: Family Myxinidae

These are distinguished from lamprevs by the four pairs of short barbels on
the head, lack of eyes, a somewhat smaller size, and a continuous dorsal fin.

MOUTH

Fig. 46. Pacific hagfsh.

THE LOWER FISHES 135

The prey is usually dead or dying fishes though it is possible that healthy
fishes may sometimes be taken. Thus, they may be considered a sort of cross
between a parasite and a scavenger. They bore into the prey, usually at the neck
with the tongue, or they may even enter the body through the mouth. Once
inside, the prey is eaten from inside out and only a sack of skin is left. Great
losses to fishermen have occurred when hagfishes have entered the bodies of
fish caught in sill nets or on set lines. Over a hundred hagfishes have been
retriexed from the bodv of a single fish. They seem to locate prey by smell
rather than by sight as do lampreys. They are mainly nocturnal and lie buried
in the mud most of the time.

Hagfishes are sometimes caught on lines themselves. They swallow a hook
deeply, even as far as the anus.

These fishes do not enter fresh water to breed. Small numbers of large, shelled,
adhesive eggs are laid in the sea where they sink and stick to the first object
they touch.

The name "slime eel" is derived from the fact that they can exude huge,
dripping quantities of mucus from the skin when caught. A large one can fill
a two gallon bucket with slime exuded from the mucus glands on the sides.

Their distribution is world-wide in temperate seas, and they seem to prefer
cool water.

PACIFIC hagfish: Bdellostoma stouti

Size: Up to 2 feet.

Distrihution: From southeastern Alaska to southern California.

Identification: Same as for the family.

Habits: This hagfish is especially abundant around Monterey Bay at depths
of 10 to 20 fathoms. It preys chiefly on disabled or netted rockfish, Sehastodes,
and various flounder. About twenty large eggs are deposited on rock or shell
bottom in early summer, but breeding may occur at any time of year. These
eggs are oblong and connected together by hooks at their ends.

Similar Species: The slime eel (hagfish), Myxine glutinosa, is the Atlantic
form, found from the arctic south to Cape Hatteras. It keeps to deeper waters
at the southern end of its range and reaches 18 inches in length.

THE SHARKS AND RAYS: Class Chondrichthyes {"cartilage
fish"), Subclass Elasmobranchi {"plated gills")

This subclass omits the strange ratfishes which will be discussed later. It is a
very ancient group which has been in existence for over 300 million years.
With all that time available for their evolution, it would be expected that sharks
and rays would be very diverse in body form and habits, but thev are not.
Evidently their body plan has been a successful one, and it has not been varied
nearly as much as the bony fishes for instance. There are but two basic body
plans, a cylindrical one as seen in sharks and a flattened one as seen in rays.

This group is a mysterious one. The underwater swimmer should avail
himself of every opportunity to observe its species since the habits of very few
are well known. For this reason, the groups will be considered here in some
detail. Furthermore, because of the great amount of talk, based on little knowl-

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UNDERWATER GUIDE TO MARINE LIFE

2'"' DORSAL FIN

PRE CAUDAL PIT

LATERAL LINE

LABIAL FUHROy

CAUDAL (tail) fin

PELVIC FIN

Fig. 47 . The external anatomy of sharks and rays.

edge, about some species, particularly sharks, one has to be careful in his
judgment about what to believe.

This is a marine group with the exception of very few species. The entire
skeleton is made up of gristle or cartilage. An enormous advance has been made
over agnathans in that sharks and rays possess true jaws and paired fins (the
pectorals and pelvics), characteristics which give great versatility in habits and
motion. The best field characteristics are (1) the possession of several gill slits,
(2) the tail in which the upper lobe is much the largest (heterocercal tail), (3)
the position of the mouth under a pronounced snout, and (4) the lack of true
scales of the type seen in bony fishes.

Sharks and rays possess scales of a verv interesting and basic type. These are
called the "dermal denticles" or "placoid scales" and are anatomically very
similar to the teeth of all vertebrates (with the exception of agnathans) in that
they possess enamel, dentine, and pulp cavity. The scales are scattered over the
body of sharks and ravs and are usually small, giving, however, a certain
roughness to the skin. Very large sharks have large scales which can produce
cuts on a diver. Formerly, carpenters capitalized on this roughness and used
sharkskin, or shagreen, as sandpaper until the advent of more modern abrasives.
In some parts of the body, these scales are greatly enlarged, on the bodies of
skates, Raja, for instance. The sting ray's spine, the sawfish's saw teeth, and,
most notably, the teeth in the mouth of all sharks and ravs are all evolutionarily
modified and enlarged placoid scales. Even we humans owe what few teeth
we have left to their origin as placoid scales.

The teeth of sharks and rays are modified greatly for a wide variety of
functions and are constantly replaced from the inside of the jaws as the functional
teeth on the outside of the jaws are worn down or lost Qfig. 48). A few species
have several rows of teeth functioning at once, particularly the shell-crushing
kinds such as Port Jackson sharks and eagle rays.

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137

Fig. 48. Top. One of the authors is holding a small nurse shark, Ginglymostoma.
The barbels, used for locating prey by taste and touch, are clearly shown. In spite of
the docile nature of this shark, it has occasionally been known to bite. Bottom.
The inside of the jaws of the tiger shark, Galeocerdo, are lined with several rows of
teeth. Those at the bottom of the picture replace those at the top as the latter are
worn down.

138 UNDERWATER GUIDE TO MARINE LIFE

Most sharks and rays possess a hole just behind the eye. This is the spiracle
and is exceedingly important to' the bottom-living species for the purpose of
breathing. In the normal breathing pattern of fishes, water enters the mouth,
passes the gills where oxygen is extracted, and is expelled through the gill slits.
In bottom-living forms, notably rays, it is not possible for water to enter the
mouth for the simple reason that in so doing the animal, with its underslung
mouth, would gulp more sand and mud than water. Therefore, water enters
the spiracle into the throat and gill cavity. Pelagic and mid-water species such
as mackerel sharks do not need the spiracle and may lose it completely. In man
a vestigial spiracle is seen in the Eustachian tube, which connects the ear and
throat cavities.

We can understand something of the durabilitv of the sharks and ravs over
the centuries by examining their senses and body form. While it is true that
sharks and rays possess very limited brain power, some senses are remarkably
developed. The sense of smell is powerful and is the chief means of finding food.
The lateral line, also important in finding food, is sensitive to low frequency
water vibration and "hears" in water in the same way, perhaps, as our ears
perceive air vibrations. The ampullas of Lorenzini on the snout sense hydrostatic
pressure and perhaps also temperature change. Thousands of tiny sensory
crypts on the skin act like taste buds. The ear, entirely internal, gives the animal
a sense of position and balance. It is no wonder that, with such equipment for
smelling, "hearing," and "feeling" water, sharks and rays have little need of
eyesight. The eyes are quite capable of defining images, but their extreme
nearsightedness is well known. It has been experimentally shown that a
dogfish will not react by sight to an object until it is only one foot away.
Nevertheless, sight should by no means be underestimated until more is
known about it. One "sense" that is poorly developed, it seems, is that of
response to pain.

In body form, sharks and rays are also well adapted. They are admirably
streamlined and beautiful to watch under water. Though none are as fast
or as maneuverable as the best among the bony fishes, the advance over
lampreys and hagfishes is great. One shark, Carcharinus, a ground shark, was
clocked at 40 mph over a very short distance (Budker, 1947). The fins of typical
sharks are beautifully designed hydrodynamically but fairly rigid in contrast
to those of bony fishes and are thus used mainly as planing devices like the
fins on a submarine. The vertical fins, dorsals and anal, prevent yawing and
rolling. The paired fins, chiefly the pectorals which are moderately movable,
give a dynamic or changing pitch equilibrium. In other words, they are used
to point the shark's body up or down. The tail fin propels the shark and also
turns it left or right. The upper lobe of the tail fin is longer, which tends to
drive the head down. To counteract this, the head is flattened and tends to point
the body upwards. If we add up all of these factors, we see that sharks have,
in spite of fin rigidity, remarkable stability in all dimensions, even though
maneuverability and some speed are sacrificed; sharks, for instance, cannot stop
suddenly but can only come to a gradual halt. Stability is desired because it
reduces to a minimum the amount of effort needed to keep the fish going
in any one direction. It makes all motion extremely smooth and graceful.
Certainly, sharks are as graceful as any animals that swim. Stability is also

THE LOWER FISHES 139

desirable for another reason. Sharks are heavier than water and possess no
swim bladder as do the bony fishes. They must swim slowly but constantly
or they will sink. Some species have become so attuned to constant motion
that they use it to help circulate water through the gills and will suffocate
if held stationary. This constant motion of the active species makes them
appear menacing.

The fastest sharks are those in which the bodv is shortened and compact and
the tail lunate, that is, has nearly equal lobes. These are the mackerel sharks,
family Isuridae. One shark familv, the hammerheads or Sphyrnidae, has made
an attempt to increase maneuverability by extreme flattening and widening of
the head which is then used as a forward rudder. Another attempt in increased
maneuverability resulted in the flattened rays, where the pectoral fin has been
greatly expanded and has gradually taken over all locomotion.

All sharks and ravs have internal fertilization, which is uncommon in bonv
fishes. The males possess claspers on the pelvic fins which are inserted into the
females. A few sharks lay eggs and are said to be oviparous. Most are ovovivip-
arous, the eggs hatching in the female's body and the young being born alive
shortly thereafter. A few sharks are truly viviparous as are mammals and have
a "placenta" by means of which the females nourish the pups as they grow. Some
ovoviviparous rays have a sort of internal feeding in which the female's
"uterus" secretes a milkv substance for the young. Sharks and ravs produce
few young, the recorded extremes in numbers varying from one to eighty-two,
and perhaps averaging below twenty.

All sharks and rays are carnivorous. A great variety of food is eaten, but the
sharks are mainly fish-eaters and the rays mainly mollusc- and crustacean-eaters.
A few are cannibalistic. Tiger sharks are especiallv liable to eat other sharks
and rays when these are disabled or hooked. Hammerheads like to eat rays.
Gudger (1932) reports finding fifty-four spines of the eagle ray, Aetohates
narinari, and sting ray, Dasyatis say, in the head and jaws of one large
hammerhead. There is a record of the skate, Raja, eating other small rays.

The Sharks: Order Pleurotremata {"side openings")

The typical shark is commonly visualized as a large, ferocious, swift predator
with very little on its single-track mind other than the general destruction of all
life of the sea, including man. We shall soon see how incorrect this vision is,
for while it is true that some sharks are among the largest and most voracious of
animals, most sharks do not conform to such a pattern.

In general, the sharks are fairly stout and subcylindrical of body, but several
are almost as flattened as rays and even parallel the rays in habits. Others are
long and slim. They range in size from 18 inches to nearly 60 feet. Several
dwell in the deep sea, and some pelagic species are brightlv luminescent.

Even though we must lay aside the stereotyped idea of what a shark looks
like, there are three characteristics that all sharks possess: (1) five to seven gill
slits on the sides just back of the head (hence the name "Pleurotremata"), (2)
pectoral fins that may be large or small but are never connected to the head,
and (3) definite eyehds. In all of these traits they diff^er distinctly from rays.

140 UNDERWATER GUIDE TO MARINE LIFE

The various shaiks are best told apart by shape and action. Except for a few
species, they offer little in the way of pattern or coloration as an aid to
identification.

Sharks are predominantly fish-eaters, but they are neither fast nor agile enough
to catch fast healthy fish so a great part of their diet consists of the disabled
or slower fishes. They prefer the easy mark, a wounded fish or a straggler.
(Exceptions to this are the fast and active members of the family Isuridae,
the mackerel sharks.) Sharks, contrary to popular account, do not have to turn
on their sides or backs to bite, even though they occasionally do so.

We shall examine the various sharks' diets under later species discussion, but
one item of diet deserves more than fleeting attention. This concerns the ever-
discussed question: Do sharks attack man? The answer is an undeniable yes.
But we must be careful in this assertion to be attentive to the circumstances
under which attack is most likely to occur and which species might be
responsible.

There is a great tendency to overdramatize the possibility of attack. This was
particularly damaging to the morale of service men deployed in "shark waters"
during the last war. There is an equal tendency toward debunking. Having
met sharks and not having been chewed to bits, some people, especially under-
water swimmers, have made the extreme assertion that sharks are not dangerous
at all. The authors have heard some underwater swimmers claim that sharks
are cowards. This seems to be based on the fact that these unfortunate people
had once or even several times met a shark which happened to run when
aggressively approached.

Sharks seem to hunt their prey in a manner somewhat as follows. The first
stimulus to feed comes from two sources: smell (olfaction) and, to a lesser
extent, reception of low frequency water vibration (through the lateral line).
These have the effect of increasing the speed of the shark's movements,
causing it to make short hunting turns and figure eights which are of an
exploratory, food-seeking nature. These responses reinforce the original olfactory
stimulus and also notify other sharks of the presence of food through the stimulus
of low frequency vibration. Gradually, as the shark or sharks approach the food,
the exploratory turns become more and more direct until the food is struck.
Sight may play a part in these last stages. Contact with food is the final stimulus
which brings on the "feeding mood." At this stage, sharks are extremely
aroused, active, dangerous, and not discriminating in taste. Tiger sharks,
Galeocerdo, have been known to become so excited when in the "feeding
mood" as to bite blindly at any object including sacks of coal, old shoes, and
tin cans.

The sharks that are implicated in attack on man are:

1. White Shark or Man-Eater, Carcharodon carcharias. This is the sole
deliberate attacker and is always dangerous. It does not seek out man but
is liable to attack because it habitually eats large-sized prey. It is aggressive,
and its triangular, trenchant teeth (to 2 inches long in a 15-foot specimen)
are extremely efficient. Large ones can swallow objects as large as a whole
man. Fortunately, this shark is not common.

THE LOWER FISHES 141

2. Tiger Shark, Galeocerdo ciivier. This common species is more nocturnal
than most sharks. It reaches large size, has large, trenchant teeth, and is
especially dangerous when in the "feeding mood." Tiger sharks commonly
congregate about areas where refuse is dumped at sea.

3. Hammerhead Sharks, Sphyrna species. This maneuverable species grows
to large size and is possibly guided to food more quickly than other sharks
because of the widely separated nostrils. The teeth are rather small.

4. Mako Sharks, hums species. These are the fastest sharks that swim and
are among the most aggressive. They may be dangerous under certain
circumstances even though they are almost exclusively fish-eaters.

5. Lemon Shark, Hy-poprion hrevirostris. It seems that this is a disagreeable
and unpredictable species that may, when large, be dangerous.

6. The Ground Sharks, Black-Tipped Sharks, etc., Carcharinus species. Any
large members of this genus may be dangerous. The teeth are large and
trenchant.

7. Sand Shark, Carchnrias taunis. There are some doubtful records of persons
being bitten by this shark.

8. Blue Shark, Prionace glauca. This is a pelagic species, long reputed to be
dangerous. There are few records of attack.'

9. Leopard Shark, Triakis semifasciata. This is a small shark which has
attacked divers on the Pacific coast.

The conditions under which shark attack is likely are not very well known.
Springer (1943), in the best work yet published on this subject, has thoroughly
studied and compiled a list of well-authorized cases of attack. The following
analysis is largely adapted from him and from Budker (1947):

1. Influence of Time of Day. There is an increase of frequency of attack with
increasing darkness. The bulk of attacks occur at dusk, but records of attack
are known for almost every time of day and night. Increased frequency
of attack at dusk is probably due to decreased visibility with darkness and
increased shark activity then.

2. Influence of Water Clarity. As is the case with dusk, decreased visibility
means that sharks increase dependency on their lateral line for feeding.

3. Influence of Water Depth. The danger seems to be slightly greater at or
near the surface. Sharks are in shallower water at night rather than during
the day. Nevertheless, there seems to be little or no danger in shallow
waters inshore of surf or inside of coral barriers. Sharks must at least have
access to deeper waters through channels or inlets. Sharks as a whole are
most abundant in fairly shallow waters not far offshore.

4. Influence of Temperature and Geographical Location. Springer has mapped
the cases of shark attack on a world-wide basis, and it is apparent that
sharks are most dangerous in tropical and subtropical waters in temperatures
of over 66° Fahrenheit. The incidence of attack is far higher in southeastern
Australia than anywhere else in the world. The beaches of Sydney are
fenced in, so great is the danger of attack thought to be. Otherwise,
shark attack does not seem to be concentrated at any one place.

142 UNDERWATER GUIDE TO MARINE LIFE

5. Influence cf Movement. Sharks seem to be attracted by inert objects at
the water's surface. During the last war, it was urged that men in the
water stay in a group and keep moving slowly. The effect of movement on
sharks is poorly understood.

6. Influence of Various Scents.

a. Refuse. Continuous dumping in any one area will soon train sharks to
visit there frequently. Many food scents are attractive to sharks and
dumping grounds are often danger spots to be avoided.

b. Blood. This is the strongest attractant of sharks. Almost any shark may
be dangerous in the presence of blood, which serves to drive them into
a frenzy leading up to the dangerous "feeding mood." De Witt (1955)
records an instance of a 3-foot leopard shark, Triakis, attacking a diver
when blood was in the water. Fast (1955) states that there is "a strong
possibility that with the present increase of spearfishing along our
[Pacific] coast, the number of attacks by sharks will increase. Those
individuals who indulge in this sport should . . . avoid seepage of blood,
fish juices, or other attractants."

c. Man. Sharks seem neither attracted nor repelled by the scent of man.

d. Shark Repellents. During the last World War it was found that
decomposing shark flesh had a repellent effect on sharks. Further
investigation by the United States government during World War II
led to the development of cupric acetate cakes, which can have up to
100 per cent effectiveness (but usually less) in repelling sharks from
baited lines for 3 to 4 hours. Springer lists several of these experiments
in which baited lines, some repellent-treated and some not, were used
to fish for sharks. The repellent lines were vastly less attractive to the
sharks, and most bites on repellent lines were made before the repellent
had had a chance to dissolve in the surrounding water.

There are no proven color-cloud repellents as is sometimes supposed,
but sound may occasionally serve to repel sharks. The definitive work
on the effect of sound on fishes is yet to be done.

To these factors we add several suggestions for an advisable course of action
when the swimmer is in the presence of sharks under water.

1. Observe all you can about the shark's behavior. Try to identify the shark.
Identification is most important. The swimmer's actions should be very
different if he meets a white shark than if he meets a nurse shark.

2. Don't panic. Keep moving in a fishlike way, smoothly and regularly. Try
to stick fairly close to protected places, like coral heads or rock outcrops.

3. If there are several of you, stay close together.

4. Avoid blood and offal in the water.

5. If attacked, fight back. This may serve to drive the shark away. The most
efficient way to disable a shark is to grasp a pectoral fin tightly as the shark
passes by and then to sht open its belly or gills with a knife. This, however,
is not a job for amateurs.

6. Don't attack sharks. They may look docile and timid and present an easy
target, but a shark, if attacked, cornered, or wounded is very liable to

THE LOWER FISHES

143

turn on the swimmer. To draw a shark's blood in the water would be
most foolish. This would only serve to incite this shark and draw others to
the scene.

Under water, sharks possess a puzzling mixture of ferocity and timidity.
Their large size, abundance in shallow and comfortably warm waters, and the
many unknown facets of their behavior make them ideal subjects for observation
and study. With the elimination of doubt, overconfidence, and hysteria, the
underwater swimmer is in the unique position of being able to study these
creatures firsthand.

The Primitive Sharks

There is but one family of these protoselachians ("shark forerunners")
remaining in the seas today. It is the sole survivor of the ancient stock that
gave rise to modern sharks and is distinguished from them in its primitive jaw
suspension, dentition, and other anatomical characters.

PORT JACKSON SHARKS: Family Heterodontidae

The Latin name of the family refers to the fact that the teeth are of two
kinds; those in the front of the mouth are small and pointed for grasping and
those in the back are flattened like molars for crushing. There are two large
dorsal fins, both preceded by a stout spine. The family contains only one genus
of wide distribution, but not occurring in the Atlantic.

Fig. 49. Port Jackson shark.

144 UNDERWATER GUIDE TO MARINE LIFE

PORT JACKSON SHARK (horned shark) : Heterodontus francisci

Size: Up to 4 feet.

Distrihtition: Point Conception to the Gulf of California.

Identification: Same as for the family.

Habits: This is a fairly common shark living near kelp in shallow or deep
water. It keeps to the bottom and eats hard-shelled invertebrates which it
crushes with its strong molar teeth. The large and unmistakable eggs may
sometimes be found wedged in among rocks near the low tide zone.

The Modern Sharks

These sharks are divided into three large groups. The rays are derived from
them.

Notidanoids: Superfamily Notidanoidea

These most primitive of modern sharks comprise a rare and poorly known
group. They reach large size and are mostly in moderately deep water of 100 to
400 fathoms, only occasionally coming within the depth range of the diver.
The single dorsal fin, long, cylindrical body, and the presence of six to seven
gill slits are good field marks. They are widespread in the temperate and tropical
waters of the world.

COMB-TOOTHED OR COW SHARKS: Family Hexanchidae

The teeth of these sharks are unique, being completely unlike in the two
jaws. These large sharks are found in all warm oceans but are not common,
it appears. They are ovoviviparous. Identification is made easy by the presence
of but one dorsal fin.

TEETH x^ ^^S-50. Cow shark.

cow SHARK (six-GiLLED SHARK, GRisET, MUD shark) : Hexanchiis griseus

Size: Up to 15 feet, exceptionally to 26 feet. Matures at 6 feet.

Weight: Up to 1,300 pounds.

Distribution: All warm seas. In the Atlantic from Cape Hatteras to the
Caribbean. In the Pacific from southern California to British Columbia. Not
rare in Cuban waters and off San Diego.

Identification: Dark brown or gray with a light streak along the lateral line.
There are six gill slits.

THE LOWER FISHES 145

Habits: This is primarily a deep-water form living at over 50 fathoms. It gets
closer to the surface in northern waters and at night. Probably it is a voracious
predator on large fishes such as dolphin, swordfish, marlin, and other sharks.
Except when feeding, it is probably a sluggish fish. Those who have eaten the
flesh report it to have a strong purgative eff"ect.

Similar Species: The perlo or seven-gilled shark (Heftranchiis ferlo) is
another widespread, large, voracious fish which looks like the cow shark, but is
without the light, lateral line stripe and has seven gill slits.

Galeoids: Superfamily Galeoidea

This is the group of the great majority of modern sharks. All have five gill
slits and two dorsal fins which are not preceded by a spine. Because these are
active sharks, there is a tendency to reduce or even lose the spiracle. In
separating the families, the size and placement of the dorsal fins and gill slits
are of importance.

CARPET SHARKS OR NURSE SHARKS: Family Ginglymostomidae

The two large dorsal fins are both posterior to the pelvics. Gill slits three, four,
and five are over the pectoral fins and four and five are so close together as to
appear as one. The mouth is preceded by two short barbels and is connected
to the nostrils by a short groove. As befits bottom-living, sluggish sharks, the
lower tail lobe is poorly developed. These sharks are ovoviviparous.

NURSE SHARK (gata) : Ginglymostoma cirratum— Figure 48

Size: Averages 5 feet. Commonly up to 8 to 10 feet. Exceptionally to 14 feet.

Distribution: Rhode Island to Brazil, but not commonly north of Cape
Hatteras. Also on the western coast of Mexico.

Identification: The young have small black spots, which disappear with
maturation, scattered over the dingy brown body. The head is large and flat, and
the eyes small.

Habits: This is a sluggish, inoff^ensive, and rather fearless shark which is very
common in shallow tropical waters. It is often seen lying in a protected hole or
cove or under a ledge near coral heads. Pairs come into very shallow water in
order to mate. At such times they loll about with their dorsal fins out of water.
It is quite a sport among local boys to grasp them by the pectoral fins in order
to secure a ride. When mating, the male holds the female by a pectoral fin with
his teeth. Thus, female nurse sharks are likely to look a bit ragged about the
pectorals after a few mating seasons. This shark, although normally inoffensive,
will definitely bite when annoyed.

Fig. 51. Nurse shark.

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UNDERWATER GUIDE TO MARINE LIFE

Nurse sharks nose about coral and seaweed in search of food which consists
of a great variety of small fishes and invertebrates. At times, they eat refuse,
amounting almost to scavengers. Several rows of small teeth in each jaw form
a crushing or holding dentition.

CAT SHARKS: Family Scyliorhinidae

The two dorsal fins are nearly equal in size and posteriorly placed, the first
being behind or over the pelvics. The tail fin is much like that of the nurse
sharks with a poorly developed lower lobe. The fourth and fifth gill slits are
over the pectoral, and the spiracles are fairly large. This group is rather uniform
with many small, cat-eyed, prettily patterned species, most of which live in
deep tropical and temperate waters beyond the range of the diver. Cat sharks
are most common in the South Pacific and Indian Oceans, but are world-wide
in distribution. The common spotted dogfishes, Scyliorhiniis species, of Europe
belong in this family. They are oviparous as far as is known.

SWELL shark: Cephaloscyllium uter

Size: Up to 3 feet.

Distrihiition: Monterey Bay to Acapulco, Mexico.

Identification: Ground color is brownish yellow. Barred with black and spotted
with black and white.

Habits: This is the only cat shark which is common inshore. It may be seen
in kelp beds particularly. It presumably eats a wide variety of animal foods,
especially fish, and can swallow surprisingly large objects with its capacious
mouth. The common name is derived from its habit of inflating like a puffer
when molested. The flesh will cause diarrhea if eaten.

SAND SHARKS: Family Carchariidae

The two dorsal fins and the anal fin are of nearly equal size and the
posterior margin of the first dorsal is just over the anterior margin of the pelvic.

Fig. 52. Swell shark.

Fig. 53. Sand shark

YOUN6

^JOCrORPlSH

COLOR PLATE 7

HO(jf=iSM

COLOR I'l.ATK N

THE LOWER FISHES 147

All of the gill slits are anterior to the pectoral fin. There is only one genus in
the family- The species are ovoviviparous and are cosmopolitan in warm waters.

SAND SHARK (sAND TIGER ) : Carcharias taurus

Size: Averages 4 to 6 feet. Up to 9 feet.

Weight: Up to 250 pounds.

Distribution: Maine to Brazil. Most common in warm temperate waters and
rare in the tropics.

Identification: Grayish brown above, fading to white below. The young have
light spots and blotches which disappear with age.

Habits: This is the most common large shark swimming over sandy beaches.
It is fairly sluggish but can move at good speed when the occasion demands.
It feeds principally at night on fishes and squids and occasional large crustaceans,
the sharp, pointed teeth serving admirably to hold such slippery prey. They
may feed in large schools in very shallow water. Although there are no records
of attacks on man, this shark is to be respected.

MACKEREL SHARKS: Family Isuridae

These are unquestionably the most active, swiftest, and most voracious of
sharks. The modifications toward swiftness are good field marks. These are
(1) a compact and torpedo-shaped body, (2) a high first dorsal fin placed at
the highest point on the back, (3) reduced second dorsal and anal fins of
nearly equal size, (4) a narrow caudal peduncle reinforced with lateral keels,
and (5) a lunate tail in which the lobes are of nearly equal size. In many of
these respects, they resemble the mackerels and spearfishes which are among
the very swiftest of bony fishes. The gill slits are anterior to the pectoral fin.
There is no spiracle.

The coloration is characteristic and like that of most pelagic fishes being a
sea-blue above and white beneath, an example of obliterative coloration
(Chapter 2).

These are primarily fish-eaters and are found in all temperate and tropical
seas. They are ovoviviparous.

MAKO (sharp-nosed MACKEREL shark) : Isurus oxyrhincus

.Size: Averages 6 feet. Up to 12 feet and possibly a little larger.

Weight: Averages 150 pounds. Up to 1,200 pounds or more.

Distribution: Tropical and warm temperate Atlantic. Common in the Bahamas.
In summer to New England.

Identification: Anal slightly posterior to second dorsal. Coloration is slate-blue
above, abruptly changing to dirty white below. The snout is conical and sharply
pointed. The teeth are slender and recurved for holding fish.

Habits: This may be the swiftest shark that swims. It is pelagic and pursues
swift, schooling fish such as mackerel and herring for food. Occas'onal squids and
sea turtles are taken. This fish is best known for its habit of leaping spectacularly
from the water especially when hooked, but it is most often seen basking at
the ocean's surface, solitary or in small schools, with the large dorsal fin pro-
truding. It can be dangerous, particularly around boats. It's near relative, the
bonito shark of the Pacific, Isurus glaucus, has been known to attack men and

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UNDERWATER GUIDE TO MARINE LIFE

Fig. 54. Mako shark.

Fig. 55. White shark.

boats. The young are few (one to five) and large at birth (20 pounds). This is
an excellent food fish.

Similar Sfecies: The Pacific bonito shark or Pacific mako, Isiiriis glaucus,
may be identical to the Atlantic form. It is found from Monterey Bav to the
south and over the entire South Pacific.

The porbeagles and mackerel sharks (Laiinza species) replace the makos
in the Atlantic and Pacific in water below 60° Fahrenheit. These are stouter
sharks than the makos and have the second dorsal and anal directly opposite
each other. The generic name Lamna, is derived from a Greek word depicting
a horrible, man-eating fish, and was used to intimidate naughtv children.

WHITE SHARK (man-eater) : Carchawdon carcharias

Size: Averages 8 to 12 feet. Rare over 15 feet. Recorded up to 36V2 feet.

Weight: At 21 feet, one weighed 7,100 pounds and its liver weighed 1,005
pounds.

Distribution: Nowhere common. Most common near southeastern Australia.
Occurs in all warm temperate and tropical seas.

Identification: Similar to mako and mackerel sharks, but the second dorsal
and anal fins are even more reduced; the teeth are triangular with serrate edoes
and the shape stouter. Coloration is slate-grav with a black axillar spot. Over
15 feet, the color fades to lead-white.

THE LOWER FISHES

149

Habits: This may be the most voracious thing that swims with the exception
of the killer whale, Orca. It is active, fast, and very powerful and is responsible
for most of the authenticated reports of attacks on man. Though principally
pelagic, it will enter very shallow water. It has been known to attack boats
without provocation or especially when hooked or harpooned. The white shark
feeds on large fishes, sea turtles, and e\en sea lions. One shark was found with
a 100-pound sea lion nearly intact in its stomach. Another specimen of 15 feet
was found to contain a large Newfoundland dog. Another ISVz-footer contained
two 6-foot sharks.

The young are few in number and large, being over 100 pounds in weight
when born.

Shnilar Species: One recently extinct Carcharadon is worth mention because
of its spectacular size. Only the teeth have been found, but they indicate a
body length of over 60 feet. A full-grown man could have stood upright in
this huge fish's mouth.

BASKING SHARKS: Family Cetorhinidae

These are the largest fishes found in temperate waters. They are much like
mackerel sharks in form, but the gill slits are very, long, the mouth huge, the
snout short, and the teeth minute and very numerous. The skin is very rough
and abrasive. They are ovoviviparous. There is but one species of circumpolar
distribution.

BASKING SHARK (bone shark) : Cetorhimis maximiis

Size: Commonly to 30 feet. Exceptionally to over 40 feet.

Weight: Commonly to 8,600 pounds.

Distribution: Temperate seas of both hemispheres. South to Cape Hatteras
and California. Not arctic but gets into very cold water. There is a center of
abundance to the southwest of Iceland.

Identification: The color is a light gray to brown, lighter on underside.

Habits: The common name, basking shark, is derived from the habit of
basking at the water's surface with the enormous dorsal fin and even part of the
back out of water. At such times, it is very easy to approach this shark in a boat
or in the water. Nevertheless, it should be remembered that this huge fish is

150

UNDERWATER GUIDE TO MARINE LIFE

extremely powerful. One stroke of the tail can easily stave in a small boat.
These fish travel singly, in small groups, or in large schools of up to a hundred.
At times, several may travel in tandem and have been mistaken for sea serpents.
As is often the case with many giant fishes, these are plankton feeders,
having fine gill rakers with which to strain their food from the water. When
feeding, they travel open-mouthed through the water. Excellent pictures of this
may be seen in the motion picture Men of Arran. Basking sharks sometimes
leap from the water. They have been decimated by oil hunters; a single liver
yields from sixty to six hundred gallons of oil. They are usually seen only in
summer when the plankton supply is good, retreating to deeper water and
possibly not feeding in winter.

WHALE SHARKS: Family Rhineodontidae

There is no fish that approaches the whale shark in size except the basking
shark. The last two gill slits are over the pectoral fin, and the first dorsal is
fairly far back over the small pelvics. The tail fin is huge. The mouth is large
and not preceded by a snout. There is only one species of cosmopolitan tropical
distribution.

Fig. 57. Whale shark.

WHALE shark: Rhincodon typiis

Size: To 60 feet or more. Very rare over 30 feet.

Weight: A 38-foot whale shark weighed 26,594 pounds.

Distribution: All tropical seas. Most numerous off the Philippines and the
coasts of southern California and western Mexico.

Identification: The coloration is a unique gray to red or green crossed with
yellowish stripes and spots. Three prominent ridges run down the sides.

Habits: This is a very inoffensive fish, so sluggish that it has been rammed
by boats on several occasions. Despite this, it can probably travel swiftly. The
feeding habits, teeth, and gill rakers are much Hke those of the basking shark.
It also basks on the surface and may school, though it is usually solitary. It
sometimes gulps plankton, small fish, or squids while standing vertically beneath
the school of food.

THRESHER SHARKS: Family Alopidae

These are large sharks with a large, extended upper tail lobe. Otherwise they
resemble mackerel sharks.

THE LOWER FISHES

151

Fig. 58. Thresher shark.

THRESHER SHARK (fOX SHARk) : AlofiaS VulfeS

Size: Matures at 14 feet. Rarely to 20 feet.

Weight: Matures at 500 pounds. Rarely to 1,000 pounds.

Distribution: Cosmopolitan in all warm seas. North to the state of Washington
and to New England in summer.

Identification: Blackish to slate and brown, sometimes with a metallic luster.
The teeth are rather small.

Habits: This is a pelagic species of ferocious appearance, but it is quite harm-
less and is almost exclusively a fish-eater. It provides one of the very few examples
of cooperative feeding among fishes, another being found among the puffers.
Several sharks herd moderate-sized, schooling fishes such as mackerel, herring,
or bonito into tight groups with the aid of their tails. Attack is thus made easier.
They may also use the tail to stun prey. The thresher is swift and voracious.
One was found off Scodand containing a bushel of fish in its stomach. Contrary
to rumor, threshers do not attack whales. It is a good food fish.

SMOOTH DOGFISHES: Family Triakidae

The first dorsal is large and just behind the pectoral fin. The second dorsal
is reduced in size, but it is not as reduced as in the similar requiem sharks,
Carcharinidae, so is noticeably larger than the anal fin. The lower lobe of the
tail fin is poorly developed. The last two gill slits are over the pectoral, and the
body is slender and tapering. These fish are very much like the requiem sharks
and are characteristic of shallow, warm temperate, and some tropical waters
the world over. However, thev tend to small size and are considered harmless.
There are both ovoviviparous and truly viviparous species. The flesh of most
species is good as food.

SMOOTH dogfish: Miistehis canis

Size: Averages 2V2 to 3V2 feet. Up to 5 feet.

Distribution: Winters from Cape Hatteras to Chesapeake Bay. Arrives in
New England from May to June when the bottom water warms to about 45°
Fahrenheit. Rare in tropics, but known to Brazil.

Identification: Plain gray to brown. Can change shade from dark gray to pale,
pearly white when over a light bottom. The change takes two days for maximum
effect. This is one of the few sharks able to change color.

Habits: This, like all smooth dogfishes, is a shallow water fish rarely straying
beyond the 10-fathom limit except in the southern part of its range. It is most
common in bays and may enter brackish and fresh water. The teeth are arranged

152

UNDERWATER GUIDE TO MARINE LIFE

Fig. 59. Smooth dogfish.

in a pavement and are adapted for shell crushing. Thus, it is a crab-eater
primarily, though a few lobsters are taken. It also takes small fishes, squids, and
some molluscs and worms. It may scavenge. This is the fish on which experi-
ments on shark feeding methods have been done. Smell is the chief aid for find-
ing food, the shark moving its head from side to side and therefore sensing food
alternately more strongly with one nostril than the other until the direction of
the food is detected. It has been shown that plugging one nostril causes the
fish to take much longer to find food. This shark is viviparous. As many as
twenty-seven foot-long young are born in June and July. The gestation period
is ten months.

Similar Species: The gray smooth hound, Mnstelus californicus, is found
from northern California to Baja California and the sicklefin smooth hound,
Mustalus lunulatus, from San Diego to Colombia. Both are very much like
the East Coast species in habits and appearance.

Fig. 60. Leopard shark.

LEOPARD shark: Triakis semifasciata

Size: Females mature at Wi feet and grow to 5 feet. Males grow to 3 feet.

Distribution: Oregon to Baja California.

Identification: The pattern of black crossbars and spots is unmistakable.

Habits: This is a bay and shallow-water shark similar to the smooth dogfish.
Although small, this shark is easily incited by the presence of blood and will
bite.

Similar Species: The brown smooth hound Triakis henlei, looks very much
like the Mustelus species. It is very common in San Francisco Bay and other
enclosed California bays.

THE LOWER FISHES 153

REQUIEM SHARKS: Family Carcharinidae

These sharks form the bulk of "typical" modern sharks and are characterized
by a large first dorsal fin which is usually far anterior to the pelvic. The second
dorsal is much reduced, just above and of a similar size to the anal. Added field
marks are the position of the fourth and fifth gill slits over the pectoral fins
and the characteristically shaped caudal fins, which is preceded by well-developed
precaudal pits. These fishes all have a well-developed third eyelid or nictitating
membrane which serves to keep the eyes free of foreign matter (fig. 64^
Spiracles are small or missing. The teeth are bladelike, triangular, and trenchant,
and only one row is functional at a time. Requiem sharks are ovoviviparous or
viviparous and characteristic of warm temperate to tropical seas the world over.

TIGER shark: Galeocerdo cuvier

Size: Common at 12 feet. Said to reach 30 feet, but largest recorded in
Atlantic was 18 feet.

Weight: Common at 850 pounds.

Distribution: Common in the Caribbean. North to Cape Hatteras and rarely
to Cape Cod. On the West Coast to southern California. Cosmopolitan in warm
temperate and tropical seas.

Identification: The snout is very blunt and rounded and the labial furrow
prominent. The sides are blotched and striped, but this pattern disappears with
age. The teeth are large, few in number, and characteristic (fig. 48^.

Hahits: This is one of the most voracious sharks, having extremely catholic
tastes in food. It eats sea turtles, sea lions, fishes large and small, crustaceans,
offal, and other sharks. It also preys on sting rays, the spines having little effect
on the shark. One, when captured, vomited the arm of a man who had been
murdered at sea and dismembered. This is the most abundant large shark of
the Caribbean and seems to be attracted by the cast-off offal of slaughterhouses.
In such dumping areas, it may be dangerous. There are records of its having
attacked man, though these are few even in areas of shark abundance. In spite
of the foregoing, this is a sluggish shark, normally becoming active only when
aroused to the "feeding mood." One expects to see tiger sharks in shallow water
near land, but they may be encountered almost anywhere, even in harbors or
the deep sea. It is the most prolific shark, normally bearing thirty to fifty living
young. The largest number of young ever recorded in a brood, eighty-two, was
from a female of this species. The young are small, only 18 inches long at birth.

e^

Fig. 61. Tiger shark.

154 UNDERWATER GUIDE TO MARINE LIFE

Fig. 62. Blue shark.

BLUE shark: Prionace gJaiica

Size: Commonly 9 to 12 feet. Rarely to 20 feet.

Weight: 164 pounds at 9 feet.

Distribution: Cosmopolitan in warm temperate and tropical seas. North to
British Columbia in the Pacific and Nova Scotia in the Atlantic. Not found
in shallow-water areas such as the Gulf of Mexico.

Identification: The coloration is a beautiful indigo blue, fading to pure white
below. The body is slim, the pectorals very long, and the snout very long and
pointed. The first dorsal is rather far back for a requiem shark.

Habits: This is the most common pelagic shark, held in fear by sailors and
in contempt by whalers. It is normally sluggish except when aroused. There are
few recorded attacks by this species on man, but it should not be counted as
harmless. It is most commonly seen at the surface, basking with the dorsal fin out
of water or following after ships in search of food. For the latter reason, they
have been named chiens de mer by the French. When hunting prey, they are
active and have been observed to repeatedly blink with the third eyelid. They
are most active at night. The blue shark's greed is practically legendary. It feeds
on all sorts of small pelagic fishes and squids. Frequently, it gathers in great
numbers about whaling ships to share in the carcass. At such times, when the sea
is clouded by blood, the sharks flounder all about the whale. Occasionally, the
whalers strike the sharks with their blubber spades and horribly mutilate them,
but even when so wounded, they go right on feeding until some of their fellows
dispose of them. There is a record of one captured blue shark, which had had its
liver removed, trying to catch a mackerel after being thrown back in the water.
Another gutted blue shark was recaught on a hook baited with its own intestines.
This shark is viviparous and rather prolific, producing as manv as fiftv-four pups
at almost any time of year.

LEMON SHARK (yellow shark) : Ncgaprion brevirostris

Size: Matures at 7 feet. To 1 1 feet rarely.

Weight: 265 pounds at 9Vi feet.

Distribution: Cape Hatteras to Brazil. Most abundant in the Caribbean. Also
in the South Pacific and Indian Oceans.

Identification: The first dorsal is small for a requiem shark and the second
dorsal rather large. The color is yellowish brown, fading to a distinct yellow
on the underside. The snout is broad and rounded.

THE LOWER FISHES

155

Fig. 6?>. Lemon shark.

Hahits: This is a strictly inshore shark and may be seen around harbors and
sounds. It even enters such fresh waters as the Amazon. It is mainly a fish-eater.
It is one of the most common of Caribbean sharks and is not to be trusted, its dis-
position supposedly being erratic. This shark is viviparous, bearing young in
the spring and summer.

GROUND sharks: Carcharinus species

This is the largest genus of sharks, containing many species that are difficult
to identify even by experts. Therefore, they will be considered as a group.
Their distribution is world-wide in warm temperate and tropical waters.

Identification: As a group, the ground sharks are bluish or grayish to brownish,
generally lighter on the belly. The first dorsal is very high and placed forward.
The second dorsal is over the anal and, like the anal, is small. The upper pre-
caudal pit is very large. There is no spiracle.

Hahits: These are inshore and reef-inhabiting sharks of fish-eating habits
largely, but they will take many foods. The larger ones are not to be trusted.
The teeth are trenchant and large. When the cry "shark" goes up along inshore
waters, the cause is usually a ground shark. They are curious fish and have
approached the authors to within a foot, returning several times for repeated
"looks," but seldom gave trouble. In fact, they usually fled when approached,
but that is no guarantee that they invariably do so. One, the Lake Nicaragua
shark, Carcharinus nicaragiiensis, is the only habitually fresh-water shark and
has been known to attack people. A list of the most common species with hints
for identification follows:

East Coast:

1. Cub Shark (Bull Shark, Fish Shark, Southern Ground Shark):
C. Leiicas

This species is never found far from land. It frequently travels in groups.
The diet is extremely varied, this shark can be dangerous at times. The
snout is very short, broad, and rounded for the genus. It attains a length
of 10 to 12 feet, though rare over 8 feet. From Cape Hatteras to Brazil
and strays to Massachusetts.

2. Small Black-Tipped Shark (Spinner Shark): C. linihatus

The eyes are large, and the pectoral, dorsal, anal and lower caudal fins
are tipped with black. It is rather small, averaging 6 feet and reaching
9 feet. This is an active, swift, largely pelagic species. It may school at the

156

UNDERWATER GUIDE TO MARINE LIFE

NICTITATIN& MEM6RAIME

Fig. 64. New York ground shark.

surface and frequently leaps from the water, turning as it does so. A
tropical species which strays to Massachusetts.

3. White-Tipped Shark: C. longiniamis

This shark has a very broad and rounded first dorsal tipped with grayish
white. The snout is rather short. It may reach 13 feet and is the most
pelagic of the ground sharks. Found in the tropical and warm temperate
Adantic.

4. New York Ground Shark (Brown Shark, Sand-Bar Shark): C. milherti

The first dorsal is very high and placed far forward, and the second
dorsal is directly over the anal. It reaches 8 feet and 200 pounds. This is
the most abundant ground shark in the shallow waters along the mid-
Atlantic Coast. It may enter river mouths and is the only large shark com-
monly found in Long Island Sound. It also enters the canals of Venice. It is
largely a bottom feeder on all sorts of fishes and invertebrates. The young
are born in shoal waters in the north from June to August. From southern
New England to Brazil. Also in the Mediterranean and off west Africa.
West Coast:

5. Bay Shark: C. lamieUa

This is a large shark of up to 15 feet, most common in bays and shallow
waters. The fins are not dark-tipped. From southern California to Mazatlan,
Mexico.

6. Gambuso: C. aziireus

This shark reaches 10 feet, is more pelagic than the former, and has
dark-tipped fins.

SHARP-NOSED SHARK: ScoUodofi teuae-novae

Size: Averages from 2 to 2^2 feet up to 3 feet.
Weight: Averages 8 to 10 pounds.

THE LOWER FISHES

15";

Distribution: Common in the Caribbean and Gulf of Mexico and in summer
to Cape Hatteras. Straggles to New York.

Identification: This shark is a southern counterpart, ecologically speaking, of
the smooth dogfish. The small size of the second dorsal fin, lack of spiracles,
short gill slits, and prominent labial furrow serve to identify it. The color is
brown to gray with the dorsal and tail fin edged in black. The body is quite slim.

Habits: A typical beach, surf, and estuary species, this shark has never been
found more than one or two miles from land. It eats a wide variety of small
in\'ertebrates and fishes and has not endeared itself to fishermen because of its
habit of preying on their baits. It is viviparous.

Similar Sfecies: The Pacific Sharp Nose, Scoliodon longurio, is found from
southern California to Panama. It reaches 3Vi feet and 9 pounds. It is rare in
scientific collections but should be common in bays in its range and should be
looked for.

SOUP-FIN (oil shark, tope) : Galeorhiniis zyopterns

Size: Females reach 6^2 feet, males up to 6 feet.

Weight: Females reach 100 pounds, males 60 pounds.

Distribution: Pacific Coast from San Francisco, to Cedros Island.

Identification: Similar to the blue shark but has short pectoral fins, no pre-
caudal pit, and is brown to gray in color. The dorsal, caudal, and pectoral fins
are tipped with black.

Habits: This voracious shark eats all sorts of fishes, squids and other inverte-
brates, and even carrion. It is the most valuable shark commercially and is
sought for its liver which is rich in vitamin A. The flesh is very good, and the
fins are used to make the famous sharks-fin soup. This is an inshore species.

Fig. 65. Sharp-nosed shark.

Fig. 66. Soup-fin shark.

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UNDERWATER GUIDE TO MARINE LIFE

common both at the surface and on the bottom. The htters are large, averaging
thirty-five and recorded from six to fifty-two. Gestation may take one year. It is
ovoviviparous.

HAMMERHEADS: Family Sphyrnidae

The widely expanded and flattened head serves to separate these sharks from
the otherwise similar requiem sharks. The eyes and nostrils are at or near the
ends of the head's extensions. Supposedly, the head, acting like a forward
rudder, gives these sharks greater maneuverability than other sharks. The very
large and wide-set nostrils are highlv efficient. These sharks are usuallv among
the first to arrive when blood is in the water. Hammerheads are found in all
warm temperate and tropical seas.

hammerhead: Sphyrna zygaena

Size: Matures at 7 to 8 feet. Averages 8 to 11 feet. Reaches 15 feet.

Weight: 900 pounds at 12 feet.

Distribution: All tropical and subtropical seas. North to Cape Hatteras (rarely
to Cape Cod) and southern California.

Identification: Slate to brownish gray in color.

Habits: This is a strong-swimming, voracious, active, surface shark, found at
sea or inshore or even in tidal, brackish waters. Like many other sharks, it often
basks at the surface with its caudal and dorsal fins protruding. Hammerheads
have a definite liking for sting rav meat. They will also eat fishes of various
kinds and other sharks as well. Great numbers of sting ray and catfish spines
have been found in the heads, jaws, and bodies of hammerheads, apparently
causing no discomfort to the shark. This shark is known to be dangerous to
men even though the teeth are rather small. The northerly migration of schools
of hammerheads in the summer consists mainly of small, 6-foot sharks. They
are viviparous, bearing up to thirty-seven young.

Similar Sfecies: Sfhyrna zygaena is merely one of three very similar hammer-
heads. The great hammerhead, Sfhyrna tudes, is the largest of these. It reaches

eONNCT

Fig. 67 . Hammerhead shark and bonnet shark.

THE LOWER FISHES

159

17 feet and 1,500 pounds. The little 5-foot bonnet shark, Sphyrna tihuro, is
found north to New Jersey and San Diego. It is a shallow-water, bay species,
and is harmless. The kidney-shaped head separates it from the three tvpical
hammerheads.

Squaloid Sharks: Superfamily Squoloidea

This is the third and last subdivision of the modern sharks. The best field
characteristic is the complete lack of the anal fin. They also possess two dorsal
fins both of which are sometimes preceded by a stout spine and fine gill slits
which are short and entirely in front of the pectoral fins. Spiracles are present
and reproduction is ovoviviparous. Presumably, this group gave rise to the rays.

SPINY DOGFISHES: Family Squalidae

The dorsal fin spines are large and the labial furrows are long. These are
small slim sharks of world-wide distribution. Many of them live in deep water,
and all have very large eyes. The tail fin has no subterminal notch.

SPINY DOGFISH (piKED DOGFISH, grayfish) : Sqiialus acanthhis

Size: Averages 2^2 to 3 feet. Up to 4 to 5 feet. The females are the largest.

Weight: Averages 7 to 10 pounds. Up to 20 pounds.

Distrihution: Subarctic North Atlantic south to Cape Hatteras. North Pacific
south to Point Conception.

Identification: Slate to brown color with yellowish spots on sides. The shape
is very slim and subcylindrical.

Hahits: This is neither a swift nor very active shark. Nevertheless it is
voracious, feeding avidly on small fishes such as herring, menhaden, and small
mackerel. It also eats invertebrates, such as jellyfish, and refuse. It is a cold-
water form, characteristic of waters of 43° to 59° Fahrenheit. Both its northern
and southern movements are determined by these temperatures, and it is thus
like the common mackerel except that its temperature range is a little lower.
During the hot months and in the south it is found in deep waters down to
100 fathoms. It is by far the most numerous shark in cooler waters, usually
found traveling in huge schools inshore, in brackish water, or a few miles
offshore. These schools are constantly on the move, so their appearance is
somewhat erratic. From one to fourteen young are born in the late autumn
offshore after two years of gestation. When caught, this shark thrashes violently
curling its body like a bow and striking out with the slightly poisonous dorsal
fin spines. The wounds these produce may be painful. The flesh is good and
is usually sold as "grayfish."

Fig. 68. Spiny dogfish.

160 UNDERWATER GUIDE TO MARINE LIFE

Fig. 69. Greenland shark.

SLEEPER SHARKS: Family Dalatiidae

The dorsal and pectoral fins are reduced in size, and the gill slits are short.
These sharks are as sluggish in appearance as they are in reality. The teeth are
very different in the two jaws. Many are inhabitants of the deep sea and have
luminous spots. Their distribution is world-wide, and they are ovoviviparous.

GREENLAND SHARK (sLEEPER SHARK, GURRY shark) : Somniosiis microcefhaUis

Size: Averages 8 to 14 feet. Possibly to 24 feet. The females are larger than
the males.

Distribution: Arctic seas to Cape Cod.

Identification: The color is coffee-brown to dark gray with tinges of violet.
There may be faint, darker crossbands.

Habits: This is the largest arctic fish and the only arctic shark. It may live
in water as cold as 28° Fahrenheit, or as warm as 55° Fahrenheit. It probably
lies near or on the bottom, rising only to feed and may be counted as the
most sluggish of large sharks, offering no resistance to capture. In spite of this,
it seems to be able to catch seals as well as large fishes such as halibut and
salmon, though it will also eat crustaceans and jellyfish. It seems to be irresistibly
attracted by carrion. Therefore, whalers know it well. In spite of rumor to the
contrary, it attacks neither living whales nor men in kayaks, and it is quite
harmless. The flesh is intoxicating and poisonous if eaten fresh, but is wholesome
if dried or allowed to become partly rotten.

Similar Species: The Pacific sleeper shark, Somniosiis j)acificus, is found south
to southern California. Its habits are like those of its Atlantic cousin.

ANGELFISHES: Family Squatinidae

These raylike fishes are shown to be sharks by the possession of gill slits on
the side of the "neck," pectorals which are not attached to the head, and free
eyelids. They also possess characteristics which are superficially raylike: much
flattened body form, enlarged pectoral and pelvic fins, two small dorsals placed
far back, a row of spines along the mid-back, and eyes and enlarged spiracles
on the top of the head. They are not to be considered the evolutionary link
between sharks and rays, but they are midway between those two groups in
habits. Thus, they are bottom-living but still use the tail in a sculling, sharklike
manner for locomotion, little use being made of the pectorals except for steering.
They are ovoviviparous and world-wide in distribution.

MONKFiSH (angel shark): Sqtiatina diimeril

Size: Matures at 3 to Wi feet. To 5 feet.
Weight: At 4 feet weighs 60 pounds.

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161

Fig. 70. Monkfish.

Distribution: Summer visitor to mid-Atlantic states. Most common near
Chesapeake, south to the Gulf of Mexico and the Caribbean. Not really plentiful
anywhere.

Identification: Blue to ash-gray above with spots and mottled pattern. May
have some reddish tints.

Habits: In summer, this is mainly an inshore fish. It lies on the bottom and
may pardy cover itself with sand or mud as rays are wont to do. From this van-
tage, it ambushes flatfish, skates, mullet, and other fishes. It also eats crustaceans

O ' 7 7/

and molluscs, which it crushes with its strong jaws. In winter it strays to water
as deep as 700 fathoms. The young are born in early summer inshore in num-
bers up to twentv-five at a time. This shark has powerful jaws and may inflict
a painful bite if molested. The teeth are small and numerous. The term
"angel shark" refers to the angel-wing shape of the pectorals.

Similar Species: The California angel shark, Squatina californica, is of similar
size to the Atlantic forms. It is found from Alaska to southern California and
is rather common in the south. The European monkfish, Squatina squatina,
gets much larger, 8 feet and 170 pounds, and is very plentiful in Europe.

Rays: Order Hypotremata {"openings beneath")

Among the most remarkable of the animals of the sea are the rays, sometimes
grouped as the order Batoidei. Most of them are greatly flattened, but just as
there are raylike sharks, there are also sharklike rays, so body form is not dis-
tinctive. The significant characteristics are ( 1 ) the enlargement and continuation
of the pectoral fins onto the head, (2) the position of the five pairs of gill slits
on the underside (forced there by the overgrowth of the pectorals), and (3)
the absence of lower and usually also of upper eyelids.

The rays probably developed from squaloid sharks in response to the develop-
ment of expanded pectoral fins for greater mobility. The evolution of the ad-
vanced rays (Myliobatoidea) from the primitive types (Pristoidea) was the
result of the following steps: (1) the pectorals took over all locomotion, (2)
dorsal and caudal fins were lost, (3) the body became flat, (4) the enlarged
spiracles and eyes were moved to the top of the head, and (5) the tail became

162

UNDERWATER GUIDE TO MARINE LIFE

Fig. 71. One of the authors is photograpJi'nig a large soutliern sti>ig ray, Dasyatis
americana, four feet in diameter, which was found covered with sand sleeping on
the hottorn.

distinct from the body- We see this evolutionary transition in following the
changes in body form from the sawfishes to the guitarfishes to skates and tor-
pedoes and finally to the eagle rays. This evolutionary trend is an adaptation to
bottom-living. But like almost every group of animals, there are departures from
the principal theme, and so the rays have also risen from the bottom to take on
the more pelagic life that we see in the eagle rays and mantas.

Paralleling these evolutionary tendencies are distictive methods of locomo-
tion. In the most sharklike and least flattened rays, the sawfishes and guitarfishes,
locomotion is accomplished by powerful sculling motions of the tail as in sharks.
The pectoral is used little. In the torpedoes also, propulsion is chiefly caudal,
but this is probably because the disc is so inflexible, it being the location of
the electric organs. The skates move almost entirely with the pectoral fins, un-
dulating waves traveling in this fin from front to rear. Sting rays also use

THE LOWER FISHES

163

undulating waves of the pectoral for slow locomotion, but flap their "wings" like
a bird more than do the skates when they desire to move fast. The eagle and
manta rays flap their wings exclusively and are able to move rapidly in this
way. Turning in all rays is accomplished mainly or exclusively by the pectoral
fins. Some rays, particularly the "flying" ones are among the most graceful of
fishes. Thev are also among the most powerful things that swim as anyone
who has hooked one can attest.

As befits their largely bottom-living habits, rays are dark on the upper surface
while the lower surface remains white and patternless. The upper surface is
sometimes patterned to resemble the substrate over which the animal lives.

Most rays are rather sluggish and nocturnal and, though powerful swimmers,
are not as speedy as sharks or bony fishes. It is expected, therefore, that they
would abandon the fish-eating diet of sharks for more easily caught food such
as invertebrates. Most of them cannot see their food as they grasp it with their
mouths, but must settle over the active food species with their bodies or dig
for the less active ones in the bottom. They are the only fishes that are known
to settle over and trap food with their bodies, but they do not envelop prey
with their wings as has been supposed. Most rays possess many rows of small,
sharp, or flattened teeth arranged so as to act in a grasping or crushing manner.

Rays vary in size from a few inches to 23 feet (across the pectorals) and are
found all over the world from arctic to tropical waters. Some sting rays and
sawfishes even enter fresh water. Rays allow close approach since they are not
timid animals. By day they are often seen asleep on the bottom. They are,
therefore, easy prey for the swimmer, but the authors do not consider it either
very good sportsmanship nor verv good sense to molest them. It must be remem-
bered that even rather small rays are powerful, and many, if not most of them,
can be dangerous, as we shall see in the following pages.

There are fi\'e major groups (superfamilies) of rays.

Sawfishes: Superfamily Pristoidea

These are the most sharklike of the rays. The presence of the extended snout
bearing saw teeth is an unmistakable and unique identifying character. This
saw can be a very formidable weapon. Sawfishes are ovoviviparous. The saw
of newly born sawfish is covered by a sheath in order to protect the female.

164 UNDERWATER GUIDE TO MARINE LIFE

This sheath is lost soon after birth. The distribution of sawfishes is world-wide
in warm, shallow seas. They enter brackish and fresh water. There is but one
family containing a single genus.

SAWFISHES: Family Pristidae

sawfish: Pristis fectinatus

Size: Commonly to 16 feet. Reaches 20 feet or more.

Weight: Commonly to 700 pounds.

Distribution: Most common off Florida and in the Gulf of Mexico. To Cape
Hatteras in summer. Also south to Brazil.

Identification: Grayish brown in color.

Habits: These bottom-living rays are most plentiful in shallow bays and
estuaries, entering brackish and even fresh waters. The shape indicates a sluggish
but powerful animal. They rarely rise far from the bottom except to attack
schools of small fishes, such as mullet, on which they feed. The saw is used in
a sideways slashing manner to stun and impale these fishes, which are later
eaten at leisure. The saw also serves for poking about in the sand or mud
bottom for various items of food, mostly invertebrates. It is also a powerful
weapon of defense. A sawfish will not attack man unprovoked, but even small
ones should not be molested. Contrary to rumor, sawfishes do not attack whales,
but they may attack fairly large fishes, although rarely. The young are born
in summer and autumn after about a year's gestation. They are 2 feet long at
birth. Young sawfishes make excellent eating.

Guitar Fishes: Superfamily Rhinobatoidea

In this group, the transition from sharklike to raylike forms is complete. The
disc is either distinctly heart-shaped or round. The tail is always stout, and the
dorsal and tail fins are well developed. A uniform shagreen covers the body.
The mid-dorsal spines are somewhat enlarged. They are ovoviviparous and found
in all warm temperate and tropical seas.

GUITARFISHES: Family Rhinobatidae

SPOTTED guitarfish: Rhinobatos lentiginosns

Size: Averages 2 feet. Reaches 3 feet. The females are larger than the males.

Distribution: Most common off Florida. To Yucatan and Cape Hatteras.

Identification: Covered with small Hght dots over a brown to ash-gray ground
color. The disc is wedge- or heart-shaped and the snout long.

Habits: Guitarfishes swim close to the bottom using sculling motions of the
tail for propulsion and the pectorals for steering. They may lie half buried in
mud or sand and eat small molluscs and crustaceans. They are not often en-
countered in water deeper than 5 to 10 fathoms and are even encountered in
surf feeding on the gammarid shrimj-)s and sand crabs, Hippa, found there.

Similar Species: Three West Coast species show a perfect graded transition
to skates in the shape of the disc, though the tail remains stout in all.

The shovel-nosed guitarfish, Rliinobatos productus, is much like the East

THE LOWER FISHES

165

Coast form. It reaches 4 feet or over and ranges from central California to the
Gulf of California.

The mottled guitarfish, Zapteryx exasperata, has a shortened snout, wider
disc, dark crossbands, and reaches 3 feet in length. It is found from San Diego
to Panama.

The thornback, Platyrhinoidis triseriata, has a skatelike rounded disc and skate-
like spines on the back and shoulders. It reaches 3 feet and is found from
central California to Baja California.

Skates: Superfamily Rajoidea

In these rays and all remaining rays, the tail is sharply marked off from the
body, and the pectorals are the chief means of locomotion. Skates also have
the dorsal and tail fins greatly reduced in size and the pelvic fins deeply notched
so that they look double. The males possess very large claspers. The discs and
tail are covered with enlarged prickles in patches which vary according to species.
Skates are characteristic of temperate and arctic waters of the world. They are
in the tropics, but only in very deep water. Some run up rivers. They are the
onlv oviparous rays. The egg cases, called "sea purses' or "sailor's purses," are
very common objects on beaches.

SKATES: Family Rajidae

This is the only family of skates and contains the largest of all elasmobranch
genera, Raja, with almost a hundred species. The species of this genus have

E&G CASE X-r

Figs. 7?) and 74. Common skate Qeft^ and spotted guitarfish (rig^it).

166 UNDERWATER GUIDE TO MARINE LIFE

similar habits and some are difficult to identify. Therefore, skates will be
considered as one group.

skates: Raja species

Skates are ground fishes found over sand, mud, gravel, or shell bottoms. They
are rather inactive by day, at which time they lie on the bottom, sometimes half
buried. To bury themselves, they stir up the bottom with their pectorals and
let the sand or mud fall back on them. They depend a good deal on protective
coloration to avoid being detected, their grayish or brownish, often spotted
or mottled bodies blending in well with the substrate. When alarmed they tend
to press their bodies closely to the bottom and may form a suction between
their bodies and the bottom which makes them difficult to dislodge. If further
alarmed, they may curl themselves into sort of a ball and lash violently with
their spiny tails. Some have electric organs on their tails able to deliver half a
volt. The adaptive value of such a small shock is not known. The skates are not
exclusively bottom fishes. Frequently, they come to the surface to bask in the sun
after the manner of many sharks. Skates, like most rays, have many rows of small,
pointed or flat teeth in the jaw which form a crushing or grasping dentition.
Their prey is quite varied but usually consists of crustaceans, molluscs, worms,
and small to medium-sized fishes. With active prey, such as fish, their method of
securing food is by ambush. They lie on the bottom until a victim comes their
way, then quickly pounce on it, holding it down with their bodies, and then
grasping it in their jaws. This method of capture is made necessary by the
position of the jaws on the underside. Locomotion is achieved by undulating
waves passing from front to rear in the pectoral fin. Skates can swim surprisingly
fast, at which time the pectorals are used in a flapping motion like the wings
of a bird. The tail may aid in steering.

Skates mate with their ventral sides together and are frequently caught in
this position. One or both claspers are inserted. The egg capsules or sea purses
Cfig. 73) are 3 to 8 inches long and contain one to several eggs. They are laid
in the summer and adhere to rocks, shells, algae, etc., hatching in four and
one-half to fifteen months. The courtship and mating procedure should be easy
to observe by the swimmer. Males are smaller than females by about one-third.
Sometimes, several follow a single female and strike each other with the spiny
parts of the pectorals. These spiny pectoral patches are also used to grasp the
female while mating. Skates make excellent food. Raie au heiirre noire is a
French culinary delicacy. Skates reach 6 feet and 60 pounds but are mostly
much smaller. A list of some common species follows:

East Coast:

1. Common Skate (Litde Skate, Hedgehog Skate): Raja erinacea

This is a small skate, reaching only 20 inches in length. The spines arc in
a distinctive pattern with no spines of large size directly on the midline.
This is the most common New England skate, found in shoal water and
to 80 fathoms, usually over a sandy bottom. It ranges from Cape Hattcras to
Nova Scotia.

2. Clear-Nosed Skate (Briar Skate, Summer Skate): Raja eglanteria

There are two translucent areas on the side of the snout and there is a

THE LOWER FISHES 167

prominent row of spines on the midline of the back and tail. The whole
tail is covered with thorns of like size. The back is spotted or barred with
dark brown. Reaches 2 feet in length. Found in shallow waters from
Maine to Florida but common only from Massachusetts to Delaware.

3. Barndoor Skate (Sharp-Nosed Skate): Raja laevis

The popular name is derived from its large size, which may attain a
length of 5 feet and a weight of 35 pounds. The snout is prolonged and
pointed and the body spines small. It is the only skate with pigmented
mucus pores on the underside. Found from Newfoundland to Cape
Hatteras.
West Coast:

4. California Skate: Raja inornata

The outer border of the pelvic fin is deeply concave and the color is
dark olive to brown with vague mottlings. It reaches 2^2 feet. Found from
the Strait of Juan de Fuca in the North Pacific south to Cedros Island,
California.

5. Big Skate: Raja hinoculata

There is a large ocellar spot on the inner side of each pectoral fin. The
outer border of the pelvic is nearly straight. It reaches 6 to 8 feet in length
and the egg cases are a foot long and contain up to seven eggs. Found from
Alaska to southern California.

6. Long- Nosed Skate: Raja rhina

The snout on this skate is very long and tapering. The overall size may
reach 4 to 5 feet. Found from Alaska to southern California.

Electric Rays: Superfamily Torpedinoidea

These are very odd rays possessing an almost circular disc and a stout, some-
what sharklike tail on which are situated two large dorsal fins and a large tail
fin. The eyes are small; some electric rays are even blind. The body is smooth
and peculiarly flabby. The pectoral fins are thick and rather immobile, being
the seat of the large electric organs, which may weigh as much as one-sixth
of the total weight. Because of the fact that typical muscle nerves go to these
organs, they are thought to be a muscle tissue in which the electrical properties
inherent in all muscle tissue have been accentuated at the expense of the
locomotory properties. They are formed of thousands of hexagonal discs piled
in columns and thus look like honeycombs. The resemblance to a voltaic pile is
striking. A shock delivered by these rays is really a "train" of twelve to a hundred
separate pulses each of which lasts about three hundredths of a second. Voltages
delivered vary from eight to 220 depending upon the size of the ray and its
species. Several shocks may be delivered in succession, but each one is a little
weaker than its predecessor. A rest period is needed to build up the power to
its full state again. The shocking power is far less than the really dangerous
electric "eel," Electrofhorus, of South American rivers. Still, it is enough to
knock down and temporarily disable a full-grown man.

The purpose of the shocking power is a matter of some mystery. Almost
certainly, it is defensive, and it seems likely that it may also be offensive.
Presumably, electric rays are too slow-moving to catch the fishes, such as dogfish

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UNDERWATER GUIDE TO MARINE LIFE

and flatfish, that they are known to eat. They swim feebly with sculling motions
of the tail, using the stiff pectorals only sparingly, if at all.

Electric rays are among the laziest of fishes. They lie buried in sand or mud
most of the time. They are found in shallow and deep waters of all temperate
and tropical seas, mostly over soft bottoms. They are ovoviviparous and range
in size from a foot in length to 6 feet and 200 pounds.

ELECTRIC RAYS: Family Torpedinidae

TORPEDO (electric RAY, NUMBFISH, crampfish) : ToYfedo nohiUana

Size: Matures at 2 feet. Up to 5 to 6 feet long.

Weight: Averages 30 to 75 pounds. Up to 200 pounds.

Distribution: Both sides of North Adantic from Nova Scotia to Cape Hatteras
(rarely Cuba) and from Scotland to west Africa. Nowhere plentiful.

Identification: The disc is very wide and round and about one-half the total
length. The color is chocolate to purplish brown, sometimes with obscure
dark spots.

Habits: Little is known other than the general information given above. This
is one of the most electrically powerful of the electric rays. It is known to eat

Fig. 75. Torpedo ray.

large and even active fish such as salmon, eels, and flatfishes, a support for the
argument that electric rays use their electric powers to secure food.

Similar Sfecies: The California electric ray, Torpedo californica, is found
from British Columbia to southern California and is locally plentiful in moderate
depths. It reaches a length of 3 feet and a weight of 50 pounds.

The litde electric ray or crampfish, Narcine braziliensis, belongs to a genus
of small rays which has oval discs, not nearly as blunt anteriorly as the torpedoes.
They have a mottled coloration which blends with the sand, resembling the

THE LOWER FISHES 169

coloration of the round sting ray. This species eats invertebrates mostly and can
produce shocks of thirty-seven voks. It matures at 9 to 10 inches in length and
reaches 18 inches. Found from Florida and Texas south to Brazil.

The True Rays: Superfamily Myliobatoidea

The remaining rays are grouped in a single superfamily. All have the tail very
well marked off from the body, usually like a whip, with one or several dangerous
poison spines at its base (exceptions to this are found among butterfly and devil
rays). This tail spine can be a very dangerous defensive instrument which can
produce excruciating pain. Known remedies are a warm Epsom salts bath or an
injection of 5 per cent permanganate of potash solution (Condy's Fluid). The
injection of antibiotics or other antiseptics may also be of value. These are
principally shallow-water fishes of the tropics and subtropics. Some enter fresh
water. The species vary in size from under a foot to 23 feet in width. They are
all ovoviviparous. Several species can utter a grunting sound.

STING RAYS: Family Dasyatidae

The discs are usually rhomboid but may be round (in the round sting
rays). The tail is long and whiplike and bears no fins (except for round
sting rays). These rays all have a long serrate spine at the base of the tail. This
spine is not only poisonous, but it is large enough to cause a dangerous wound
by itself. The stingers may vary from an inch or so to over a foot long. If one is
lost or worn out another grows in its place so that two or even three may be
present at once. The spine appears to be used mostly in defense but may
rarely be used off^ensively. It was a matter of debate for many years whether
or not the spine actually carried a poison. It was thought that the jagged wounds,
and mucus and other foreign matter introduced into the wound, were enough
to cause the extreme pain, swelling, cramps, inflammation, gangrene, or, rarely,
death. (Stings are not always serious, but the fact that they may be so should
be warning enough.) Then it was discovered that the narrow grooves along each
edge of the spine contained a glandular, poison-secreting tissue. Furthermore,
the poison is of a virulent nature. Poison glands may also be present at the base
of the spine.

Sting rays are usually not active, lying buried in sand with only the eyes and
spiracle showing. However, .they are not nearly as sluggish as torpedoes and
may frequently be seen swimming over reefs and sandy bottoms, being capable
of considerable speeds. They are mostly crustacean- and mollusc-eaters, but do
take fishes also. They commonly stir up the bottom with their pectorals in search
of food. At times they are extremely abundant over shallow, sandy bottoms,
almost seeming to pave the bottom. Large ones are powerful, but inoffensive.
The authors, in order to stir one very large southern sting ray for purposes of
photography Qfigs. 71 and 76X grasped it by the tip of the tail. It rose, circled
slowly, swam a short distance, and sank to the bottom, burying itself by throwing
sand over its back with its pectoral fins. This afforded an excellent chance to
observe and photograph its exceedingly graceful and beautiful "flight," not
forgetting, of course, that this seemingly inoff^ensive beast possessed a formidable
weapon. Sting rays are ovoviviparous and found in warm shallow waters the
world over.

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UNDERWATER GUIDE TO MARINE LIFE

r, /

Fig. 16. Top. The round sting ray, Urolophus, is mottled to resemble its suhstrate.
This ray, though small, has a very -powerful sting. Bottom. The southern sting ray,
Dasyatis americana, is most easily identified hy the large, finlike fold beneath
the tail.

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THE LOWER FISHES

171

ROUND STING RAY: Urolofhus jamaicensis
(^Also known as Urohatis^— Figure 76

Size: Usually 16 inches to 2 feet long.

Distribution: Florida to the Caribbean. Sometimes to Cape Hatteras.

Identification: The disc is round and light-colored with dark mottlings which
blend in with the sandv bottom. The pattern may vary with the nature of the
bottom, but this has not been demonstrated. The tail is short and has a caudal
fin and highly developed spine.

Habits: This is a species of shallow shoal and reef waters. It is not timid.
One swam directly under the arm of one of the authors and settled quietly on
the sand not two feet in front of him. It is more common than supposed, as
swimmers will surelv discover, being found often about reefs in the Bahamas
particularlv. It scoops out holes in the sand to expose its invertebrate food. In
spite of its small size, the sting is dangerous, said to be more dangerous than
other sting rays of much larger size.

Similar Species: Members of this genus are common in most tropical waters.
The Californian round sting ray, Urolophtis helleri, is very similar to the eastern
form and is found from Point Conception to Panama.

STiNGAREE: Dasjatis sabina

Size: To only 15 inches across, the smallest Atlantic member of its genus.

Distribution: Gulf of Mexico to Florida and the Caribbean. To Cape Hatteras
and, rarely, to the Chesapeake Bay.

Identification: The snout is pointed and rather long, and the pectorals are
very rounded. It is yellow-brown to dark brown with a dark line down the
midline. The midline of the back possesses prickles.

Habits: This ray is more or less strictly tropical and is found in very shallow
water. When walking through shallow water, it is well to use a shuffling motion
of the feet. This tends to drive the rays ahead if they are present. The sting is
probably not as painful as that of the round sting ray.

Similar Species: The southern sting ray, Dasyatis americana (_fig. 76'), is the
most common large species from Cape Hatteras to the Caribbean. It replaces

Fig. 77. Stingaree.

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UNDERWATER GUIDE TO MARINE LIFE

the northern sting ray south of Cape Hatteras and these two rays are very
similar in habits. It is easily recognized by the finlike folds under the tail behind
the spine, a keel above this fold on the tail, and the angular shape of the
pectorals. It averages three feet across the pectorals and probably reaches 4 feet.
It often enters very shallow water, at which times the pectoral fins and tail
may break the surface.

The northern sting ray, Dasyatis centrura, reaches 13 to 14 feet in length
and 5 feet in breadth. At Wz feet in breadth, it weighs 180 pounds. It is much
like the southern sting ray but has a thorny tail with no keel on top of the tail.
It is locally plentiful in shallow waters from Cape Hatteras to Cape Cod.

The diamond sting ray, Dasyatis dipteninis, is much like the preceding
species. It is found from British Columbia to Central America and is common
in bays from San Diego southward. It reaches a length of 6 feet.

Fig. 78. Butterfly ray.

BUTTERFLY RAY (sAND skate) : Gyuinura viicTiira .

Size: Averages 2 feet in breadth. To 4V2 feet across, rarely.

Distribution: From Massachusetts to Brazil. Most common from the Gulf of
Mexico to the Chesapeake.

Identification: The breadth is much greater than the length, and the spineless
tail is very short. The color is gray, brown, or even greenish or purplish. It can
change its color to match the surroundings somewhat.

Habits: This ray behaves much like the Dasyatis species, but is more active,
especially in response to tide changes. This ray prefers coastal sandy bottoms
and feeds on a wide variety of molluscs and crustaceans. It may enter brackish
waters. It bears young from May to August.

Similar Species: The giant butterfly ray, GyMiniira altavela, grows to a
breadth of 7 feet or more. It is found from Massachusetts to Brazil. This ray has
small spines on the tail base. It is known to utter a grunting sound when in
distress.

The butterfly sting ray, Gymnura marmorata, of Point Conception to Mazat-
Ian, has a small sting and reaches a breadth of 5 feet. It is common in shallow
bays along beaches.

THE LOWER FISHES

173

Figs. 19 and 80. Spotted eagle ray (left) and cow-nosed ray Qright').

EAGLE RAYS: Family Myliobatidae

These rays have largely abandoned bottom-living habits, but still feed on the
bottom on hard-shelled molluscs and occasional crustaceans. The teeth are well
adapted for crushing such resistant fare and are flat and like a pavement in the
jaws. When feeding, thev swim near the bottom in order to detect, probably
by smell, the currents emitted from clam siphons. Then they dig the clams by
flapping their powerful pectorals or by rooting about like a hog with their noses.
When not feeding, they swim gracefully and rapidly through the water near
the surface and may even leap from the water completely. They rarely rest on the
bottom. Because of their active habits, these rays are not as flat as most rays.
There is a definite head with an elevated crown, which has the eyes and spiracles
on the side rather than on top. The body is heavy and the pectorals powerful
and thick. There are one or more poisonous spines at the tail base, but these
are so near the body that they cannot be used as efficiently as those of sting
rays. Nevertheless, the presence of spines as well as the large size of up to
8 feet across and 600 pounds in weight should be enough to caution the
swimmer that he had best not tamper with these normally inoffensive fishes.
They are very hard to handle and dangerous if hooked or speared.

Eagle ravs travel over deep water but are most common in sandy or muddy
bays where shellfish abound. They seem not to enter enclosed bays and
estuaries as sting rays do. They are ovoviviparous and found in all warm
temperate and tropical seas.

SPOTTED EAGLE RAY (SPOTTED DUCK-BILL RAY, LEOPARD RAy) :

Aetohatus narinari

Size: Averages 3 to 4 feet across. Up to almost 8 feet across.

Weight: Up to 500 pounds or more.

Distribution: Almost cosmopolitan in warm seas. North to North Carolina
(rarely the Chesapeake) and over much of the Indo-Pacific.

Identification: The vivid light spots on the dark olive, brown, or black
background form a distinctive pattern. The snout is almost like a duck's bill.

Habits: These large and spectacular rays are almost exclusively mollusc-eaters.
They travel singly, in pairs, or in large schools of hundreds of individuals. A

174 UNDERWATER GUIDE TO MARINE LIFE

large school in an oyster bed can very well spell the end of almost the entire
bed. Large rays are able to crack thick-shelled molluscs, an indication of the
immense power of their jaws. But the jaws are delicate as well as powerful since
the meat of the molluscs is separated from the shell so skillfully that very little
shell is swallowed. These are powerful swimmers and are known to leap from
the water. One specimen only a little over 5 feet across was easily able to drag
a 22-foot boat containing three men. They are known to emit a harsh cough
when captured. The young are released into the air one at a time by the mother
as she leaps out of the water, a spectacular method of childbirth which is seldom
observed.

Similar S'pecies: The eagle ray, Myliohatus freyninvillei, is smaller than the
spotted eagle ray, reaching 5 feet across, and maturing at 2 to 3 feet across. There
are no spots, and the snout is not like a duck's bill. It strays to Cape Cod in
summer, but lives the year round in the Caribbean.

The bat sting ray, Myliohatis californiciis, is very similar to the eagle ray
and is common inshore in bays from Oregon to Magdalena Bay.

COW-NOSED ray: Kliinoftera qiiadriloha

Size: Averages 3 feet across. Up to a width of 7 feet.

Weight: Averages 25 to 70 pounds.

Distribution: New England. Less common in tropical than in warm temperate
zones of both hemispheres.

Identification: The peculiar bilobed nose is distinctive. The color is a yellowish
brown.

Habits: This is the commonest of the eagle rays. Like the rest of them, it is a
mollusc-eater. A school of these rays rooting about in clam or oyster beds is
reminiscent of a drove of hogs. It is commonest in shoal water and may leap
from the surface. The young are produced in spring and summer. Little is
known of their habits in spite of their reasonable plentifulness. Cow-nosed rays
have the disturbing habit of "rounding" a swimmer, but in doing so have no
aggressive intentions.

DEVILFISHES: Family Mobulidae

These rays have completely abandoned the bottom-living habit and do not
even feed there. Thus, the eyes are on the side of the head, and the spiracles
are so reduced that respiration is sharklike, most water entering the gills through
the mouth. Devilfishes are easily identified by the large cephalic fins that look
like devil's horns on either side of the mouth. These are used to funnel and
scoop plankton and small fishes into the ray's mouth. A gill sieve filters the food
from the water much as in the whale and basking sharks. There are no poisonous
tail spines, but the great size and famed power of these fishes should be
enough to caution the unwary. Contrary to rumor, these are inoffensive fishes
showing little fear of man. Rarely are we treated to a sane view of the manta,
for instance. Magazines and movies would rather show them gushing blood
from harpoon wounds or making alleged attacks on swimmers. If molested,
however, one can hardly blame them for fighting back. The pectoral fins are
used to deliver repeated sledge-hammerlike blows. Devilfishes are ovoviviparous
and found in all temperate and tropical seas.

THE LOWER FISHES

175

LITTLE devilfish: Mohulu hjfostoma

Size: Up to 4 to 5 feet in width. Near relatives reach 23 feet in width.

Weiolit: Up to 40 pounds. Near relatives reach 3,500 pounds.

Distribution: Cape Hatteras to Brazil. Recorded north as far as New York.

Identification: The mouth is on the underside beneath the short snout. The
color is a blackish brown. The tail is relatively long.

Habits: Little devilfish travel in schools and feed by rushing at schools of
small fishes or plankton. They drive the prey toward shallow water near shore
and may even beach themselves temporarily in their vigorous feeding rushes.
They are inveterate leapers. According to Coles (1916) these rays leap clear of
the water and land with a great splash. The larger manta also leaps, but usually
not completely clear of the water. Females also leap during childbirth. The
young are ejected one at a time as the female leaps into the air. If a female
devilfish is harpooned, this will often cause a forcible ejection of the young.
Little devilfish can utter a musical barking sound.

Similar Species: The lesser devilfish, Mobida lucasana, reaches 7 feet in width
and is found from Baja California to Central America.

The manta, Manta hirostris, has a large mouth terminal on the snout and a
shorter tail than the little devilfish. It ranges in all tropical and subtropical seas
and is fairly common. It reaches 23 feet in breadth and 3,500 pounds. Contrary
to the similar little devilfishes, it usually travels alone, moves slowly as it feeds,
and leaps only partly out of the water. It still makes a tremendous noise in its
leaps however. Tales of its power in pulling boats are legendary. It likes to bask

Fig. 81. Little devilfish..

176

UNDERWATER GUIDE TO MARINE LIFE

in the sun with the upturned "horns" protruding from the water, at which times
it is easily approached. The word "manta" means "blanket" in Spanish.

GHIMAERAS: Glass Chondrichthyes, Subclass Holocephali

These very odd fishes are mostly found in the deep sea and have the long,
pointed tail that is characteristic of so many deep-sea fishes. The reason for this
is unknown. Chimaeras do not seem to use the tail much for propulsion, this
task mainly being the job of the flapping pectorals. Very commonly there are odd
appendages on the head of the male which may be of some unknown reproduc-
tive function. They have an operculum like bony fishes. Despite their preference
for deep waters, chimaeras do get into shallow water. The long dorsal spine is to
be avoided. It is poisonous and able to inflict a painful wound.

CHIMAERAS: Family Chimaeridae

RATFiSH (chimaera) : Hydrolagiis colliei

Size: To 3 feet.

Distribution: Northwest Alaska to Baja California. Fairly common in shallow
water in northern California and northward.

Identification: The color is silvery with gold, blue, and green iridescent sheens.

Hahits: The egg cases are unique. Very little is known of the habits. Presum-
ably, ratfishes eat invertebrates, as the chisellike front teeth and crushing back
teeth would indicate.

Similar Species: The Atlantic chimaera, Chimaera affinis, reaches 3 feet and is
a deep-water fish of waters to the north of Cape Cod.

E6S CASE

Fig. 82. Ratfish.

X^

CHAPTER ^

MASTERS OF THE WATER— Bony Fishes

CLASS OSTEIGHTHYES {"bony fish")

We have previously mentioned that the primary aims of this book are to give
identification of groups (such as famihes) rather than of species and to see into
which niche each group falls in the economy of the sea. Perhaps nowhere is the
usefulness of this procedure better exemplified than in the case of bony fishes,
for the following reasons:

1. Bony fishes are the dominant animals of the sea, receiving far more
attention than any other of the sea's inhabitants. They are tremendously
numerous and, in contrast to the sharks and rays, extremely diverse both
in form and habits. To understand this great diversity, it is best to think
not in terms of thousands of species, but in terms of families.

2. By keeping groups in mind, the swimmer will not be completely lost when
confronted by strange, new fishes elsewhere in the world. For instance,
both the red tai of Japan and Europe's huge dentex become species of
porgies, Sparidae, rather than just a couple of unknown, isolated species.

3. The bony fishes are much more difficult to identify than sharks and rays,
demanding the use of comparatively complex characters for proper
identification. For instance, demoiselles, Pomacentridae, are not too diffi-
cult to identify as a group, but species identification is complex and is still
a matter of dispute among ichthyologists.

It is difficult, if not impossible, to give a list of characters that strictly define
bony fishes. All have skulls that are composed of a complex system of bones,
but this information is of little use to the underwater swimmer. However, there
are two field characters which vary little; the possession of an operculum which
covers the gills (if absent, as in some eels, there is never more than one gill
opening) and the presence of fins which are supported by bony rays. The fins
are very mobile, in contrast to those of the cartilaginous fishes. Usually, also,
there is a covering of bony scales which overlap like the shingles on a roof.

The movement of fishes is a topic of great interest, to which the observations
of the underwater swimmer can add much. The ffight characteristics of birds

177

178

UNDERWATER GUIDE TO MARINE LIFE

SPINX DORSAL FIN
LATERAL LINE . | SOFT DORSAL FIN

KEEL SCUTES

OPERCULUM \y

y PECTORAL FIN

t
PELVIC, (ventral) fin

THORACIC POSITION

r

CAUDAL (tail) fin

PELVIC (VfNTRAL) FIN
ABDOMINAL POSITION

Fig. 83. External anatomy of hony fishes.

through their medium, air, have been well studied, but fish movement is less
understood, though they, too, fly, in a sense, through water. Bony fishes are
more efficient swimmers than sharks and rays because of the combination of
three factors: (1) the shortened, compact body allowing short, efficient, lateral
strokes of the tail (a tendency seen in the mackerel sharks), (2) the possession
of an internal hydrostatic organ, the swim bladder, which adjusts the specific
gravity of the fish so that stabilization in any depth of water is possible (sharks,
as we pointed out earlier, cannot do this), and (3) the great mobility of the
fins, resulting in increased maneuverability, and the ability to start and stop
suddenly (sharks and rays cannot do this). Fish movement is so intimately
related to the habits of fishes and is so useful in identification of groups that
we will give it considerable attention in our review of the families.

Breder (1926) has set up three main categories of fish movement:

1. Carangiform (like the jack, family Carangidae). The typical fish movement
in which propulsion is accomplished by short lateral strokes of the tail, and
steering is accomplished largely by the paired fins.

2. Anguilliform (like the eel, family Anguillidae). The long-bodied fishes
such as eels progress by a long series of sine waves which pass down the
body. (Most sharks, being long-bodied, have a modified and shortened
movement of this type.)

3. Ostraciform (like the trunkfishes, family Ostraciidae). Propulsion becomes
largely a task of the pectoral, dorsal, and anal fins. The tail is used mainly
for steering.

Within these very broad categories many variations occur, and these shall
be mentioned as they are met, particularly as departure from the typical

COMr</lON TRIGOERFISH

SOUTHERIM PUFFniR.

COLOR PLATE 9

TPLACHYLI^4E
M e DUSA

sevPHOZo/\rs(
M e DUS/\

COWFtlE

QUEEN COMCH

Kl MG CONOH

COLOR PLATE 10

MASTERS OF THE WATER-BONY FISHES 179

carangiform movement is made. Carangiform movement is an adaption for speed.
Just how fast fishes can travel is not well known. Some tuna and spearfishes
probably can travel over 40 mph.

The various senses are as highly developed in bony fishes as in sharks and
rays, but the emphasis is on the eye rather than on the nose. As in sharks and
rays, the lateral line serves to detect water vibrations. Taste is well developed
and hearing is somewhat less so. Barbels about the mouth, when present, are
delicate taste organs used for detecting food. The nervous system is developed
to a fairly complex degree as compared with invertebrates. Groupers can be
trained to follow a swimmer who has fed them a few times and, in fact, can
be a nuisance. The social behavior of fishes is complex and a huge topic in
itself. Some fishes are known to perform extraordinary migrations (many
mackerels and eels) and others have complex courtship behavior (demoiselles,
wrasse, gobies, blennies, and possibly grunts), but most piscine social behavioral
patterns remain unknown.

Most marine fishes lay large numbers of pelagic or adhesive eggs. Some, such
as demoiselles, build nests. Only a few bear living young as do most sharks
and rays.

Bony fishes exhibit a wide range of colors. Many of them are able to change
their colors greatly and rapidly. Color change is accomplished by the expansion
of pigment-bearing cells in the skin. These cells are called "chromatophores" and
are under both nervous and hormonal control (pituitary gland). A spectacular
color and pattern control is known for flatfishes, whei'e agreement of color
with the surroundings is remarkable. It is even possible for these fishes, if placed
on a checkerboard, to assume the checkerboard's pattern. Many fishes exhibit
several color phases which confuse identification.

Color and body form may differ strikingly in young and old fish of the same
species. A well-known example is the black angelfish in which the young are
striped and the adults are not (Co/or Plate 7). The underwater swimmer,
however, is very likely to see, especially about coral reefs, many small, oddly
shaped, brilliantly colored fishes that are hard, if not impossible to identify.
These are the voung of reef species, and it must be admitted that very little is
known of them.

These several topics— motion, the senses, social behavior, food, color vari-
ation, and change of form during growth— merely touched on here, offer
almost unlimited opportunities for observation and study. In this age, when man
is constantly expanding his numbers and activities, the sea is assuming a vital
importance, and bony fishes are, perhaps, the chief reason for this because of
their value as food.

THE PRIMITIVE BONY FISHES: Subclass Chondrostel

{"cartilage bone")

Ancient chondrosteians possessed bone, but the modern ones, the sturgeons,
have skeletons of cartilage. These huge fishes are possibly the largest of bony
fishes. They are toothless, bottom-feeding, sluggish, and reminiscent of sharks
both in movements and form. The tail is asymmetrical, with a longer upper lobe
(heterocercal), and there are five rows of large bony plates along the body.

180 UNDERWATER GUIDE TO MARINE LIFE

Their food is detected with the barbels on the snout and is strained from mud
and soft bottoms with the protractile mouth. The name "sturgeon" is derived
from a German word meaning "to rummage around." Sturgeons are found in
the seas and large rivers of Eurasia and North America. Like salmon, they spend
most of their lives in the sea, entering fresh water to breed. The flesh and roe
(caviar) are prized as food.

STURGEONS: Family Acipenseridae

SEA STURGEON (coMMON sturgeon) : Acipetiser sturio

Size: Rarely over 8 feet. Recorded up to 18 feet.

Weight: Recorded up to over a ton.

Distribution: From the St. Lawrence River to the Carolinas. Most common
about the Chesapeake Bay. Also found in European waters.

Identification: Separated from other smaller sturgeons by the shape and
number of dorsal plates (scales).

Habits: Because of the value of this large fish and the pollution of so many
of our large rivers, it is much reduced in numbers. In spite of its clumsy build
and sluggishness, a sturgeon is capable of bursts of speed. The lateral scutes
on the tail are used as weapons and can cause serious cuts. Sturgeons are known
to leap from the water upon occasion, a peculiar show of energy for so sluggish
an animal. In May, the adults ascend rivers to spawn, as many as two or three
million eggs being produced by a single female. Isinglass used to be made
from the swim bladders of sturgeons.

Similar Species: The white sturgeon, Acifenser transmontaniis, is a West
Coast species found from Alaska to Monterey Bay. It enters large rivers, such
as the Sacramento, Columbia, and Eraser, to breed. It is comparable in size and
habits to the Atlantic species. Formerly thought to be worthless, demands for its
flesh have made it rare and it is strictly protected by law.

^.

Fig. 84. Sea sturgeon.

THE MODERN BONY FISHES: Subclass Teleostel {"true hone")

The vast and imposing array of modern bony fishes can be best considered
as falling into five orders as follows:

1. Isospondyli, primitive forms with the ventral fins on the belly and no
spines in the fins (herrings, trapons, salmon, etc.).

2. Apodes, the eels.

3. Ostariophysi, primarily fresh-water fishes, of which only the catfishes
will concern us.

4. Mesichthys, or "middle fishes," a collection of se\'eral groups thought to

MASTERS OF THE WATER-BONY FISHES 181

be a transition from the isospondylous type to the acanthopterygian type
(killifish, flying fish, sea horse, etc.)-
5. Acanthopterygi, fishes which have the ventral fins up under the pectorals or
chin, the pectorals high on the sides, the body compact, and spines in
the fins (perches, mackerels, flatfishes, etc.)-

The evolution of the bony fishes is not at all clear. As in sharks and rays,
silhouette, placement and form of the fins, and habits are important in
identifying them.

Herringlike Fishes: Order Isospondyli

The fin rays are all soft and the pelvic (ventral) fins are placed far back
on the belly. The pectoral fins are placed low on the body and the tail fin is
forked except for a few species in which it is square (Salmonidae). All the rest
of the bony fishes probably descended from members of this order. In spite of
their relative primitiveness, members of this group are vastly important. The
tarpons, bonefishes, salmons, and trouts are among the gamest, if not the gamest,
of all game fishes and without them, fishing, the world's most popular sport by
far, might not be as popular as it is. The herrings, sardines, menhaden, and a
host of others are vitally important for both the economy of the sea and the
economy of man.

TARPONS: Family Megalopidae

These brilliant silver fish are among the largest of this suborder. Anyone who
has seen one under water has experienced one of the greatest thrills of under-
water swimming. The huge scales, large enough to be used as jewelry and
ornaments, seem to catch and reflect every possible gHnt of hght as the powerful
tail propels the fish silently and swiftly through the water. The undershot jaw,
the large size, and the shape of the dorsal fin serve to identify the single species.

TARPON (grande ecaille, sabalo, SILVER king) : Tarpon atlanticus

Size: Up to 8 feet. Averages 5 feet.
Weight: Up to 350 pounds. Averages 50 pounds.

Distribution: Cape Cod to Brazil. Chiefly in the Caribbean, off Florida, and
in the Culf of Mexico.

Identification: Same as for the family.

Fig. 85. Tarpon.

182

UNDERWATER GUIDE TO MARINE LIFE

Habits: This greatest of all game fishes is mainly an inhabitant of shallow
waters along channels, flats, mangroves, and estuaries. It pursues small fishes
with great vigor chiefly at night and also eats crustaceans. It migrates north in
the warm months, but is very sensitive to cold. In its leaps from the water the
posterior filament on the dorsal fin is used to determine the direction of the fall.
Tarpons can leap 8 to 10 feet vertically from the water or 20 feet horizontally,
and these leaps have sometimes resulted in injury to innocent bystanders. One
knocked a man from a boat, so stunning him that he drowned. Another landed
on a man's neck, breaking it. Tarpons are immensely prolific, producing millions
of eggs. The voung larvae look very different from the adults, being band-shaped
and transparent (probablv for protection) and like eel larvae. Adults are usually
solitary but may also school.

TEN-POUNDERS: Family Elopidae

These, like tarpons, are bright silvery fishes, but they are slender and have
the ventral fins slightly anterior to the dorsal fin. The one species is cosmopolitan
in warm seas.

TEN-POUNDER (ladyfish, chiro) : E/ops saiirus

Size: Up to 3 feet.

Weight: Averages Wi to 5 pounds. Up to 15 pounds.

Distribution: Florida to the Caribbean. Straggles to Cape Cod. Gulf of
California to Mexico. Also in the Salton Sea of California.

Identification: Same as for the family.

Habits: Like the following bonefish, the ten-pounder is primarily a fish of
shallow water which comes inshore over soft bottoms with the tides to feed
upon small fishes and crustaceans; it may even enter fresh waters. The young

Fig. 86. Ten-founder.

Fig. 87. Bonefish.

MASTERS OF THE WATER-BONY FISHES

183

are band-shaped and transparent, 2 to 3 inches long, and are frequently thrown
upon beaches by the waves, known locally as "ghost fishes." This is a schooling
species and is occasionally found over deep waters.

BONEFISHES: Family Albulidae

These are, like the two previous species, brilliant, silvery, and game species.
There is but one species of cosmopolitan distribution in warm seas. The
bonefishes have a mouth under a piglike snout. The dorsal fin is large, high,
and in advance of the ventrals, and the body is stout.

BONEFISH (lADYFISH, BANANA FISh) : Alhulu VulfeS

Size: Up to 3 feet.

Weight: Averages 2 to 5 pounds. Up to 16 pounds.

Distribution: The tropics north to Florida and San Diego. Rarely north to
Cape Cod and Monterey Bay.

Identification: Same as for the family.

Habits: As is suggested by the position of the mouth, this is a bottom feeder,
apparently the only isospondylous fish that is. It comes inshore in shallow
water with the tide to feed over sand or mud on small fish, crustaceans, and
worms. It is extremely fast and wary. The Latin name means "whitish fox."
It is usually solitarv but schools when small, and is sought after as a game fish,
there being few fish that are harder to hook and land. Like the two former
fishes, it also has transparent, bandlike, larval young, and like the ten-pounder,
these young are sometimes thrown ashore in great numbers.

The underwater swimmer will be lucky to see a bonefish and will need all
the skill and stealth at his command to approach one, for the least disturbance
will send it off at high speed. Bonefish are kept only with difficulty in aquariums.
Slight disturbances by spectators send them smacking into the walls of their
tanks in efforts to escape.

Fig. 88. Milkfish.

MILKFISHES: Family Chanidae

This is the fourth and last of the large, brilliant, silvery, game, isospondylous
fishes of North America. The body is spindle-shaped and compressed, and the

184

UNDERWATER GUIDE TO MARINE LIFE

tail is very large. There are no teeth in the mouth. The single species of this
family is widely distributed in the tropical Pacific.

MILKFISH (salmon HERRING, AWA, WHITE MULLEt) : ChunOS chaUOS

Size: Up to 5 feet.

Weight: Averages 7 pounds. Up to 30 pounds.

Distribution: Abundant in the Gulf of California, northward to San Francisco.
Over the whole tropical Pacific.

Identification: Same as for the family.

Hahits: This is a schooling, vegetarian, surface feeder. It may enter harbor
mouths and inlets and is also found over deep water.

HERRINGS: Family Clupeidae

If any one group of the sea's inhabitants were singled out as being most
vital to man, this one would be chosen. Whole nations quite literally would
be bankrupt were it not for species of this family. But more important than their
importance to man is their vital position in the sea. Most of them serve as the
link in the food chain from plankton to the larger carnivorous animals, such
as tuna, shark, diving birds, and seals.

The herrings, almost without exception, travel in huge schools, usually at
sea near the surface but also close inshore. They have feeble teeth and long
gill rakers as befits their plankton-feeding habits. The predominant color is
silver tending to be greenish and bluish on the back. There is little pattern
if any. The body is usually compressed, and the belly is frequently sharp-edged,
bearing a ridge of sharp scales. There is never a lateral line, and the tail is
always deeply forked. Herrings are exceedingly numerous in all seas and many
species are difficult to identify.

COMMON herring: C/tipea harengus

Size: Averages 1 foot or smaller. Up to Wz feet.

Distrihiition: All of the North Atlantic. Common north of Cape Cod. Straggles
south to Cape Hatteras.

Identification: The shape is distinctive. The color is dull silver with a bluish
back. The sharp-edged belly scales are not strong.

Hahits: This is the most numerous fish of the Atlantic and also perhaps of
the world. It is a plankton feeder, but will pursue small fishes and invertebrates.
Huge quantities of herring are caught both by man and by the larger carnivorous
fishes. Small ones are packed and sold as "sardines." Schools of herring are

Fig. 89. Common herrin

MASTERS OF THE WATER-BONY FISHES

185

Fig. 90. American shad.

gigantic, composed of millions or billions of individuals. Herrings are fall
spawners. A female lays thirty thousand or more heavy, adhesive eggs in shallow
water, where they adhere to the bottom and to plants.

Similar Sj^ecies: The Pacific herring, Clupea -pallasi, is very similar to the
Atlantic species. It is found south to San Diego. The Spanish sardine, Sardinella
anchovia, is one of several true sardines found in the temperate and tropical
Atlantic. It is like a small edition of the common herring.

AMERICAN shad: Alosa suftdissima

Size: Males average 14 to 18 inches. Females average 18 to 24 inches. Up to
30 inches.

Weight: Males average 3 to 4 pounds. Females average 3 to 6 pounds. Up to
12 pounds.

Distrihution: In or near rivers and river mouths from the St. Lawrence to
Florida. The shad was the first exotic fish to be introduced on the West Coast
(1871) and is now found from Alaska to southern California.

Identification: It has a deep silvery body, a blue-green back, and a prominently
notched upper jaw into which the lower jaw fits. There is a row of spots on the
upper back.

Habits: This is the most delicious of the herrings and its roe is a delicacy.
The shad runs up rivers to spawn when the water is 56° Fahrenheit or more
(January to June, depending on location) and produces up to 156,000 eggs
though the usual number is 30,000. The shad feeds on plankton. It has become
much diminished in numbers because of pollution and overfishing. The location
of shad at sea during the nonbreeding season is something of a mystery.

MENHADEN (moss-bunker) : Brevoortia tyrannus

Size: Averages 1 foot to 18 inches.

Distribution: Nova Scotia to Brazil. Numerous from New England to Florida,
being the most abundant fish in that range.

Identification: The head is very large for a herring. There is a series of spots
behind the operculum.

Habits: This is not a good food fish but is used extensively as fertilizer and
as a source of oil. Menhaden are exclusively plankton eaters and the gill rakers
are extremely fine. Schools of menhaden form one of the staples in the diets of

186

UNDERWATER GUIDE TO MARINE LIFE

Fig. 91. Menhaden.

Fig. 92. Striped anchovy Qahove left) and green fry (below right).

sea birds and many fishes. In response to the great stress put on them bv many
animals including man, menhaden are very prolific and deposit up to 150,000
floating, pelagic eggs.

TRUE ANCHOVIES: Family Engraulidae

The mouth is exceedingly large and under a pronounced snout. There is
almost always a wide lateral silvery stripe. The size is under 8 inches. The species
are very plentiful in all warm seas. Like the true herrings, these are schooling
plankton feeders of both open seas and waters near shore. They form a basic
food for many fishes.

STRIPED anchovy: Auchoviella epsepus

Size: Up to 6 inches. Usually smaller.

Distribution: Cape Cod to Uruguay. Most abundant in Florida and the
West Indies.

Identification: There are many species of anchovies, all very similar. No
attempt is made here to separate them.

Habits: This is one of the densely schooling, little silver-sided fishes which
stream through tropical and temperate waters in endless lines. When so mov-
ing, it is very difficult to tell them apart from similar but quite distinct little
fishes, such as silversides (Antherinidae) and green fry, jenkinsia, which they
superificially resemble and with which they frequently school. It is a unique
experience to swim into a cloud of these fishes, all of which seem to be pur-
posefully running off for some unknown appointment. They are common in

MASTERS OF THE WATER-BONY FISHES 187

shallow water and spawn in the summer. They form a staple food for lish-
eaters like mantas and gars.

Similar Species: The green fry, Jenkinsia lainprotaenia, is a small-mouthed
greenish member of the herring family which schools densely, sometimes with
anchovies, in tropical waters.

SALMON AND TROUT: Family Salmonidae

This well-known family is chiefly characteristic of fresh water of the north
temperate and arctic zones, and all of its species at least breed there (with the
exception of the closely related deep-sea viper fishes). A few of the larger ones,
however, spend most of their lives at sea, where their migrations and habits
are poorly known. Salmons and trout all have large mouths armed with power-
ful teeth. The bodies are elongate, powerful, not much compressed, and bear
a small adipose (fatty) fin between the dorsal fin and the tail. Silver is the
predominant color, but there are beautiful red, green, and blue iridescences
that make these fishes verv striking.

The name "salmon" was first applied to the Atlantic species, which is actuallv
a large trout, genus SaUno. The true salmons, genus Oncorhynchus, are all of
the North Pacific. Nevertheless, species of both genera have very similar habits
and will be considered as a unit. Most live predaceous, fish-eating lives in the
sea (some of the species are plankton feeders) until thev mature at an age of
about 3 to 5 years. Then, in the spring or summer, depending upon the location
and the species, they begin their fabled trek up the streams. The males become
grotesquely hook-jawed, humpbacked, and reddened, and the females become
heavy with roe. They lay several thousand eggs in shallow riffle areas. Then
the parents die exhausted, thin, and covered with fungus-infested wounds
CSahno species do not die after spawning). One cannot help marveling at this
life-giving, yet still hugelv destructive, process as one surveys the literally
thousands of pounds of highly aromatic, dead fish which line the breeding
streams after spawning is complete.

Descriptions and distributions follow. Coloration is given for the species when
at sea; in fresh water it is much redder.

GENUS ONCORHYNCHUS

Spawns only once. Mouths black inside. Head large. Long anal fin with twelve
to ninteen rays.

Fig. 93. King salmon.

188

UNDERWATER GUIDE TO MARINE LIFE

Fig. 94. Atlantic salmon.
KING SALMON (cHiNOOK salmon) : Oncorhytichus tschawytscha

Size: Averages 3 feet. Up to 5 feet.

Weight: Averages 20 to 30 pounds. Up to 125 pounds.

Distribution: Ventura River, California to Alaska and Kamchatka.

Identification: The color is silvery with small black spots on back, dorsal fan,
and caudal fin. The flesh is red or white and, though preferred red for canning,
is thought by many Alaskans to have a superior flavor when white.

SILVER SALMON (coHO salmon) : Oncorhynchus kisntch

Size: Averages 2 to 2i/2 feet.
Weight: Averages 6 to 12 pounds.
Distribution: Alaska to southern California.

Identification: Like the king salmon, but the spots are not as extensive, none
being on the lower tail lobe.

GENUS SALMO

Spawns more than once. Mouths white inside. Short anal fin with 9 to 12
rays. Head comparatively small.

ATLANTIC salmon: Sahuo salar

Size: Averages 2 to 2V2 feet.

Weight: Averages 10 pounds. Known to reach over 80 pounds.

Distribution: Northern New England to Hudson Bay. Also in Europe.
Pollution and overfishing have resulted in its extermination in large southern
rivers such as the Hudson and the Delaware.

Identification: Covered liberally with large, black spots which are usually
X-shaped. Silvery with a brownish tinge above.

STEELHEAD RAINBOW TROLtT: Salvio gairdncri

Size: Averages 2 to 2Vi feet.
Weight: Averages 10 pounds.
Distribution: Alaska to southern California.

Identification: There are numerous dark spots on the back and unpaired fins.
The color is a steely blue.

SMELTS: Family Argentinidae

These small, mostly marine, silvery fishes arc among the finest if not the

MASTERS OF THE WATER-BONY FISHES

189

Fig. 95. American smelt.

finest of all pan fishes. They are slim of body and very similar to the salmonids,
being separated from them by internal characters.

Smelts are schooling, shallow-water fishes which feed mainly on smaller fishes
and crustaceans. Like salmon, they enter fresh waters to breed and may become
landlocked. Most of them are characteristic of north temperate and arctic seas.

AMERICAN SMELT: Osuiems viordax

Size: Averages 8 inches. Up to 14 inches.

Weight: Up to 1 pound.

Distrihiition: The St. Lawrence River to Virginia.

Identification: There is a broad silvery stripe along the lateral line.

Hahits: Smelts school in huge numbers and enter fresh water in late winter
or early spring to breed, laying thousands of eggs. They prefer cool waters and
move offshore in the summer. Several eastern lakes, such as Lake Champlain
and some of the Great Lakes, have landlocked forms of this fish. These are
active little fishes which feed mainly on small fishes and shrimplike crustaceans.

Similar Species: The surf smelt or whitebait, Hypoviesiis pretiosus, has the
dorsal fin inserted anteriorly to the pelvic and is similar to the American smelt.
It is found from Alaska to central California.

LIZARD FISHES: Family Synodontidae

These are shallow-water members of a largely deep-sea group, the lantern
fishes, which is often placed in a separate order, Iniomi, by ichthyologists. They
are rather troutlike with long round bodies, large jaws, an adipose fin, and
ventral fins that are larger than the pectorals. All the lizard fishes are fiercely
predatory. They sit on the bottom, resting on their ventral fins until some
unsuspecting fish or crustacean swims by. Then they rush so quickly at the
prey that the movement can hardly be seen. They prefer sand bottoms but may
be found about reefs and rocks as well as over mud and grass.

This is one of the groups in which the normal swimming pattern has been
altered. For sudden rushes, the tail fin is used, but lizard fishes do not often
swim when at leisure, preferring to creep about on the bottom on their very
large pelvic fins. The pectorals are held out like wings and are probably used
as planing devices in their sudden rushes after prey. Lizard fishes are usually
sandy-colored with dark blotches, and the head has a distinctly lizardlike
appearance. They are found in the shallow, warm seas of the world.

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UNDERWATER GUIDE TO MARINE LIFE

Fig. 96. The snakefish, Trachinocephalus, 10 inches long, is usually seen motion-
less over sand or dead coral waiting to dart at some small fish or crustacean.

snakefish: Trachinocefhalus myops— Figure 96

Size: Up to almost 1 foot in length.

Distribution: West Indies north to South Carolina and south to Brazil.

Identification: The body is heavy and almost perfectly round in cross section.

Habits: This fish remains motionless even on close approach by swimmers.
It is not readily frightened, and observation of it is easy, though its coloration
and lack of movement make it difficult to spot.

Similar S'pecies: The lizard fish, Synodus foetens, is olive-colored with yellow
vermiculations, or wavy outlines, on the back and sides, and is found from Cape
Cod to Brazil.

The California lizard fish, Synodus luciocefs, is similar to Atlantic members
of this genus. It is olive-brown with a golden luster and slaty reticulations, or
netlike patterns, on the back and sides. It is found from San Francisco to
San Diego. Both of these fishes are much slimmer than the snakefish but have
similar predatory habits.

The Eels: Order A pedes ("without feet")

The eellike shape is repeated in several groups of fishes. Electric eels and
eelpouts, both superficially like eels in appearance, are not true eels. The parallel
development in these groups of the eellike shape is an adaption to a common
mode of life, a life in holes and crevasses. The true eels are all rather degenerate
in that there is a marked tendency toward loss of the fins and scales. The ventral
fins are always missing, and the pectorals are sometimes also lacking. This forces
them to swim like a snake with sinuous lateral body movements. Some have
even lost the vertical fins and, hence, cannot swim but must slither about on
the bottom. The operculum is also lost, and the gill opening is small, resembling
a pore. In spite of all this, eels are active, voracious carnivores with dangerous
teeth and unreliable tempers. Most, if not all, are chiefly nocturnal. Eels form

MASTERS OF THE WATER-BONY FISHES 191

an isolated group, their origin and evolution being a mystery. They are found
in most temperate and all tropical seas. Bertin (1942) gives a detailed account
of eels.

COMMON EELS: Family Anquillidae

These most primitive eels are recognized by the presence of small scales
imbedded in the skin and the large pectoral fins. They are really fresh-water
fishes, which, opposite to the salmon, enter salt water to breed (a situation
described as "catadromous"). Members of this family are practically world-wide,
but are not found on our Pacific coast.

COMMON eel: Anquilla rostrata— Color Plate 1

Size: Averages 2 feet. Exceptionallv up to 5 feet. The females are larger.

Weight: Averages 1 pound. Exceptionally up to 7 pounds.

Distribution: St. Lawrence River to Brazil. A very similar species on the
Atlantic coast of Europe.

Identification: The color varies from brown to black and is usually olivaceous.

Habits: The story of the common eel is one of the most remarkable known,
both from the standpoint of the history of scientific speculation and that of
animal adaptation. Ley (1951) tells it in excellent fashion and in some detail.

The story revolves around the eel's extraordinary reproductive habits which
from earliest times were shrouded in mystery. Aristotle said that "the eel has
no sex, no eggs, no semen, and originates from the the entrails of the sea." Such
a statement could have been made because fishermen had never found roe or
milt in eels which they captured. Up until 1777 various explanations of eel
reproduction were given: they generated from slime from other eel's bodies,
from bits of hair, or from sod wet with May dew. In that year a man named
Mondini found what he believed were female sex organs (ovaries), but it
was not until 1824 that Syrski found comparable male organs. Then in 1895
Grassi and Calondruccio kept what they believed to be an entirely different
animal called "leptocephalus," a bandlike, transparent fish of up to 3 inches
in length, in a tank and observed that these animals (which were actually larvae)
shrank, became slimmer, and then transformed into baby eels or elvers. It was
these two men that brought forth the theory that eels are in the rivers only
to grow and mature and go to the sea to breed. Where and when eels breed was
not known until a Dane named Johannes Schmidt, with the help of the fisher-
men he had supplied with deep nets, observed that the nearer to the Sargasso
Sea that leptocephalus larvae were caught, the smaller they were. This was
in 1904, and in 1913 Schmidt went to the Sargasso Sea and found the tiniest,
most recently hatched leptocephalus of all. The mystery was solved. Eels leave
the streams in the fall and travel the Gulf Stream to the Sargasso Sea to
deposit their eggs, one of the most remarkable of all fish migrations.

No less remarkable is the trek the larvae make back to the streams. European
larvae take three years to travel the three thousand miles, and American
eels, having the shorter distance of one thousand miles to go, take only a year.
The larvae grow to 3 inches in this time. When they enter fresh water, they
become slim, transparent, "glass eels" and soon thereafter darken to miniatures
of the adults. These young may be extremely plentiful, seeming to clog streams

192 UNDERWATER GUIDE TO MARINE LIFE

with their wriggHng bodies. The males probably remain in brackish waters to
grow, but the females go as far upstream as they can and may even leave the
water to travel overland for rather remarkable distances for a fish. The eels
remain in fresh water to grow until they are about 5 to 8 years old, at which
time they again go to sea. Eels only breed once, dying soon thereafter.

The mystery is not completely solved as yet. Just where in the Sargasso Sea
(at what depth) the eggs are deposited is not known. They are not deposited
on sargasso weed nor on the bottom, which is too deep. The smallest larvae
are found at a depth of 1,000 feet, so perhaps the eggs float in deep water.

One more interesting facet should be mentioned. In 1930, the Danish ship
Dana found a leptocephalus larva 6 feet long off South Africa at a depth of
1,000 feet. This would produce an adult eel of 60 to 70 feet. Sea serpents? No
one knows.

Eels have very delicate and tasty flesh. They are largelv nocturnal and eat
a wide variety of animal foods. They can be pugnacious. But these eels are
usually timid.

Similar Species: The conger eel, Leptocephalus conger, is very similar to the
common eel. However, it has no scales and is put in a diff^erent family,
Leptocephalidae. Congers are often confused with common eels, but are larger,
reaching 8 feet and 12 pounds and have the dorsal fin prominently edged
with black. They are also mainly of offshore habitats, never entering fresh
water. They are found in the Atlantic from Cape Cod to Brazil.

SNAKE EELS: Family Ophichthyidae

These are very pretty and comparatively docile tropical eels. The dorsal and
anal fins do not extend to the tip of the tail, and the pattern is usually a
spotted one. The pectoral fins are present but small. As the name implies, these
eels are extremely suggestive of snakes as they crawl about reefs and even in
harbors. As they do so, they constantly poke about with their noses, on which
are situated two short, stout barbels containing the nostrils. The species are
numerous in all tropical seas.

SPOTTED SNAKE EEL: Opliichthys ophis— Figure 97

Size: Averages 2 feet. Up to 4^2 feet or more.

Distrihiition: Florida and the West Indies to Brazil. Also to Bermuda.

Identification: Pattern as illustrated.

Habits: One of the authors had an interesting experience with one of these
eels in the harbor of Nassau, British West Indies. The eel was crawling exactly
like a snake over the rubbish in the harbor when it was first seen. Remember-
ing that eels are usually not to be trusted, the author nevertheless extended a
gloved hand slowly and was surprised to have the eel crawl into it. The eel
did not even object to being slowly picked up off the bottom. Once again placed
on the bottom, the eel found a hole, nosed about it, and retreated unhurriedly.

Snake eels probably eat a wide variety of animal food, such as invertebrates
of all kinds as well as refuse and small fishes.

MASTERS OF THE WATER-BONY FISHES

193

^ '•*. -«^N /^ -^^^ » ^"V ^to^

Fig. 97. Top left. This spotted snake eel, Ophichthys, is beautifully colored with
■pale yellow ground color and hrown spots. Top right. The trumpetfish, Aulostoma,
will frequently imitate gorgonian sea whips when alar-ined. Bottom. This is the
truynpetfish as it normally appears, Riding slowly through sea feather gorgonians.

MORAYS: Family Muraedinae

These reef fishes of tropical seas have no pectoral fins. The skin is wrinkled
near the small, circular gill openings so that the neck seems like a pouch. They
have the habit of sitting entwined in reefs, gaping menacingly. The pugnacious
disposition and large, sharp teeth are well known. In spite of the fact that
they are not known to bite if left unmolested, it would be very unwise to
attempt to provoke one. Several persons have been very badly injured and

194

UNDERWATER GUIDE TO MARINE LIFE

even killed when unwisely spearing or otherwise tormenting morays. They
are especially dangerous if brought into a boat. Rather small morays have
been known to strike viciously at men in boats, driving them into the water
and leaving the eel in sole possession. Contrary to popular belief, American
morays do not have poisonous bites, but the bites are very likely to become
infected.

Morays ambush small fishes and crustaceans from their holes in the reef.
They do not like to swim in open water, probably because of larger predators.
They are chiefly nocturnal and are much more common on reefs than a first
glance would reveal. All one has to do is drop a bit of fish or lobster head near
a likely hole and a moray will often appear. Morays can be trained in captivity.
One zookeeper had a moray that allowed him to handle it.

Morays, which are edible, are found on reefs the world over. The species
range from 2 inches to over 10 feet in length.

SPOTTED MORAY: Gyninothorax moringa— Color Plate 1

Size: Up to 3 feet.

Distribution: Florida and the West Indies to Brazil.

Identification: The color varies from almost white to a yellow or greenish-
brown ground color. There are prominent dark spots and reticulations. The
color may vary to match the environment.

Habits: This is the most common West Indian moray. It is common in holes
and interstices in coral heads or even in harbors about pilings.

Similar Sfecies: The Californian moray, Gyrnnothorax mordax, has a similar
pattern and color. It reaches 5 feet and is found from Point Conception to
Cedros Island.

GREEN MORAY: Gyvinothorax funehris— Color Plate I

Size: Averages 3 feet. Commonly to 6 feet and may very rarely reach 10 feet.

Weight: Rarely 30 pounds.

Distribution: Both coasts of tropical America. Common from Florida to the
West Indies.

Identification: The color is usually a brilliant to brownish green. The coloration
is unique, caused by the combination of a blue skin and a yellow mucus. Dark
gray or brown individuals may lack the yellow coloring in the mucus.

Fig. 98. Sea catfish.

MASTERS OF THE WATER-BONY FISHES 195

Habits: The habits are the same as those oF the spotted moray although the
green moray gets into somewhat deeper waters. It is a very powerful predator.

Gatfishes: Order Ostariophysi {"inflated bone")

The catfishes are only a part of this large, mainly fresh-water order, but they
are the only marine members. The great majority of fresh-water fishes are
ostariophysians. Minnows, suckers, chubs, carp, and others make up one
group called "cyprinids" and many tropical aquarium fishes, including South
America's dreaded piranha, make up another large group called "characins." The
electric eel and its relatives compose still another group. The catfishes them-
selves, though not the largest group in the order, have almost a thousand
species. Out of all this great array, only two species of catfishes habitually
get into sea water in North America, and these do not stray far from land.

Ostariophvsians are closely related to the herringlike fishes but possess one
very important difference which, though internal, is important in understanding
these fishes. It is the Weberian apparatus, a series of large, inflated vertebrae
near the head which are connected to the air bladder and the inner ear and
therefore act as a completely unique organ of ■ hearing. The use to which
this more sensitive hearing apparatus is put is not known.

The catfishes may immediately be recognized by the long barbels about
the mouth. These are used as tactile and taste organs to detect food, and as
feelers in general. The dorsal and pectoral fins are each armed with a single
stout spine, which is able to inflict a painful wound. Luckily, the spines of the
North American marine catfishes are not poisonous as are those of the mad tom
and stone cats, Notiirns and Schilheodes, both inhabitants of fresh water. The
spines are used defensively only.

Catfishes have the ventral fins far back on the belly and possess an adipose
fin. These bottom fishes eat a wide variety of food, being practically omnivorous
in habits.

SEA CATFISHES: Family Siluridae

These fishes are distributed over the world's warm seas with the exception
of the North Pacific and European waters.

SEA catfish: Galeichthys felis

Size: Up to 1 foot.

Distribution: Cape Cod to the Gulf of Mexico. Not common north of Virginia.

Identification: Silvery green above and white below. There are two barbels on
the upper jaw and four on the lower.

Habits: This is an abundant shore fish in harbors and over all kinds of bottoms,
but prefers rocky shores. It feeds mainly at night on just about anything it can
swallow. Sea cats travel in schools of up to 200 fish.

GAFF-TOPSAIL CATFISH: Bagre marinus

Size: Averages 15 inches. Up to 2 feet.

Weight: Averages IVi pounds. Up to 3 pounds.

Distribution: Cape Cod to Panama. Not common north of Delaware.

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UNDERWATER GUIDE TO MARINE LIFE

Fig. 99. Gaff-topsail catfish.

Identification: The two upper jaw barbels are very long, and the lower jaw
barbels are only two in number. The fish is named from the shape of the
dorsal fin.

Hahits: The habits of this catfish are similar to those of the former species,
but there is a tendency to be more active. The breeding habits are interesting.
Very large eggs, up to an inch in diameter, and only about four or five dozen
at most in number are laid in June and July. The male carries these eggs in
his mouth until they are hatched. After the young hatch out, they are still
carried in the male's mouth until the yolk sac is absorbed, at which time they
are 3 inches long. During this whole time, a period of two weeks, the male
takes no food.

The "Middle Fishes": Order Mesichthys

Several quite different suborders are here grouped together because they
represent a transition from the herringlike fishes to the advanced spinv-rayed
fishes. There is a tendency in these suborders for the ventral fin to be moved
forward, the pectorals to be placed high on the body, and the dorsal fin to
acquire spines. But, as we shall see, these groups are so different that this order
is probably less biologically real, in terms of evolution, than merely con\'enient.

Pikes: Suborder Haplomi

Here we meet another predominantly fresh-water group with manv famous
members ranging all the way from the powerful pikes and muskellunges to
the modest guppies, mollies, swordtails, and platics. There is only one family
that reaches salt water, that of the killies.

KILLIES: Family Cyprinodontidae or Poecilidae

The round body is compressed behind but depressed at the head so that
the mouth is very wide. The ventrals are placed back on the belly and are
nearly equal to the pectorals in size. The best field mark is the placement of
the dorsal fin far back directly over the rather large anal fin. The many species
are usually olivaceous in color and swarm in shallow, salt, brackish, or even

MASTERS OF THE WATER-BONY FISHES

197

fresh water, being favorite pets of small boys at the shore in summer. Killies
are among the hardiest of fishes, able to survive an amazing variety of salinities,
temperatures, and pollutions. They are found on both coasts of North and
South America and in Asia and Africa.

Fig. 100. Couivwn killifish.
COMMON killifish: FiinduUis heteroclitiis

Size: Averages 2 inches. Up to 6 inches.

Distribution: Gulf of the St. Lawrence to the Gulf of Mexico.

Identification: The males have pearly spots, and the females are a solid
olive-green.

Habits: Killies are active, swarming little shore fish which eat almost anything,
including large numbers of mosquito larvae. They like weedy places along
the tide zone and are frequently trapped in high-sided tidepools. They are
not usually trapped in low-sided tidepools since they are able to climb out
of these and travel overland for ten feet or so to open shallow waters. Killies
lay eggs in weeds in spring. The male takes on orange hues at that time.

Synentognaths : Suborder Synentognathi

This group includes the gars, halfbeaks, and flying fishes. All of these fishes
are primarily silvery with bluish or greenish backs, and all are characteristic
of surface waters of warm temperate and tropical seas. The ventral fins are far
"back on the belly, and the lateral line is unique in that it follows the belly
outline. There is a marked tendency for these rapidly moving, active fishes
to take to the air, so most have an enlarged lower lobe of the tail fin, and
some also have enlarged pectoral and ventral fins, a trend culminating in the
flying fishes.

A good rule of thumb for recognizing members of the group is that all either
possess winglike pectoral fins or elongate, beaklike jaws, and all have the dorsal
and anal fins far back on the body. The diets of synentognaths vary. Their eggs
have threadlike tufts on them which serve to anchor them to seaweed and to each
other. Most of them are schooling. They are cosmopolitan in warm seas.

GARS, BILLFISHES, AND NEEDLEFISHES: Family Belonidae

These are the largest of the synentognaths and the most voracious. The
elongate jaws and needlelike teeth are admirably suited for catching small fish.

198 UNDERWATER GUIDE TO MARINE LIFE

The flesh is green but is very good to eat. Gars are extremely swift and, when
disturbed, are known to leap like spears through the air. People have been
known to be seriously injured when struck by a leaping fish. They are often
seen skittering very rapidly for some distance over the water's surface with
only their tails in contact with the water. They are common near shore in
all tropical seas and are often seen in harbors. The authors have seen them
under water but found them difficult to photograph because of their constant
activity and speed. Gars travel in small schools usually. The species are many
and hard to separate.

houndfish: Strongylura raphidoma— Color Plate 1

Size: Averages 2 feet. Up to 5 feet. Largest of the family.

Distribution: Florida and the Caribbean. Straggles to New Jersey.

Identification: The beak is rather short and strong, and this fish is large
compared with others in the family.

Habits: This species in particular has the habit of leaping from the water
and can be dangerous to people in small boats who get in their way. The
houndfish is a voracious feeder on small, surface fishes.

HALFBEAKS OR SCISSORS: Family Hemirhamphidae

These fishes are very similar to the gars but are slightly less elongate and
have only the lower jaw lengthened. (Only one species, the hardhead,
Chriodorus antherinoides, has both jaws short.) Half beaks are swift, surface fishes
and tend toward "flying" even more than do the gars. One, the flying halfbeak,
Euleptorhavi-phus velox, has expanded, winglike pectoral fins. Like the gars,
they are characteristic of all warm seas, mainly near shore, but unlike the gars,
most are small and all are herbivorous. Most also have a wide silvery lateral
stripe. The toothless jaws are used to scoop algae into the mouth though the
details of how this is done are poorly known. Hesse, Allee, and Schmidt (1951)
say that they eat some algae from the bottom, but this seems odd for this surface
fish. The schooling tendency is more marked than in the gars.

halfbeak: Hyporhamphiis unifasciatus— Color Plate I

Size: Up to 1 foot.

Distribution: Florida and the West Indies. Reaches Massachusetts in the
Gulf Stream.

Identification: Same as for the family.

Habits: Schools of this common surface fish are common in quiet, shallow
waters throughout its range.

Similar Sfecies: The West Coast halfbeak, Hyporhauiplnis rosae, reaches
only 6 inches and is common in sheltered bays from southern California
southward.

The Atlantic saury or skipjack, Scoinberesox saiirus, belongs to a different
family, Scomberesocidae, but is very similar to the halfbeaks. The jaws are
toothless and thin, and the upper is nearly as long as the lower. The dorsal
and anal fins are followed by finlets as in the mackerel. Great schools of these
herbivorous fish arc mainly found in temperate seas offshore.

The Pacific saury, Colobis saira, is like the Atlantic species and is found

MASTERS OF THE WATER-BONY FISHES 199

from Baja California to Japan. Both reach P/2 feet, though the Atlantic form has
been recorded to 30 inches. Schools of thousands of individuals will rise at once
out of the water, leaping, and skittering on the surface, when pursued by
predators such as tuna and bluefish.

FLYING FISHES: Family Exocoetidae

The "little bluebirds" of the sea do not have extended beaks like other
synentognaths, but they can be immediately recognized by the very large wing-
like pectorals. In these fish, the leaping tendencies of all synentognaths reach
a climax. Almost anyone who has traveled tropical seas in a boat has seen them
repeatedly spring up in front of the boat either singly or several at a time.
They may sail off singly in any direction regardless of the direction of the
wind or several may sail in precise formations. Flying fishes are swift, pelagic
fishes usually found over deep water.

Breder and Edgerton (1946) have examined the flight of these fishes by
using a high-speed camera and stroboscopic lights. They found that before
take-off^ the tail beats as many as fifty times a second in order to drive the fish
to the 40 mph necessary for take-off. The pectorals (and sometimes also the
expanded ventrals) are kept folded against the sides until the fish's foreparts
leave the water. Then thev are spread. The long lower tail lobe leaves the
water last and gives the extra taxiing push (of V2 to 1 second duration) neces-
sary to add speed for a sustained glide. As the speed drops to 25 mph, the fish
either re-enters the water or dips its tail in for another push and another
glide. Single glides average 2 to 6 seconds and 40 to 50 yards but have been
observed lasting up to 10 seconds. The fish can bank by manipulating the
pectorals. Several single glides may be made together so that one flight may
cover a quarter of a mile or more. The pectorals may seem to vibrate but are not
flapped. Only one fish, the fresh-water hatchet fish, Gastropelecus, is known
to flap its pectorals in flight.

Flying fishes eat all sorts of small surface-living invertebrates. Atlantic species
build nests for their eggs by binding floating Sargasso weed together. They "fly"
in order to escape their many enemies, particularly the dolphin, Coryphaena,
and the bonito, Katsiixvoniis. They are found in all tropical seas.

SHORT-WINGED FLYING FISH: Parexocoetus viesogaster— Color Plate I

Size: Up to 7 to 8 inches.

Distrihiition: Cosmopolitan in warm seas. Straggles to Cape Cod in the Gulf
Stream.

Identification: The "wings" are somewhat shorter than those of other species.

Similar Species: The largest of all flying fishes and the one with the best
developed powers of flight is the Californian flying fish, Cypsehinis californiciis.
It reaches 18 inches in length and is found solely off southern California.

Hemibranchs: Suborder Hemibranchi

This group includes the sticklebacks and trumpet fishes. There are several
spines preceding the dorsal fin and the ventrals are abdominal. The families are
widespread over the world and are varied in habits.

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UNDERWATER GUIDE TO MARINE LIFE

STICKLEBACKS: Family Gasterosteidae

These are small fishes typical of bays, estuaries, brackish waters, and streams
of north temperate and arctic seas. The ventral fins are each supported by a
stout spine, and there are 2 to 9 spines preceding the soft dorsal fin. They
are mainly olivaceous in color, but in the spring when thev enter fresh water
to breed, the males become flushed with a striking and quite beautiful red on
the sides and head. At that time, the eggs are laid in nests built around the
stems of water plants, and the pugnacious male guards the nest.

Two-spiNED stickleback: Gastewstetis aculeatus

Size: Up to 4 inches. Females are larger than males.
Distribution: Circumpolar. South to New Jersey and to Baja California.
Identification: Separated from most other sticklebacks bv the presence of onlv
two dorsal spines.

Habits: The food is varied from small fishes and crustaceans to algae.

Fig. 101. Two-spined stickleback.

TRUMPET FISHES: Family Aulostomidae

These are extremely odd, elongate, and compressed fishes, characteristic of
coral reefs all over the world. The colors are mostly browns and dull yellow.
It is the movement of this fish that is most fascinating. They seem to float
through the water with no body motion whatsoever. Actually, the nearly
transparent dorsal and anal fins are the active propulsion units, waving rapidly
to and fro. If the fish has to move quickly, it does so by a strong lateral motion
of the tail as do other fishes, but the trumpet fish would rather not so exert
itself. It far prefers to move on its slow course, head up or head down, back-
wards or forwards surveying all with its large eves. It seems to depend on con-
cealing coloration and habits for protection. It has been observed bv the authors
to stand with its head down in imitation of the branches of a oorgonian when
approached, and it will frequently keep to the opposite side of objects in the
water like a squirrel does on a tree trunk. Trumpet fishes are solitary and very
common. They eat small fishes, crustaceans, and worms. The small mouth
is at the end of a very long snout.

TRUMPET fish: Aidostovia vmcidatiis— Figure 97

Size: Up to 3 feet long and possibly longer. Averages Wi to 2 feet.
Distribution: Coral reefs of Bermuda, Florida, and the West Indies.
Identification: The principal ground color is brown, but occasionally very
yellowish ones arc seen.

MASTERS OF THE WATER-BONY FISHES 201

Similar Species: The cornet fish, Fistiilaria tahacaria, is of a different but very
similar family, Fistulariidae. It is typically West Indian, and reaches larger size
(to 6 feet) and has a proportionately longer snout than the trumpet fish. There is
a long filament proceeding backward from the middle of the caudal fin.

Lophobranchs: Suborder Lophobranchi

This group includes the sea horses and pipefishes. The scales in these very
specialized fishes form a stiff but movable encasing armor. The mouth is small
and at the end of a long snout.

All lophobranchs are carnivorous, feeding on very small animals, mosdy
crustaceans. Most have reduced tail fins (sea horses have none) and depend
on the fluttering dorsal and pectoral fins for movement. In addition, the tails of
many (especially sea horses) are prehensile. Movement is stiff but graceful.
The breeding habits are very odd. The female deposits the eggs, up to a few
hundred, in a pouch on the male's belly. There they incubate and hatch.
Miniature young emerge to relieve the male of his burden. The male fre-
quentlv rubs his pouch against some object to hasten the multiple birth.
Lophobranchs are probably degenerate offshoots of the hemibranchs. They are
t\'pical of the sandv, shallow, eelgrass-covered waters of temperate and tropical
seas.

SEA HORSES AND PIPEFISHES: Family Syngnathidae

The sea horses and pipefishes differ only in that the latter are straight while
the former ha\'e a head that is bent sharply down and travel upright, looking
like a chess knight. Both of them depend on concealing coloration and habits
for protection. Some (notably the East Indian Phylloyteryx) even have fantastic
filamentous extensions on their bodies so that they resemble seaweed.

NORTHERN pipefish: Syngnathxis fiisciis—Color Plate 1

Size: Averages 6 inches. Up to 1 foot.

Distrilmtion: Halifax to North Carolina. Most common near New York.

Identification: The color varies from green to brown, depending on the
environment.

' Habits: Moves stiffly in shallow water over weedy beaches. It is fond of
the little shrimp Gannuarns. Most movement is by means of the dorsal fin as in
the sea horse. The tail is used for movement only when the fish gets excited.
The courtship is very strange. The two mates swim erect, their bodies in
S-shaped curves. As they pass each other, they touch and become more and
more aroused until they twine their S-curved bodies together— looking verv
much like the U.S. Army Medical Corps insignia— and the female deposits
some eggs in the pouch of the male. This process is repeated several times
until all the eggs are laid.

Similar Species: A large 18-inch species, the great pipefish, Syngnathiis
calif orniensis, occurs on the California coast and northward.

NORTHERN SEA HORSE: Hippocavipiis hiidsoniiis—Color Plate I

Size: Averages 4 to 5 inches. Up to over 6 inches.

202 UNDERWATER GUIDE TO MARINE LIFE

Distrihution: Carolinas to Cape Cod. Rarely to Nova Scotia.

Identification: The size is rather large (for a sea horse), and the color is
brownish over all.

Habits: This is a slow-moving fish, most often seen anchored to eelgrass
or other objects with the prehensile tail. The dorsal fin is the principal organ of
propulsion. The earlike pectorals also help, but these fishes are not very mobile.
Because of this, the swim bladder is large and well developed, and if a little
gas is removed from it, the fish will sink to the bottom (Gudger, 1905).

By means of stroboscopic lights and a high-speed camera, Breder and Edgerton
(1942) found that the dorsal fin movement is very complex and fast. The fin
moves from side to side thirty-five times a second, nearly as fast as a humming-
bird's wing. There are also wavelike motions in this fin passing from the top
to the bottom, ten waves passing through this fin in a second. This locomotor
method, as well as the habit of living in seaweed, limits sea horses to a small
size. It is probably not coincidence that the largest sea horse lives where there
are the largest seaweeds. Movements of the head and, thus, the pectoral fins,
change the direction of travel.

Similar Species: The giant sea horse, Hippocam-pus ignens, of Magdalena Bay in
Baja California and southward, grows to 1 foot long and is the largest sea horse.

Spiny-Rayed Fishes: Order Acanthopterygi {"spiny fins")

The great majority and the most varied of fishes belong in this group. The
great array of species presents difficult problems in identification because of the
similarities in appearance between species as well as the variations of color
and pattern within many of them. Nevertheless, this cannot help but be a
fascinating group, as well as a challenging one, because the most colorful of all
fishes, as well as those with the most complex and interesting social behavior,
are found here.

All spiny-rayed fishes have at least one, and usually all, of the following
characteristics: (1) spines on the forward ends of the pectoral and \'entral
fins, (2) the pectorals placed high on the body above the abdomen, (3) the
possession of two dorsal fins, one spiny and one soft, and (4) ventral pins placed
under the pectorals.

There are several large suborders. These are the dominant fishes of todav.

Mulletlike Fishes: Suborder Percesoces

These are the only spiny-rayed fishes that still have the ventral fins placed on
the abdomen in back of the pectoral fins. Their bodies are rather elongate. There
is a small, spiny dorsal fin widely separated from the soft dorsal. The three
families of this suborder constitute the most primitive of all spiny-raved fishes.
They are typical of the warm temperate and tropical seas of the world.

SILVERSIDES: Family Antherinidac

These small fishes, also known as "smelts," "whitebait," and "frv," school
by the thousands and look much like anchovies or small smelts, but these latter
do not have two dorsal fins. Silversides have a brilliant silver stripe on the

MASTERS OF THE WATER-BONY FISHES

203

Fig. 102. Tidewater silverside.

side and none of them has a lateral line. All live near shore and may enter
brackish water and fresh water. They furnish excellent food and for that
reason are also called fescados del rey or "fishes of the king." They are cosmo-
politan in warm seas.

TIDEWATER SILVERSIDE (whitebait) : Menidia beryllina

Size: Up to 3 inches.

Distribution: Massachusetts to the Gulf of Mexico.

Identification: Same as for the family.

Habits: This is a typical schooling silverside which is carnivorous, feeding
on all kinds of small animal life. It is common in shallow water and enters
brackish and fresh water. Spawning occurs in the summer. The eggs have ad-
hesive threads by which they are anchored to the bottom and attached to each
other.

Similar Species: One of the West Coast species, the grunion, Leiiresthes
tenuis, deserves mention because of its extraordinary breeding habits. It is a
small, 6-to-8-inch fish common from San Francisco to Baja California. From
March to August, grunion come in to sandy shores to breed. The timing is
precise. They ride the crest of a wave to the beaches about fifteen minutes after
high tide on the first four nights after the highest tide of the full moon. Between
the time the wave has receded and the onrush of the next wave, the female
digs tail first into the sand and, with the male curled about her head, deposits
her two thousand eggs. Spawning continues for about an hour, different fish
coming in and going out with each wave. The eggs remain in the sand until
the next high tide wets them exactly two weeks later. Then the eggs hatch,
and the young escape into the sea. So striking is this procedure that local
chambers of commerce formerly advertised it as a tourist attraction, and it
became necessary to protect grunions from April to June by law.

MULLETS: Family Mugilidae

Mullets are schooling fishes which are similar to silversides but which have
small mouths, no silvery lateral stripe, and are comparatively robust. They are
mud-eaters, that is, they take mud in the mouth, strain animal and plant
substance from it with a sievelike arrangement in the throat, then spit the
remaining material out. They are raised in oriental fishponds for food on a
commercial basis. The ama-ama is one particularly well-known mullet of
Hawaii much fabled in song and story by the Polynesians. Mullets are cosmo-
politan in warm seas. They are an excellent food fish.

204

UNDERWATER GUIDE TO MARINE LIFE

nUet.

STRIPED MULLET (fatback, jumper) : MiigU cephalus

Size: Averages 1 foot. Up to 2 feet.

Weight: Averages 1 pound. Up to 4 pounds.

Distribution: Cosmopolitan in warm seas. North to Maine and Monterey,
south to Brazil and Chile. Also in the Sakon Sea.

Identification: The sides are brassy or silvery with faint, dark, horizontal
stripes.

Habits: Mullets prefer still, shallow water with grassy, sandy, or muddy
bottoms. They frequently enter brackish or salt waters. These are somewhat
dull fishes which grub around, head down, in mud like a bunch of chickens.

BARRACUDAS: Family Sphyraenidae

These fishes are impossible to mistake for anv others. The large mouth is
armed with very heavy, compressed teeth. There is a slim, pikelike body with a
huge tail. The eye is large, silvery, and appraises the swimmer with an
inquisitive, menacing look. The ground color is silvery. There are sometimes
blotches on the sides and back. The fins are dark. Barracudas are very much
like pike in habits. They depend on extremely fast rushes at living fish prey
for food, using the teeth in a slashing manner. All are powerful and voracious,
but most of the several species are rather small, not reaching over 18 inches
(the sennets and the guaguanche). Their distribution is world-wide in the
tropics.

great barracltda (picuda): Sfhyraena barracuda— Figure 104

Size: Averages 2^2 feet. Reaches 6 to 8 feet. Doubtfully reported up to 10 feet.

Weight: Averages 5 pounds. Large at 50 pounds. Reaches 100 pounds.

Distribution: Florida to the West Indies.

Identification: This is the largest barracuda and is compressed compared to
other species.

Habits: This very swift, predatory, shallow-water fish is undoubtedlv dan-
gerous under certain circumstances. It travels singly or in schools. A swimmer
in tropical waters can count on having one or more about him much of the
time, not because the fish is aggressive, but because it is curious. Barracudas
will approach the swimmer rather closely, but do not themselves like to be
approached. Frequently, if approached, they will gape, show their teeth, and
retreat out of sight, usually to return in a few minutes. The fish will advance

MASTERS OF THE WATER-BONY FISHES 205

and retreat a few times, then leave. The best tactic to use to entice one to come
close for photographic purposes is to nonchalantly turn your back and pretend
not to notice. The barracuda will approach quite closely. Barracudas have been
known to follow persons walking along the shore, another illustration of their
curiosity.

There are times, however, when the barracuda is not just nosy. There are
definite records of attack. The bite can always be recognized because it is clean
and straight, not like a shark's round and jagged wound. Barracudas usually
strike only once, leaving as rapidly as they came. Springer (1943) has analyzed
the factors influencing barracuda attack and finds that the danger increases
with (1) water over 66° Fahrenheit, (2) increased water turbidity, which
impedes the barracuda's vision, (3) the presence of bright colors, shiny or
fluttering objects, and (4) fast, sudden, irregular movements across the field
of vision.

Barracudas are diurnal and depend upon their eyesight to hunt. If the
swimmer acts like a fish, avoids carrying wounded fish or spearing fish in the
barracuda's presence, and does not splash on the surface, there is very little
likelihood of attack.

The flesh of barracudas is good eating. Although it has been reputed in some
places to cause "ichthyocism," a form of food poisoning, this seems doubtful
according to present knowledge.

Siviilar Species: The Pacific barracuda, Sphyraena argentea, grows to 5 feet
and is found from San Francisco to the south. It is slimmer than the great
barracuda.

Threadfins: Suborder Rhegnopteri

The one family of threadfins is very much like the mullets, but the unique
pectoral fins are split into two parts, the lower one of which is composed of
seven or eight threadlike rays. The mouth is under a pronounced snout. They
are common in all warm seas except those of Europe.

Fig. 104. The great barracuda, Sphyraena, is often seen followed hy several skip-
jack, Caranx ruber, which -might share in the criinihs of the table. This barracuda
was four feet long.

206

UNDERWATER GUIDE TO MARINE LIFE

Fig. 705. Threadfin.

Fig. 106. Sand launce.

THREADFINS: Family Polynemidae

threadfin: Polynemus octonernns

Size: Up to 1 foot.

Distribution: West Indies and the Florida Keys. To the Gulf of Mexico,
straggling to Cape Cod.

Identification: The color is yellowish white, olivaceous above.

Habits: This is a fish of shallow, sandy shores. It travels solitarily or in small
groups and is carnivorous, feeding on all sorts of small animals. The threadlike
fins are probably tactile in function.

Sand Launces: Suborder Ammodytoidei

There is one family of these very odd fishes. They dive like lances into the
surf sand of shallow shores, and this habit has given them their name. The shape
itself should be enough to identify them. The skin has many curious cross
folds, and the scales are very reduced. These are fishes of the North Atlantic
and North Pacific.

SAND LAUNCES: Family Ammodytidae

SAND LAUNCE: Ammodytes americaniis

Size: Lip to 6 inches.

Distribution: Newfoundland to Cape Hatteras.
Identification: Same as for the family.

Habits: These fishes travel in huge schools near the shore, particularly in the
north. They dive in and out of sand with great facility and often remain there

MASTERS OF THE WATER-BONY FISHES 207

while the tide is out. Their reason for doing this is not known. As pan fish, they
are excellent.

Berycoids: Suborder Berycoidei

Several archaic characters seem to indicate that these fishes bear an ancestral
relationship to the rest of the spiny-rayed fishes, probably forming a link
between these and the herringlike fishes. The bodies are largely compressed
and the fins and bodies very spiny. There are two distinct families in our waters.

SQUIRREL FISHES: Family Holocentridae

These are among the most numerous and beautiful of reef fishes. Their
bodies are red, and the fins are tinged with yellow. The exceptionally large
eye indicates nocturnal habits. Nearly every coral head forms the home of several
squirrel fishes. By day, they stay holed up, but they will come out to curiously
view a swimmer. By night, beginning at dusk, they become active and feed
out in the open. The large eye and large spiny fins identify them. Squirrel
fishes also have a large pre-opercular spine which can inflict painful wounds
on persons handling them. They are common in all coral seas.

SQUIRREL FISH (soLDiER fish): Holocentnis ascensionis— Color Plate 3

Size: Averages 8 inches to 1 foot commonlv. Rarely to 2 feet.

Distrihntion: Florida and the West Indies.

Identification: Same as for the family.

Habits: This is a timid fish by day, but it actively and pugnaciously feeds
on fishes and crustaceans at night. It is among the most common of reef fish
and, as is the case with many of them, seems to "home," or return to the same
hole on the reef, probably not straying far from it even by night. It is solitary as
would be expected from the foregoing.

SURMULLETS: Family Mullidae

These are very easy fishes to recognize, both because of the long chin barbels
that all of the species possess and the wide separation of the spiny and soft
dorsal fins. The feeding method is also distinctive. The two chin barbels are
held like long, active feelers in front of the fish, exploring the bottom over
which the fish is feeding. When so engaged, the fish presents a very amusing
appearance as it grazes and pokes busily about like a chicken. The diver usually
can approach them closely. Some school and some swim solitarily or in the
company of other reef fishes. They are carnivorous, feeding on small inverte-
brates. Many books about fish report that most surmullets are bright red, but
the diver Vv^ill discover that this is true of many of them only when the fish
is dead, dying, or excited. When naturally swimming about, most species have a
pale whitish to pink or rosy ground color.

Surmullets are found in all tropical and subtropical seas and are extremely
characteristic of reef areas.

spotted goatfish: Ufeneus maculatus— Color Plate 3

Size: Up to about 10 inches.

Distribution: West Indies north to Florida.

208 UNDERWATER GUIDE TO MARINE LIFE

Identification: The ground color varies somewhat with the environment, but
the three or four large dark blotches on each side are the best identifying
mark. The most common ground color is white to rose. Red specimens are
sometimes seen.

Habits: This fish is usually found swimming singly or with other reef fish
such as small parrot fishes. It feeds in sand near coral heads.

Similar S'pecies: The northern goatfish, Mullus auratus, is another West
Indian sandy bottom fish, but it strays north to Cape Cod. It is red above with
light yellow sides and with two rows of light blue spots on the sides above
the lateral line.

The yellow goatfish (^color fhotografVi), U^eneus martiniciis, differs from
most of the goatfishes in that it schools densely and acts much like the
smaller schooling grunts in habits. There is a bright yellow stripe extending
horizontally from the eye, down the middle of the pale, whitish body, and onto
the tail. This coloration thus strongly resembles that of the yellowtail snapper
COcyurus^.

The only common West Coast goatfish is Upeneiis dentattis. It occurs from
Cape San Lucas southward. It is rosy with a red stripe running down the side
and onto the tail fin.

Mackerellike Fishes: Suborder Scombroidei

These primarily oceanic fishes are mainly offshore predators and are so
diverse, numerous, and confusing that we will be able to treat them onlv in a
summary way. They are mostly rather large, schooling fishes of the open seas
and as such are difficult for the swimmer to observe. Nevertheless, the oppor-
tunity to study them under water should be grasped because little is known
about most of them. In general, they have smooth, streamlined bodies that offer
little resistance to the water. They have pointed heads, constricted caudal
peduncles, and large lunate tails. These are all adaptions for swift movement.
It is in this group that we find the swiftest of fishes as well as the swiftest things
that swim. Some of them even have slots into which the dorsal and pectoral
fins fold in order to further reduce water resistance. The typical families of the
group have separate spinv and soft dorsal fins, and the soft dorsal and the anal
fins are of similar size and shape, being directly over and under each other.
Most of them are highly predacious, and many are schooling. The color is
usually silvery with a greenish or bluish back. As we shall see, there are a
number of families which seem to fit none of these rules. The most constant
features are the silvery, iridescent ground color and the similar soft dorsal and
anal fins, but even these rules are frequently broken.

TRUE MACKERELS: Family Scombridae

The swimmer will not often encounter the largest of the species of this family,
but if he does he is in for an almost unmatchable thrill because of the speed,
size, and silvery beauty of these fishes. There are about sixty very similar
species in the world of these mostly predacious fishes. Many of them are
cosmopolitan, of great size, and commcrciallv xaluable. All are schooling and of
wide distribution.

MASTERS OF THE WATER-BONY FISHES 209

As a group, identification is rather easy, there being a series of small finlets
behind the soft dorsal and anal fins. The shape does not vary much from a
torpedolike spindle, the caudal peduncle being very slim and supported by
strong lateral keels. The colors are primarily silvery with blue or green and some
yellow markings.

These and the spearfishes are the swiftest of the swift. A speed of 40 to 50
mph is probably attained by the larger species. The body is very smooth, even
the eyes and gill cover being practically flush with the extremely powerful
body. Among the fishes, these are the wolves of the sea, running down prey. A
few, however, are plankton eaters. Most are primarily pelagic and wandering,
coming inshore when the seas are calm and warm. In most, the pattern and
causes of migration and the breeding habits are not well known.

COMMON ATLANTIC MACKEREL: Scomher scomhriis—Color Plate 2

Size: Averages a little over 1 foot. Up to 2 feet.

Weight: Averages a little over a pound. Up to 7 pounds.

Distribution: In the North Atlantic from Labrador to Cape Hatteras and from
Norway to Spain.

Identification: Its small size and the wavy blue markings on the back serve
to identify it.

Habits: Contrary to most of the family, this is a plankton feeder primarily,
though many small fishes are also eaten. The long gill rakers serve to strain small
animals from the water. The schools are especially large, and they move in
response to temperature. The northerly migration begins at Cape Hatteras
in March and ends at the St. Lawrence by June. This migration is a coastal
one. In the fall, the southerly migration is offshore and in deeper waters.
Mackerels produce huge numbers of floating eggs, up to 500,000 per female,
in the summer. The mackerel's enemies are many. In the north the gannets,
among the birds, take a heavy toll. Many fishes and squid prey upon the young.

Similar Species: The Atlantic chub mackerel, Pneuvratofhonis colias, is very
similar in appearance to the common mackerel, but the wavy lines on the back
are about twice as fine and numerous, and the size is smaller, rarelv being over
1 foot or 14 inches. It is found from the St. Lawrence south to Virginia.

The Pacific mackerel, Pneinnatophorus japonicns, is very similar to the chub.
It is found from Alaska to Baja California and is abundant from Monterey Bay
southward. It reaches 20 inches.

The frigate mackerel, Aiixis thazard, is a species found in all warm seas,
reaching northward to Cape Cod and probably to southern California. There
are onlv a verv few fine wavv marks on its back. It reaches 14 inches in lenoth.

SPANISH MACKBREh: Scoinberomoriis inacidatns— Color Plate 2

Size: Averages 18 inches. Up to 4 feet.

Weight: Averages 2 pounds. Up to 20 pounds.

Distrihittion: Tropical waters from Cape Hatteras to Brazil. Straggles to Maine.

Identification: This is among the slimmest and most beautiful of mackerels.
The head is comparatively small and the body rather compressed. The color
is silvery with blue-green above and large yellow spots on the sides.

Habits: This fish is found inshore in shallow waters in late summer, when it

210 UNDERWATER GUIDE TO MARINE LIFE

may be commonly seen leisurely swimming singly or in small pods. The authors
have seen them in shallow coral areas in August. They school more densely
in deeper waters. The spawning occurs offshore in late spring and early summer.
The eggs are floating and very numerous. Menhaden and other small fishes
are its principal food.

Similar Species: The Mexican sierra, Sconiheroviorus sierra, is very similar
to the Atlantic form. It is common in the tropical eastern Pacific and reaches
north to Baja California and rarely to San Diego.

The cero (painted mackerel, kingfish, pintado), Scomheromonis regalis, is
found from Cape Cod to Brazil and is not generally common. It has the soft
dorsal fin inserted directly above the anal (in the Spanish mackerel the soft dorsal
is a little ahead of the anal) and a solid or broken yellowish-brown lateral stripe.
It tends to be a bit larger than the Spanish mackerel but is otherwise very
similar.

The king mackerel (cero, cavalla, kingfish, etc.), Sconiberomorus cavalla,
is the largest of its genus, weighing up to 50 pounds. It is completely silvery,
with no markings, and has the lateral line abruptly decurved under the soft
dorsal fin. It is typical of the West Indies and reaches north to Cape Hatteras.

The wahoo (kingfish, peto), Acanthocyhiiim soJandri, has a very wide tropical
distribution. It is found in the Western Hemisphere north to Maryland in the
late summer, and is also found off the western coast of Mexico, but it is found
chiefly in the West Indies. The body is long and slim and crossed by dark
vertical bars its whole length. Because of the large size, averaging 25 to 45
pounds and reaching 6 feet and 133V2 pounds, and the beaklike snout set with
large teeth, it has been confused with the barracuda.

OCEANIC BONiTo (skipjack): Katsuwonus felamis— Color Plate 2

Size: Up to 2i/i to 3 feet.

Weight: Averages 4 to 5 pounds. Up to 25 to 35 pounds.

Distribution: Cosmopolitan in warm seas. North on our coasts to Cape Cod
and Point Conception.

Identification: The belly has a series of dark longitudinal stripes. There is
a corselet of scales around the body near the pectoral fins (as is common in many
of the tunalike fishes).

Hahits: This is the most likely to be encountered and one of the smallest of
the tunalike fishes, many of which are practically cosmopolitan in warm seas.
All are exceedingly swift and voracious, and are found principally offshore. These
fishes travel in moderately large schools that are constantly on the move.
The nature and causes of their movements are poorly understood. The chief
food of all tunalike fishes consists of smaller oceanic schooling fishes. The oceanic
bonito is fond of eating flying fishes.

Similar S'pecies: The confusing array of oceanic tunalike fishes is best divided
into three groups: (1) tunas, Thunnus and Neothunnus, (2) bonitos, Sarda,
and (3) albacorcs, Germo. The tunas are huge, reaching 1,500 pounds, and are
usually plainly colored. The bonitos are smaller, rarely over 3 feet, and
are obliquely striped on the back (stripes run up and back from the mid-body).
Albacorcs attain 80 pounds in weight and have very long, sickle-shaped pectoral
fins that reach back to behind the origin of the anal fin.

Branching antler coral sometimes forms dense forests and affords a home for
many fishes including this sergeant major..

Fan worms make their homes in massive corals like this brain coral, one of the
foundation stones of reefs.

These plant-like animals, red sponges, hydroids, and gorgonians, live by filtering
plankton from the sea.

A flower-hke anemone, nestled between a sponge and a coral, waits for some
unlucky, small fish to wander into its poisonous, stinging tentacles.

MASTERS OF THE WATER-BONY FISHES 2n

The false albacore, Katsiiivonus alletteratus, belongs to none of these groups,
but is very closely related to the oceanic bonito. It has no ventral stripes.

CUTLASS FISHES: Family Trichiuridae

These degenerate eellike fishes are like mackerels in the appearance of the head,
but otherwise are very odd. The silvery to silvery brown color, the general lack
of fins, and the scaleless body identify them. Cutlass fishes can move swiftly
and strongly but usually keep to the bottom.

They feed voraciously on other fishes. They are generally distributed in all
tropical seas and are excellent food.

CUTLASS FISH (scABBARD FISH, siLVERFiSH, machete): Trichinuis lefhirus

Size: Up to 5 feet but usually smaller.

Distribution: West Indies to Virginia. West Coast north to southern California.

Identification: Same as for the family.

Habits: The authors have never seen this fish, but suspect that it might be
a very nasty customer to handle. Little seems to be known of it. It is not common
over most of its range but may be fairly plentiful near Puerto Rico where the
name "machete" is used for it.

Vig. 107. Cutlass fish.

SPEARFISHES: Family Istiophoridae

All of the several species of spearfishes, sailfishes, marlins, and the related
'swordfishes are very large, very swift, pelagic fishes of wide distribution in
tropical and warm temperate Seas. Their speed and endurance is as great as that
of any fish.

All have a long round spear or flat sword projecting out from the snout and
all are toothless or practically so. The dorsal fin of all except the swordfish can
fold down into a dorsal furrow. All are fish-eaters on the medium-sized schooling
kinds such as herrings or mackerel. It would be of great interest to see one of
these under water, though this would not be without its dangers; there is some
evidence that these very powerful fishes attack boats and sharks with their
spears when molested. None of them seems to be exactly even-tempered, and
they may even be listed as dangerous fishes. These are rather mysterious fish
even though they are not rare and are even common in places. Their manner
of feeding seems to be to approach a school of small fishes and to slash at it
with their spear. Then the stunned and mutilated prey are eaten at leisure.

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UNDERWATER GUIDE TO MARINE LIFE

Fig. 108. Atlantic sail fish.

Spearfishes are solitary or may travel in pairs. The predominant color is a
beautiful silvery blue, frequently with vertical stripes. The colors become more
vivid when the fishes are fighting or dying.

ATLANTIC SAILFISH:

Istioph

orus amencanus

Size: Averages 6 feet. Up to 8 feet.

Weight: Averages 30 to 50 pounds. Up to 123 pounds.

Distribution: West Indies to Florida. Straggles to Cape Cod.

Identification: The saillike fin makes this fish unmistakable. When traveling
speedily through the water this fin is folded back in a slot on the back. The
slim body and small size (for spearfishes) then becomes the best means of
identification. The ventral fins are long.

Habits: Sailfishes are the most common, the smallest, and the most spectacular
and beautiful of the spearfishes. There is a good chance of seeing them under
water for they come quite close to shore. Often, they travel in pairs. The sail
is always raised when they fight on the line and presumably also when they
are otherwise annoyed or excited. The purpose of such a large fin is not known.
Sailfishes and other spearfishes like to bask at the surface.

Similar Species: The Pacific sailfish, Istiophorus greyi, grows to a larger size
than the Atlantic sailfish, averaging 100 pounds and reaching 275 pounds. It is
found north to southern California.

There are several marlins which look like sailfishes, but none of them has the
very high saillike dorsal fin. The blue marlin, Makaira nigricans, is a bulky fish
with no visible lateral line. It reaches 750 pounds but averages 300 to 400 pounds
and is found in the warm Atlantic. It is not very common. The white marlin,
Makaira albida, is another warm Atlantic species of rather small size (up to 1 50
pounds) and comparatively light coloration. It has a conspicuous lateral line.
The striped marlin, Makaira mitsiikurii, is the only striped Pacific species and
is the most vividly striped of all spearfishes. It is of the warm Pacific and reaches
huge size, weighing up to over 1,000 pounds, and reaching a length of 14 feet.

The swordfish, Xiphias gladius, is of the family Xiphiidae, and its distribution
is world-wide in all warm seas. It reaches 600 pounds (Norman and Eraser, 1938,
list it as the largest marine fish— up to 20 feet long and 1,000 pounds) and is

MASTERS OF THE WATER-BONY FISHES 213

exceedingly swift and powerful. It has a huge, flat sword that is over one third
of its total length. The coloration is grayish to brown, and the shape of the body
is reminiscent of a mackerel shark, especially because of the high dorsal fin
placed just behind the head. The swordfish is by no means to be trusted. It has
been known to drive its sword through the bottoms of boats, though talcs of its
ferocity are usually exaggerated.

JACKS: Family Carangidae

This is primarily a tropical family. It is composed of a large assemblage of
predacious species most of which are deep-bodied, compressed silvery fishes,
more typical of inshore waters than are the true mackerels. There are a great
number of very similar species. Most school when young but are found in small
pods or even singly as adults. These swift fishes often have the posterior part
of the lateral line reinforced by hard, bony scutes. The scales are small. On
the whole, one is strongly reminded of the true mackerels, but some of the
adaptions for speed, such as the bullet-shaped, fusiform body have been lost.
Almost all jacks have two short spines preceding the anal fin. Their distribution
is world-wide in warm seas, and most are excellent food fishes. They are liable
to be stand-offish with the swimmer. It is unfortunate that in this prominent
group the common names are extremely confused. On top of that, manv common
species are difficult to identify, even for the ichthyologist. The group is arranged
below starting with the species that are most like the mackerels and progressing
outward from these toward the deeper-bodied, more compressed species.

LEATHER-JACKET (ZAPATERO) : OUgapJjtes SOmS

Size: Up to 1 foot.

Distribution: Both coasts of tropical America. North to San Diego and New
York.

Identification: Compressed body. There are five dorsal and two anal spines
before the soft dorsal and anal fins. These fins reflect each other in size and
shape and are broken up into finlets posteriorly. The color is bluish to whitish
on the sides and bluish to bright green above.

Habits: This is an inshore predator on small fishes. Its sharp dorsal and anal
spines are capable of inflicting injury, but thev are not poisonous. It flops about
"vigorously when caught and should not be handled with bare hands.

YELLOWTAiL JACK (amberjack, coronado) : Seriolu dorsalis— Color Plate 2

Size: Averages TVi feet. Up to 5 feet.

Weight: Averages 10 pounds. Up to 60 pounds.

Distribution: Monterey Bay to the Gulf of California and south to Chile.

Fig. 109. Leath

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UNDERWATER GUIDE TO MARINE LIFE

Identification: The mackerellike body is not very compressed. The spiny
dorsal is small and the anal is much shorter than the soft dorsal fin. A prominent
wide yellow stripe runs along the side and onto the tail.

Habits: This large and speedy predator travels solitarily, in small pods, or in
schools near reefs or over deeper water on the prowl for the small fishes which
are its prey. It has the habit of driving its prey into shallow water near shore.
It spawns in the summer, probably at sea.

Similar Species: There are several members of this genus, all of which are
best recognized by the general silhouette and fin pattern which they all have
in common. The great amberjack, Seriola lalandi, is also called the horse-eye
bonito and has the distinguishing mark of many of this genus— the dark stripe
running diagonally through the eye from the base of the spiny dorsal to the upper
lip. It ranges from Cape Cod to Brazil, being most common in the West Indies.

The rainbow runner, EJagatis hifinnulatus, has the shape and fins of the
Seriola species but has a very striking pattern consisting of four beautiful irides-
cent longitudinal stripes of dark blue, Hght blue, yellow, and again hght blue
from back to stomach in that order. It is not a common fish, but it is pelagic
in all tropical seas, being found north to New York and to southern California
in summer. It reaches a weight of 12 pounds.

PILOT fish: Naucrates ductor

Size: Up to 2 feet.

Distribution: Offshore in all warm seas.

Fig. 110. Pilot psh.

Fig. 111. Round scad.

MASTERS OF THE WATER-BONY FISHES 215

Identification: This fish is characterized by wide, dark, vertical crossbands.
The spiny dorsal is A'ery reduced. The anal fin is much shorter than the soft
dorsal.

Hahits: This is the fish that is commonly seen following sharks and vessels
at sea. It does not lead sharks to food but probably only hangs around them
for the scraps of the table. It is too fast and agile for the sharks to catch. The
eggs are laid at sea in the summer.

Siviilar Species: The banded rudderfish, Seriola zonata, is banded while young
and replaces the pilot fish in following sharks and vessels inshore. It has a small
spinous dorsal as do other members of the genus Seriola.

ROUND scad: DecaiHerns fiinctatus

Size: Up to 1 foot.

Distrihution: Cape Cod to Brazil.

Identification: The body shape is slim and round like that of a mackerel. The
posterior lateral line is well armed with bony scutes in this genus. The dorsal
and anal fins are followed by a finlet in the true scads and the soft dorsal and
anal are of similar length.

Hahits: The several species of small scads school in- and off-shore. They feed
mostly on small invertebrates. These are among the smallest fishes of this family.

Similar Sj^ecies: The Pacific counterpart of the scads is the saurel (rough
scad or California horse mackerel), Trachurus symnietricus. Its entire lateral line
is armed with large scutes from head to tail, this being the only jack to show
such a feature. Otherwise it is like a typical scad, although of somewhat stouter
shape. It reaches 2 feet but is mostly much smaller. The range is from San
Francisco southward through the tropics.

There is an Atlantic representative of the rough scad, and there are also several
species of Decapterus on the Atlantic and Pacific Coasts, which are difficult
to separate from the member of that genus already described. The goggle-eyed
scad or big-eyed scad, Trachnrops cnimenopthalmns, is much like Decapterus
species, but it has a huge eye and a slightly stouter shape (like the rough scad).
It grows to 2 feet and is found on both coasts north to Cape Cod and Cape
San Lucas.

JACK CREVALLE (coMMON jack) : Curunx hippos—Color Plate 2

Size: Up to 2!/2 feet or larger.

Weight: Averages 2 to 5 pounds. Up to 20 pounds or more.

Distrihution: Cape Cod to Brazil. Chiefly West Indies in the Atlantic. In the
Pacific, from Gulf of California southward.

Identification: With this fish and others of this genus there is a very definite
tendency toward (1) the development of the high forehead and back, (2)
decurved lateral line armed posteriorly with bonv scutes, (3) deep, compressed
body, and (4) soft dorsal and anal fins of very similar size and shape— features
that we think of as being typicallv jacklike. The species are manv and
extremely difficult to identify. This species has a particularlv blunt forehead
and also possesses a dark spot on the rear edge of the operculum.

Hahits: This fish is characteristic of inshore and offshore waters, chiefly
around coral areas. When young, this fish and others of its genus school. As an
adult, it is mostly seen in small pods. It is largely a surface predator on fishes.

216 UNDERWATER GUIDE TO MARINE LIFE

Similar Species: The members of this genus are so confusing that we must
refer the reader to other works for the details. Only a few of the common
relatives can be mentioned here.

The little skipjack, Caranx ruber (/ig. 104^, is the species most commonly seen
by swimmers in the West Indies. It has a dark dorsal stripe extending down the
back and onto the lower tail lobe. This little jack reaches the length of a foot.
It is often seen scampering after sting rays and barracudas. These larger fishes
do not seem to bother this speedy little fellow.

The blue runner (jack crevalle, hard-tailed jack), Caranx crysos, reaches
almost 2 feet in length and is very similar to the common jack crevalle, having
the opercular spot. It differs chiefly in its lower forehead, smaller size, and more
inshore habits. It is chiefly West Indian and ranges north to Cape Cod.

The yellow jack, Caranx hartholomaei, has a deep, golden-tinged bodv and
no opercular spot. It reaches a size of up to 2 feet, but is usually seen smaller
and is found from the West Indies and rarely to Cape Cod.

The horse-eye jack, Caranx sexfasciatiis, is also called "yellow jack" and is
another deep-bodied species. It has a small opercular spot, deep body, and very
large eyes. It is common in all tropical seas reaching north to Virginia and to
northwest Mexico. It reaches two feet in length.

The green jack, Caranx cahallus, is very much like the blue runner but tends
to be greener. It is found from San Pedro, California, southward. It reaches
15 inches in length.

The little bumper, Chloroscomhrus chrysurus, is similar to the typical jacks,
but it has no scutes on the lateral line, and the curvature of the belly is greater
than that of the back. It reaches only 10 inches and feeds mostly on plankton
inshore and offshore. The young frequently take refuge under jellvfishes. It
ranges from Cape Cod to Brazil, is chiefly West Indian, and has a West Coast
representative of western Mexico, the xurel de castilla, Chloroscoinhrus orgneta.

PALOMETA (oLDWiFE, ALEwiFE, GAFF-TOPSAIL POMPANo) : Trachinotus yaloMieta

Size: Averages 1 foot.

Weight: Averages 1 pound. Up to 4 pounds.

Distrihiition: Virginia to Argentina. Most common in the Caribbean.

Identification: In members of this genus, the body is very deep and compressed,
the mouth small, the snout rounded, the color silvery (frequently with yellow
about the head, belly, and tail), and the spiny dorsal fin very reduced. The first
few soft dorsal and anal rays of this genus are usually long, but in this species
they are exceptionally so. This species also has four dark vertical bars. The name
"pampano" (anglicized, "pompano"), is a Spanish word for "grape leaf" and
refers to the shape of the body.

Hahits: Pompanos are shallow-water tropical fishes. The species of the genus
are frequently found inshore in surf and about coral areas as well. The larger
ones are found in deeper waters frequently, but as a whole, these fishes keep
more to inlets or sand and mud bottoms than do the typical jacks. Almost all
of them travel in small schools or pods. Because of the small mouth, the food is
limited to small fishes, crustaceans, and molluscs.

Similar Species: This is another large and confusing genus which contains
some of the finest food fishes that swim.

MASTERS OF THE WATER-BONY FISHES

217

The pompanito, Trachmohis rhado'pus, is very similar to the palometa and
is found from the Gulf of California southward.

The common pompano, Trachinotus carolinus Cfig. 112'), is a much sought-
after food fish. It has a prominent, yellowish belly, throat, and head. It is
quite as deep-bodied as the palometa and has no vertical bars. The maxillary
bone just reaches the front part of the eye. The fish reaches 18 inches in length
and 7 to 8 pounds and is most common off the Gulf States and Florida around
surf and inlets over soft bottoms. This fish is reported by Phillips (1952)
to indulge in a strange "flight." The fish sails through the air on its side, head
slightly elevated, looking like a sailing paper plate.

The permit (great pompano, alewife), Trachinotus goodei, reaches large size,
up to Wi feet and 47 pounds, but averages 20 pounds. It is very similar to the
common pompano, separated from it by having the maxillary bone extended past
the pupil of the eye and by rather technical features, such as its possession of

Fig. 112. Palometa Qufper left) and ■pompano (lower right).

nineteen to twenty soft dorsal rays and seventeen to nineteen anal rays, in
contrast to the common pompano's twenty-five and twenty-two respectively. It is
not often found in the same waters as the common pompano, being mainly
West Indian.

The round pompano (permit), Trachinotus falcatus, is very round and deep-
bodied, as is the palometa, and has a rounded profile. It is found in common
pompano waters, but it is also found from Cape Hatteras south to Brazil.

The African pompano, Hynnis cuhensis (Hynnis hopkinsi in the Pacific),
is a rather rare offshore fish of the West Indies and is also found from Mexico
to Panama. It reaches 30 or more pounds and has scutes on the posterior lateral
line. The color is a plain bluish silver, and the shape is like the jack cravalle,
but the fins are like those of the pompanos.

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UNDERWATER GUIDE TO MARINE LIFE

Fig. 113. Roosterfish.

LOOKDOWN (horsehead, moonfish) : Selene vomer— Color Plate 2

Size: Averages 7 to 8 inches. Up to a little over a foot.

Distribution: Cape Cod to Brazil. Baja California to Peru. Most common
in the tropics.

Identification: This most compressed and deep-bodied of all jacks is easilv
recognized. The pearly, iridescent colors on the wafer-thin body reflect all
possible delicate shades of the spectrum.

Habits: This is a schooling fish which is most common over sandy shores.
It feeds on all sorts of small fishes and invertebrates. At times, it takes refuge
in pilings, under bridges, around reefs, but it seems to be most common in
rather open water.

Similar Species: Only the moonfish, Vomer setapinnis, could be confused
with this fish. The shape, size, and color are the same, but the soft dorsal and
anal fins are not extended as they are in the lookdown. It is found from Maine

MASTERS OF THE WATER-BONY FISHES 219

to Brazil and from Cape San Lucas to Peru, but it is chiefly tropical. The young
are common in the fall north to New York (via the Gulf Stream).

threadfish: AJectis ciliaris— Color Plate 2

Size: Up to 7 inches including fins. Body usually not larger than 2 inches
in diameter.

Distribution: Cosmopolitan in tropical seas. Drifts north in warm currents.

Identification: The dark bands on an intensely silver body and long dorsal
and anal fins identify it.

Habits: This is a somewhat mysterious little fish. It is much more common
beneath the surface than reported in most books, though it is by no means really
plentiful. In the young the dorsal and anal fin extensions are like bands and
are three times the body length. As the fish sits under ledges in reefs, these fins
ripple to create a truly exquisite picture. As the fish grows older, the fins wear
down and become shorter and thinner. It is not a timid fish and may be
approached quite closely in contrast to most jacks.

PAPAGALLOS: Family Nematistiidae

roosterfish: Nematistius joectoralis

Size: Up to 3 to 4 feet.

Distribution: Gulf of California to Panama.

Identification: The extremelv long dorsal spines are unmistakable. The color
is a beautiful, iridescent, silvery blue, darker on the back.

Habits: This is a very beautiful and stately fish which swims singly inshore
or offshore. It is predacious and very much like the jacks in habits. The dorsal
is held erect only when the fish is excited, lying in a groove on the back at
other times.

BLUEFISH: Family Pomatomidae

BLUEFiSH (taylor, snapper) : Poviatomtis saJtatrix

Size: Up to 4 feet or more.

Weight: Averages 1 to 5 pounds. Up to 25 pounds or more.

Distribution: Cape Cod to Venezuela and most warm seas, but not found off
Europe or the West Coast of North America. Very erratic in appearance and
abundance.

Identification: Basslike shape and bluish color. Large mouth and head. There
are no scales on the lateral line.

Habits: This living chopping machine is one of the most voracious of all fishes.
Schools travel constantly, destroying schools of fishes in their way. They are
common off channels and outside beaches in the warmer months, but their
continual movement makes their appearance extremely variable. Jordan (1908)
gives a good account of this species. Favorite foods are weakfish and the herrings.
Bluefish spawn in the spring and early summer. Not much is known of its habits
even though much has been written of it and it has been a favorite of anglers
and gourmets for vears.

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UNDERWATER GUIDE TO MARINE LIFE

SERGEANT FISH: Family Rachycentridae

coBiA (sergeant FISH, CRAB-EATER, CUBBY YEw) : Rachycentwn canadus

Size: Up to 5 feet.

Weight: Averages 10 to 15 pounds. Up to 125 pounds.

Distribution: Nearly cosmopolitan in warm seas, gets as far north as the
Chesapeake and straggles to Gape God. Most common in the Gulf of Mexico
off Mississippi. Not found on the Pacific Goast.

Identification: The elongate shape, longitudinal stripe on the midline from
the eye to the tail, and the brown body are unmistakable.

Fig. 115. Cohia.

Habits: This is not a particularly common fish, but it is not rare if one looks
in the right spots. Its favorite haunts are offshore near channel markers, buoys,
lighthouses, and rocks. Upon occasion it has been known to travel with king
mackerels, Scombewviorits, and manta rays. It is a swift fish and will pursue
menhaden, bluefish, and other schooling forms, but prefers to feed on the bottom
on crabs and flatfish. It is found in schools, groups, or alone.

MAN-OF-WAR FISH: Family Nomeidae

MAN-OF-WAR FISH: Novieiis gTonovi—Color Plate 10

Size: Up to 8 inches.

Distribution: Gosmopolitan in warm seas. Rather common in the Gulf Stream.
Identification: This fish can be recognized by its exceedingly large ventral
fins and a mottled black-and-silver pattern.

MASTERS OF THE WATER-BONY FISHES 221

Habits: This is a pelagic species usually found in the powerful company
of the Portuguese man-of-war, Physalia. This fish is not immune to the poison of
the jellyfish, but somehow has learned to skillfully dodge the tentacles as it
runs in among them for protection against larger fishes. It eats small invertebrates
mostly and comes inshore only when the man-of-war drifts in. Not much is
known of it.

DOLPHINS: Family Coryphaenidae

There are only two species, both very similar.

DOLPHIN (dorado): CorypJiaena hippiinis

Size: Reaches 6 feet.

Weight: Averages 5 pounds. Reaches 35 pounds.

Distrihution: Cosmopolitan in warm. seas. North to Long Island in the Gulf
Stream. Not very common in the eastern Pacific.

Identification: The shape and the soft dorsal fin, as illustrated, are distinctive.
In life, the colors are a beautiful series of changeable blues, greens, yellows,
and silver. The body is very streamlined and compressed. In old males, the
foreheads become verv high as shown in the drawing.

Habits: The dolphin is one of the fastest fishes, capable of spurts of up to 50
mph. It prefers blue water and is pelagic on the surface, feeding avidly on small
fishes, especially the flying fish. Large ones usually travel in pairs, but small
ones school.

Similar Species: The dolphin is often confused with the little dolphin,
Coryfhaena eqiiisetis, which reaches only 2!/2 feet and never has a high forehead.
The only way to separate the two is by comparing the number of lower fin rays
(litde dolphin: anal, 24 to 26, dorsal, 51 to 55; dolphin: anal, 26 to 30, dorsal,
55 to 65). The little dolphin is also cosmopolitan in warm seas, and is the most
common dolphin from southern California southward.

HARVEST FISHES: Family Stromeidae

These are plankton-feeding, silvery, pelagic, schooling fishes found in all warm
seas. All have a symmetrically round and deep body and lack ventral fins. When
small, these fishes have the habit of swimming under the bells of large jellyfishes,
but sometimes they get careless, bump into a tentacle, and are killed and eaten
by the jellvfish.

BUTTERFiSH (dollarfish, HARVEST fish) : Pownotus tricanthiis

Size: Averages 7 inches. Up to 1 foot.

Distribution: Nova Scotia to Cape Hatteras. Deep water to Florida.

Identification: This fish is compressed and silvery.

Habits: This is a summer fish, schooling near shore at that time, appearing
and disappearing at about the same time as the common mackerel, Scomber.
The pelagic eggs are released in June and July.

Similar Species: The harvest fish, Peprilus alepidotus, is of similar habits and
size as the butterfish, but it is much deeper of body, being nearly round when
viev.ed from the side. It is known from Cape Cod to Brazil, becoming more
common as the butterfish becomes rare to the south. It sometimes occupies the
area under the bell of the Portuguese man-of-war.

222

UNDERWATER GUIDE TO MARINE LIFE

BtUterfish.

The large pomfret, Brama rai, family Brarriidae, is very similar in shape to the
butterfish but is of dusky coloration and has small ventral fins. It reaches 2 to 4
feet in length and is rare in the Atlantic but not uncommon in the Pacific from
southern California southward.

The California pompano, PaJometa simillima, is found from Puget Sound
to southern California. It is sought for food and has a similar appearance to
the butterfish.

Perchlike Fishes: Suborder Percoidei

The perchlike fishes, often called "typical fishes," are the principal inshore
predators, conforming to the preconceived notion of a fish more than any other
group. This is a group that is even more complex than the mackerellike fishes.
Most are not of pelagic habits as mackerellike fishes tend to be, and they are
more familiar to the swimmer than the mackerels. Therefore, they may not
offer as much trouble as mackerels in identification.

These fishes are closely related to the mackerellike fishes, and, with them,
make up the bulk of spiny-rayed fishes. The fins are very spinv, and the tail
is not constricted at its base as in the mackerels. The scales are rather large and
the colors extremely variable, including all the shades of the spectrum, being
silverv in only a few groups.

There are large numbers of these important and common fishes in all seas.
The greatest diversity is in the tropics. The various families are anatomicallv
very similar to each other and are separated by ichthyologists on a technical
basis. Even though the field study of fish habits is in its infancv, certain
characteristics— their habits, general silhouette, and movements— are known that
serve to separate the families. The swimmer should look for and learn to use
his own clues, however.

CARDINAL FISHES: Family Cheilodipteridae

These are large-eyed, usually red, little fishes, typical of coral reefs of all
tropical seas. These are the only small red perches in which the spiny and soft

MASTERS OF THE WATER-BONY FISHES

223

dorsal fins are widely separate from one another. One peculiar habit usually
identifies them. These little fishes are most often seen in the company of large
conchs or other shellfish, whose living shells they use for retreat. Cardinal fishes
are largely nocturnal and some carry their eggs in their mouths for incubation.

conchfish: Apogonichthys stellatiis— Color Plate 3

Size: Up to 2 inches.

Distribution: West Indies to Florida.

Identification: This is one of the smallest cardinal fishes, and has exceptionally
large ventral fins.

Hahits: Among the cardinal fishes, this one in particular is addicted to using
the mantle cavity of the large queen conch, Stroinhus gigas, for retreat. It is
also known to use the cavities of sponges for the same purpose. Its food consists
of small invertebrates.

SNOOKS: Family Centropomidae

There is but one genus containing a few very similar species, all found in
the American tropics.

SNOOK (sergeant FISH, PIKE, ROBALo) : Centrofomus undecimalis

Size: Up to 5 feet.

Weight: Averages 4 to 8 pounds. Up to 60 pounds or more.
Distribution: West Indies to Florida. Baja California to South America.
Identification: Pikelike build and a black lateral line which extends onto the
tail. The color is straw-brown.

Fig. 118. Snool

Habits: This is a large, swift, predatorv fish of shallow waters. It especially
likes brackish waters of mangrove areas and river mouths, sometimes traveling
in small schools. Its food, taken largely at dusk or at night, consists of small
fish and crustaceans.

SEA BASSES: Family Serranidae

The four hundred to five hundred species of sea basses found the world
over in warm temperate and tropical seas offer some of the most rewarding
experiences under water. The large tropical species (groupers), if not frightened
because of spearfishing pressures, are fearless and very easy to train by chum-
ming. After only a few feedings, large groupers will follow the swimmer

224

UNDERWATER GUIDE TO MARINE LIFE

around like a faithful dog. Even if not so trained, these fishes are engaging
and fearless fish.

Basses are almost insatiably curious. Bright objects, like polished metal or
mirrors, serve to attract them very close to the swimmer. The voracity of basses
is almost legendary. They rush at their prey by sudden movements of the large
pectoral and tail fins. As the mouth opens, a suction is created, water passing
in the mouth and out the gills, and the prey is drawn in. The many small
teeth in the jaws and on the tongue and palate hold the prey, which is swallowed
whole. The food varies from fishes to crustaceans and other invertebrates.
Groupers are fond of octopuses as food.

Some basses reach huge size, having mouths into which a man could fit
his head and shoulders. Their size and fearlessness could make these fellows
rather dangerous, although one could probably not call anv of them, with the
possible exception of jewfishes, naturally pugnacious if left unmolested. Most
basses travel singly and "home" to very definite holes in rock or coral, not
straying far from a single spot throughout their lives. Basses are variable in
almost every respect, color, size, pattern, etc., but they are best separated from
near relatives by the rather massive head with its very capacious, thick-lipped,
underslung lower jaw, the anal fin which is a little shorter than the soft dorsal.

Fig. 119. White perch.

Fig. 120. Striped bass.

MASTERS OF THE WATER-BONY FISHES 225

and the solitary, inshore habits. There are exceptions to all these rules, but the
exceptions are not hard to identify. Most of the confusion arises with the
great mass of typical sea basses, the groupers or rockfishes, whose common
names and coloration are maddeningly variable, and also with the many species
of midget basses. Color is, on the whole, not a good species indicator here.
Better are silhouette, habits, color pattern, and distribution.

WHITE PERCH (siLVER BASs) : Mowne muericana

Size: Averages 10 inches. Up to 15 inches.

Weight: Up to 2 to 3 pounds.

Distrihntion: Nova Scotia to South Carolina. Most common near the
Chesapeake.

Identification: The most unbasslike bass in appearance and habits. It is
compressed and deep-bodied with whitish, silvery, or olivaceous sides and
faint longitudinal stripes. The spiny dorsal fin just reaches the soft dorsal.

Habits: This is really a fresh-water fish. It is not found far from the brackish
waters of bays and river mouths and goes upriver to breed, frequently becom-
ing landlocked. It schools in very large numbers and eats small fishes and
crustaceans.

STRIPED BASS (rockfish) : Rocciis saxatiUs

Size: Commonly to 3V2 feet. Recorded to 6 feet.

Weight: Averages 1 to 10 pounds. Commonly 25 to 40 pounds. Recorded to
125 pounds.

Distrihxition: St. Lawrence to Florida. Most common from Cape Cod to
Cape May, New Jersey. Introduced on the West Coast in 1879 and now
found from southern California to the Columbia River.

Identification: The spiny dorsal fin does not reach the soft dorsal. The color
is a brassy silver with seven or eight longitudinal black stripes.

Habits: This anadromous fish is found singly or in small to large schools
around rocky shores, bays, beaches, and the mouths of rivers. Since it ascends
rivers to spawn, it has suffered from pollution and also from overfishing, but is
still rather plentiful. Before 1900 up to thirty-eight thousand pounds of stripers,
manv over 60 pounds, were landed in one haul of the nets. The spawning
season is in the spring. Nonadhesive, heavy eggs, up to 2 to 3 million per
female, are laid in large rivers. The striped bass is a voracious feeder on fish
and large crustaceans.

CALIFORNIA KELP BASS (rock BASS, cabrilla) : Pavalabvax calthratus

Size: Averages Wi feet. Up to 20 inches.

Weight: Averages 3 to 4 pounds. Up to 5 pounds.

Distribution: San Francisco to Cape San Lucas.

Identification: The dorsal spines are long anteriorly. Color is grayish green
with broad, dusky, vertical bars. There are spots in similar species, but not in this
one.

Habits: This is a fish of the kelp beds and rocks, being one of the most
common rather large fish found there. It is carnivorous on smaller fishes. The
kelp bass strays over sandy bottoms and spawns in the summer.

226

UNDERWATER GUIDE TO MARINE LIFE

Fig. 121. Spotted kelp hass.

Fig. 122. Black sea hass.

Similar Species: There are eight species of this genus, all of which are of the
eastern Pacific. Most are spotted as shown in figure 121.

BLACK SEA BASS: Centwpristes striatiis

Size: Large at 18 inches. Lip to 22 inches.

Weight: Averages 1 to 2 pounds. Large at 4 pounds. Lip to 8 pounds.

Distribution: Cape Ann to north Florida. Most common from Cape Cod to
Cape Hatteras.

Identification: The color is dark gray with blotchy markings and light spots
on the scales. The top ray of the tail fin is elongated to form a filament.

Hahits: This is a voracious but sluggish bottom fish most common around
wrecks, pilings, or rocks at a depth of about 100 feet. It eats a wide \'ariet\'
of fishes, crustaceans, and squids. In habits it much resembles the tautog but
is found in deeper waters and has a very different profile.

Similar Species: The Gulf sea bass or tally-wag, Centropristes ocynrus, looks
like a small black sea bass, reaching a length of only about a foot. It is a deep-
water form found in the Gulf of Mexico.

MASTERS OF THE WATER-BONY FISHES

227

lEWFISHES: Stereolepis, Promicrops, Garrupa

These three largest of the basses are considered as a group although thev
are quite distinct from each other in appearance. They are separated from
the groupers by size chiefly. The habits of all three are rather similar. All are
somewhat clumsy-looking, extremely heavy, and rather sluggish. Nevertheless,
they are voracious, very powerful, and swift in short spurts as the large fins
would indicate. The jewfishes keep pretty much to the bottom, lurking in holes
in shallow to moderately deep water. Not much is known of their habits.
Jewfishes of large size are warv yet pugnacious fishes. Even small spotted jew-
fishes are known to snap if touched on the nose, but thev will not attack
if left unmolested. They learn very quickly that men with spears are up to no
good and will avoid them very efficiently. These fishes school when young and
are not often seen when small. Jewfishes are found in all tropical seas. The three
North American species are as follows:.

SPOTTED jewfish: Prouiicwps itiara

Size: Up to 8 feet.

Weight: Averages 20 to 100 pounds. Up to 700 pounds.

Distrihiitiori: West Indies to Florida. Gulf of California to Panama.

Identification: The bodv, head, and fins are a drab brown with manv small
dark spots. The ground color is often broken up by blotches and is somewhat
\ariable. The tail fin is short and rounded and the spiny dorsal fin is long
and low and not separated from the soft dorsal by a notch.

Similar Species: The huge Protnicrops lanceolata of the South Pacific reaches
a length of 10 to 12 feet and is the largest of the basses.

F/g. 123. Spotted jewfish.

BLACK JEWFISH (black grouper) : Ganupa nigrita

Size: Up to 6 feet.

Weight: Up to 500 pounds.

Distrihtition: South Carolina to Brazil. Eastward to the Mediterranean.

Identification: The dorsal fins are like those of Epinephehis species (see the
following pages on groupers) but are anteriorly high. The head is huge, and
the color is a uniform brown to blue-black.

228

UNDERWATER GUIDE TO MARINE LIFE

CALIFORNIA JEWFISH: Stereolepis gigas

Size: Up to 7 feet.

Weight: Averages about 200 pounds. Up to 800 pounds.

Distribution: Farallone Islands to southern California.

Identification: The spiny dorsal fin is long and low and is separated from
the soft dorsal by a notch, which separates this fish from the otherwise very
similar spotted jewfish. Adults are a uniform greenish black to gray or brown.
The young are blotched and have light edges to the dorsal, anal, and tail
fins. This is one of the many species which undergoes great changes in shape
and coloration during growth (Walford, 1937).

GROUPERS: Myctewperca, Efinepheliis and allied genera

There are many very confusing species of these fishes which are hard to
identify. Ichthyologists separate the species by counting gill rakers, scales, and
fin rays. Field identification of groupers is a studv that has yet to be made in
detail. It is complicated by the fact that there are many species which have
very similar coloring. In addition, most of these have no one characteristic
coloration but go through a series of complex color phases, which may in some
cases adapt to environmental colors but often do not. Some of these color changes
are probably due to the excitement of capture or other disturbances. Red be-
comes a dominant color in deep water in many species. All groupers have
similar habits and are typical of rocky of coral areas in warm, mostly tropical
seas, staying near the bottom usually, lying up in coral and in the holes of
rocks or reefs. Their habits are similar to those of jewfishes, but their smaller
size leads to greater activity. The great curiosity of basses has been noted, and it is
probable that groupers surpass all other basses in this respect. It is virtually useless
trying to get close to groupers that have repeatcdlv experienced the spear fisher-
man, but they are easy to approach if they have been unmolested or have been
chummed. In relatively unfished areas in the Bahamas, the authors have fre-
quently had groupers rise out of the reefs to greet them. Like jewfishes, they
are not schooling, but will group together to feed or to spawn.

The largest North American groupers reach 4 feet and 60 to 100 pounds.

MASTERS OF THE WATER-BONY FISHES 229

Spawning is in shallow water in spring or early summer. The young school.
The dominant species are given below. (For the many less common species,
reference will have to be made to the Bibliography.) We will consider the
groupers as belonging to three groups below.

Genus Myctero-perca. The members of this huge and confusing genus have
a rather broad, high forehead, a short upper jaw like a bulldog, and a long
anal fin of eleven to twelve soft rays. The tail fin is usually square or rounded.

BLACK GROUPER (rockfish, bonaci arara) : Myctewperca honaci— Color Plate 4

Size: Up to 4 feet.

Weight: Common at 20 pounds. Up to 100 pounds.

Distribution: West Indies to Florida Keys. Straggles to Cape Cod.

Identification: Variable color. Usually a gray-olive, or blue-black ground color
with large, dark quadrate blotches. The vertical fins often have a black border
surmounted bv a narrow light line. The pectoral fins are never tipped with
yellow.

Similar Species: The gag, Mycteroperca microlepis, reaches 3 feet and 50
pounds and is very common in Florida from Pensacola around the peninsula
northward to North Carolina. It is not found in the West Indies. It is a greenish,
palely colored fish and has only indistinct blotches. The fins are dark olive to
bluish with blue-black borders edged with white, as is common with several
groupers. The scales are very small.

The scamp (salmon rockfish), Mycteroperca falcata, reaches 2 feet and 12
pounds or more. There are two distinct forms, a West Indian and a southern
Florida one. The coloration of the scamp in the West Indies is brownish to
gravish, faintlv covered with small dark spots. The southern Florida scamp
is a pale but pretty pink to purple-gray, spotted with smaller spots above and
larger, obscure blotches on the sides. The fins of both are tipped with a darker
gray, sometimes with whitish borders.

The broom-tailed grouper, Mycteroperca xenarcha, ranges from Mexico to
Peru and reaches 60 pounds or more. It is dark gray to brown or green and
blotched, and the tail fin rays are extended beyond the fin webbing so as to
give a ragged look to this fin.

. YELLOW-FIN GROUPER (rED ROCKFISH, BONACI CARDENAl) : MyctCropCrca

venenosa— Color Plate 4

Size: Up to 3 feet.

Weight: Averages 10 to 15 pounds. Up to 35 pounds.

Distribution: West Indies to Florida. North rarely to Cape Hatteras.

Identification: The spiny dorsal and the pectoral fins are tipped with yellow.
The ground color is light gray to olive or red and is covered with dark, oblong
blotches and small dark spots. The vertical fins have a black border. The
flesh is reported to be poisonous at times.

Similar Species: The Gulf grouper (cabilla de astillero, baya), Mycteroperca
jordani, is common in bays and protected waters of western Mexico, particularly
around Mazatlan and Guaymas. It reaches 3 feet in length. The color is
olivaceous, darker above, with obscure, darker, quadrate, diffuse blotches ar-
ranged in four vertical series. The side of the head has wavy black streaks.

230 UNDERWATER GUIDE TO MARINE LIFE

The princess rockfish, Mycteroperca inter stitialis, is a small and very beautiful
grouper which reaches a length of a little over a foot. There are many color
phases, but in all these there are large spots, and bright colors predominate as
a ground color. The commissure is yellow to yellow-green.

The tiger rockfish, Mycteroperca tigris, also has yellow-tipped pectorals. Its
pattern is a rather striking blotched one with light stripes crossing the dark
body. It is West Indian and grows to 2 feet in length.

The golden grouper (sardinera, leopard grouper), Mycteroferca •pardalis, is
greenish to brownish with small brown spots or a brilliant orange-yellow (some-
times blotched with black). It reaches 2 to 3 feet and is found from the Gulf
of California southward.

Genus Efinefhelus. This is fully as confusing a genus as the last. It is char-
acterized by a low, narrow forehead, which makes the head look relativelv long
and pointed, and a short anal fin of seven to eight soft rays. The overall size of
some is rather small. The tail fin is most often rounded, never concave or forked
(except in the red grouper).

NASSAU GROUPER (harilet, cherna criolla) : E'pinefhehis striatus— Color

Plate 4 and Figure 12

Size: Up to 31/2 feet.

Weight: Averages 15 pounds. Up to 50 pounds.

Distribution: Florida to the West Indies and Brazil. Straggles to Cape Hatteras.

Identification: This is one of the most familiar and easily identified of groupers.
There are several color phases, but there is typically a diagonal stripe through
the eye, a strong vertically barred pattern, and a black spot over the caudal
peduncle. The black spot over the peduncle is the only characteristic that is
unchanged in all color phases. The tail fin is rounded or nearly straight. A
series of black spots rings the eye.

Similar Species: The red hamlet (mutton hamlet), Alphestes afer, looks
roughly like a deep-bodied Nassau grouper and has a yellowish-brown ground
color with indistinct, dark, vertical, mottled bars. The head is spotted heavily
with yellowish to orange-brown spots and the breast with pale blue spots. The
fins are dusky. It grows to a little over a foot and is West Indian, being
particularly common in Puerto Rico, where it is an important food fish.

RED GROUPER (cHERNA AMERICANA): Epinepliclus viorio—Color Plate 4

Size: Up to 3 feet.

Weight: Averages 10 pounds. Up to 40 pounds.

Distribution: The most common grouper in the West Indies and Florida.
Reaches Virginia and Rio de Janeiro.

Identification: There are several confusing color phases, but this is the only
member of the genus with a distinctly square to concave tail. The spiny dorsal
is high in front, tapering behind. The pattern is blotched, and there is con-
siderable pattern resemblance to the Nassau grouper, but the color is a warmer
reddish brown and the blotches are not arranged in distinct vertical bars.
A plain, unblotched color phase is generally assumed when the fish becomes
active.

MASTERS OF THE WATER-BONY FISHES 231

ROCK HIND (polka dot) : E'pinefhelus adscensionis— Color Plate 4

Size: Averages 16 inches. Up to 18 to 20 inches.

Weight: Averages 2 pounds.

Distribution: West Indies north to Florida, straggling to Cape Cod.

Identification: This is one of the profusely spotted species. Small red to
orange-brown spots cover the whole body, and small white spots are on the
fins. The ground color is olivaceous, greenish, or grayish. There are usually
large pale spots scattered among the reddish ones. The fins and tail are fre-
quently yellowish.

Similar Species: The red hind (cabrilla mora) E-pine-phehis guttata CColor
Plate 4), is similar to the rock hind in having a profuse covering of reddish
spots. The body is usually reddish and has no lighter supplementary spots,
large or small. The soft dorsal, tail, and anal fins are strikingly edged with
black. It is a very common West Indian species found north to South Carolina.

The speckled hind (john-paw), E'pinefhelus drmnviond-hayi, is a large fish,
principally of the Gulf of Mexico and ranging north to South Carolina. White
spots cover the entire body and most of the fins. The ground color is a rich red-
dish brown. This beautiful fish reaches a weight of 30 to 50 pounds.

The snowy grouper, Epine-phelus niveatus, is a deep-bodied, especially large-
headed species with a lower jaw that projects even more than is normal for
groupers. It has a brown ground color with fairly large white spots, a little
smaller than the pupil of its eye, arranged in four vertical and five horizontal
rows. The rows are sometimes irregular.

The spotted cabrilla (cabrilla pinta), Efinefhelus analogus is abundant
from Baja California to Ecuador. It is very similar to the rock hind in color
pattern but tends toward a reddish ground color. It reaches a weight of 15 to
20 pounds, the largest of the western cabrillas (Efinefhelus species).

The flag cabrilla, Epinefhehis lahriformis, reaches 20 inches and ranges
south of Cape San Lucas. It is gray to brown or green and is covered with
white spots.

Genera Cephalcpholis and Petrometopon. These two genera both contain
few species. Both are small and rather active fishes for groupers, and both
exhibit a wide variety of color change. They are separated from other groupers
by technical characters and by the fact that they have nine rays in the spiny
dorsal fin instead of the usual ten or eleven. The caudal fin of both is rounded,
and the forehead is low.

coney: Cephalopholis fulvus— Color Plate 4

Size: Up to about 1 foot.

Distribution: Florida and the West Indies.

Identification: There are several color phases. The ground color may be green,
yellow, cream, or red and either mottled or not. There is always a sprinkling
of light blue spots over the whole body. The jaws are tipped with black, and
there are two spots over the caudal peduncle.

Similar Species: The Gulf coney, Cephalopholis acanthistius, is a chunky.

232

UNDERWATER GUIDE TO MARINE LIFE

uniformly red fish with very high, soft dorsal spines. The rose coney, Ce'phalo-
fholis fofino, is also red. Both species are found from the Gulf of Galifornia
southward. They both reach about 2 feet in length. They are probably rather
rare and should be looked for.

graysby: Petrovietofon cruentatus— Color Plate 4

Size: Up to about 1 foot.

Distribution: West Indies to Florida.

Identification: The ground color varies from nearly white to a mottled brown
but is usually brownish-red. The body is covered with small dark spots. There
is sometimes one row of large black or white spots just below the dorsal fin. A
conspicuous row of black dots is sometimes present below the soft dorsal fin.

Similar Sfecies: The enjambre, Petronietofon 'panamaensis, is reported from
Concepcion Bay to Panama. It much resembles the graysby.

OTHER BASSES

SOUTHERN CREOLE FISH: Paranthias fiircifer

Size: Up to 10 to 12 inches.

Distribution: Gape San Lucas to the Galapagos Islands. Guba to Brazil.

Identification: This is a bright red to dark reddish-gray fish with several bright
blue spots on the sides and a bright blue spot at the base of the pectoral fin.
The tail is very noticeably concave, and the entire dorsal fin is low.

Habits: It is probably a carnivore found in rocky places like others of the
family.

Fig. 125. Southern creole fish.

Two-spiued soapfish.

MASTERS OF THE WATER-BONY FISHES

233

Two-spiNED soapfish: Ryfticus histrisfinus

Size: Averages 8 inches. Up to 1 foot.

Distribution: West Indies, straggling to Cape Cod. Also western tropical
Mexico.

Identification: The peculiar shape, with only two spines in the soft dorsal,
identify it. The color is a dusky olive to dull purple.

Habits: The authors have seen these fishes around coral heads in shallow
water, but they probably keep to moderately deep water much of the time.
When handled, they secrete a mucus remarkably like soap suds.

Fig. 127. Midget sea basses. Prionodes (/eft) and Diplectrum (rig/zt).

HARLEQUIN SERRANiD: Prionodes tigrinus— Figure 12

Size: Rarely over 4 inches.

Distribution: West Indies.

Identification: The very low forehead, long snout, and distinctive barred
pattern identify this fish. This species and those similar to it have forked or
lunate caudal fins.

Habits: This little bass is one of a number of very small basses of tropical
"seas. Most keep to fairly deep water. Their movements are quick, flitting,
and altogther birdlike as they dart about reefs in search of small invertebrates on
which to feed. This species is one that keeps to shallow water.

Similar Species: Among the many midget basses is the sandfish, Diplectrum
formosum. It reaches a length of almost a foot but is usually smaller, has a
very spiny preoperculum, and is found along eastern shores from North Caro-
lina to Texas. It is gray or tan with stripes on the body and head and has a large
eye.

The phoebe or tattler, Prionodes fhoebe, grows to 8 inches, has a prominent
white bar on the side, is typical of deeper water, and is found in the West
Indies.

The butler hamlet, Hypcplecturus unicolor, looks a great deal like a demoiselle,
with its compressed deep body, but the head and mouth are large. The coloration
is extremely variable. The colors are usually bright yellows, lavenders, greens, or

234 UNDERWATER GUIDE TO MARINE LIFE

blues. There is usually a pattern of vertical bars. It rarely grows over half a
foot but does occasionally reach a foot. It is found about rocky or coral areas
in the West Indies.

Three species of serranos, genus Prionodes, and three species of squirrel fish,
genus Di-plectriim, are known on the West Coast from the Gulf of California
southward.

BLUE AND GOLD FAIRY BASS: Gramma hemichry SOS— Color Plate 3

Size: Up to 2 to 3 inches.

Distribution: West Indies to Florida and Bermuda.

Identification: The long ventrals and the extremelv vivid coloration, the
anterior half of the fish purple, the posterior half orange-gold, are unmistakable.

Hahits: This is one of the most beautiful of all fishes. Its very striking color
and lively flitting movements make it truly like a jewel. This fish was thought
until recently to be a rather rare fish, but this is certainly not so. The reason
it was so seldom seen by surface ichthyologists is simple. This fish lives
habitually under dark ledges and holes in reef areas. The underwater swimmer
finds it extremely common. It lives in an upside-down world, traveling belly
up very close to the undersides of ledges as it gleans small bits of invertebrate
food from these surfaces. Unlike the little fresh-water upside-down catfish, the
fairy bass can travel normally right side up, but it seems to prefer its upside-
down position. It is rarely seen alone. A few individuals, up to a dozen or so,
form small social groups.

TRIPLETAILS: Family Lobotidae

There is but one genus of two to three species which are found in all warm
seas.

TRiPLETAiL (flasher, chobie, DUSKY PERCH ) : Lohotes surinamensis

Size: Up to 3 feet.

Weight: Averages 5 to 10 pounds. Up to 40 pounds or more.

Distribution: West Indies to Europe and Africa. Gulf of Mexico, Atlantic
coast to the Carolinas, straggling to Cape Cod.

Identification: The "triple tail" of the soft dorsal, caudal, and anal fins is
the best field mark. The head is small and short. The color varies from dark
brown to greenish or light yellow-brown.

Habits: The young are often seen in sargasso weed. The adults school or are
solitary in water about 50 feet deep around rocks, wrecks, pilings, or reefs.
The habits are probably much like those of the groupers.

Similar Sfecies: The West Coast tripletail, Lobotes pacifciis, is found from
Panama lo the Indo-Pacific.

BIG-EYES OR CATALUFAS: Family Priacanthidae

There are several quite similar species of these beautiful red fishes distributed
in all tropical seas around reefs. The eyes are huge and glassv, capable of re-
flecting a beam of light upward. The habits are like those of squirrel fishes
in that these fishes are largely nocturnal and carnivorous and live singly in
holes in reefs. They may be easily separated from squirrel fishes by the anal

MASTERS OF THE WATER-BONY FISHES

235

Fig. 128. Tripletail.

fin's shape and length and the bulldoghke, underslung lower jaw. Many big-eyes
live in moderately deep water.

coisiiMON BIG-EYE (glass-eye) : Priacanthtis arenatus— Color Plate 4

Size: Averages 8 inches. Up to over a foot.

Distrihiition: West Indies. The young straggle to Cape Cod.

Identification: The eye, the color, and the long anal fin identify it.

Habits: The authors have found this fish lurking deep in holes by day, only
occasionally appearing in the open then. It becomes active by night. Little is
known of its habits.

Similar Species: The deep big-eve, Pseiidcpriacanthus alius, is an almost
round, shorter version of the common big-eye. It is West Indian and found
north to the Carolinas.

SNAPPERS OR PARGOS: Family Lutianidae

Second onlv to the basses in abundance, diversity, and importance in the
tropics are the snappers. There are 250 species of these fishes in the world,
many of them identified by very technical characters such as tooth pattern.
Snappers are carnivorous, voracious fishes which feed primarily on other fishes
and crustaceans at night. They contrast with groupers in that they are schooling
and rather wary. Under water they like to keep quite a few feet of water between
themselves and the swimmer. It is said of some species that if one is taken from
a school, the rest will become very wary and stop feeding. The head is more
pointed, the mouth smaller, and the body less massive than those of the groupers.
The pectoral fins are pointed rather than rounded as in basses. Though some
of them reach a very large size of 80 pounds or more, the usual maximum
size is 2 feet and 15 to 20 pounds. In this family and the following families of
perchlike fishes, the maxillary bone slips into a slot beneath the eve, making
the rear part of the upper lip look more slender than in the preceding perchlike

236 UNDERWATER GUIDE TO MARINE LIFE

families. The dominant color is a barred dark green on the body with yellow
or red fins, but almost all species show several color phases. There is a tendency
for many species to become red in deep water. In almost all of them some
teeth in the front of both jaws are enlarged and caninelike. Some large snappers
have been observed to stand with their mouths wide open, allowing butterfly
fishes to probe deep in their throats for parasites.

Most snappers are delicious as food, but some are variously reported to
cause a fish poisoning called "ciguatera."

GRAY SNAPPER (mangrove SNAPPER, PARGO PRiETo) : LuHanns griseiis—Color

Plate 5

Size: Averages IVi feet. Up to 3 feet rarely.

Weight: Averages 2 to 3 pounds. Rarely up to 18 pounds.

Distribution: West Indies. North to New Jersey.

Identification: The body is usually dark greenish, becoming reddish in deep
water. The dorsal and caudal fins are dark gray or blackish. The anal and paired
fins are flesh-colored or rose. The greenish, shallow-water forms are faintly barred
as are many snappers.

Hahits: This is the most common of the snappers. It lurks in mangrove groves,
coral areas, and harbors, and strays to deeper water. It is catholic in tastes, eating
fishes, tree crabs from the mangroves, and even a certain amount of refuse.
LaMonte (1952) reports that it often schools with the yellowtail snapper.

Similar S'pecies: The dog snapper or jocu, Lutianus jocu, is found from the
West Indies to Florida and straggles to Cape Cod. It reaches a weight of 20
pounds. The color is much like that of the gra}' snapper, but the sides are
distinctly reddish or coppery, and the dorsal and caudal fins are reddish, the
paired fins yellowish. There is also a large whitish area below the eye. The dog
snapper may, in some places, be poisonous as food.

The muttonfish (pargo criollo), Lutianus analis, reaches over 2^2 feet and 25
pounds. It is common from the West Indies and Florida and straggles to
Cape Cod. It strongly resembles the gray snapper, but all the fins are reddish,
and there is a prominent blue bar under the eye from the nostril to the rear
end of the gill cover. There are rows of pale blue spots extending obliquely up
and back from the lateral line. The iris of the eye is fiery red.

The pargo prieto or dog snapper, Lutianus novemfasciatus, reaches 80 pounds
or more and is common from Cape San Lucas south to Panama. It is like a gray
snapper in body color when young, frequently having a slate tinge above, with
the lower parts white. Older specimens, are a uniform reddish-brown color.
The inside of the mouth is a reddish yellow and bears very large, caninelike
teeth.

SCHOOLMASTER (pARGO AMARiLLo) : Liitianus apocliis—Color Plate 5

Size: Averages 18 inches. Reaches 2 feet.
Weight: Averages 2 to 3 pounds. Reaches 8 pounds.

Distribution: West Indies north to Florida. Straggles to Cape Cod when
young.

Identification: The ground color varies from a barred greenish or grayish with

MASTERS OF THE WATER-BONY FISHES 237

orange tints to a plain, pale slate color. This is the only snapper whose fins
are all yellowish. The young have a blue bar below the eye from the nostril to
the rear edge of the operculum. There is a reddish-brown, barred phase in which
the fins are also yellowish.

Hahits: This is a very abundant and pretty fish. It eats fishes and crustaceans
and is commonlv found lurking in inshore coral heads in small schools. Like
other snappers, it is wary and nervous in the swimmer's presence.

Similar Sjjecies: The pargo amarillo or yellowtail snapper, LtUianiis argen-
tiventris, is a West Coast species found from Mazatlan southward. It resembles
the schoolmaster but is rosy on the front part of the body and yellow to the
rear. It reaches 2 feet.

The spot snapper (lane snapper), Lutiamis synagris is very common from
Tampa southward through the West Indies. Identification is made easy
by the presence of a large dark spot, larger than the eye, below the juncture
of the spiny and soft dorsal fins on the back. Like the schoolmaster, it is a color-
ful species. It has vellowish stripes running horizontally on its sides. It reaches
only a foot in length.

RED SNAPPER (pARGO GUACHINANGO, PARGO COLORADO): LutianiiS ajU—

Color Plate 5

Size: Averages 20 inches. Up to 3 feet.

Weight: Averages 5 pounds. Up to 20 pounds.

Distribution: Gulf of Mexico and the West Indies. A very similar fish,
common on the Florida East Coast north to South Carolina and rarely to Cape
Cod, has been named as a separate species by some.

Identification: The color is a pretty rose-red. The anal and soft dorsal fins are
angular, not round, and this should separate it from other snappers which have
reddish deep-water forms.

Hahits: This is the most sought after of the snappers for food. It normally
lives in fairly deep water of over 100 feet and feeds on fishes and crustaceans.
Apparently it schools quite densely off coral banks called "snapper banks."

Similar Species: Many species of snappers tend to become reddish when they
get large or live in deep water. The Colorado snapper or pargo Colorado,
Lutiamis Colorado, found in the Gulf of California to Panama, has the angular
anal and soft dorsal fins and the reddish color of the red snapper. The silk
snapper, Lutianus vivanus, is West Indian and weighs up to 40 pounds. It
is red of body, but the tail fin is yellow.

YELLOWTAIL SNAPPER (rabirubia) : Ocyuriis chrysurus—Color Plate 5

Size; Up to 2 feet.

Weight: Averages 1 pound. Lip to 6 pounds.

Distribution: Southern Florida through the West Indies to Brazil.

Identification: A very large, forked, yellow tail and a broad yellow stripe from
the eye to the tail are distinctive. Above this stripe the pattern is a spotted
yellow on a blue ground color, and below the stripe the pattern is one of thin
yellow stripes. This coloration is variable, but not as much as in other species
of snappers. The anal fin is relatively long.

Hahits: Contrarv to most snappers, this species is found singly as often as it

238

UNDERWATER GUIDE TO MARINE LIFE

is found in schools. It is, perhaps, not as wary as other snappers, but it is very
speedy and active; it can be a frustrating fish to observe and photograph. It feeds
on fishes and crustaceans and may also take certain amounts of plant matter.
It swims over a wide variety of bottoms, from mud to sand or grass, but it is
usually found near reefs. It seems to prefer gorgonian beds. The yellowtail is
rather unique among snappers since it is quite commonly seen swimming four to
six feet from the bottom in open water of up to twenty-five feet in depth rather
than lurking under ledges or in dark places.

Similar Species: The Pacific rabirubia, Rahiruhia inermis, has the general
shape, the forked tail, and the long anal fin of the yellowtail, but it is rose-
colored, and there are oblique rows of spots above the lateral line and hori-
zontal rows below. It reaches 12 inches and is found from Cape San Lucas to
Panama.

STRIPED PARGO (pARGO RAisERo) : Hoplopagnis gjintheri

Size: Reaches 2 feet.

Distribution: From Guaymas and Mazatlan southward to Panama.

Identification: The heavy body and the coloration are good identifying char-
acters. The ground color is dark brown to greenish gold on the upper side,
coppery to maroon on the lower side, and there are oblique, downward-running
bars, six in number, present on the back. The bars may be lost in older
individuals.

Habits: This is a snapper of rocky shores. Not much is known of its habits,
and it is not very abundant.

GRUNTS OR RONCOS: Family Haemulidae

These extremely plentiful, tropical fishes are very closelv related to the
snappers, but they are usually much smaller, less wary, and do not have en-
larged teeth in the front of the mouth. Like snappers, the maxillarv bone slips

MASTERS OF THE WATER-BONY FISHES

239

into a slot below the eye. Yellow is a predominant color, and there is often a
red lining inside the mouth. Many species show light and dark color phases
which adapt to the environment, a light phase being common when the fish
swims in open water. Some of them are deep-bodied. They are usually schooling
in habits, especially in the breeding season in summer. They are carnivorous,
mainly on fishes and invertebrates, feeding principally at night. The Spanish
name "ronco" comes from roncar, "to snore," a description of the sound these
fishes are able to make with the pharyngeal teeth and complex swim bladder.

Several species of the genus Haemidon have the peculiar habit of rushing
at each other open-mouthed and "kissing" Cfig. 131^. The authors have seen
several species, notably the blue-striped grunt, do this repeatedly in late summer,
the breeding season. The reason for this habit is not known. It may be a sexual
display of some sort since the same pair of fishes has been observed by the
authors to kiss repeatedly, even driving intruders away. Another theory is that
this is an aggressive display, leading to the establishment of hierarchies, but the
most popular idea is that this is a territorial display of some sort.

Grunts lay pelagic eggs. They are cosmopolitan in warm seas, but the large
genus, Haetnulon, is solely American. There are over fifty species in North
and Central America.

CAESAR (tom TATE, RED-MOUTH grunt) : Bathystovui r'uuator

Size: Up to 10 inches, but normally 5 inches.

Distribution: From Cape Hatteras southward through the West Indies.
Identification: Members of this genus are elongate grunts with large, very
red mouths. The color of this species is silvery white to gray, bluish above.

Fig. 130. Caesar.

There are rows of horizontal yellow spots below the lateral line and oblique rows
of yellow spots above. There are two prominent yellow stripes, one from the
eye to the caudal fin and another above that from the head to the end of the
soft dorsal. The fins are not colored. Young fish have horizontal dark lines and
a caudal spot.

Habits: This is a swarming, inquisitive little fish common around docks and
shores. It is omnivorous and very active as it noses about for food.

240 UNDERWATER GUIDE TO MARINE LIFE

Sivtilar S'pecies: The yellow torn tate (white grunt), Bathy stoma aureoline-
atutn, grows to only 8 inches and is common from the West Indies to Bermuda.
It is grayish with several yellow longitudinal stripes, the one through the eye
being the largest. There is sometimes a dark spot at the base of the caudal fin.

The common tom tate (white grunt), Bathy stoMia striatum, is another West
Indian species. It is very similar to the yellow tom tate, its chief difference
being its smaller mouth, the maxillary not quite reaching to the middle of the
eye. Both of these species are slimmer of body than the caesar.

The burros, genera Brachydeiiterus and Pomadasis, are small grunts of the Gulf
of California south and the West Indies. They are named after the burrowlike,
snoring noise that they can make. There are several species which are hard
to tell apart.

YELLOW GRLiNT (FRENCH grunt) : Haevudon fiavoUneatum—CoJoT Plate 5

and Figure 131

Size: Averages 6 to 8 inches. Up to 1 foot.

Distribution: West Indies to the Florida Keys and Bermuda.

Identification: The coloration consists of very striking longitudinal striping
of alternating blue-gray and yellow. The fins are all yellow. The eyes are large
and glassy, and the inside of the mouth is a brilliant red.

Habits: This is one of the most common of West Indian fishes. It is usually
seen swimming around inshore reefs and wrecks and sandy shores. This species
and the species similar to it are the ones most frequently observed to "kiss."
Yellow grunts gather in large schools in the late summer breeding season. At
other times they travel in smaller schools or even singly.

Similar Species: The white or common grunt, Haemidon pJiimieri, is the
most common grunt and one of the most common fishes from Cape Hatteras
to Florida; it is also common throughout the Caribbean. It averages under a foot
and reaches 18 inches. This fish is common almost everywhere, especially on
sandy shores. It is light bluish and has yellow and blue lines like the yellow
grunt, but on the head only.

The blue-striped grunt (yellow grunt, boar grunt, ronco amarillo), Haevudon
sciurus, strongly resembles the yellow grunt, but the vertical fins are dark-
bordered, and the size is larger, averaging 8 to 12 inches and reaching 18
inches (fig. J3i).

MARGATE FISH (sailor's CHOICE, bream) : Haeuudon album— Color Plate 5

Size: Up to over 2 feet.

Weight: Averages 1 to 2 pounds. Up to 10 pounds or more.

Distribution: West Indies and the Florida Keys.

Identification: The color is pearl-gray to olivaceous, faintlv bluish below with
olivaceous fins and a dark stripe running from the nose, through the eye, and
back to the tail. There are two more curved stripes running above this one.
Color phases occur in which the stripes are obscure.

Habits: This is an offshore, reef species coming to shallow water to feed on
various invertebrates. The name "margate" is derived from the English seaport
of the same name, which was the original home of some of the inhabitants of
the West Indies. The spawning time is early summer, at which time this fish
schools.

MASTERS OF THE WATER-BONY FISHES

241

Fig. 13 i. Top. Yellow grunt, Haemulon flavolineatum, school around reefs and
wrecks like the propeller shaft of this World War I tanker. Bottom. Why the hlue-
striped grunt, Haemulon sciurus, "kiss" is iinknown, hut the cause may he sexual,
territorial or aggressive and leading to the estahlishnient of hierarchies.

Siviilar Species: The sailor's choice (ronco), Haeimdon parra, is a gray fish
with dark fins. Small black spots above the lateral line form oblique, backward-
running streaks. It reaches a foot in length, swimming alone or in small groups
among the reefs, mangroves, and shallow waters of the Florida Keys and the
West Indies. The mojarra prieta, Haemulon scudderi, is the West Coast
representative of the sailor's choice, being of the same small size and having a
similar pattern. It is found from the Gulf of California to Panama.

porkfish: Anistotremus virginiciis— Color Plate 5

Size: Averages 6 inches. Up to 16 inches.

Weight: Up to 2 pounds.

Distrihiition: Florida to the West Indies.

Identification: The two black bars on the head and fore-body and the yellow-

242 UNDERWATER GUIDE TO MARINE LIFE

and-blue horizontal body striping are unique. The forehead is very steep, the
mouth small, and the body deep in members of this genus. The young are
yellow on the head and back, fading to gray below; the sides bear two dark
longitudinal stripes, the lower one extending from the eye to the tail fin.

Hahits: This is a very common and pretty little fish. It is typical of shallow,
inshore waters and feeds at night on invertebrates. It schools densely in shoal
waters in the summer spawning season. Longley and Hildebrand (1941) report
that the young peck at the surfaces of large fishes such as barracudas, jacks, and
snappers, presumably to remove ectoparasites.

Siviilar Species: The pompon or black margate, Anistotremis surinamensis,
is the largest of the grunts, reaching 3 feet and 20 pounds but averaging only
1 to 4 pounds. This is a silver-gray fish with dark gray vertical fins and most often
with a dark gray saddle on the bellv and sides just behind the pectoral fins. As
in the porkfish, the forehead is high. It swims in rather deep water around reefs
and channels and ranges from Florida to the West Indies.

The sargo, Anistrotremiis davidsoni, is a dark-spotted, silvery fish with a
prominent black bar running from the base of the spiny dorsal to behind the
pectoral fin. The fins are yellow. It is a small fish of under a foot found in many
types of habitats from the shallow waters of Point Conception to Baja California.

piGFiSH (sailor's choice) : Ortlwpristis chrysoptems— Color Plate 5

Size: Averages 6 inches. Up to 15 inches.

Weight: Up to 2 pounds.

Distrihtition: Gulf of Mexico, Florida, north to the Carolinas and Virginia.
Straggles to Massachusetts.

Identification: The anal fin is long for a grunt and reflects the soft dorsal in
size, shape, and its edging of black. The head is long and pointed. The color
pattern of orange-brown spots extending in oblique rows up and back from the
lateral line on a blue ground color, and spots of the same color in horizontal
rows below the lateral line, is distinctive.

Hahits: This is a very common fish over sand, rock, or grassv bottoms of
shallow coastal waters. Its food consists of small invertebrates largely. It is an
excellent pan fish.

Similar Species: There are several confusing members of this genus on the
West Coast from the Gulf of California southward and in the West Indies. All
have the long head and long anal fin.

PORGIES: Familv Sparidae

This group is closely related to grunts, but carries further the tendencv of
grunts to be deep at the shoulder and compressed of body. This gives most
of them a steep profile with the eve placed high o\cr and in back of the small
mouth. The anal fin tends to be longer than in grunts and reflects the shape of
the soft dorsal fin. There are over one hundred species of porgies found the world
over, chiefly in tropical seas. Most of these are of moderate to rather small size,
and most school inshore or offshore over hard or soft bottoms. Several species
are common about reefs, but manv are more tvpical of sandv or grassv shores;
several reach into temperate waters, where grunts are not commonlv found.
Larger ones are wary in the presence of the swimmer. The teeth are project-

The red parrotfish, a common reef-grazer which, hke other parrotfishes, can
crunch coral with its hard beak, shows its red fins ten feet underwater.

Green parrotfishes, with blue tang and an indigo parrotfish, do not school, but
are usually seen grouped together feeding.

One of the smallest and most common of parrotfishes, unattractively called the
mud-belly, provides a decoration for stone coral.

The four-eyed butterflyfish masks its real eye with a stripe and has a false
eye-spot near its tail to confuse predators. It is usually seen travelling in pairs.

MASTERS OF THE WATER-BONY FISHES

243

ing and like incisors in the front and like molars in the rear. The possession
of more than one kind of tooth in fish is rare. This condition is called "hetero-
dont." Porgies are practically omnivorous. They eat small fishes, invertebrates,
shellfish, and some plant matter. The predominant ground color is silver, and
there are usually rather dull markings of black and flecks of brighter colors.
Most species show plain, light color phases over sand bottoms and darker, barred
phases over reefs, grass, or dark bottoms. Many are important food fishes. Two
of the most famous of these are the European dentex and that symbol of good
luck and well-being, Japan's red tai.

NORTHERN PORGY (scup) : Stenotomns chrysofs

Size: Averages 8 to 10 inches. Up to 18 inches.

Weight: Averages 1 to IV2 pounds. Lip to 4 pounds.

Distribution: Cape Hatteras to New. England, moving north in spring and
summer.

Identification: The body is about the same depth along the whole length of
the dorsal, giving it a different shape from that of the genus Calamus. The color
is a dull silver, becoming olivaceous above. There are bright silvery blotches on
the sides, and the fins are dusky.

Habits: This is a schooling, migratory fish which comes north and inshore
during the warmer months. It feeds on a wide variety of animals, chiefly
molluscs, worms and crustaceans. It is most common over sandy or hard gravel
bottoms.

Similar S'pecies: The southern porgy, Stenotomus aculeatiis, replaces the
northern porgy south of Cape Hatteras and ranges to Texas. It is very similar
to the northern porgy, but has a less steep profile.

Fig. 132. Northern forgy.

Fig. 133. Jolt-head porgy.

JOLT-HEAD PORGY (bluebone PORGY, GRASS porgy) : Colamus bajonado

Size: The largest of the genus, reaching 2 feet or more.

Weight: Reaching 10 pounds or more.

Distribution: West Indies and Bermuda to the Florida Keys.

244 UNDERWATER GUIDE TO MARINE LIFE

Identificatioyi: All members of this genus have the peculiar, high, rounded
forehead, the high-placed, large eye, and the body depth greatest through the
shoulder that make a characteristic silhouette. The teeth are also odd, being
like canines rather than like incisors in the front of the mouth. This species
is usually of dull, brassy, plain coloration. There is a slender blue streak below
the eye. When feeding over a grassy bottom a banded phase may be displayed
and when over sand, a clear gray phase.

Habits: This is a typical, omnivorous, schooling porgy and is the most common
member of this typically American genus, all species of which are inshore
inhabitants of the West Indies. The common name of this fish is reported by
Breder (1940) to be derived from the habit this fish has of jolting molluscs loose
from rocks with its jaws.

Similar S-pecies: The following species all have the silhouette of the jolt-head
and are best separated by color pattern. All are found in the West Indies,
ranging north to the Florida Keys.

The saucer-eye porgy. Calamus calamus, reaches a length of about Wz feet,
but is usually much smaller. The color is silvery with bluish reflections and a
yellowish wash, which is strongest anterio-dorsally. Golden spots on each scale
form indistinct longitudinal rows. There is usually a violet stripe below the eye.
A banded phase may occasionally be encountered over a dark bottom.

The little-head porgy. Calamus fwridens, reaches 12 inches, is of a brighter
silver than other Calamus species, and has violet longitudinal rows of spots
on the sides and pale orange spots below.

The grass porgy. Calamus arctifrons, lives chiefly in the grassy, shallow water
of the Gulf of Mexico. It has conspicuous dark bars and blotches, over a dull
silver ground color, which serve to camouflage it. It is the smallest of the porgies,
reaching only a foot.

sheepshead: Archosargus fwhatocephalus

Size: Up to 3 feet.

Weight: Averages 1 to 4 pounds. Large at 5 to 15 pounds. Up to 30 pounds.

Distribution: Cape Cod to Texas. Overfishing has caused it to become scarce
in much of its range.

Identification: This large, chunky fish is immediately distinguished by the
wide, vertical, nearly black bars that cross its body. These fade in large
individuals.

Habits: The sheepshead derives its name from its flat molar teeth, used to
crush its food, which consists mostly of molluscs and crustaceans. The fishes
group or school inshore over hard, rocky, or even reef bottoms. They will stray
into brackish water or even into the fresh water of rivers. They are most common
inshore in the summer. This is especially true north of Cape Hatteras, where
they are not present at all in winter.

Similar Species: The brim (salema), Archosargus unimaculatus, is a southern
Florida and West Indian species. It reaches the length of only a foot but has
the same shape as the sheepshead. The coloration is pretty and distinctive. There
are only faint dark crossbars. The back is blue, with wavy streaks of brilliant
gold. There is a black spot above the pectoral fin base, and the underside is
silvery.

MASTERS OF THE WATER-BONY FISHES

245

The pinfish (sailor's choice), Lagodon rhomhoides, reaches only 10 inches.
It ranges from Cape Cod to Cuba and Texas, being common only south of
Delaware. The vertical barring is faint or absent, and there are gold stripes,
fainter than those of the brim, running on the back and sides from gill cover
to the tail fin, which is yellowish. There is also a dark spot above the pectoral
fin as in the brim.

Fig. 134. Sheepshead

Fig. 135. Bream.

Fig. 136. Gray mojarra

BREAM (silver porgy, sargo, PINFISH, spot) : Dij^lodzis holhrookl

Size: Averages 8 to 12 inches. Up to 20 inches.

Distribution: From Cape Hatteras south to the Gulf of Mexico.

Identification: The black spot on the caudal peduncle is distinctive. There may
be faint dark crossbars on this otherwise plain, silver fish.

Habits: This fish swims in small groups about shallow reefs or in rocky waters.
It seems to prefer to swim in the shallow, sandy areas near or between rocky
places or coral heads, and it often schools with snappers, grunts, porkfish and
smaller parrot fish. It is omnivorous on various animal and plant foods.

Similar Species: This species is replaced by the silver bream, Diplodus
argenteus, in the West Indies.

MOJ ARRAS: Family Gerridae

These are small, intensely silver fishes predominant in American waters but
found in all tropical and subtropical seas. The mouth is extremely protrusible,
and the maxillary bone folds into a noticeable slot below the eye and on the
snout. This gives the lips a peculiar pursed look. The spiny dorsal fin is high
anteriorly, sloping behind. There are several species, but all are quite similar
to one another and are principally inhabitants of sandy shores.

GRAY MOJARRA (sHAD, MOJARRA blanca) : Gervcs cinereiis

Size: Averages 8 inches. Up to a little over a foot.

Distribution: The West Indies north to Florida. Tropical west coast of Mexico.

246 UNDERWATER GUIDE TO MARINE LIFE

Identification: The usual intense silvery color of mojarras is crossed by dusky
bands, which are more evident in young fish.

Habits: This little fish swims actively in shallow water, usually over a sandy
bottom. It is omnivorous and schooling.

Similar Species: The mojarra, Eucinostomus calif ornien sis, reaches 8 inches
and is common in bays from Cape San Lucas to Panama. The common mojarra,
Eucinostomus gula, reaches 6 inches and ranges from Cape Hatteras to Brazil.
Both of these lack the crossbanding of the gray mojarra, though indistinct
blotches may be present.

RUDDERFISHES: Family Kyphosidae

Rudderfishes received their name from their habit of following in the wake
of boats. They have incisor teeth in the front of the small mouth but have no
molars. This befits their algae-eating habits. They also eat some small inverte-
brates. The body is spindle-shaped, and the dorsal and anal fins are long and low.
There are not many species, but their distribution is world-wide, chiefly in the
tropics. Small pods or large schools of them mill about rocks grazing on algae,
depending upon alertness and speed for protection.

BERMUDA CHUB (chopa) : Kyphosus sectatrix^Colov Plate 8

Size: Averages 1 foot or more.

Weight: Up to 20 pounds.

Distribiition: From the West Indies north to Florida. Straggles to Cape Cod.

Identification: The ground color is slaty. There are thin, dull yellow, horizontal
stripes, and there is a color phase which has large light spots on the back and
sides. The color becomes darker when the fish swims under coral ledges or in
holes.

Habits: This is an active and curious fish. It swims chieflv in reef waters that
have access to the open sea and will follow ships long distances out to sea,
probably to feed on garbage. Its flesh is very firm and delicious to eat.

Similar Species: There are several similarly shaped species ranging north to
the Canary Islands and on the West Coast from the Gulf of California
southward. One of these, the California halfmoon, Mediahina calif ornien sis,
is found from southern California to Cedros Island. It has a steely ground color
with oblique rows of spots and blackish fins.

OPALEYE (greenfish): Girella nigricans— Color Plate 8

Size; Averages 10 inches. Up to 15 inches.

Distribution: San Francisco to Cape San Lucas.

Identification: The color is uniform light to dark green. There is a prominent
yellowish spot below the spiny dorsal fin on the back.

Habits: This is an active little inshore fish, speedy and alert, common in
shallow, rocky waters where it browses on seaweed.

CROAKERS: Family Sciaenidae

This is the last of the complex pcrchlike families, and it is a large one,
containing 150 species. Though these species are extremely \'ariable in form, the
habitat variation is not extensive. Croakers are conspicuous in warm temperate

MASTERS OF THE WATER-BONY FISHES

247

or tropical waters, never far from shore and rarely over any but sandy bottoms.
Most school or are found in small groups. Most of them have the spiny and soft
dorsal fins separated by a deep notch. The anal fin is usually much shorter than
the soft dorsal fin. The lateral line extends all the way to the end of the tail fin.
There is no one dominant ground color in the family, but very few species
have bright coloration.

Many of the species reach a very large size and are very important
commercially (especially the various sea "trout"). Almost all species are able
to make a noise, variously described as drumming, croaking, snoring, or grunting,
bv using their complex swim bladders as resonating chambers. Strangely
enough, members of one genus, Menticirrhns, lacks the swim bladder completely.
All croakers are carnivorous. So far as is known, all lay pelagic, floating eggs,
which hatch in a \'cry short time.

SILVER PERCH : Bairdella chrysiira

Size: Up to 1 foot. Usually smaller.

Distribution: New York to Texas.

Identification: The color is a dull silver with .greenish above. The scales on
the back and sides each have a dark spot.

Habits: This is a common shore fish often confused with the white perch. It
schools heavily and feeds on all manner of animals, mostly invertebrates.
During the colder months it migrates offshore.

Fig. 237. Silver 'perch.

SEA TROUTS: Genus Cynoscion

There are several species of these very important and large fishes all of which
resemble each other strongly in habits. They will be considered as a group. The
sea trouts are mostly schooling, but are sometimes seen in small groups or even
alone. Thev feed inshore over sandy bottoms, especiallv in tidal inlets and bays,
on small fishes and crustaceans. Some get into brackish waters and even go far
up rivers. They are highly valued as food fishes, but their flesh is tender and
may spoil quickly. This has given some of them the name of "weakfish." These
fishes are among the most common fishes in their proper habitat. To swim near
a school of them is a thrilling experience. Thev are swift and graceful swimmers
and behave and look very much like trout. The common species are as follows:

WEAKFISH (coMiNioN SEA TROUT, squeteague) : Cynoscion regalis

Weight: Av^erages 3 to 6 pounds. Up to 30 pounds very rarely.
Distribution: Massachusetts to Florida and the eastern Gulf of Mexico.

248

UNDERWATER GUIDE TO MARINE LIFE

Identification: The color is silvery, becoming lightly olivaceous on the back.
The dorsal fins are dusky, and the ventrals and anal are yellow. Spots or
blotches form wavy lines running up and back from the lateral line. This fish
is one of the gamest of sea trouts.

Similar S-pecies: The spotted squeteague (spotted weakfish), Cynoscion nehu-
losus, averages 2 to 5 pounds and reaches 15 pounds. Its color is silvery with a
grayish blue above, and small black spots cover the back and the soft dorsal and
tail fins. It ranges from the Chesapeake to Texas.

Spotted squeteague.

Fig. 139. Charjnel hass

CALIFORNIA WHITE SEA BASS (corbina) : Cynoscion nohiUs

Size: Up to over 4 feet.

Weight: Averages 5 to 25 pounds. Up to 80 pounds or more.

Distribution: Alaska to Chile.

Identification: The back is steel-blue, and the sides and belly silvery to white.
The tail is square cut. The shape is like that of the weakfishes.

Similar Species: The shortfin sea bass, Cynoscion parvipinmis, is of a similar
coloration but has an S-shaped or concave tail fin and small, dark spots all over
the body. It is common only in the Gulf of California.

The little queenfish, Seriphus politiis, is another bluish-to-silvery fish, but it
reaches only a foot in length and has an anal fin as long as its soft dorsal fin.
It schools in shallow water over sand from central to Baja California.

totuava: Cynoscion macdonaldi

Weight: This is the largest sea trout. Averages 50 to 100 pounds. Up to 225
pounds.

Distribution: From the head of the Gulf to California to Mazatlan. Present
from October to May. Abundant in March.

Identification: The central rays of the tail fin are longest giving the tail fin the
shape of a diamond. The color is a coppery or brassy silver. The shape is like that
of the other weakfishes.

MASTERS OF THE WATER-BONY FISHES

249

Fig. 140. Black drum.

CHANNEL BASS (redfish, RED drlim) :' Sciaenops oceUata

Size: Up to 5 feet.

Weight: Averages 5 pounds. Common to 15 pounds. Up to 85 pounds.

Distrihiitiou: Atlantic Coast from Delaware to Texas, straggling to Cape Cod.

Identification: The shape is slim, but this fish shows the beginnings of the
blunt snout common in many croakers. The color is reddish to brassy. The black
spot above the caudal peduncle is distinctive.

Habits: This very common and popular fish schools or swims solitarily over
sandy shores and bays. It enters brackish and fresh water. It feeds on small
fishes and invertebrates on the surface or at the bottom.

BLACK DRUM (sEA drum) : Pogonjas croviis

Size: Up to 4 feet.

Weight: Averages over 10 pounds. Up to 146 pounds.

Distribution: Massachusetts to Argentina.

Identification: The body is very heavy, deepest at the shoulder. There are
four or five dark crossbands on a dull silver ground color, and the chin bears
a series of short pendant barbels.

Habits: This is a very powerful, rather slow-moving fish. It feeds chiefly
on shellfish, which are located by the sensitive barbels. Among all members of
the family, this fish is the one most famous for the sound it produces, which is
a loud drumming noise. The drumming is probably done to attract the opposite
sex since it is loudest in the males and done chiefly during the breeding season.
Schools swim over beaches, inlets, and bays and migrate during the colder
months to ofil^shore waters.

CROAKERS: Genera Leiostonins, Microfogon, Sciaena, Roncador,
Genyonenms, Umbrina
These are the central members of the family. They are all moderately small
fishes which have the fairly deep bodies and the rounded, somewhat projecting

250 UNDERWATER GUIDE TO MARINE LIFE

noses of typical croakers. The habits of all are very similar. Small groups or
schools swim over sandy or muddy to hard bottoms, especially in the surf,
where they feed mainly on small invertebrates. They breed in bays and inlets,
usually in early winter.

ATLANTIC CROAKER (hardhead, corbina) : Micropogofi ufidulatus

Size: Averages 1 foot. Up to 30 inches.

Weight: Averages I pound. Large at 6 pounds. Up to 8 to 10 pounds.

Distribution: Massachusetts to Texas. Very common south of the Chesapeake.

Identification: There are very small barbels on the lower jaw. Color is brassy,
becoming white below. There are large numbers of small dark spots on the sides
and back. The flesh is tinged, not unpleasantly, with the flavor of iodine.

Similar Sf)ecies: The spot, Leiostomus xanthurus, has a stouter body shape
and no chin barbels. The name is derived from the black, round spot just above
the pectoral fin. About fifteen wavy dark bars extend up and back from the
lateral line. It ranges from Cape Cod to Texas.

YELLOW-FIN CROAKER: Umhrina roncador

Size: Up to IVi feet.

Weight: Up to 5 pounds.

Distribution: San Francisco to the Gulf of California.

Identification: This fish is a very metallic brassy color to steel-blue or green
above. There are wavy lines on the sides extending up and back above the lateral
line and horizontally below. The dorsal fins are dark. Other fins are yellow.
The shape is like that of the Atlantic croaker.

Similar Species: The California kingfish, Genyonenms lineatus, is a silvery
to brassy color and has small barbels on the chin. There is a black spot at the
pectoral fin base. It reaches a weight of a little over a pound and is found from
Vancouver to central Baja California.

The spotfin croaker, Roncador stearnsi, is a brassy to steel-gray color and has
a dark spot at the pectoral fin base. It averages 5 to 6 pounds and reaches 12
pounds. It ranges from Point Conception to Baja California.

The black croaker, Sciaena saturna, is blackish with coppery tints. It has a
light band from the dorsal fin to the belly, which is especially apparent in fish
which have been in subdued light. It reaches 15 inches and is found from Santa
Barbara to the Gulf of California.

NORTHERN KING WHITING (kingfish) : Menticirrhns saxatilis

Size: Up to IV2 feet.

Weight: Averages 1 to IV2 pounds. Up to 3 pounds.

Distribution: Maine to Florida. Common from Long Island to Virginia.

Identification: Members of this genus have a rounded, very projecting snout,
a single stout barbel on the chin, an S-shaped tail, and an anteriorly high spiny
dorsal fin. Kingfishes have no swim bladder. This species is irregularly blotched.

Habits: The whiting schools over sandy bottoms in shallow water. It feeds
mainly on crustaceans and molluscs but will take small fishes. It migrates north
and inshore for the warm months. As befits the lack of swim bladder, it often
lies on the bottom.

MASTERS OF THE WATER-BONY FISHES

251

x$;:^lHfy:!ii'n^

Fig. 141. Atlantic croaker.

Fig. 142. Southern king whiting

Similar Species: The southern king whiting, Menticirrhiis americanus, has
six or seven wide dark crossbands sloping forward and downward over the back
and sides. It replaces the northern whiting south of the Chesapeake Bay and
ranges from New Jersey to Texas. It reaches 15 inches.

The Gulf king whiting, Menticirrhiis littoralis, has no blotchings or barrings.
It reaches 15 inches and 2 pounds, and ranges from the Chesapeake to Texas,
tending to replace the southern whiting in the Gulf of Mexico.

The California corbina, Menticirrhiis undiilatus, is a steely blue above,
changing to white below, and has wavy, oblique lines of dark spots on the
scales. It reaches 2 feet and ranges from San Francisco to the Gulf of California.

ribbonfish: Eques lanceolatus

Size: Up to 8 to 10 inches.

Distribution: West Indies to southern Florida.

Identification: There are three stripes: a vertical one through the eve, an
oblique one from the forehead to the pectoral fin, and a horizontal one from
the spiny dorsal to the tail fin. A similar species is shown in figure 12.

Habits: This fish is the exception to all croaker rules. It is a solitary reef fish
which can be seen holed up in reefs by day. It is a crustacean feeder, but
probably takes small invertebrates in general.

Similar Species: The cubbyu, Eques acuminatus, has a size and shape similar
to the ribbonfish but has seven narrow horizontal stripes of dark brown running
along the silver to gray sides. It ranges from the West Indies to Cape Hatteras.

Surf Fishes: Suborder Holconoti {"furrowed back^')

This group of twenty-odd species is found only off the Pacific Coast of North
America (with three species in Japan). All are small, compressed fishes which
closely resemble the porgies, but they do not have such a steep profile. They also
have long soft dorsal anal fins composed of many fine rays, and a furrow running
along the back on each side of the dorsal fin (hence the name "Holconoti"). The
marine species all travel in schools in bays or shallow water over rocky or sandy
bottoms, or in surf where they bear their young. A few live in the large California
rivers. Surf fishes bear a maximum of a dozen living young which are about
one fourth to one third the length of the mother. The species are hard to

252

UNDERWATER GUIDE TO MARINE LIFE

distinguish. Barnhart (1936) should be consulted for details. Most of them are
crustacean-eaters. They swim actively in much the same way that small perchlike
fishes do. Many are of brilliant coloration with the metallic colors of brassy and
silver being common.

SURF FISHES: Family Embiotocidae

STRIPED SEA PERCH (blue PERCH ) : Taeniotoca lateralis

Size: Averages 8 inches. Up to 15 inches.

Distribution: Alaska to central Baja California. Common north of central
California.

Identification: The alternating horizontal bars of orange and green, both
metallic, are distinctive. The shape is like that of the rubberlip sea perch.

Habits: This is an exceedingly common fish around rocks, wharves, and in
the surf.

ip sea perch.

RUBBERLIP SEA PERCH: RhacochUus toxotes

Size: Reaches P/2 feet. The largest surf fish.

Distribution: San Francisco to San Diego.

Identification: The lips are very thick and drooping.

Habits: Similar to those of the striped perch. This is a valued food fish.

Similar Species: The barred surf perch, Amphistichus argenteus, is a very
metallic, silvery gray with dark vertical bars and rows of spots above the lateral
line. It reaches 12 inches, averages 6 inches, and is common from central to
southern California.

The Pacific white perch, Phancrodon furcatus, is very abundant in central
to southern California and ranges north to Vancouver Island. It has a very
large forked tail, and the spiny dorsal fin, which is highest in back and lowest
in front, is continuous with the soft dorsal fin, which is highest in front and
lowest in back.

Demoiselles: Suborder Chromides

Because of its habits, this group can be mistaken for no other. All, with the
exception of the reef fish, are pugnacious, very active little fishes, which have

MASTERS OF THE WATER-BONY FISHES 253

the general shape of a deep-bodied perch. When adult, especially when breeding,
they live solitarily or in small groups in holes in reefs or rocks that they have
chosen for their homes, vigorously defending these against all comers. They
greet the swimmer as he swims near their holes with quarrelsome curiosity and
will even harmlessly nip at a finger that is thrust too near. It is in this hole
that four hundred to five hundred eggs are laid in a circular pattern. Both
parents take meticulous care of the eggs, fanning and picking over them
continuously during incubation. Some species lay eggs in the empty shells
of conchs. The breeding habits of one species are given bv Breder and
Coates (1933).

Demoiselles are among the most beautiful and jewellike of reef fishes. Many
of them, especially when young, are covered with brilliant, shining blue spots.
Some are very confusing, their nomenclature having not yet been straightened
out by ichthyologists. This is because several species show a wide and confusing
range of color variations, and it is not certain whether these variations are
species differences or not. The lateral line of demoiselles stops at the rear end
of the soft dorsal fin. The mouth is small although these are carnivorous fishes
which eat small invertebrates. They will also scavenge. These bold little fishes
depend upon alertness, aggressiveness, bluff, and speed for defense. Their
distribution is world-wide in all tropical seas.

garibaldi: Hypsyfofs nihicundiis—Color Plate 6

Size; Averages 8 inches. Up to 1 foot. This is the largest demoiselle.

Distribution: Southern California to the tropics.

Identification: The brilliant uniform gold color identifies them. The voung
are green with brilliant blue spots.

Habits: This fish is ubiquitous about kelp and rock. It is a common and
constant companion of the underwater swimmer.

SERGEANT MAJOR (nuISANCE, COCKEYE PILOT, PINTANO, JAQUETa) :

Abiidefdiif saxatilis— Color Plate 6

Size: Up to 6 to 7 inches.

Distribution: West Indies and Bermuda to Florida. West coast of Mexico.

Identification: The black vertical bars on a pale yellow to orange-yellow or
greenish ground color are distinctive. There is a dark slate-blue color phase in
which the vertical bars are obscured.

Habits: This may be the most common of all demoiselles. The young swarm
about every reef and wharf. Adults are much more solitary and seem to stick to
reef areas. This is a pugnacious and curious fish, often accompanying the diver.
It is very easily chummed.

beau GREGORY (yELLOW BELLY, PESCADO AZLTl) :

Poniacentriis leiicostictiis— Color Plate 6

Size: Up to 6 inches.

Distribution: West Indies and Bermuda to Florida. West coast of Mexico.

Identification: The coloration is exceedingly variable. The color plate shows
the most brilliantly colored phase— the so-called "jewelfish." This is, however,
a confusing term since the young of many other species are covered with very

254 UNDERWATER GUIDE TO MARINE LIFE

bright and sparkling blue spots. The colors of this species vary from a dull,
uniform, dusky brown to phases like that pictured when blues and yellows
predominate. Females are generally browner than males. The shape of the body
is less deep than in the previous species, and the size is smaller.

Habits: The authors believe that this fish tends to keep more strictly to holes
in reefs than do the previous species. It is not as often seen in groups swimming
about and is probably more or less solitary, especially as an adult. The male
guards the eggs and is extremely intolerant of the approach of all fishes. The
ever-present small wrasses are the chief threats to the eggs and are driven off by
pursuit and nips.

YELLOWTAiL DEMOISELLE: Microsfuthodon chrysurus—Color Plate 6

Size; Up to 6 inches.

Distribution: West Indies and Bermuda to Florida.

Identification: The young are covered with brilliant light blue spots. Adults,
in contrast to some phases of the beau gregory, lose the spots and acquire yellow
lower parts and a brilliant yellow-orange tail.

Habits: Next to the sergeant major, this is the most common West Indian
species. Its habits are much like the sergeant major.

REEF FISH (cHROMis): Chwmis marginatus—Color Plate 6 and Figure 144

Size: Up to 5 to 6 inches.

Distribution: West Indies and Bermuda to Florida.

Identification: The forked tail fin with outer rays colored black is distinctive.
There are two color phases, one light brown and one bright blue. The eye is
large and dark.

Habits: This is a reef-living species not found often near shore and at wharfs
as are other demoiselles. It has habits unlike others of the family, schooling
densely around coral heads and behaving like a small wrasse in its swarming
movements. Schools of this fish often follow the sv/immer in his journeys under
water. The forked tail is often opened and closed, the black outer rays appearing
like scissors.

Similar Sfecies: The West Coast form in tropical waters is the blacksmith,
Ayresia functifinnis. It is very similar in appearance and habits to the East
Coast species, but it is of dark coloration. Other species are found near reefs
the world over.

Labroid Fishes: Suborder Pharyngognathi {"throat teeth")

There are two largely tropical and distinct families, both of which have
heavy pharyngeal teeth with which they crush their food.

WRASSE: Family Labridae

These very abundant and varied fishes are chiefly typical of tropical seas, but
they are also found in the temperate zones. All have a very characteristic
buck-toothed profile, which is the result of projecting caninelike teeth in the
front of the mouth, protrusible jaws, and thick lips. They are variable in body
form, but most are elongate, brightly colored, and have a continuous dorsal fin
in which the spiny part is long. The anal fin reflects the soft dorsal in size

MASTERS OF THE WATER-BONY FISHES

255

Fig. 144. Reef fish, Chromis marginatus, swarm over reefs in schools, their forked
tails reminiscent of ham swallows. Stinging coral, Millepora, and variotis gorgonians
are helow the reef fish.

and appearance. Several facts make this a difficult family to comprehend. There
are 450 species in the world, many of which are very confused in both common
and scientific names. Furthermore, many of the species change greatly in
shape and coloration during growth. During the breeding season the adults
take on special nuptial colors. The basic color seems to be green, but many
of them are marked with yellow, blue, or red.

The smaller ones are grouped under the terms "slippery dick" or "razor fish."
They are the most common of all reef fishes, swarming like birds literally
everywhere. They eat shellfish, molluscs, and other invertebrates, which are
crushed in the heavy pharyngeal teeth.

De Latil (1955) describes the breeding habits of some Mediterranean wrasse.
They build nests of stones and seaweed and defend these avidly. Egg-laying is
preceded by a strange nuptial dance in which the breeding pair advances and
retreats in a vertical position, waving their pectoral fins and opening and closing
their mouths. The eggs and milt are shed, and then the seaweed and stones
are pushed around the eggs. These little piles of seaweed and stone are common
in summer in reef areas. The nest is defended until hatching time. The nature
of nesting material would be expected to vary greatly from place to place.

Most wrasse, big and small, are not schooling, but usually swim near or with
others of their own kind or as part of a motley crew composed of species of
similar habits.

TAUTOG (blackfish, oysterfish) : Tatitoga onitis

Size: Up to 3 feet.

Weight: Averages 2 to 4 pounds. Up to 22 pounds.

Distribution: Maine to the Carolinas. Common from Cape Cod to Delaware.

Identification: The snout is blunt and the body heavy. Ground color is brown
to black or olivaceous. There are irregular blotches, and the conspicuously whitish
chin makes a good field mark.

256

UNDERWATER GUIDE TO MARINE LIFE

Fig. 145. Tmitog.

Habits: This familiar fish is very common about rocks in shallow water near
shore. It is not easily frightened and will round rocks just ahead of the
swimmer, shortly returning to its accustomed place from which it was driven.
Several are usually seen together, but it is not a schooling species. It is a
mollusc- and crustacean-eater. Tautogs lay buoyant eggs in June and July in
fairly deep water.

Similar S-pecies: The cunner (bergall), Tautogolahrns adspersiis, is the most
northern wrasse. Its habits are much like those of the tautog, and the two species
are often seen together. The head is more pointed than that of the tautog, and
the color is a mottled brown to olivaceous. It reaches 15 inches and ranges from
Labrador to the Chesapeake.

CALIFORNIA SHEEPSHEAD (redfish): Piuielotuetopon fulcher—CoJor Plate 8

Size: Up to 3 feet.

Weight: Up to 25 pounds.

Distrihution: Monterey Bay to the Gulf of California.

Identification: This is a very bizarrely colored fish. The males have a black
head and black rear parts with an orange mid-bodv. The females are uniformlv
reddish to black and occasionally blotched. The scientific name means "beautiful,
fat forehead."

Habits: This is an inshore fish of the rocks and kelp beds. Its habits are much
like those of the tautog, but it is a pugnacious fish, fighting both its own species
and others as well.

HOGFiSH (capitan) I Lachnolaimus viaximns— Color Plate 8

Size: Up to 2^/2 feet.

Weight: Averages 4 pounds. Lip to 20 pounds.

Distribution: West Indies to Florida.

Identification: The silhouette is completely unique with steep profile, deep
body, and long first dorsal ravs. The color varies from a reddish blotched pattern
QColor Plate 10) to a rather plain "red-fronted" phase.

Habits: This fish swims singly or in small groups in open spaces, such as

MASTERS OF THE WATER-BONY FISHES

257

gorgonian beds, in a stately fashion which befits its appearance. It is an excel-
lent food fish although its sale on the market was at one time forbidden due to
the supposedly poisonous character of the flesh. This fish is easily chummed with
bits of broken sea urchin or mollusc.

Similar Species: The Spanish hogfish, Bodianus rufus QColor Plate 8), is less
deep-bodied than the hogfish and has no long dorsal fin extensions. It swims
solitarily over reefs and is West Indian but somehow lacks the dignity of the
hogfish. It reaches Wz feet and is mostly smaller. The color is distinctive, being
greenish to crimson above and forward and golden below and to the rear.

BLUE-HEAD (king SLIPPERY dick) : Tlialassoma hifasciatiivi— Color Plate 8

Size: Up to 6 inches.

Distribution: West Indies to Florida.

Identification: Mature males are conspicuously collared with two black bands.
The head is blue, and the body and tail are greenish yellow. The females are
uniformlv yellow with black blotches in a row on the sides.

Habits: This is the most common of all West Indian reef fishes. Females and
young, brightly yellow, swarm everywhere. The males are less common but are still
very abundant. Groups of these fish often will follow a swimmer. They are very
easily chummed. They graze over reefs on a wide variety of small invertebrates.
Like manv other small wrasse, the blue-head buries itself in sand by night.
Longley and Hildebrand (1941) state that the young frequently peck at larger
fishes such as tang, chubs, demoiselles, and, most commonly, skipjacks. Presum-
ably, this is done to remove ectoparasites from these fishes, but oddly enough
no parasites have been found in stomachs of blue-heads.

Similar Species: The senorita, Oxyidis californica, reaches 7 inches and is
found from Monterey to Guadalupe Island. It frequents kelp and rocks and is
of a kelp-brown color, with cream below and a black blotch at the tail base.

SLIPPERY DICKS AND RAZOR FISHES: Genera Iridio and Xyrichthys

There are many species of these fishes. They are all of small size, averaging
about 6 inches, but some reach IVi feet, though rarely. Most of them are pearly
and iridescent wnth flecks and blotches of many shades of color on the body. The

Fig. 146. Razor fish Qeft')
and slippery dick Qright^.

258 UNDERWATER GUIDE TO MARINE LIFE

razor fishes, Xyrichthys, are much compressed and have a rounded forehead
which is often so compressed as to have a sharp leading edge. No attempt will
be made to separate the numerous West Indian species. There is only one
southern Californian form, the so-called "parrot fish," Iridio semicinctus. Razor
fishes and slippery dicks build nests of sand or coral in which to lay their eggs.
Most of the smaller ones bury themselves in sand or stones, where they are able
to hide from enemies or sleep at night. The razor fishes, in particular, are adapted
to living near sandy bottoms. They build homes of bits of debris and keep them
in constant repair. When pursued, they are able to move freely under sand.
Agility under sand is due mainly to their knife-edged forehead and compressed
body.

PARROT FISHES: Family Scaridae

The large scales, bright colors, heavy bodies, and lumbering movements of
parrot fishes are strongly reminiscent of huge goldfishes. The name is derived
from the parrotlike beak of fused teeth in the mouth. These, even more than
wrasses, are typical of reefs, being found almost no place else. About reefs, they
are the most common large fishes. They are nonschooling but are gregarious,
swimming with their own kind, near relatives, or near other reef fishes, such as
the doctorfishes. The strong beaks, which can snip a stout wire in two, are
used to graze over reefs for both animal and plant substances. The diver will
often hear them crunching on coral. After a meal, large ones often stand erect
and let small wrasse clean the coral fragments and sand from their heads and
mouths.

Parrot fishes will usually not allow close approach. It is far better to let them
approach the swimmer; they are skittish but still moderately curious. If ap-
proached closely, they swim away in a very characteristic manner, using a flap-
ping motion of their large pectorals and using the tail for little but steering.
They occasionally roll ever so slightly from side to side in order to peek back at
their pursuer, first over one shoulder then the other. Swimming like this, they
do not move speedily, but they can easily outdistance the swimmer. Like many
other fishes, parrot fishes learn very quickly to avoid a man with a spear. Parrot
fishes become very large and heavy and enter very shallow waters occasionally.
They are frequently gaudily colored with green, red, yellow, or blue. There are
over one hundred species of parrot fishes the world over. Ekman (1952) says
there are none on the West Coast of North America, but Jordan and Everman
(1900) report one rare species. Some are quite small, attaining a maximum size
of under 1 foot. Large ones seem to have few enemies.

RED PARROT FISH (loro COLORADO): Sparisovia ahUdgaardi—Color Photograph

Size: To 1 foot.

Distrihution: West Indies to Florida.

Identification: Members of this genus are all rather small and have a lower
jaw that is as long as the upper. The scales on the head are few and large, and
the beak is white or rosy. This species has bright red fins and a distinctive colora-
tion in which the scales are clearly outlined in black. Some scales are white,
giving the fish a sparkling, mottled appearance, but spotting and blotching can
vary considerably.

MASTERS OF THE WATER-BONY FISHES 259

Hahits: This fish and similar parrot fishes swim with other parrot fishes or
with tang and goatfish, grazing about reefs, and on the sand near reefs, on
animal and plant substances.

Similar Species: The mud parrot fish, Sfarisoma flavescens, is a dingy gray-
brown to olivaceous. The scales are clearly outlined. It is small, up to 1 foot, and
found in the West Indies.

The green parrot fish, (loro verde) Sparisoma viride Qcolor fhotograph^, is
very common in the West Indies. It is a dull greenish color, but the tail is a bril-
liant, bright green with several large orange scales at its base and a blue posterior
margin. It reaches Wi feet or more.

BLUE PARROT FISH (clamacore) : Scurus coeruleus— Figure 147

Size: Up to 3 feet. Averages 1 to IV2 feet.

Distribution: West Indies to Florida. Straggles rarely to the Chesapeake.

Identification: The members of this genus have a lower jaw that is shorter than
the upper. The beak is either whitish or rosy, and the scales on the head are
rather numerous. Some of them grow to large size. This species has the mouth
placed noticeably under the snout and is a beautiful, uniform sky-blue in color.
Older individuals have long outer tail-fin rays and a very pronounced swollen
snout.

Hahits: The larger members of this genus are lumbering in their movements
as are the larger members of the following genus (^Pseudoscarus^. This species
has the widest range and is perhaps the most common of all parrot fishes, par-
ticularly over outer reefs. It may often be seen swimming in small groups around
the base of coral heads, feeding in sand or on the coral.

Similar Species: The blue parrot fish (oldwife, vieja), Scarus vetula, is a very
striking predominantly blue fish. The jaws are edged with light blue and red.
The tail and pectoral fins are edged with a reddish color, and the pelvic fins are
yellow to red. It reaches 2 feet or more in length and is common in the West
Indies.

The white-banded parrot fish, Scarus gnathodus, is a wine-brown with a very
wide lateral white stripe. It grows to a little over a foot and is fairly common in
the West Indies.

The painted parrot fish (ribbon parrot fish), Scarus punctulatus, is a lovely
little West Indian fish which is commonly seen in small groups. It reaches only
10 to 12 inches in length at most and has two green stripes on the head above
and below the eye.

The mud-belly, Scarus croicensis Ccolor photo grapK), reaches only 10 inches,
is brownish to slate-blue with a light belly, and usually has two light bands
running horizontally on the sides and a yellowish area on the nose. It is fairly
common from the West Indies to Florida.

rainbow parrot fish (guacamaia): Pseudoscarus guacamaia— Color Plate 8

Size: The largest parrot fish. Averages a little over a foot. Up to over 3 feet.

Distribution: West Indies to Florida.

Identification: Members of this comparatively small genus are like Scarus
species but have distinctly green or blue beaks. This species is of very gaudy
coloration, especially when adult. The young are greenish with a brown spot

260

UNDERWATER GUIDE TO MARINE LIFE

Fig. 147. Tof. The indigo pairotfish, Pseudoscarus coelestinus, second largest of
the North American farrotfishes, probably reaches IVz feet in length. Bottom. The
bhie parrotpsh, Scarus coeruleus, is a beautiful sky-blue color and develops a large
fleshy lump on the nose when it matures. A blue-striped grunt scowls from under
part of a wreck in the background.

on each scale. The belly and throat are reddish brown. The vertical fins are
edged with blue-green. As they get older, they take on a reddish-brown color
anteriorly and are greenish posteriorly, as pictured, but the coloration is always
subject to great variation.

Habits: Like those of the senus Scarus.

Similar Species: The indigo parrot fish (purple parrot fish, wine-colored parrot
fish), Pseudoscarus coelestinus (/ig. 147'), is a very dark blue or purplish parrot
fish with the jaws, forehead, and base of the spiny dorsal fin colored a very bright
greenish blue. The authors found it common in the Bahamas, and the individual
shown in the photograph was a minimum of 2 feet long.

MASTERS OF THE WATER-BONY FISHES 261

Scaly-Fin Fishes: Suborder Squamipinnes {"scaly fin")

Very few fishes can match the beauty of color, form, and movement of these
mostly tropical fishes. They glide effortlessly through the water, their lustrous,
velvety bodies never failing to impress the diver. There are three quite distinct
families. All possess dense scalation on the vertical fins, which adds to the soft
and veh'ety appearance. All are strongly compressed and deep of body, and most
use the pectoral fins in a flapping manner to aid in their movements. This method
of propulsion is not so exclusively used as it is in the parrot fishes. The mouths
of the scaly-fins are small and the teeth small and brushlike (except in tangs),
so most are invertebrate- and algae-eaters exclusively. Various shades of yellow,
blue, and black are predominant colors. Their distribution is world-wide, chiefly
over and around reefs.

SPADEFISHES: Family Ephippidae

These fishes are a bit off^ the beaten track for scaly-fin fishes. The color is
predominantlv silvery, and there is a prominent spiny dorsal fin. Spadefishes
school rather densely inshore and about reefs, wrecks, rocks, and pilings. They
swim faster than do other scaly-fins and more in a typical "fishy" manner than
most scaly-fins do, using the tail for propulsion. There are few species, mostly in
tropical seas.

SPADEFiSH (paguala) : Chactodifterus faber— Color Plate 7

Size: Averages 1 foot. Up to 3 feet.

Weight: Up to 20 pounds.

Distribution: Cape Cod to Brazil. Most common in the West Indies.

Identification: The silvery to whitish color with black crossbands is distinctive.
As the fishes get larger, the bands disappear. The silhouette is the best field mark.

Habits: The food consists primarily of invertebrates, mainly crustaceans. Cteno-
phores also are eaten.

Similar Species: Chaetodifterus zonatiis is the similar spadefish of the western
coast of Mexico. It ranges rarely as far north as San Diego.

BUTTERFLY FISHES AND ANGEL FISHES: Family Chaetodontidae

Size is the characteristic which separates the butterfly and angel fishes. The
former are small and very active, almost birdlike in their movements, and are
mostly seen traveling in pairs. The latter are larger, have stately movements, and
travel singly, in pairs, or in small groups. The young of both are usually very
diff'erent from the adults in pattern and in coloration. These are among the most
typical of reef fishes, found throughout the world.

BUTTERFLY FISHES: Chaetodon species

The habits of these species are so similar that they had best be considered as
a group. All are very active fishes and have the flitting movements of a butterfly,
hence their name. They are exceedingly brightly colored, principally with yellow
and black. Owing to their small size and their lack of great speed, it would be
expected that they would be secretive, but they are not. They depend on extreme
alertness and activity, as do the demoiselles, for safety. Many of them also add

262 UNDERWATER GUIDE TO MARINE LIFE

two interesting types of protective coloration, both of which create the illusion
that they are swimming backwards, thus forcing a predator to miss its mark. First,
the eye is camouflaged by a vertical line which runs through it. The eye is
the most difficult part of the body to hide since it is round, moving, and shiny.
Many animals, therefore, have evolved a line through it or a mark over it. The
raccoon, wood frog, and shrikes are familiar examples of this. The butterfly fishes
not only destroy the outline of the forward, true eye, but frequently add a false
eye to the rear in the form of a large, dark, usually ocellar, spot. A predator
aiming for this "head end" with its large "eye" is deceived and comes up with
nothing but a mouthful of water as the little fish scampers off unexpectedly in
a direction which looks backward.

Butterfly fishes have pointed, extended snouts with the small mouth situated
at the end. With this snout they are able to poke about every nook and cranny
of reefs or rocks for their small invertebrate or plant food. They commonly eat
parasites attached to other species. Some large predators even allow them to
probe in their throats for parasites. The common East Coast species are three in
number. There are many similar Pacific species, mostly Polynesian.

BANDED BUTTERFLY FISH: Chaetodofi striatiis—CoJor Plate 6

Size: Up to 6 inches.
Distribution: West Indies to Florida.

Identification: There is no rearward spot. The color is a very pale yellow or
white crossed with vertical black bands.

COMMON BUTTERFLY FISH: Chaetodon ocellatns

Size: Up to 8 inches.

Distribution: West Indies to Florida. Straggles to Cape Cod.

Identification: This is a yellow fish with a dark line through the eye and
usually with a dark nonocellar spot at the base of the soft dorsal fin, but this
may be missing or enlarged (in young fish) to form a vertical band. The shape
is like that of the four-eyed butterfly fish.

FOUR-EYED BUTTERFLY FISH: ChaetodoH caj)istratus—Color Plate 6
and Color Photografh

Size: Up to 6 inches.

Distribution: West Indies to Florida. Straggles to Cape Cod.

Identification: The large ocellated spot on the rear part of the body is unmis-
takable. The body is delicately yellow to white and covered with very fine rows
of spots. This is the most common West Indian species.

ANGELFISHES: Genera Pomacanthus, Holocanthus and Angelichthys

These large and exceedingly lovely fishes are constant sources of the aesthetic
inspiration which many divers seek under water. Their movements can only
be described as majestic and stately. As the diver approaches them, they will
at first face him, swim toward him a bit, then turn in an arc so as to present the
full beauty of the velvety sides and fins, lending themselves admirably to pho-
tography. These fish will occasionally do this over and over, coming at the diver
first from behind a coral, then from out of a hole.

MASTERS OF THE WATER-BONY FISHES 263

In habits, the angelfishes are really only larger editions of butterfly fishes.
They also very often travel together but usually in small groups of up to half a
dozen. Some are most often seen alone. The brushlike teeth aid them in grazing
over reefs for invertebrates and plants. All of these fishes have a large sharp
spine directed back from the preoperculum, which can inflict injuries when the
fish is handled. The mouth and lips are usually a different color than the head,
giving some of them a Jolson-in-blackface look. The dorsal and anal fins are
elongated at the corners. The species are as follows:

BLACK ANGELFisH (chirivita) : Pomacanthus arcuatus— Figure 148

Size: This is the largest angelfish, reaching 2 feet.

Distribution: West Indies to Florida.

Identification: Members of this genus have very deep bodies, almost round,
and the dorsal spines are obscure. This is a grayish species with each scale bear-
ing a small black spot which gives a gray, velvety lustre. The inside of the pec-
toral fin is bright yellow, and this color is flashed as the fish swims with the
aid of that fin. The mouth is conspicuously white. The young are black with
vertical yellow bars that disappear with age. This species is usually seen in groups
of three to six fish, swimming in rather open water near reefs.

Similar Species: The French angelfish, Pomacanthus -paru QColor Plate 7),
reaches a length of 14 inches and is found in the West Indies north to Florida.
The color is black with each body scale outlined with yellow. The base of the
pectoral fin is yellow. The young with their vertical yellow stripes QColor Plate 7)
are common and striking reef fish. The West Coast member of this genus is
Pomacanthus zonifectus and is found south of Mazatlan.

ROCK BEAUTY (vAQUETA DE DOS coLOREs) : Holocauthus tricolor— Color Plate 7

Size: Up to I foot.

Distribution: West Indies to Florida Keys.

Identification: The very striking color pattern of a yellow head, belly, and tail
combined with a black body is distinctive. The shape is somewhat rectangular,
and the dorsal spines are small but noticeable. This fish is usually seen singly
in and about holes in reefs.

QUEEN ANGELFISH (isabelita) : AngcUchthys ciUaris—Color Plate 7

Size: This is as long a fish as the black angelfish, reaching 2 feet, but its lesser
body depth makes it appear smaller.

Distribution: West Indies to Florida.

Identification: The sides are predominantly yellow with a blue cast. This blue
may become quite dark at times. The dorsal and anal fins are yellow, edged with
blue. The pectoral and caudal fins are yellow. There is a very distinctive black
ocellus ringed with blue on the forehead. The blues on this fish are interference
colors and are more iridescent than the yellow pigment colors. The shape is some-
what rectangular, and the spines of the dorsal fin are noticeable. The young
show a dark bar through the eye and pale bars posteriorly. This fish is usually
seen singly about coral heads.

Similar Species: The common angelfish, Angelichthys isabelita, is found from
the West Indies to Florida and is identical to the blue angelfish of Bermuda. It

264

UNDERWATER GUIDE TO MARINE LIFE

Fig. 148. Top. The ocean triggerpsh, Canthidermis sabaco, mistakenly called
"turhot," moves through the water hy flapping its dorsal and anal fins from side to
side. It is exceedingly ctirious and found mostly over offshore reefs. Bottom. Black
angelfishes, Pomacanthus arcuatus, might easily pass for ]olson-in-hlackface. The
sharp preopercidar spine is shown on the individual to the left. This pod is travelling
over a meadow of sea plume gorgonians.

MASTERS OF THE WATER-BONY FISHES 265

has no ocellar spot on the forehead, and the pectoral and caudal hns only are
edged with vellovv. The young are barred as are the young of the queen angelfish.

TANGS: Family Acanthuridae

There are many species of these tropical reef fishes found throughout the
world. All are characterized by their silhouette, in which the dorsal and ventral
curvatures and fins are verv similar, giving the body an ovoid shape. Tangs are
no less velvety than angelfish in appearance. They have a formidable weapon
in the scalpellike vertebral spine, which is usually folded forward in a groove
in the tail, but which may be erected and used in a slashing manner to inflict
deep cuts on an adversary. This weapon has given them the names of "surgeon-
fish" or "doctorfish." Among Spanish-speaking peoples they are known as "bar-
beros" or "medicos." In early davs, it was the barber who practiced phlebotomy,
or blood-letting, and who was the local general practitioner.

Tangs usually swim in small groups, often with parrot fishes, and often use
the pectoral fins in a flapping manner for propulsion, though this kind of pro-
pulsion is not as predominant as in parrot fishes. The teeth are different from
those of other scaly-fin fishes. A single series of incisorlike teeth is present in
each jaw. These are used to scrape away plant arid animal substances from the
reefs on which they graze. Dark brown and blue colors predominate. The young
are colored very differently from the adults.

BLUE TANG (blue DOCTORFISH, surgeonfish) : Acatithurus coeruleus—

Color Plate 7

Size: Averages 8 inches. Up to 1 foot.

Weight: Up to 1 pound.

Distribution: West Indies to Florida. Straggles to New York.

Identification: The blue color is dark, exceptionally velvety, and very hard
to catch on film, requiring more exposure than would appear necessary. This
color, however, is variable, becoming very pale over a sandy bottom, so the very
deep, almost circular shape and the tail lancets of white are the best marks.

The young of this fish, formerly described as a separate species, is an exceed-
ingly brilliant, jewellike yellow fish up to the time it is about 3 inches or so long
(it has been reported to 6 inches). It is common in the company of wrasse about
coral heads and has the shape of a butterfly fish, but the tail spine gives it away.
It tends to keep close to the protection of the coral.

Habits: Tangs are found in groups, singly, or swimming with other reef fishes
(parrot fishes commonly). They graze, much after the manner of parrot fishes,
and show some of the same wary habits, though less pronounced.

Similar Swedes: The doctorfish, Acanthurus hepatus QColor Plate 7)-, is a
West Indian species which also goes as far north as Cape Cod accidentally. It
is less deep of body than the blue tang and varies from a dark to light brownish
color. The lancet on the tail is dark. This fish reaches 10 inches.

The ocean tang, Acanthurus bahianus, also has dark and light brown phases
but keeps more offshore, and large specimens have the upper lobe of the caudal
fin elongated into a filament. Its range is the West Indies, accidentally to Cape
Cod, and it commonly reaches 1 foot.

The barbero negro, Acanthurus crestonis, is found from Mazadan south and
is usually very dark in color.

266 UNDERWATER GUIDE TO MARINE LIFE

Plectognaths: Suborder Plectognathi {"jaws woven together")

Here are united three rather distinct groups which have formerly been consid-
ered separate suborders: (1) the Sclerodermi ("hard skin") or triggerfishes and
filefishes, (2) the Ostracodermi ("box skin") or trunkfishes, and (3) the Gym-
nodontes ("naked tooth") or puffers and porcupine fishes. But because of the
common origin of these fishes from scaly-fin fishes and because of several trends
which these three groups show in common, the splitting of this group in three
parts may not be justified. All show a very reduced gill opening, a trend defi-
nitely present in some scaly-fin fishes, notably tangs. All reduce or lose the
ventral fins. All have lost typical scales, having plates or spines in their place.
All have several jaw bones fused, hence the term "Plectognathi." Many, espe-
cially the gymnodonts, develop poisonous alkaloids in their flesh or viscera. The
Polynesian maki-maki or deadly death, Tetraodon hispidus, has deadly flesh.
The flesh of porcupine fishes causes a nerve poisoning called "ciguatera." Some,
however, are good eating. Northern puffer tails are sold as "sea squab." The
plectognaths all have small mouths and are feeders on small invertebrates or
marine vegetation.

TRIGGERFISHES: Family Balistidae

The word "balistes" means "crossbow" and is applied to the triggerfishes
because of the very odd arrangement of the spiny dorsal fin. The large first
spine locks erect into place and can be released by depressing the third spine.
These compressed, deep-bodied fishes have hard scales imbedded in the skin
and no mucus and therefore feel decidedly leathery. The bones of the ventral
fins beneath the skin form an erectile flap which gives the bellv outline a very
odd shape, pointed and deep just ahead of the anal fin. The soft dorsal and anal
fins are much alike in size and shape and are used in propelling the animal.
They flap from side to side, both fins flapping first to one side then to the other.
This is especially noticeable in the ocean triggerfish, which keeps more to open
water than the others and also swims more constantly. These are primarily
tropical reef fishes of world-wide distribution.

COMMON TRIGGERFISH (cucuYo) : Balistes caprJsens—Color Plate 9

Size: Averages 10 inches. Up to 20 inches.

Weight: Up to 4 pounds.

Distribution: West Indies to Cape Hatteras. Strays to New York. Western
coast of Mexico.

Identification: Dull brown with mottled sides when near cover such as sargasso.
Plain gray in open water.

Habits: This fish is found either singly, in small pods, or swimming with other
small fishes such as grunts. It keeps to reefs, rocks, and hard bottoms, swims
actively, and feeds on worms, crustaceans, and molluscs primarily. The voung
keep to the shelter of sargasso weed or floating objects.

QUEEN TRIGGERFISH (oLDWiFE, cociNo) : Balistes vettda—Color Plate 9

Size: Averages 1 foot. Up to I'/z feet or more.

Distribution: West Indies to Florida, stragplina to New York.

MASTERS OF THE WATER-BONY FISHES 267

Identification: This is a brilliantly marked species which shows great varia-
tion in intensity of color, matching the lightness or darkness of the bottom, but
which always has iridescent blue stripes on the head and an iridescent blue tail
base. The back is usually blue to green and the throat and belly orange. The
adults have the soft dorsal fin and corners of the tail fin elongated into long
filaments.

Hahits: This is a fish of hard bottoms and reefs. It is usually seen singly and
acts much like some angelfishes, such as the rock beauty, in its almost sinuous
movements. Its lustrous colors are shown off to great advantage as it swims in
and out of holes in reefs.

Similar Sj^ecies: The ocean triggerfish or turbot, Canthidermis sahaco Cfig.
148'), is a uniform dark gray and swims just fast enough to keep out of the reach
of the swimmer, chieflv around outer reefs. It is insatiably curious. The authors
have chased them away just to see how long it would take them to return. As
soon as they were ignored, back they would come to look the situation over. This
is one of the largest triggerfishes, reaching 2 feet and ranging through the West
Indies and off Florida.

The Pacific triggerfish, Verriincidiis iwlylepis,. is another very large species
reachmg 2 feet or more in length. It varies from dark to light brown in color and
is found from Catalina Island to Baja California.

A very pretty East Indian and West Mexican species, of predominantly violet
coloration and with dark lines on the cheeks and longitudinal rows of blue spots
on the sides, is Xanthichthys lineopunctatiis. It reaches 10 inches and rarelv
strays as far north as San Diego.

FILEFISHES: Family Monocanthidae

These are degenerate offshoots of the triggerfishes in which the dorsal fin has
been reduced to one long spine. The skin is rough and was formerly used as
shagreen. The ventral outline is even more bizarre than in triggerfishes, some-
times being anteriorly very deep. With the change in shape of the dorsal and
anal fins, to low and long rather than high and pointed as in triggerfishes, there
is a change in the method of propulsion. Waves pass down these fins toward
the rear to move the fish slowly forward (/ig. 149). The tail fin, though large, is
kept motionless and folded and is usually not used at all. The very small mouth,
often at the end of a long snout, is used to graze over pilings for both plant and
animal substances. Most of these fishes keep to the protection of wharfs, rocks,
or reefs and assume odd positions, head up or down, reminiscent of the trumpet-
fish, as they graze over the rocks or pilings for food. They are found in all tropical
and some warm temperate seas.

ORANGE filefish: Alutcru schoeffi— Color Plate 9

Size: Averages under a foot. Reaches 2 feet.

Distribution: West Indies to Maine and Texas.

Identification: The color is a mottled orange to brown or olivaceous. It is cov-
ered with dark spots.

Hahits: This is a typical fish of inshore rocks, pilings, and seaweed. So slow,
awkward, and unfishlike are its movements and so close to rocks does it stay,
that it can quite easily be overlooked. The adults usually prefer inshore waters,

268 UNDERWATER GUIDE TO MARINE LIFE

Fig. 149. This scrawled filefish, Alutera scripta, measured about eighteen inches. It
has a very large tail fin which it keeps folded, propulsion being accomplished by
means of sine waves travelling rearward in the dorsal and anal fins.

especially over eelgrass-covered sand, but Crawford and Powers (1953) report
that they sometimes school several miles offshore. The resemblance to plant
leaves is striking, and groups of these fishes have been observed to form a
rosette pattern with the head of each fish pointing inward, accentuating the
resemblance to floating seaweed. The young are frequentlv found in sargasso
weed or among other floating objects.

Similar Species: There are several smaller filefishes on North American coasts.
The common filefish, Monacanthns hispidns, is most common in eelgrass and
can change its color to match its environment— mottled green in eelgrass, brown
in sargasso, pale gray over sand. It reaches 10 inches and is found from the West
Indies as far north as Maine.

The scrawled filefish, Alutera scripta Qfig. 149^, is a large species, reaching
3 feet in length, which is found very widely in tropical seas of the world. It has
a concave profile to the snout, is covered with light blue and small black spots,
and has a very long tail which is usually kept folded. This fish is verv curious
and, like the ocean triggerfish, swims slowly around and around the swimmer
up to a distance of about 10 feet, never seeming to satisfy its curiosity. It keeps
to rather open waters over hard bottoms.

The unicorn filefish, Ahitera monoceros, reaches a length of 2 feet and is cos-
mopolitan in warm seas. It looks much like the scrawled filefish, but has a convex
profile, mottled body, and shorter tail.

TRUNKFISHES: Family Ostraciidae

These little fishes have resorted to the same means of protection as have the
turtles, that of enclosing almost the whole bodv in a shell. The shell is com-
posed of fused, six-sided, bony scales, and it is usuallv triangular in cross section.

MASTERS OF THE WATER-BONY FISHES

269

This has restricted the fishes' movements greatly. These fishes, not having flexible
operculums, utilize movements of the pectoral fins to help circulate water through
the gills. Propulsion is accomplished by rapid sculling motions of the dorsal
and anal fins, the tail fin being used only in moments of dire stress. As the
swimmer approaches one of these fish, it will at first face forward, then turn
around and flee with all its might. In flight, its dorsal and anal fins work very
hard and comically, moving the fish at a speed well under that of a swimmer
with flippers. The fish will rock from side to side every so often to look back
over its shoulder at its pursuer. It somewhat resembles parrot fishes in this
respect. After a while, discovering that escape is not possible, it will come to
rest near some protecting ledge or hole.

Trunkfishes have very small mouths. They eat small invertebrates and plant
substances. Their distribution is world-wide in tropical seas.

cowfish: Lacto-phrys tricornis— Color Plate 9

Size: Averages 8 inches. Up to a little over 1 foot.

Distribution: West Indies to Cape Hatteras. Straggles to Massachusetts.

Identification: There is a spine over each e3'e and two spines near the rear
end of the shell. The coloration is a blotched green with beautiful iridescent
yellow and blue spots.

Habits: This is a bottom fish found around reefs, rocks, and harbors. When
badlv frightened, it assumes an iridescent, light blue color.

Similar Species: The shellfish hactofhrys bicaudaiis is a tropical reef species
reaching a length of 16 inches. It ranges throughout the West Indies and north
to Florida. There are spines on the lower rear angles of the shell, which is light
brown or greenish and covered with round, dark spots.

Fig. ISO. The trunkfish, Lactophrys trigonias, moves slowly hy flapping
and anal fins. It steers with the tail fin spread fan-shaped behind. For pr
depends on its hard shell of fused, bony scales and adaptive coloration.

; its dorsal
otection it

270 UNDERWATER GUIDE TO MARINE LIFE

The common trunkfish, Lactophrys trigonias (/ig. 150^, is like the shellfish
in distribution and coloration, but is smaller and has black bases to the fins.

A species with a spine over each eye, Ostracion diafhanutn, is reported by
Barnhart (1930) to have been picked up dead on southern California beaches.
It should be looked for.

PUFFERS: Family Tetraodontidae

These fishes possess the almost unique ability, along with the swell shark, of
inflating themselves with either air or water or both so that they assume an
almost globular shape. They are able to do this very quickly, and by this means
they make themselves larger to discourage enemies which would otherwise attack
them. When swollen with air, they bob helplessly, belly up at the surface. Defla-
tion is accompanied by ludicrous belching noises and bubbling at the mouth.

Puffers can make a grinding noise by rubbing their teeth together. The teeth
of puffers are fused into a beak which is divided by a median suture, hence the
name "Tetraodontidae," meaning "four-toothed." They eat shellfish such as
crab and molluscs as well as other invertebrates, cracking them with this beak.
They swim by using the pectoral, dorsal, and anal fins principally. Puffers are
mostly small, active little fishes which nose about reef and sandy bottom areas
in tropical seas.

Many species develop poisons in their liver and gonads, or more rarelv in the
flesh. It is not known what causes some puffers to become poisonous and
some not. The eggs are known to carry poison, and if a puffer ate its own eggs,
as some are known to do occasionally, this might cause the liver or even the
flesh to become poisonous also. However, the nature of fish poisoning is very
poorly known (Chapter 4).

RABBiTFiSH (sMOOTH puffer) : Lagocephaliis laevigatus— Color Plate 9

Size: Up to 2 feet. Largest of the puffers.

Weight: Up to 7 pounds.

Distrihution: West Indies to Cape Hatteras. Straggles to Cape Cod.

Identification: The color is silvery, becoming greenish above. The head is
blunt compared to other puffers. There is a fold of skin on the lower body
especially posteriorly.

Habits: Rabbitfish are not able to distend their bodies as greatly by swelling
as other puffers, a fact no doubt related to their alreadv large size. They swim
over a wide variety of sandy or hard bottoms and are found in harbors, but they
prefer shallow channel waters. Their food consists of crustaceans and molluscs.

SOUTHERN puffer: Sfheroidcs spengleri— Color Plate 9

Size: Lip to 1 foot or more. Mostly seen under 8 inches.

Distrihution: West Indies to Florida. Strapgles to Massachusetts.

Identification: There are a series of black spots along the sides. The tail fin
has two black bands, one at the base and one at the tip.

Hahits: This species can distend itself to an extreme degree. Normally it is
quite slim. Even the young are able to swell up, forming curious little pea-sized
balloons. This is a common fish in shallow waters in harbors and over sandy
bottoms. It has been seen attacking large crabs in groups, one fish biting the crab,
then another, until the crab is immobilized. Even so small a puff"er has a beak

MASTERS OF THE WATER-BONY FISHES 271

fully able to bite through a crab's shell. Examples of cooperative feeding, in
which several individuals are able to get a meal where one could not, are rare
in animals of such a supposedly low order of intelligence. The example of the
thresher shark, given earlier, is the only other one that is known for fishes.

Similar Species: The northern puffer, Spheroides maculatus, is without bands
on the tail but is otherwise like the southern puffer in size, habits, and appear-
ance. It replaces the southern puffer to the north and is found as far north
as Maine.

The sharp-nosed puffer, Canthigaster rostratiis, is a tiny puffer of the coral
reefs. It swims alone or with other small reef fishes and is altogether a very
attractive and amusing fish as it bobs about among sea fans, gorgonians, and
coral. It reaches only about 4 to 5 inches and is West Indian. It is a soft brown
above and cream below, with dark lines radiating out from the eye. The tail fin
is black on the upper and lower edges.

The Gulf puffer, Spheroides annidatus, is dark brown with light, curved
streaks on its back. The back is covered with small dark spots as well. It reaches
Wi feet and is found north to San Diego in summer.

PORCUPINE FISHES: Family Diodontidae '

These extremely bizarre derivatives of puffers do not have their beaks divided
by a median suture and for this reason are named "Diodontidae" ("two-toothed")-
Their habits are very similar to those of puffers, and they are able to inflate
themselves to an equal degree. All of them are covered with stout spines which,
in some species, are long enough to inflict painful injury. The profile, as well
as the cross section, of these fishes is squarish, hence they are often referred to
as "boxfishes." Their flesh is reputed to be poisonous especially in the tropics.
Their distribution is world-wide in tropical seas.

PORCUPINE fish: Diodon hystrix— Color Plate 9

Size: Averages over 1 foot. Up to 3 feet.

Distrihjition: Cosmopolitan in warm temperate and tropical seas.

Identification: The yellowish color and long, dangerous spines separate this
fish from all others.

Habits: This fish is dangerous to handle. The spines are not poisonous, but
they are erectile, very sharp, and capable of inflicting painful wounds. Their food,
like that of puffers, consists mostly of shellfish and crustaceans. Some oriental
people inflate the dried skins of these fishes and use them for lamps.

Similar Sj?ecies: The spiny boxfish (swell toad), Chilomycterus schoeffi, has
broad short spines and wavy dark markings on its yellowish body. It is very
boxlike in shape. It reaches 10 inches and is the most northerly species of the
family, ranging to Cape Cod from its normal West Indian home. A rare West
Coast boxfish, Chilomycterus affinis, ranges north to San Pedro. It looks much
like the East Coast form.

Mail-Cheeked Fishes: Suborder Loricati

This suborder includes several families in which spiny-headed bottom fishes
predominate. All are voracious and carnivorous and usually have very stout
dorsal and anal fin spines. All have a hard and usually spiny bone running

272 UNDERWATER GUIDE TO MARINE LIFE

just beneath the eye on the cheek. This is one of the largest and most varied
of all fish groups and its members are prominent in all seas from arctic to tropical,
but they are most numerous and varied in cold temperate to arctic waters.

ROCKFISHES AND SCORPION FISHES: Family Scorpaenidae

This is one of the largest of fish families with 250 species. We shall consider
this family as a series starting with the least spiny rockfishes, proceeding through
the spiny rockfishes, and terminating with the most spiny and bizarre member
of the family in our waters, the scorpion fish. The rockfishes are found in great
profusion on our Pacific Coast, where they form the largest single group of fishes
of over fifty species. Only the common, shallow-water species are included here.
Most rockfish get in quite deep waters. There is a decided tendency for
rockfishes to become red in deep water and to remain on the bottom among
rocks, where they are able to ambush the smaller fishes and invertebrates on
which they feed. Most of them are ovoviviparous. The rockfishes look very much
like moderate-sized basses, but the fin spines are stouter, and the heads are bonier,
spinier, and rougher than in basses. The most advanced species in the family,
the tropical scorpion fishes are extremely bizarrely marked, very spiny-headed
fishes. They have lost the swim bladder in response to their exclusively bottom-
living habits. Their habit of lying concealed in rocks and their excellent
protective coloration make them difficult to see in reefs. Add to this the fact that
their dorsal spines are virulently poisonous, and it is not so hard to see that here
are formidable fishes, indeed.

Three species of the South Pacific and Indian Oceans, the black nohu,
Emmydrichthys, the lionfish, Pterois, and above all the stonefish, Synanceja, are
especially dangerous. Their dorsal spines convey a principally neurotoxic poison
which causes the most extreme and excruciating pain, the result of which is
often delirium and death. Scientifically trained persons have been "stung" by
these fish and have accurately recorded the effects. Such tales are trulv horrible.
One of them is given by Smith (1951). He was pricked by two of the dorsal
spines in his thumb. Seconds later he felt severe shooting pains up his arm to
his neck. Using snake-bite treatment, he cut across the wounds, sucked them
vigorously to remove what poison he could, and bound off the thumb from the
rest of the body. Five minutes after the puncture, a pain of "an intensity never
before experienced" spread over his hand. A very short time later, he was shaken
with spasms and experienced "an insane desire to ease the mounting agony by
rolling on the ground." This pain persisted for three and a half hours, after which
time immersion in hot water was tried. "The effect was dramatic. The agonv
diminished rapidly to bearable proportions, and I returned to normal conscious-
ness and unquenchable thirst." The thumb turned black that day and was
without sensation. The next day large yellow blisters formed and, when
punctured, drained for six days and were very painful. The swelling reached
a maximum the third day after the wound. Penicillin was injected and probably
saved his thumb by reducing the blistering and the possibility of infection. A
month later, the black portions of the thumb fell away. Eighty days after the
stab the hand was weak and the thumb still swollen and painful. The poison
had a detrimental effect on Smith's health. Smith had previously been stung
by an eagle ray and puts the stonefish "in a class by itself." It is fortunate that
North American scorpion fishes arc not as dangerous as the stonefish.

MASTERS OF THE WATER-BONY FISHES

273

PRiESTFiSH (black rockfish, ROCK COD, PECHE pretre) : Sehastodes mystinus

Size: Up to Wi feet.

Distribution: San Diego to Puget Sound. The most abundant rockfish around
San Francisco and in the Juan de Fuca Strait.

Identification: Because this is one of the species that is least spiny, it looks
much like a bass, but the head of the priestfish is bonier than that of a bass and
there is a spiny preoperculum as well as a bony stay under the eye. This species
has a blackish ground color mottled with dark and light blotches and has a
white belly.

Habits: This is a voracious bottom fish very characteristic of rocky shallow
waters. It eats small fishes and crustaceans. Large numbers of young, a quarter
of an inch long, are born alive in the summertime.

Similar Species: The only Atlantic rockfish is the rosefish, Sebastes inarinus,
which is a rose-red in color and found in waters colder than 50° Fahrenheit,
north of Maine in shallow waters and north of New Jersey in deeper waters.
It reaches 2 feet in length.

The bocaccio, Sebastodes faucisfinis, is dark brown above, orange to pink
below, and generally flushed with red. It ranges from San Diego to British
Columbia.

The green rockfish (yellowtail rockfish), Sebastodes ftavidus, is a common
shore form from San Francisco to San Diego. The body is grayish, becoming
brown above and white below, with yellowish fins and tail.

RED ROCKFISH (tambor) : Scbastodes ruberrimus

Size: Largest of rockfish. Up to 2V2 feet.

Distribution: San Diego to Puget Sound.

Identification: The head tends to be blunt with the top and sides covered
with moderate spines. The color of this species is vermilion.

Habits: Like those of the priestfish.

Similar S'pecies: The brown rockfish, Sebastodes auriculata, is the only rockfish
that commonly enters bays. It is a blackish brown, mottled with light brown

274

UNDERWATER GUIDE TO MARINE LIFE

and flushed with red. It ranges from Cape Mendocino south to Cedros Island.
The Spanish flag, Sehastodes ruhrovinctus, is very handsome with alternate
vertical bands of red and rosy white. It is most common in southern California
and ranges from Monterey to San Diego. It grows to 15 inches and keeps to
moderately deep water.

treefish: Sehastodes serricefs

Size: Up to 1 foot.

Distribution: Point Reyes to Cedros Island.

Identification: The body is stout and the head blunt and noticeably spiny.
This species has an olivaceous body, becoming blackish above and yellowish
below, with seven vertical black bands.

Habits: Like those of the priestfish. This fish has been observed to rest in holes
in rocks with its belly up against the top of the hole.

Similar S-pecies: The black and vellow rockfish, Sebastodes chrysomelas, is
another small, heavy species which ranges from San Diego to Puget Sound. It has
yeljow and orange blotches on its dark brown body.

SCORPION FISH (lionfish): Scorpaena grandicornis— Color Plate 3

Size: Common at about 8 inches. Up to about 1 foot.

Distribution: West Indies to Florida. Straggles to Maine.

Identification: The head is very spiny and shaggy with fleshy protuberances.
The dorsal spines are sharp and strong, and the first few of them are hollow
and act like hypodermic needles. The poison glands are at the bases of the spines.
The coloration is brownish to gray, mottled with many other colors, principally
reds and yellows to form a concealing coloration. The color is rapidly adjusted
to match the surroundings.

Habits: The concealing coloration and sluggish habits make this a difficult
fish to spot. The danger of the spines has already been discussed. This is a
voracious fish depending on ambush to get its small fish prey. It has been found
with demoiselles in its stomach. It lies in rocks and reefs and, in the summer

Squids, among the speediest and most intelligent of marine invertebrates, are
usually seen swimming in formation.

Sea slugs grow almost to football size, squirt dark, inky fluid when molested,
and are one of the few animals that graze on large marine algae.

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this picture.

Yellow goatfishes may either school densely or associate singly with mixed groups
of miscellaneous reef fishes such as parrotfish and tang.

MASTERS OF THE WATER-BONY FISHES 275

and fall, it lays balloonlike eggs in pairs. These float and are colorless. These
floating eggs may be an aid to the dispersal of this sluggish fish. The young fall
immediately to the bottom on hatching.

Similar Species: The "sculpin," Scorfaena guttata, is a West Coast form. It
grows to 15 inches and ranges from Baja California to Monterey. There are
many other similar species in all tropical seas.

SKILFISHES: Family Anoplopomidae
This is a small North Pacific family.

SKiLFiSH (sablefish): Anoflofoma fimhria

Size: Up to 3 feet. Mostly much smaller.

Distrihiition: San Diego to the Aleutians.

Identification: The shape is long and slim and codlike. The spiny dorsal fin
is like that of greenlings but the soft dorsal is shorter and is reflected by the
anal in size and shape. There is a bony stay just under the skin below the eye.
The color is slaty above and white below.

Habits: This is a common coast fish of the North Pacific. It is commonly sold
in markets and is delicious smoked.

GREENLINGS: Family Hexagrammidae

This is another strange group of the North Pacific, the evolutionary place of
which is not clear. The dorsal, and anal fins are very long, and there are usually
several lateral lines. The bony stay beneath the eye is present. The several species
are all tvpical of inshore waters where there is kelp and rock. They are
carnivorous on fishes and invertebrates.

KELP GREENLiNG (sEA TROUT, ROCK trout) : Hexagrammos decagrammus

Size: Up to IVi feet.

Weight: Up to 2 to 4 pounds.

Distribution: Point Conception north to Kodiak Island, Alaska.

Identification: The male is bluish with brown mottlings. The female is
brownish with dark mottlings. There are five lateral lines on the sides and back.

Habits: This is a fish of the rocks and kelp beds, which eats crustaceans
primarily.

Fig. 153. Keif greenling.

276

UNDERWATER GUIDE TO MARINE LIFE

Similar S-pecies: There are several other members of the genus Hexagrammos
on the West Coast north of Monterey.

The cultus cod (Hng cod), 0-phiodon elongatiis, is the largest of the greenlings,
commonly reaching 3 feet and 30 pounds, and even growing to 70 pounds. It has
a large mouth and strong teeth, indicating fish-eating habits. There is only one
lateral line. The color varies with the habitat from dark brown to green, and
there are green or yellow spots of small size over the body. The flesh is also green
but is wholesome. It ranges from San Diego to southeastern Alaska.

The convict fish, Oxylehius f ictus, is a small, very active wrasselike or gobylike
greenling with a white to gray ground color crossed by six black bars. It is
common in rocks and seaweed, ranges from San Diego to Puget Sound, and
grows to 10 inches.

Fig. 154. Convict fish.

SCULPINS: Family Cottidae

There are a great number of species of these principally arctic fishes. None
are found south of California or Virginia. They are bottom fishes which lie on
rock bottoms, usually among seaweed, waiting for prey to come within their
reach. The larger ones are fish-eaters mainly. The smaller ones are more
omnivorous. Some of them look very much like the scorpion fishes with their
large, fanlike pectoral fins and spiny heads. Sculpins are never completely scaled
and are frequently quite pretty, especially the smaller species. These are sluggish
fishes, which depend on concealment for protection as well as for getting food.
As might be expected, the coloration varies to match the environment. If
approached by a swimmer, they usually remain still until the last moment when
they dart away with a sudden burst of energy and speed, but they never go very
far. Frequently, the preoperculum with its spines will be erected in a threatening
gesture. Most sculpins live in shallow water near shore or even in tidepools,
but some get into very deep water. They range in size from a few inches to 2^2
feet. A few species are found in fresh water and are very common there, for
example, the miller's thumb, Cottns.

CABEZONE (marbled sculpin) : ScoT'paenichthys marmoratus

Size: The largest sculpin, reaching 2^2 feet.

Weight: Reaching 25 pounds.

Distribution: British Columbia to San Dieoo.

MASTERS OF THE WATER-BONY FISHES 277

Identification: The color varies. In eelgrass, the ground color is green, and in
seaweed, it is brown. There are blotches and reticulations of green and brown
on the body. The flesh is green. The shape is like that of the Greenland sculpin.

Hahits: This is a fish of shallow waters, where it lies among rocks and
vegetation. It ambushes fishes and crustaceans from its hiding place.

TiDEPOOL sculpin: CUnocottus analis

Size: Up to 7 inches.

Distribution: Monterey to southern California.

Identification: The color matches the environment. The shape is similar to that
of the Greenland sculpin.

Hahits: This and the very many similar small sculpins of shallow, rocky
shores lie motionless to ambush all sorts of small animal prey. It lays its adhesive
eggs on or under rocks and guards therti until hatched.

GREENLAND SCULPIN: Mjoxocefhalus scorfius

Size: Up to 2 feet, but mostly much smaller.

Distribution: The arctic south to Cape Cod, and possibly to New York.

Identification: The separation of this fish from other sculpins is made on the
technical basis of the possession of fourteen anal fin rays and only moderately
long preopercular spines (see Breder, 1948). The color is mottled and variable.

Habits: This is a very voracious fish-eater, which may, at times, be omnivorous,
eating any living thing it can swallow. It is sluggish and can even be touched
while in the water. A grumbling sound may be uttered which is produced by
muscles in the mouth and amplified by the throat cavity. Reddish, adhesive
eggs are deposited in winter among rocks in a spongy mass. The male broods
over them until they are hatched.

Similar Species: There are many abundant East Coast species. Among these
is the sea raven, Hemitrif terns americanns, which has the dorsal fin spines
placed very high anteriorly. It can inflate to some extent like a puffer or a swell
shark when handled. It ranges from Labrador to the Chesapeake, being rare
south of Cape Cod. It is usually a dingy red to purplish, but some are yellow
and are viewed by superstitious fishermen as omens of foul or fair fortune,
depending on the locality (Breder, 1948). The sea raven grows to 2 feet but is
'rarely over 1 foot.

278

UNDERWATER GUIDE TO MARINE LIFE

Sea Robins: Suborder Craniomi

This suborder is clearly a derivative of the mail-checked fishes. The suborbital
bony stay is even better developed in sea robins than in mail-checked fishes, but
sea robins add another characteristic that sets them apart. The pectoral fin is
divided into an upper winglike part and a lower part of several independently
movable rays. With these pectorals and the pelvics, these fishes can perform
an amazing variety of functions. The large pectorals serve as oars (or improbably
as wings for short flights out of water in the most advanced species). The finger-
like pectorals can turn stones, prod about for food, and act altogether like hands.
The pelvics (and lower pectorals as well) serve as legs on which the fish walks
slowly and stealthily when it is on the bottom. Sea robins are principally
crustacean- and invertebrate-eaters and are found in most temperate and tropical
seas. The colors are often quite beautiful, with red predominating in the tropics.

SEA ROBINS: Family Triglidae

The pectoral is large but not developed into a large wing in these fishes. The
tropical species are usually found in fairly deep water. Some of these are very
bizarre, with long chin barbels and pointed snouts.

CAROLINA SEA ROBIN: Pfionotiis catolmus

Size: Averages 1 foot. Up to IV2 feet.

Weight: Up to 2 pounds.

Distribution: Bay of Fundy to the Carolinas.

Identification: This species is not stronglv marked except for a few blotches.
The chin is black.

Habits: This is mainly a bottom fish which mav be found creeping about
over sand. It moves to deep water in the cold months. It would be of great
scientific interest to photograph this fish in its natural habitat and to make
careful observations of the use of the fins particularlv. This fish lays floating,
nonadhesive eggs in the summer.

Similar Species: There are many species in temperate and tropical waters. Most
of the latter are of deep-water habitat. The southern sea robin, Prionotus trihuhis,
is a very common Gulf of Mexico and South Atlantic shallow-water form. It has
three or four dark, blotchy, vertical bars on a yellow-tan ground color.

MASTERS OF THE WATER-BONY FISHES

279

Fig. 157. Flying gurnard.

FLYING GURNARDS: Family Dactylopteridae

These fishes have very large, winglike pectorals which, when folded back,
reach nearly to the tail. They are of tropical distribution. The coloration varies
with the surroundings. The ground color is usually olive or brownish, and the
pectoral fins are mottled.

FLYING gurnard: Dactyloptevus volitans

Size: Up to 1 foot.

Distrihution: West Indies to Cape Cod. Rare to the north.

Identification: Same as for family.

Habits: This is, as Beebe and Tee-Van (1933) say, the most versatile of fishes.
It can walk, use its fins as hands, feet, or oars, and, of course, swim. The special
adaptations of this suborder reach their epitome here. Otherwise, the habits are
similar to the sea robins. Beebe and Tee- Van (1933) say that they are able to
glide. Breder (1948) adds that the flight is not as long as that of flying fishes.
Longley and Hildebrand (1941) doubt that this fish can fly, since "the pectorals
are so thin and flexible that the fin droops almost of its own weight." They can
walk on their pelvic fins better than the sea robins can and are most often seen
propped up or moving on these fins over sandv bottoms in shallow water. The
activities of gurnards may deserve even more careful observation in their natural
habitat than those of the sea robins.

Gobies: Suborder Goboidei

This is a distinct group of unclear relationships. Typical gobies have no lateral
line and have the ventral fins united into a sucking disc. The spiny and soft
dorsal fins are typically distinct, and the soft dorsal and anal fin reflect each
other in size and shape. In all of these respects, gobies differ from the very
similar blennies, but the best way to tell gobies and blennies apart is not,
in most cases, anatomical. Gobies are much less eellike in shape than blennies
and their movements are likewise much less serpentine. They are frequently
seen propped up, or adhering by their ventral fins, on sand and mud flats, rocks,
reefs, or in tidepools, but their movement is very quick and of a darting nature,

280 UNDERWATER GUIDE TO MARINE LIFE

almost jerky in contrast to the blenny's quick, but more flowing, wavelike
motions. Gobies cannot walk on their ventral fins as blennies can.

This is as confused a group regarding its names as one is liable to meet. There
are hordes of species found in tropical and temperate zones the world over, both
in salt and fresh waters. Furthermore, males and females not only difi^er from
each other in colorations, but also change their colors widely in response to
emotional as well as environmental stimuli. In spite of these difficulties, these
are among the most rewarding of fishes to study. They are small, unafraid,
common in shallow water, can be approached closely, and have remarkable
courtship and breeding behavior. In all these respects they parallel blennies
ecologically. Several of them show a marked tendency to become semiterrestrial.
They can trap water in their gill chambers by means of a membrane and thus
they can live for several hours out of water. Fishermen are able to keep some
species alive for a week stored in damp seaweed.

Gobies "home" to a particular spot and have good memories for their home
territory.

If the swimmer remains stationary in the presence of gobies, they will soon
grow accustomed to him and may even use parts of his body as vantage points.

Gobies have elaborate courtships. The male selects a hole in the reef or rocks
or a shell or even builds a house of mud and sand. Then he entices a female to
his lair by means of peacocklike displays of fins and movements. The female lays
eggs and departs. The male may then fickly entice one or more additional
females to lay eggs in the same fashion. Then the male guards his precious
horde, being extremely intolerant of intruders and not eating until the eggs are
hatched.

These pert, lively, somewhat irascible little fishes are rarely over 6 inches in
length. One of them matures at half an inch. The largest reaches 2 feet. Most
are able to survive in very stagnant water. They are fiercely carnivorous on small
invertebrates and range throughout tropical and warm temperate seas.

GOBIES: Family Gobiidae

MAPO (sheep's head MOLLY miller) : Bathygohtus sof orator— Color Plate 3

Size: Up to 6 inches. Mostly much smaller.

Distrihtition: West Indies north to Cape Hatteras. Western coast of Mexico.

Identification: The five pectoral rays on the dorsal side of the pectoral fin
separate this fish from all other gobies. The color is variable but is usually pale
gray to green or brown with mottlings or vertical bars. When over light bottoms
or when alarmed, the fish assumes a very light phase.

Habits: This fish is very common in shallow waters and tidepools throughout
its range. It is a typical goby in size, shape, and habits. This is the species that
has been the most studied of the gobies. Aronson (1951) made a fascinating study
of its homing and leaping behavior. He noticed that mapos frequently leap un-
erringly from tidepool to tidepool, even though they could not possibly see where
they were going to land due to the steep sides of the tidepool from which they
leapt. The leap is accomplished by an extremely rapid straightening of the tail.
Aronson says that this accurate jumping does not result from trial and error
learning, but "it is suggested that these gobies swim over the tidepools at high

MASTERS OF THE WATER-BONY FISHES

281

tide and acquire an effective memory of the general features of the topography
of a Hmited area around the home pool which they are able to utilize when
locked in their pools at low tide."

Tavolga (1954) has studied the complex breeding behavior of this fish, which
seems to be fairly typical of gobies and also of blennies. The male fishes are
vigorous in their protection of a home territory, which is usually a small area
surrounding some crevice or hole in the rocks. They may even choose a shell
or tin can as a home and can be captured by placing empty cans in waters where
gobies are found. Usually they show colors that somewhat match their environ-
ment, but at times of fighting between males or mating, dark, background-
contrasting colors are put on. Fighting males also show "throat-puffing, gasping,
quivering, butting, and biting movements." After a site is chosen, it is cleaned
bv the male. He then approaches the female with a vibrating motion of the fins
and tail, and both male and female change colors with their emotional state.
The female enters the nest cavity twelve to twenty-four hours before laying her
15,000 to 18,000 eggs, a feat that takes three to nine hours. The female departs,
and the male guards and fans the eggs. Females can lays eggs every seven to
sixteen days. With a fall in water temperature,, the male will brush the eggs
vigorously to induce hatching five to seven days after the eggs were laid.
Tavolga says, ". . . the natural temperature stimulus may be the inundation
of the tidepool bv cooler water by a rising tide. This would insure a wider
dispersal of the pelagic larvae by the tidal water current."

Similar Species: Other small gobies are found north to Cape Cod. On the West
Coast there are numerous similar species found south of Vancouver. Most
West Coast forms are small (up to 3 inches) and are most common in bays
and on mud flats.

sleeper:

Dormitator maculatus

Size: The largest goby, up to possibly 2 feet. Mostly under a foot.

Distrihution: West Indies to South Carolina.

Identification: The mulletlike shape, large size, and gobylike fin pattern
identify it. Its colors are extremely varied.

Habits: The sleeper can live in salt, brackish, and fresh waters. Like the
killies, it can stand a wide range of pollutions and temperatures, so it makes a
good aquarium pet. In spite of the large size, its habits are like those of the
smaller gobies.

Fig. 158. Sleeper.

282 UNDERWATER GUIDE TO MARINE LIFE

Fig. 159. Shark remora.

Remoras: Suborder Discocephali {"disc head")

These remarkable, elongate fishes are easily recognized. The top of the head
bears a laminated disc by which means these fishes are able to attach strongly
to sharks, rays, large fishes such as spearfishes and barracudas, sea turtles, or
other large animals for the purpose of securing a ride. They are not parasitic,
but just hitchhikers which share in the scraps left by large predators. They are
swift swimmers in their own right (as they have to be able to pick up their
rides) but probably cannot travel long distances by themselves. They are rarely
seen unattached. The strength of this sucker is remarkable. In order to capture
turtles, West Indian natives pay remoras out on a line and allow them to attach
to the turtles (Beebe and Tee-Van, 1933). Most of the species are cosmopolitan
in warm seas and all are carnivorous.

REMORAS: Family Echeneidae

SHARK REMORA (sucKFiSH, pegador) : Echeneis naucrates

Size: Averages 18 inches. Up to 3 feet.

Weight: Up to 2 pounds or more.

Distribution: Cosmopolitan in warm seas.

Identification: The color is gray with a wide, longitudinal black band.

Hahits: This is the largest of the remoras. It is most often seen attached to
large sharks or other large fishes. Other smaller species attach to smaller fishes
for free transport.

Trachinoids: Suborder Trachninoidei

This group contains a large assemblage of fishes which defy exact definition.
Just as the species of the order Mesichthys are transitional from primitive bony
fishes to the spiny-rayed fishes, the trachinoids are transitional from spiny-rayed
fishes, which have ventral fins placed in the thoracic (chest) position under the
pectoral fins, to the fishes with the ventral fins placed in the jugular (throat)
position. None of the families have many species.

BLANQUILLOS: Family Malacanthidae

These are mostly tropical fishes of world-wide distribution. A few are found
in temperate zones. They are elongate and compressed with long, low dorsal
and anal fins. The colors are silvery or whitish with overtones of yellow and
green.

SANDFiSH (wHiTEY, BLANQuiLLo) : Molaconthus fluiuieri
Size: Averages about 1 foot. Up to 2 feet.

MASTERS OF THE WATER-BONY FISHES 283

Fig. 160. Sandfish.

Distribution: West Indies to Florida.

Identification: This is an elongate, almost eellike fish. The colors are delicate
and quite beautiful with whitish and pale yellow predominating. There are
canines in the front of the jaws.

Habits: This fish is quite common and is most often seen wending its way
in a rather eellike fashion in and out of holes of reefs near sandy places and
gorgonian beds. It is a feeder on invertebrates.

Sivtilar Species: The ocean whitefish, Caiilolatilus frincefs, is found inshore
among rocks from Monterey to the tropics. It grows to over 3 feet. In shape it
is like a deep-bodied sandfish, and it has a rather small mouth.

The tilefish, Lopholatilus chaynaeleonticefs, is an offshore fish which feeds
in the deep water near the outer continental shelf. Its ground color is whitish;
numerous blue and yellow spots cover the body. Ahead of the soft dorsal fin
on the head is a fleshy, erect tab. It ranges from Maine to the Chesapeake and
averages 3 feet and 30 pounds.

ELECTRIC STARGAZERS: Family Uranoscopidae
This is an odd family, widely distributed in warm seas.

NORTHERN STARGAZER: AstYOSCO'pilS gllttatUS

Size: Up to a little over 1 foot.

Distribution: New York to Cape Hatteras.

Identification: The chunkv body with vertical mouth and eyes on the top of
the head identifies it.

Habits: This fish is much like the anglers in habit. It lies buried in sand with
only the eyes and mouth protruding. A little filament in the mouth looks like
a worm and is wiggled to lure small fish which are then snapped up in the large
jaws. These fishes lay floating eggs in the summer. The stargazer can deliver
a noticeable electric shock. The electric organs are formed by modified optic
nerves.

The habit of lying buried in sand presents a difficulty in breathing, since
water entering the mouth would bring sand with it. This problem has been
solved in this fish by passing water in and out through its nostrils, which are
connected to the throat cavity by a tube. These are the only fishes in which
the nostrils are not a blind pouch used for smelling only.

Similar S-pecies: The southern stargazer, Astroscopus y-graecum, replaces the
northern species south of Cape Hatteras and is found over the West Indies.

284

UNDERWATER GUIDE TO MARINE LIFE

Fig. 161. Southern star gazer.

Jugular Fishes: Suborders Haplodoci, Xenopterygi, Blennoidei,
Ophidioidei, Anacanthini

Several suborders, listed above, all have one feature in common, the jugular
(throat) position of the ventral fins. This position is more concerned with the
internal bony support of these fins than with their outward appearance, so it
cannot invariably be used as a field character. These suborders are so different,
however, in many other respects that they cannot be included in any one
suborder (Jugulares) as they were several years ago. Nowadays, the term
"jugular fish" is most often used to designate the last order mentioned, the
Anacanthini, including the cods and lings. Nevertheless, the general trend of
the bony fishes to move the ventral fins forward reaches its culmination in these
suborders. The authors believe that these suborders should be grouped under
the common name of "jugular fishes" without any single suborder name being
set aside for them. Several of the jugular suborders show a tendency to be
northern in distribution and somewhat degenerate in form.

Toadfishes: Suborder Haplodoci

These are sculpinlike, bottom fishes which lie concealed or buried on sandy,
weedy, or rocky bottoms. They may be distinguished by the great reduction of
the spiny dorsal fin and by the long, soft anal fin. There is one family of
temperate to tropical distribution in North and South America. Some South
American species possess poisonous spines.

TOADFISHES: Family Batrachoididae

toadfish: O'psanus tau

Size: Averages 8 to 10 inches. Exception^ally to 15 inches.

Weight: Exceptionally to 2 pounds.

Distribution: Maine to the West Indies. Most common from Cape Cod to
Cape Hatteras.

Identification: This fish has no scales and appears to be almost all head. It is a
mottled brown and yellow-brown. From the lower lip are hung fleshv tabs, which
probably serve to break the outline of the menacing jaws.

Habits: This is a slugoish fish and is verv common hiding among rocks, weeds,
and rubbish, from which vantage it darts quickly out at its prey. Gill (1907)
states that toadfishes eat a wide variety of animal food, and it is the authors'

MASTERS OF THE WATER-BONY FISHES

285

Toadfish.

Fig. 163. Midshiftnan.

experience that just about anything of proper size will be swallowed. This
pugnacious fish will not usually retreat before the underwater swimmer, but
will threaten by opening its mouth and it will snap quite freely at fingers
thrust its way, being able to give a painful bite with its powerful jaws. Toadfishes
may be easily captured by thrusting a blunt stick into their jaws, whereupon
the fish takes a firm hold and may then be netted. When so disturbed, a toadlike
croak is usually uttered. The breeding season is late spring or early summer.
The adhesive eggs are fastened to a stone, tin can, or similar crevice and are
guarded by the male, whose natural pugnacity is magnified at that time.

MIDSHIPMAN (bagre sapo, SINGING fish) : Ponchthys ]yorosisshnns

Size: Up to about 8 inches.

Distribution: South Carolina to Argentina. Fairly common in the Gulf of
Mexico.

Identification: The shape is distinctive. There are rows of silvery, dark-outlined
pores on the sides and head.

Habits: When captured, this fish makes a peculiar vibratory, humming sound
with its air bladder, which accounts for the name "singing fish." In habits, it is
much like the toadfish, but it is not as pugnacious.

Similar Species: The California singing fish, Porichthys notatiis, is very similar.
It is found off the coasts of California.

Cling Fishes: Suborder Xenopterygi

These are extremely tadpolelike fishes. Briggs (1955) has monographed them,
stating that this suborder of odd fishes is probably most closely allied to the

286 UNDERWATER GUIDE TO MARINE LIFE

Haplodoci (toadfishes). They are scaleless, covered with a thick coat of mucus
(probably a protective device w^hich renders them very sHppery), and have the
ventral fins united into a sucking disc, allowing them to maintain their position
adhered to rocks in streams or in shallow seas. Their flat shape offers little
resistance to currents or waves, so they are often found in places where the water
is quite rough. There are less than a hundred species, of world-wide distribution
in warm seas. They are usually not numerous and are hard to see. One odd,
elongate clingfish of the Indo-Pacific hides habitually among the spines of a sea
urchin. In size they range from less than an inch to 10 inches. There is only
one family.

CLINGFISHES: Family Gobeisocidae

clingfish: Gohiesox strumosus

Size: Up to 4 inches or more.

Distrihiition: Chesapeake Bay to the West Indies.

Identification: Same as for the suborder. The color is a dull monotone of dark
gray to brown, as it is in many clingfishes.

Hahits: Clingfishes spend most of their time adhering to rocks or other hard
items of substrata. They eat crustaceans and other invertebrates, and probably
some plant matter as well.

Similar Sfecies: This genus is confined to the New World, four species on
the Atlantic side and twenty-two species on the Pacific. All are very similar and
range throughout the American warm temperate and tropical zones.

Blennoid Fishes: Suborder Blennoidei

The three families of blennoid fishes are largely of arctic and tropical seas,
being curiously scarce in the temperate zone. Most are small, and there is a
definite tendency for them to become elongate and eellike, and to adopt
burrowing habits. The dorsal and anal fins are long and continuous. The ventral
fins are slender, not united in a sucking disc, and are placed far forward. Some
blennoids even lack ventral fins.

BLENNIES: Family Blennidae

These are small arctic or tropical fishes which are sometimes scaleless and
eellike (particularly the arctic species). Much that has been said of the tropical,
shallow-water gobies also applies to the tropical, shallow-water blennies, of
which there is a huge array of prettily colored species with fascinating habits.
They resemble gobies in being common in shallow water in tidepools, coral
reefs, and rocks, and in their habit of appraising their surroundings from a
position propped up on their ventral fins. They also show resemblance to gobies
in their equally as fascinating social and breeding behavior, their tendcncv
toward semiterrestrialism, their alertness, and lack of fear, and their accessibility
for study by the swimmer. They differ from gobies in their more flowing
serpentine movements and shape, their slender ventral fins on which thev prop
themselves up, and their continuous dorsal fin. The ventral fins are used like
feet in walking or even like hands in manipulating objects. The authors have
had blennies fearlessly crawl over their bodies using these ventral fins.

MASTERS OF THE WATER-BONY FISHES 287

Like the gobies, blennies can live a very long time out of water, providing
they are kept moist. Some of them even have the habit of sun-bathing out of
water on rocks or mud flats. When approached, they will leap back into the water
with a flick of their tails. In or out of water they have excellent eyesight and hunt
their invertebrate food bv sight. Their large eyes and active movements make
them appear to be rather intelligent. It should not be hard to test their intelli-
gence in their natural habitat, for blennies are quite fearless.

Their colors are quite often extremely attractive, being satiny and smooth
and among the prettiest found in fishes. These colors are quite variable, matching
the environment or correlated with the excitement of courtship. The breeding
behavior is much like that of gobies. The male selects and cleans a hole or cavity
in rocks or weeds for a nesting site. He then entices a female to his lair by
raising and lowering himself on his ventral fins or by brushing at her and even
bumping her with his nose. De Latil (1955) says that occasionally the female
becomes aroused first and reverses the procedure by enticing the male. After
egg-laying, the male guards the nest, being extremely intolerant of intruders,
especially other males of the same species. He fans the eggs until they hatch and
does not eat during the incubation period. It is amusing to watch a male blenny's
reaction to a mirror. He can be driven to an extremelv excited, furious state,
especially if the mirror is presented between him and his nest. Like gobies,
blennies may be caught by placing empty tin cans in areas where they are found.

This is one of the largest and most confusing of fish families. There are five
hundred species ranging in size from an inch or two up to almost 2 feet and
distributed over the entire world, especially in the tropics or the arctic. These
species seem to be almost as confused among scientists as among laymen.
The various adaptive types of blennies are reviewed here, but no attempt is made
to be comprehensive as to species or even genera.

KELP blenny: Heterostichiis rostratus

Size: The largest blenny. Up to 2 feet.

Distribution: San Francisco to Baja California.

Identification: The head is long and low in contrast to most blennies. The color
varies with environment; it is brown in seaweed and barred with green in
eelgrass.

Habits: This is a fish of the rocky, kelp- or seaweed-covered shores. Just as the
largest sea horse is found among the largest seaweeds, the kelps, it is probably
no coincidence that the largest blenny is also found in that giant forest. Strings
of eggs are bound around seaweeds and guarded by the male. The habits are not
significantly diff^erent from those of smaller, tropical blennies.

MOLLY miller: Blennius cristatus

Size: Up to 4 inches.

Distribution: Florida to Brazil.

Identification: The comb on the top of the head identifies this small species.
The colors are variable; they are often in a series of bands. The shape is similar
to the blenny shown on Color Plate 3.

Habits: This is one of the tvpical, small, shallow-water or tidepool species that
are mostly of tropical seas, though some do get into warm temperate waters.
These species are very hard to separate from each other. Some of these are semi-

288

UNDERWATER GUIDE TO MARINE LIFE

Sarcastic hlenny.

^^^^^^^

Fig. 165. Rock eel.

terrestrial in habits, sun-bathing on rocks or mud flats. All are alert, big-eyed, and
have the typical blenny stance, propped up on the slim ventrals, which are also
used in "walking."

SARCASTIC blenny: Ptewgnathiis satiriciis

Size: Up to 9 inches.
Distribution: Monterey Bay to San Diego.

Identification: The large mouth caused by the extreme elongation of the
maxillary, or upper jawbone, identifies this odd blenny.
Habits: The habits are like those of other small blennies.

ROCK EEL (gunnel) : PhoUs giinelliis

Size: Up to 12 inches, but mostly much smaller.

Distribution: Arctic south to Cape Cod, straggling to New Jersey.

Identification: The long, eellike shape and the tail fin which is separate from
the dorsal and anal fins identify the various species of rock eels. The ventral fins
are extremely small. The color varies from greenish brown to red.

Habits: These eellike blennies are tvpical of arctic and cold temperate
members of this family. This shape is adapted to a secretive life on rockv shores.
One of the authors found a very plentiful similar species among rocks and stones
in the tidal zone on southeastern Alaskan shores. Almost every stone that was
turned yielded one or more. Rock eels are exceptionally slippery and agile,
however, and are more difficult to catch than they would seem to be at first
sight. They feed mostly on small invertebrates and lay eggs in a cluster in their
rocky home. Breder (1948) states that one of the parents apparently coils itself
around the incubating epRS.

Similar Species: There are several West Coast species found south to Cali-
fornia. Elongate, eellike blennies of several other kinds are also found in northern
waters, but very little is known about them.

MASTERS OF THE WATER-BONY FISHES

289

WRY MOUTHS: Family Cryptocanthodidae

These are arctic and north temperate fishes which are very eelHke and which
lack both ventral fins and lateral line. The tail fin is joined to the dorsal and
anal fins. The gill openings are large, a characteristic which separates wry
mouths from true eels.

WRY mouth: Cryptocanthodes macidatus

Size: Up to 3 feet.

Distribution: South to Cape Cod, straggling to New York.

Identification: Same as for the family.

Habits: This is a heavy-jawed fish which feeds on the larger invertebrates and
fishes, which it probably ambushes. It lives at the bottom, particularly in mud,
in branching burrows.

WOLF FISHES: Family Anarhichodidae

These are the largest blennoid fishes. They are of northern distribution in the
Atlantic and Pacific and of eellike appearance. The jaws are large, extremely
powerful, and armed with an impressive array, of teeth, pointed in the front
of the mouth and molarlike in the rear. There are no ventral fins. These are
extremely voracious fishes which can be very dangerous to handle.

COMMON WOLF FISH: Anavhichas liifus

Size: Up to 5 feet.

Weight: Up to 30 pounds.

Distribution: South to Cape Cod, straggling to New Jersey.

Identification: The body is crossed by nine to twelve dark bars.

Fig. 166- Wry month.

Fig- 167- Common wolf fsh.

290 UNDERWATER GUIDE TO MARINE LIFE

Habits: The food, as would be indicated by the very heavy, powerful molars,
consists mostly of hard-shelled molluscs and crustaceans. Like many other
northern fishes, its spawning season is in winter.

This fish is pugnacious, and care should be taken in approaching it under
water. Wolf fishes are mostly sluggish and nocturnal, but don't be fooled by
this. They will bite, and very painfully, too.

Similar Sfecies: Several other species are found in the Atlantic. On the
Pacific Coast wolf fishes are found south to Monterey, California, to which
point the wolf eel, Anarhichas ocellatus, ranges.

Ophidioids: Suborder Ophidioidei

These are degenerate derivatives of the blennoid fishes. There are no spines
in any fin except a few in the dorsal. There is usually no definable tail fin, the
dorsal and anal fins, with few exceptions, being continuous with it, with no
breaks. In this feature, they parallel the true eels but are unlike true eels in
possessing large gill openings. Several of them are very similar to the eellike
blennies. The distribution of the several families is world-wide from the tropics
to the arctic. All of these fishes are bottom-living. They show a tendency toward
burrowing habits.

EELPOUTS: Family Zoarcidae

The ventral fins of these fishes are small and placed at the throat. They much
resemble the eellike blennies in habits and appearance but are larger. They are
found in both the Atlantic and Pacific in the arctic and north temperate zones.
Some eelpouts give birth to living young.

SHORE eelpout: Zoarces anguillaris

Size: Up to 3Vi feet. Uncommon over IVi feet.

Weight: Up to 12 pounds.

Distribution: North temperate waters south to Delaware.

Identification: This is one of the few ophidioids which has discontinuous
dorsal and anal fins.

Habits: The movements of this fish are snakelike. It lives among stones in the
tidal zone or in shallow water, and in the summer it moves to cooler waters
offshore. It eats large invertebrates and fishes.

Similar Sfecies: Several West Coast species are found from the arctic south
to southern California.

CUSK EELS: Family Ophidiidae

These are very similar to eelpouts, but they are usually small and range in the
deeper waters of warm or tropical seas. The ventral fins are very far forward,
appearing to be two long barbels under the chin, and are used as tactile organs
to find food. Though there are several species found the world over, they are
apparently not common anywhere— but this may only be a consequence of their
secretive habits, which prevent them from being observed. Most species reach
a maximum size of 1 foot, but one species of South Africa reaches 5 feet.

MASTERS OF THE WATER-BONY FISHES

291

Fig. 168. Shore eelpont.

Fig. 169. Northern slippery dick.

Fig. 170. Pearlfish.

NORTHERN SLIPPERY DICK: Rissola viaroinata

Size: Up to 6 inches.

Distribution: New York to the Gulf of Mexico.

Identification: Same as for the family.

Habits: This fish is a burrower in shallow sandy shores. It probably eats
invertebrates.

Similar Species: Several Atlantic species are found in the West Indies and
north in warm temperate waters. On the West Coast several species range north
to southern California. Herald (1953) reports that a spotted cusk eel, Oto-
phidiiim taylori, adapted to captivity quickly. He says that this fish adopts a
position standing on its tail on the tank bottom and customarily enters hiding
places tail first as does the pearlfish.

PEARLFISHES: Family Fierasferidae

These are among the most specialized and interesting of fishes because of their
habit of living nonparasitically in the mantle cavities of oysters, where they are
sometimes trapped and covered with mother of pearl by their host, or, more
often, in the cloaca of a sea cucumber, especially the beche-de-mer. These are
small fishes with large heads and a body that tapers off to a point behind. There
are several species of the single genus in tropical seas. They are pearly in color
and semitransparent.

pearlfish: Fierasfer affinis

Size: Up to 5 inches. Usuallv smaller.

Distribution: Florida to the West Indies.

Identification: Same as for the family.

Habits: This fish lives symbiotically in the cloaca of sea cucumbers, or in the
shells of molluscs. It is not a parasite, but merely uses these retreats as a home,
as a blenny might use a tin can or rock crevice. At night, thev wander from these
homes to search out their invertebrate food. They may be captured bv collecting
large sea cucumbers and examining them with a probe or cutting them open.
Linton (1907) placed a pearlfish in a dish with a large, living sea cucumber and
observed that the fish hunted around the dish aimlessly until contact with the
sea cucumber was rriade, then forced its way, tail-first, into the cloaca, a feat
taking about thirty seconds.

292

UNDERWATER GUIDE TO MARINE LIFE

hake.

Hakes and Gods: Suborder Anacanthini

These are mostly northern and deep-sea fishes. There are no spines in any of
the fins. The vertical fins have been derived from a single, continuous dorsal-
caudal-anal fin by breaking this fin into sections. Typically, these sections appear
as multiple dorsal and anal fins with a single caudal fin. However, in some eel-
like forms such as cusks, there are only single dorsal and anal fins. The better-
known members of this suborder are large, voracious fishes, which tend toward
bottom feeding.

HAKES: Family Merluccidae

This is a small group of the North Atlantic, North Pacific, and Ghilean waters.
All the species are extremely voracious, large-mouthed feeders on fishes and
larger invertebrates, such as squids and large crustaceans. There are no barbels
on the chin. The dorsal fin is divided in two parts (the second part is long and
appears to be divided); the anal fin is single. The build is pikelike, and the color
is a dull silver-tan.

SILVER HAKE (whiting) : Merlucchis hilinearis

Size: Averages a little over 1 foot. Up to 2 feet.

Weight: Averages a little over 1 pound.

Distrihiition: From the Grand Banks off Newfoundland to the Bahamas, in
deep water.

Identification: Same as for the family.

Hahits: This is a schooling dish, most common over sand or pebble bottoms. It
comes nearest to shore in autumn during the breeding season, when it lays
several thousand pelagic, nonadhesive eggs. It ranges through a great depth of
water from the surface to 1,500 feet, in other words, through the whole of the
lighted zone of the sea.

Similar S-pecies: The California hake, Merhiccius prodiictiis, is found from
the Gulf of Galifornia to Puget Sound. It is abundant in water of moderate
depth and reaches a length of 3 feet.

CODS: Family Gadidae

These fishes of the North Atlantic and North Pacific seas have a single chin
barbel, a large mouth, and feed mostly near the bottom on a wide variety of
animal foods. They are all extremely prolific, laying pelagic, nonadhesive eggs,
sometimes literally by the millions. Most of the species travel and feed in very
large roving schools and are the object of important fisheries. Some of the deep-
water forms have single dorsal and anal fins, but the well-known species have

MASTERS OF THE WATER-BONY FISHES

293

Fig.. 172. Cod.

three dorsals and two anals. There is a tendency for these fishes to keep to
moderately deep water.

cod: Gadus callarias

Weight: Commonly to 25 pounds. Rarely from 60 to 70 pounds. Known to
reach 200 pounds.

Distrihution: Greenland to Cape Hatteras. Very abundant from Newfound-
land to Cape Cod the year round. Goes offshore in warm months to the south
of its range.

Identification: Three dorsal fins and two anal fins, all spineless. The lateral
line is paler than the rest of the brownish body. (Small cods are reddish and are
called "rock cod.") The tail fin is squared off.

Habits: This exceedingly voracious fish travels in huge roving schools and
feeds on small fishes and invertebrates, mostly over rocky or sandy bottoms. Cods
come inshore in shallow water but also range in waters as deep as 1,500 feet.
This fish is immensely prolific. A large female of 70 pounds has been estimated
to produce about 9 million eggs, only about one seventieth of which ever
reach the hatching stage, so harsh are the environmental forces of destruction of
pelagic eggs. Spawning is probably indiscriminate, since no breeding pairs are
formed. The school itself forms the breeding unit. Cods occasionally get land-
locked in fresh water, where they become extremely large-headed and canni-
balistic.

Similar Species: The Alaska cod, Gadus macrocephaliis, ranges from the Bering
Sea to Oregon and is very similar to the Atlantic species.

The pollack (Boston blackfish), Pollachins virens, ranges south to Long Island
and reaches 3V2 feet and 35 pounds, but it averages only 4 to 5 pounds. It feeds
closer to the surface than most members of the family. It is most easily recog-
nized by its lustrous greenish-brown color, white lateral line, and forked tail fin.

The haddock, Melanogravimiis aeglifinuSy has a black lateral line and a dark
spot behind the pectoral fin. It ranges south to New Jersev and to Cape Hatteras
in deep water and averages 3 to 4 pounds, reaching 25 pounds rarely. Finnan
haddie is made from haddock.

The tomcod, Microgadus tomcod, is a dwarf species reaching only 15 inches
in length. It ranges south to Virginia and may be recognized by the rounded
tail fin and comparatively long ventrals, the first ray of which is extended like
a filament. It is a shore fish, especially in early winter when it spawns, some-
times ascending rivers for this purpose.

294

UNDERWATER GUIDE TO MARINE LIFE

Sqiiirrel ling.

The California tomcod, Microgadiis inoximus, is found from Monterey to the
Aleutian Islands.

SQUIRREL ling: Phjcis chiiss

Size: Up to 21/2 feet.

Weight: Up to 8 pounds.

Distribution: From the St. Lawrence to Virginia.

Identification: The shape is elongate, with two dorsal fins, the second much
longer than the first. There is a single anal fin. The ventral fins are long and
slender and reach the anal fin.

Habits: This fish keeps close to the bottom in waters from moderate depths
to 1,800 feet. Its food consists mostly of small crustaceans and fishes. It lays float-
ing eggs, and the young supposedly seek shelter in the mantle cavity of the
ocean scallop. Pectin gigantea.

Similar Species: There are many species of elongate cods, all of which have
the codlike head and single chin barbel, and which have only one or two dorsal
fins and are usually nonschooling fishes of deep waters out of the range of the
diver. The lings, Phycis, form the largest and most common group of these and
are, perhaps, most likely to be encountered. Also included are the rocklings,
burbots and cusks. (We must refer the reader to the Bibliography for identifica-
tion of these.) They range from the arctic south to the Gulf of Mexico. The
elongate forms of the Pacific are of deep-sea waters.

Flatfishes: Suborder Heterosnmota {"differing body")

The suborder name is a masterpiece of understatement, for these fishes differ
completely in body symmetry from all other fishes. Their head is twisted so that
both eyes are on one side. If the eyes are on the right side, the fish is said to
be "dextral." If the eyes are on the left side, the fish is said to be "sinestral."
Occasionally, a single species shows both dextral and sinestral indixiduals (the
starry flounder, for instance). Some efforts have been made to correlate tem-
perature with the presence of eyes on one side or the other. The eyed side of
flatfishes is the up side, both when the fish swims and when it rests on the
bottom. This side is pigmented, while the down side, or blind side, is white.
Flatfishes are among the most adept of all fishes at changing their colors to match
their environments. The color and texture of the substrate are matched very
closely as they lie motionless on the bottom waiting to ambush their prey. (The

MASTERS OF THE WATER-BONY FISHES 295

color photograph shows this adaptive coloration to a remarkable degree in one
of the small tropical species.) It is even possible for these fishes to assume checker-
board or polka dot patterns when placed on such a background.

Flatfishes do not rest flat against the bottom as might be supposed, even though
they sometimes partly bury themselves. They support themselves slightly off
the bottom on their decurved dorsal and anal fins. This is done to allow water
to pass more easily out of the gill opening on the blind side and also to allow
quick getaway after prey (Orcutt, 1950). These fins may also be used for crawl-
ing either forward or backward slowly on the bottom by use of wavelike manipu-
lations of the fin rays. In swimming in open water, the pectoral and tail fins are
used. Flatfishes prefer soft bottoms such as sand or mud or fine gravels.

These are all highly carnivorous fishes. Some of them have heavy pharvngeal
teeth with which they can crush hard-shelled molluscs and crustaceans.

It is not clear what the relationships of flatfishes are. They have no fin spines
and might have been derived from primitive berycoid stock. They are found
in all seas, but they predominate in temperate zones. There are many species
that are difficult to tell apart.

FLOUNDERS: Family Plcuronectidae

The eyes are large and well separated and the mouth is large and toothed in
these fishes. The family may be divided into three distinct parts— the halibuts,
the flounders, and the turbots. In the first two, the ventral fins are symmetrical,
while the turbots have dissimilar ventral fins. The halibuts have large sym-
metrical mouths and are the largest members of the family as well as the most
primitive. They may be either sinestral or dextral. The flounders have asvmmet-
rical mouths and are mostly dextral fishes. The turbots, as well as having asvm-
metrical ventral fins and mouths, are usually sinestral, \'ery round in outline, and
small in size.

The common names of these fishes are much confused. On our Atlantic Coast,
"sole" refers to a member of the flounder group. The following are examples from
each of the major groups— halibuts, flounders, and turbots.

HALIBUTS

PACIFIC halibut: Hippoglossus stenolefis

Size: Reaches 8 feet.

Weight: Reaches 700 pounds. Rare over 400 pounds.
Distrihition: Bering Sea and Alaska south to California.

Identification: Dextral. This fish is usually a plain brownish to gravish color.
Halibuts are not as deep-bodied as most flatfish.

Atlantic halihitt.

296

UNDERWATER GUIDE TO MARINE LIFE

Habits: This is a giant fish which, probably because of its size, pursues its food
through open water more than do other flatfishes. Halibut are found in shallow
to deep water over mud or sand bottoms and are the object of an intensive fishery.

Similar Species: The Atlantic halibut, Hij^iioglossus hip-poglossus, ranges from
the Arctic Ocean to New Jersey. In the southern part of its range, it keeps to
deep water.

NORTHERN FLUKE (suMMER flounder) : ParaJichthys dentattis

Size: Up to 4 feet.

Weight: Averages 3 pounds. Common to 10 pounds. Up to 25 pounds.

Distribution: Cape Cod to Cape Hatteras.

Identification: Sinestral. Brownish and mottled with black and white spots.

Habits: The food consists of a wide variety of large invertebrates and fishes.
This fish comes inshore in the summer months. It prefers sandy bottoms near
beds of vegetation or sandy spots among vegetation and is most often seen partly
buried with only the head showing. The beadv eves protruding from the head
give this fish away to the diver.

Similar Species: There are several allied species found south to the Gulf of
Mexico. The California halibut, Paralichthys calif orniciis, is a greenish brown,
sometimes mottled species found from San Francisco to the Gulf of California.
It reaches a weight of 60 pounds.

///^y-9.

Fig. 175. Northern fiiike.

Fig. 176. Starry flounder, j^-' a.- -^^

FLOUNDERS

STARRY flounder: PlatJchthys stellatiis

Weight: Averages 2 to 5 pounds. Reaches 20 pounds.

Distribution: Coastal waters from Japan to Alaska and south to Santa Barbara
County, California.

Identification: Sinestral or dextral. The body color varies. The dorsal and anal
fins are orange-tinted, marked with several conspicuous dark bars.

Habits: Orcutt (1950) studied this fish in detail. The starry flounder rests on
various bottoms, but it avoids rock and is most common o\'er soft sand. It buries
itself in the bottom bv flutterina the dorsal and caudal fins, thus disturbing the
sand, which then falls back on its body. If disturbed, it will not mo\'e, for it

MASTERS OF THE WATER-BONY FISHES

297

Fig. 177. Winter flounder.

Fig. 178. Sand dab.

depends upon its protective concealment for defense. If the disturbance con-
tinues, it will burv itself more deeply or, finally, swim rapidly away.

When starrv flounders are first born, their food consists of plankton. At a
medium size, they ambush prey from the bottom, but as larger size and maturity
are reached and their heavy pharyngeal teeth have developed, they spend more
time hunting openly for crustacean or mollusc food. This is a good example of
the change in habits that almost invariably accompanies growth (Chapter 2).

The spawning season is winter. As many as eleven million eggs may be laid
by a large female. This fish is found from depths of zero to 1 50 fathoms and can
stand a wide varietv of salinities. It is one of the most widely distributed of
shore fishes. Throughout its range it shows a tendency to be sinestral in some
waters, such as those of California, and dextral in others, such as those of Japan.
The sinestral form is less common than the dextral.

WINTER flounder: Pseudopleurofiectes aniericamts

Size: Averages about 1 foot. Up to Wi feet.

Weight: Up to 5 pounds.

Distribution: Labrador south to Georgia. Also found in deeper water to the
south.

Identification: Dextral. Mottled like the northern fluke but has no white spots.

Habits: This is the "sole" of the Atlantic. It is inshore in the cooler months
primarily and has habits that are like those of the northern fluke.

TURBOTS

SAND dab: Citharichthys sordidtis

Size: Up to 1 foot.

Distribution: British Columbia to Baja California.

298 UNDERWATER GUIDE TO MARINE LIFE

Identification: The color is brown. The male has orange blotches and dusky-
margined fins, and the female is of a lighter color without dusky margins to
the fins.

Habits: This delicious little food fish is found the year round on sandy shores.

Similar Species: There are a number of species of this genus on the Atlantic
Coast, where they are called "whiffs." They are not usually over 6 inches long.

PEACOCK flounder: Platophrys lunatus

Size: Up to 18 inches. Mostly seen much smaller.

Weight: Up to 2 pounds.

Distribution: Florida and the West Indies.

Identification: There are a number of attractive, small blue spots and larger
dark rings arranged in various patterns. The pectoral is very long and filamentous,
and the shape is like the eyed platefish.

Habits: The spotted pattern of this fish gives excellent concealing coloration
in such places as limestone reefs. It is also found over sand.

Similar Species: There are several turbots ranging in warm temperate and
tropical waters of both coasts which resemble this species. The authors have
seen the eyed platefish, Platophrys ocellatus Qcolor fhotograph\ lying in the
rocks of gorgonian beds. This fish is very well camouflaged, being distinguish-
able only when it moves. It reaches 8 inches and ranges from New York to
Brazil, but it is common only in the tropics.

Fig. 179. Eyed platefish.

SOLES: Family Soleidae

These are the most specialized of flatfishes, represented on our shores bv a
few small species. The true English sole of Europe belongs to this familv. Manv
of the soles are of tropical distribution. None is arctic or north temperate. The
mouth is small and very asymmetrical. The eyes are very small and set close
together, and the body is very round (except for tonguefishes). Thcv arc usualh*
dextral. Soles are uncommon on the West Coast.

HOG CHOKER SOLE: Acliiriis fasciatus

Size: Up to 6 inches.

Distribution: Cape Ann to the Gulf of Mexico.

Identification: There is a pattern on both sides of the bodv. The blind side
is spotted with black, and the eyed side is crossed by dark lines. The pectoral
fins are tiny.

MASTERS OF THE WATER-BONY FISHES

299

Fig. 180. Hog-choker sole.

Fig. 181. Tonguefish.

Hahits: This is a fish of soft sand or mud bottoms. It will enter brackish or
even fresh waters and is omnivorous on invertebrates and sea plants.

Siviilar Species: The broad sole, Achirus harnharti, is a rare fish of Californian
waters. It much resembles the hog choker.

tonguefish: Symphurus plagiusa

Size: About 6 inches.

Distribution: Cape Hatteras to the West Indies.

Identification: Sinestral. The eyes are very tiny, and the shape is distinctive
since there is no definitive caudal fin.

Hahits: This is a fish of sandy shores. It is common in some places and prob-
ably is somewhat omnivorous in food habits.

Similar Species: The West Coast representative is Symphiiriis atricaudus. It
is found from central California to Baja California and is common around San
Diego.

Angler Fishes: Suborder Pediculati

Completing the list of fishes is perhaps the most extraordinary group of all.
The sea "toads," or "fishing frogs" as they are sometimes called, are specialized
for a highly carnivorous existence, but many of them catch their prev in a
unique way. Although several groups of animals employ lures with which they
attract their prey, notably the stargazer and the alligator snapping turtle, no
other animals have this lure attached to a "fish pole." This pole is formed of
the first dorsal spine, which is inserted on the snout and which overhangs the
mouth. These fishes wiggle the lure so as to attract curious small fishes, which
are snapped up when they approach closely.

Not all anglers have such a fish pole, but the dominant ones do, so it is fairly
typical of the family as a whole. With this sedentary mode of fishing, there are

300

UNDERWATER GUIDE TO MARINE LIFE

other changes. The powers of locomotion by swimming are weak. But the powers
of crawHng along the substrate have become well developed. The ventral and
pectoral fins are inserted on angulated, armlike extensions, which makes them
very useful as limbs. The small gill openings are behind the pectoral fin. A third
adaptation is the highly developed concealing coloration and form. Almost always
these fishes are colored to blend with their environment and are very hard to
spot. They are also frequently adorned with frills, tabs, and extensions to help
destroy their appearance as fishes.

It might be suspected that such great specialization in form and habits would
restrict the adaptability of anglers to a few habitats, but such is not the case. The
sea has room for sedentary angling forms in many places; anglers are found all
over the world, from shallow shores to the deep sea, and over many types of
bottoms, from cold temperatures to tropical waters. They are rare, however, on
the West Coast. Many of the deep-sea forms, incidentally, have a luminous lure
on the end of their fish pole.

Not all anglers angle (in fact, some people say that none do, but it would
be hard to explain the fish pole otherwise). Some stealthily stalk their prey, and
even though they may sometimes angle, they do not use this means of capturing
prey exclusively. All anglers, however, must be close to their food before they
are able to suck the food into the huge mouth by a sudden, sucking gulp.

ANGLERS: Family Lophiidae

These are the typical large, depressed angler fishes. They are widespread in
the Atlantic and Pacific Oceans, particularly in the temperate zones.

ANGLER (fishing FROG, MONKFisH, allmouth) : Lofhias piscatorhis

Size: Commonly up to 4 feet.

Weight: Commonly up to 45 pounds. Recorded to 70 pounds.

Distribution: Gulf of the St. Lawrence to Cape Hatteras. Also ranges to the
southern tip of South America, but is found only in very deep water in the
tropics.

Af7gler.

Identification: The shape is distinctive. The bumpy body is beautifullv camou-
flaged to look like a weed or a barnacle-encrusted rock.

Hahits: This is an extremely voracious fish that appears to be all head. The
mouth is huge and beset with large, recurved teeth. This fish angles for fishes,

MASTERS OF THE WATER-BONY FISHES 301

but it also eats molluscs and crustaceans. It has even been known to feed on
diving birds or to take ducks and loons From the surface by swimming up under
them and grasping them from below.

The spawning season is in the late spring and summer. Huge masses of pur-
plish eggs float at the surface. Breder (1948) reports that these masses some-
times weigh as much as 30 pounds or more and measure as much as 1 to 2 feet
in width by 40 feet in length.

Similar Sj)ecies: The West Coast angler, Lophiomus, is smaller than the East
Coast form. It ranges south to the equator and is very rare in the eastern Pacific.
Its normal haunts are the coasts of eastern Asia.

FROGFISHES: Family Antennariidae

These are mostly small tropical fishes, rarelv reaching a maximum length of
over a foot. They are somewhat compressed and probably none of them angle
in order to capture food. Instead they use their very well-developed ventral and
pectoral fins as limbs and stalk their prey as a cat stalks a mouse. The very
highly developed protective coloration and form-breaking indentations on the
body protect them from being noticed by either prey or their enemies. The
teeth and mouth are not as large as they are in the previous family, but these
are still very voracious fishes which will eat nearly anything they can swallow.
Mostly, they are shore fishes, but some live in the floating seaweed, sargasso.
They are common in the East and West Indies.

SARGAssuM FISH: Histuo histrio—Color Plate 3

Size: Up to 6 inches.

Distrihution: Florida to the West Indies.

Identification: Distinguished from other similar species bv having the first
dorsal ray, which is situated on the snout, bifurcate at its tip. The color matches
that of sargassum, or sargasso weed.

Hahits: One of the authors has fed and observed this fish in captivity. It may
be presented a small guppy or other live food in the fingers. After stalking to
within a third of its body length from the food, the sargassum fish opens its
mouth suddenly and the food quickly disappears, drawn into the mouth by a
current of water created by the sudden expansion of the throat cavity. This fish
makes a very interesting pet, but requires large amounts of live food to keep it
alive. Only one should be kept in an aquarium for they are quarrelsome. Gill
(1908) reports that a sargassum fish 6 inches long swallowed a 4-inch sargassum
fish while in captivity. In the wild, it rarely swims but uses its ventrals and
pectorals to clamber about in masses of sargasso weed. It is almost exclusively
confined to floating sargasso weed, especially in the Sargasso Sea. It may drift
far north with masses of this weed in the Gulf Stream. It requires very careful
examination of the weed to find this well-camouflaged fish, although it is very
common there. The eggs are laid in a floating "raft" about 4 inches long. The
eggs of the flying fishes found in sargasso weed were for a long time thought
to be those of this fish.

Similar Species: A rare member of this family reaching at least 13^2 inches in
length is found in warm waters of the West Coast. It is the frogfish, Ayitennarlus
avalonis.

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UNDERWATER GUIDE TO MARINE LIFE

BATFISHES: Family Ogcocephalidae

The pectoral "arms" of these unique fishes are especially well developed.
Their distribution is world-wide on sandy bottoms of warm seas, and they are
often seen in harbors.

BATFiSH (toad, diablo) : Ogcocefholus ves'pertilio

Size: Up to 9 inches.

Distrihution: West Indies to Florida, rarely north to New York.

Identification: Same as for the family.

Habits: The warty, sand-colored body makes this fish very hard to see. It is
flattened and broad so as not to cast a shadow (Chapter 2). The authors observed
this fish in the harbor of Nassau. It crept slowly over the sandy bottom, search-
ing for its food, which might comprise almost any living object of a size which
would fit into the rather small mouth. When approached, it froze; then on close
approach, it spread its pectoral and tail fins, exposing a striking banded pattern.
This is a display designed to focus an enemy's attention on an apparently dan-
gerous part of the body, in other words, an intimidation based on advertisement
(Chapter 2).

Fig. 183. Batfish.

CHAPTER

y^

THE RE-ENTRANTS

Life spread from the place of its origin in the sea up the rivers and to the
marshes and lakes of fresh water. From fresh water, the land became populated,
and reptiles, birds, and mammals came into being. Since each group of animals
tends to evolve by adaptive radiation into all the niches available to it, within the
limits of its own body plan, these higher vertebrate groups have returned to the
sea, each retaining the basic characteristics of its group, however. The sea turtles
and the birds lav eggs on land, and the mammals suckle their young. All breathe
air. But each has also become molded to its watery environment, having paddles,
flippers, or fins for propulsion, and pursuing fish or other harvest of the sea
for food.

The animals included here are those that live and feed in the sea, not those
that spend only a small part of their lives there.

REPTILES: Glass Reptilia

The age of reptiles is over. For 150 million years the earth— air, land, and sea-
was ruled by this scaly clan. Now a remnant, a fascinating remnant to be sure,
remains. These are the snakes, lizards, crocodiles. New Zealand sphenodons, and
turtles. Of these, two groups in North America have marine representatives,
•turtles and snakes. (The American crocodile is not a truly marine representative
since it lives in brackish waters.)

Turtles: Order Testudinata or Chelonia

About 225 million years ago turtlelike reptiles first appeared, having evolved
from a primitive reptile stock. Even at that time turtles were marked by the
beginnings of a shell, consisting of an upper part, the carapace, and a lower one,
the plastron. They lost teeth and replaced these with a horny beak. By the
Cretaceous Period, over 100 million years ago, modern turtles were present.
Shelled and toothless, the turtles have conservatively remained to this day,
spreading over the earth to the ponds and rivers, the deserts, and to the sea.
But while their habits vary greatly, their body form has been remarkably un-
changed. Clumsy as this body may appear, it is persevering. No other air-breath-

303

304 UNDERWATER GUIDE TO MARINE LIFE

ing vertebrate group has lasted more or less unchanged as long as turtles have.
The life span of turtles is not precisely known, but they are probably the most
long-lived of all animals, surpassing ages of 100 to 150 years.

SEA TURTLES: Family Cheloniidae

Sea turtles probably arose from marsh-dwelling, primitive shelled turtles as
long ago as the Triassic Period (over 150 million years ago). They live in the
sea but betray their role as converted land animals by breeding on land and by
breathing air. Their feet have turned to flippers, and the manner of propulsion
is different from fresh-water aquatic turtles since the flippers are not used as
paddles but as "wings." They literally fly through the water. This is an efficient
mode of progression since these turtles are able to cover 100 yards in 10 seconds
and thus qualify as the speediest of reptiles, with the possible exception of some
desert lizards. (The leatherback turtle, of a different family, is probably even
faster than these.) On the fore-flippers of the male is a single claw used to grasp
the female during copulation. This claw can inflict a painful wound on the
unwary. Males also have a long tail.

For all turtles, enclosure within a shell poses a respiratory problem. Since the
lung cannot expand within a rigid box, the exposed areas of skin around each
of the four legs act as little diaphragms, expanding for inhalation. But in the
case of sea turtles, the shell has been somewhat reduced, and the plastron has
a longitudinal hinge which does, in fact, allow the chest to expand so that great
quantities of air can be inhaled for prolonged submersion. The authors have
held young hawksbill turtles in their hands and have found this accordionlike
expansion to be marked on inhalation.

Sea turtles come onto land to lay eggs and thus expose themselves to the hard-
ships there, particularly the danger of that rapacious carnivore, man. In the late
spring and summer primarily (some sea turtles breed the year around), the
females, heavy with eggs, drag themselves onto a sandy shore. There, above the
high-water mark, a neat little hole is delicately dug with the hind flippers and
up to three hundred eggs are laid, a record for turtles. Then the hole is filled
in, and the fore-flippers aid in generally disturbing a large area of sand so that
the exact location of the nest is obscured. During the whole time, the mother's
eyes secrete tears profusely as if the whole project were breaking her heart, but
this wetness is probably only to protect the eyes, which are accustomed to salty,
aqueous surroundings. Then she drags herself, exhausted, back to the sea. The
young, only an inch or so in carapace length, hatch at summer's end and head
away for a precarious life at sea, where mortality is high. They are eaten by
crabs, sea birds, and fishes. At these egg-laying periods, the females are often
caught, and eggs are confiscated by man. Large numbers of turtles are also netted
or speared at sea. The result has been the decimation of a valuable food source.
It will probably take international treaty to save at least one species, the green
turtle, from eventual extermination, for modern freezing methods have increased
the demand for them. Turtle populations in their present state could not stand
concentrated fishing. However, restored to former abundance and with proper
conservation, the sea turtles could once again become an important and valuable
food source.

There are only four genera of sea turtles, all of world-wide distribution in

THE RE-ENTRANTS

305

Fig. 184. Green turtle (left') and hawkshill turtle (rig/it).

warm seas. The habits of none of these are well known, and those of one, the
ridley, is shrouded in mystery.

GREEN TURTLE: Chelon'm mydas

Size: Up to 4 feet.

Weight: Up to 500 pounds. Formerly reported to 800 pounds or more.

Distribution: Gulf of Mexico to Caribbean and Atlantic. Straggles north to
Cape Cod. On West Coast north to southern California. Cosmopolitan in
warm seas.

Identification: The carapace is smooth and brownish in the Atlantic, greenish
to olive-brown in the Pacific. The head is small and blunt and, unlike other
sea turtles, bears only one pair of prefrontal shields on the top of the snout be-
tween the eyes and nostrils (other sea turtles have two pairs).

Habits: The habitat of this turtle is restricted to shallow shoal waters (2 to 4
fathoms) where there is a good growth of eelgrass, Zostera, or other marine
vegetation, which it eats almost exclusively, although it will eat some inverte-
brates. Near these vegetable gardens, the green turtle requires rocks or reefs,
in the protection of which it sleeps. During sleep, the metabolism is low so
that little oxygen is required. It is occasionally seen out at sea. It has a mild
temperament.

Formerly, the green turtle bred over a wide area, but its numbers have been
greatly depleted, and the Atlantic form is now found chiefly in Central America
and off Ascension Island. It was exterminated from Florida shortly after the
turn of the century. This is the most valuable of all reptiles and could be, if
properly restored, a major food source. Its flesh is exquisite and the eggs are
a delicacy. This animal is not now on the verge of extinction but it could shortly
be brought to such a state with an increase in fishing pressures.

HAWKSBiLL TURTLE: Eretniochelys imbricata

Weight: Common at 40 to 50 pounds. Large at 100 pounds. Up to 280 pounds.
Distribution: Gulf of Mexico and Caribbean. Tropical Indo-Pacific north to
Baja California.

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UNDERWATER GUIDE TO MARINE LIFE

Identification: The shell, familiarly known as "tortoise shell," is heart-shaped
and is a beautiful mottled brown, reddish, and yellow, as are the head and
flippers. Old animals have the shell pattern obscured by encrusting algae and silt.
The shields of the carapace are imbricated like shingles on a roof and can inflict
cuts. The head is small with a hawklike beak.

Habits: The range of habitat is more extensive than is the case for the green
turtle. Muddy or sandy bottoms or reefs are inhabited. Still, it stays in shallow
coastal waters. In food habits, it is omnivorous, but no careful scientific study
of this turtle has been made. It is known to eat the Portuguese man-of-war, keep-
ing its eyes closed to avoid the tentacles. It lays up to three hundred eggs in
summer. The authors found it fairly easy to approach. If the swimmer hovers
above one in the water, waiting until the turtle is about out of breath, he can
dive straight down on it and catch it with his hands. Care should be taken to
avoid the beak since hawksbills will occasionally bite. Large ones can give a
swimmer quite a ride. The shell and eggs of this turtle make it commercially
valuable, and though it is not depleted to the extent of the green turtle, care
should also be taken to avoid decimation.

F;'g. 185. Loggerhead turtle (left') and ridley turtle Cright').

LOGGERHEAD TURTLE: Cavetta caretta

Weight: Rare over 300 pounds today. Reliably recorded to 900 pounds; doubt-
fully reported to 1,600 pounds.

Distribution: The tropics north to Nova Scotia and southern California. Most
common in warm waters but is found out of tropics more than other sea turtles.
World-wide in warm seas.

Identification: The shields on the back are not imbricated. The plastron is
heart-shaped, broadest under the fore-flippers, and brown to reddish in color.
The head is large. The shape of the carapace separates it from the ridley.

Habits: This turtle is a confirmed wanderer over the whole area of the conti-
nental shelf and rarely to the open sea. It is often seen basking on the surface
over waters of moderate depth. It nests, or used to, north to Virginia. This is
not a commercially valuable species. It is pugnacious and will bite savagely at

THE RE-ENTRANTS 307

times. It feeds mostly on bottom invertebrates like crustaceans and molluscs and
also eats jellyfish and fish.

Ridley's (kerip's loggerhead): Lepdochelys oUvncea

Size: Recorded to 28 inches in carapace length. The smallest of the sea turdes.

Distribution: Shores of the Gulf of Mexico, eastern coast of Florida and north
to Massachusetts and England in the Gulf Stream (as young). Not in Caribbean.
Baja California to Chile.

Identification: The carapace is nearly round, broadest at its middle, and is
gray in the Atlantic and olivaceous in the Pacific. The head is large.

Habits: This is one of the true mystery animals of the sea as Carr (1955) so
excellently points out. Though it is not rare in its range, very little is known of
it. It prefers shallow, protected waters (near mangroves on the East Coast) and
is most abundant in the Florida Gulf coast waters. Its food seems to consist of
crustaceans, molluscs, and sea plants. Its temper is exceptionally short, and
handling one can be risky business.

The West Coast ridley turtles are known to breed on beaches in summer in
the normal sea turtle fashion, but the Atlantic species is not known to breed
at all! This is Carr's "riddle of the ridley," and it can easily tax the imagination
of the best of us. It seems more than logical that turtles should breed, but no one
has ever seen the eggs, nests, copulation, or a pregnant female of the Atlantic
ridley. No one has ever seen a young one of under a few months old. Some
people think that the ridley is a sterile cross between a green turtle and a logger-
head and, like the mule, is at the end of the road, but this, as well as numerous
other suggestions, appears to be ill-founded. Probably on some obscure beach
somewhere this turtle breeds. Where? When? No one knows, but the proba-
bilitv is that this occurs in the Gulf of Mexico. The breeding of the ridley is not
the only strange thing about this animal. Its very name is a mystery. The origin
of the odd name "ridley" is not known. And why isn't it found in the Caribbean
where suitable habitat is apparently plentiful? Again, no answer.

LEATHERBACK SEA TURTLES: Family Dermochelidae

One must resort to superlatives to describe the leatherbacks. They are the
most aquatic, most powerful, the fastest, largest, and among the rarest and most
peculiar of all the turtles. They are placed in an entirely different suborder from
all other turtles, Athecae ("no shell"), because they have greatly reduced both
plastron and carapace and have a leathery skin over their massive bodies. The
black skin of the carapace has seven longitudinal ridges. The unclawed flippers
are huge, and it is said that these turtles can travel at remarkable speeds, but
thev have never been clocked. There is one species.

LEATHERBACK SEA TURTLE (trunk turtle) : Derviochelys coviacea

Weight: Recorded to 1,200 pounds. Probably reaches 1 ton.
Distribution: Tropical seas. Recorded north to Nova Scotia and Vancouver.
Identification: Same as for the family.

Habits: Very little is known of this pelagic turtle. It comes into shallow water
seldom, preferring the open sea. In the summer it breeds on sandy beaches as

308 UNDERWATER GUIDE TO MARINE LIFE

Fig. 186. Leatherhack turtle.

other sea turtles, and the luckv swimmer or beachcomber may see one then. If
so, he should not molest it but observe all he can and contact the nearest scientific
institution as soon as possible. This is a rare animal of great scientific interest.

Leatherbacks are powerful and able to inflict damage with their beak and
flippers. Thev frequently roar or scream when molested. They probably are
more or less omnivorous.

Snakes: Order Squamata

There is one small family of sea snakes typical of the Indo-Pacific and repre-
sented in our seas by one species.

SEA SNAKES: Family Hydrophidae

These snakes live exclusively on the sea, never coming on land, except for
one Indo-Pacific species which comes ashore to lay eggs. They are, if placed
on land, almost helpless since they have lost the large, flat belly scales of most
snakes and cannot crawl on land except by considerable effort. But in the sea,
they are completely at home and are excellent swimmers. Their tails are com-
pressed like oars and even their bodies are a little compressed. Their nostrils are
placed on the top of the snout for easy access to surface air. Under water, the
nostrils are closed by a valve. Sea snakes are closely related to the coral snake-
cobra clan, all members of which possess a powerful neurotoxic poison. The sea
snakes may surpass even these in the drop-for-drop power of their venom, but,
fortunately, they are very reluctant to bite. Fishermen remove them from nets
with their bare hands, and these snakes are not known to attack or bite humans
in the water. They arc almost exclusivelv fish-eaters. They bask on the surface
almost motionless. Small fishes gather around them, as they would gather around
a floating stick, and are captured and eaten. Sea snakes inhabit shallow coastal
waters, particularly near river mouths, and shun the deep sea. They are ovovi\'ip-
arous or oviparous. At times they congregate in huge masses at the surface. One
such mass was reported to be 10 feet wide and 60 miles long. The reason for
such congregation is not known, but it mav be for copulation. When so congre-
gated, they lose their normal alertness and are easilv approached.

THE RE-ENTRANTS 309

fig. 187. Yellow-bellied sea snake.

YELLOW-BELLIED SEA SNAKE: PelaVlis j)latuniS

Size: Up to 3 feet.

Distribution: Ecuador to the Gulf of California. West to Africa.
Identification: The dorsal half of the body is dark bluish brown, and the
ventral half bright vellow to orange. The tail is yellow with dark bars.
Habits: Same as for the family.

BIRDS: Glass Aves

There are several families of birds that feed by di\ing in the sea, particularly
near land, and a great number that float or fly over the sea. None of these is
exclusively a marine group since they go beneath the surface only to feed. The
swimmer may be treated to seeing birds swimming beneath the surface, where he
will be startled bv the speed these animals can attain. Underwater photography
of diving birds is a fascinating pastime. (We refer the reader to the excellent
field guides to birds, given in the Bibliography, that are a\'ailable for identifica-
tion.) A list of prominent families that dive to feed in the North American seas
and swim below the surface follows:

Loons (Gaviidae)

Grebes (Golvmbidae)

Cormorants (Phalacrocoridae)

Some ducks and mergansers (Anseridae)

Auks, murres, and puffins (Alcidae)

Many other birds dive just below the surface but do not swim under water.
Some of these are shearwaters, petrels, tropic birds, pelicans, gannets, man-of-war
birds, some ducks, gulls, and terns.

MAMMALS: Class Mammalia

Four groups of mammals enter the sea: sea otters, seals and walruses, manatees,
and whales and dolphins. The last two groups are exclusively marine, never
appearing on land. The others enter the sea mainly to feed, although the sea
otter has been driven to become more and more exclusi\'ely marine in its habits
because of persecution by man.

Carnivores: Order Carnivora

There is some confusion surrounding the term "carnivore." Used as a reference
to habits it means "of flesh-eating habits" and may apply to sharks, killer

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UNDERWATER GUIDE TO MARINE LIFE

whales, cats, etc. Used as a term of scientific classification, it applies to a specific
order of mammals, which includes bears, raccoons, cacomistles, mongooses,
weasels, otters, skunks, dogs, cats, seals, and walruses. It is thus possible to speak
of a carnivorous, or meat-eating, carnivore (cat), an omnivorous, or both animal-
and plant-eating, carnivore (bear), a piscivorous, or fish-eating, carnivore (seal),
and even an herbivorous, or plant-eating, carnivore (panda).

WEASELS: Family Mustehdae

The sea otter is the only seagoing member of the weasel family and is on a
par with the wolverine as being the largest member of that family. Many of the
weasels have aquatic tendencies, but the sea otter is better adapted for living
in water than any other weasel.

SEA OTTER (sEA BEAVER, KALAN, A-MI-KUk) : Enliydra hltris

Size: Wi to Wz feet.

Weight: 25 to 75 pounds.

Distribution: Baja California coastwise to Alaska, the Aleutians, and Japan.

Identification: The foot-long tail (short compared to other otters), short legs,
and otterlike face make this animal unmistakable. The color is dark brown to
nearly black, lighter about the head and neck.

Habits: It is almost impossible to be unemotional about this animal, for it is an
immensely appealing, yet tragic one which has sufi^ered greatly at the hands of
man, its only enemy besides the killer whale and sea lion. Its story is briefly told
here and serves as an example of the worst kind of man's abuse of a valuable
resource as well as being an example of his sometimes consuming greed and
stupidity.

The sea otter was discovered in 1737. Evidence points to the fact that it was a
different animal then than it is now. Early reports indicate that the sea otter
much resembled the seal in habits, going to the sea to feed and lying in droves
on the land to rest and bear young. Now, through great diminution in numbers
and constant persecution, it is principally a beast of the kelp beds near shore,
rarely coming onto land. It is probably a much more wary animal than it was,
and it is difficult to see and to approach except when it is sleeping on the surface.

Fig. 11

Sea otter.

THE RE-ENTRANTS 311

The persecution that caused this change involves the fur, by far the most valuable
fur, pelt for pelt, that is known. Fur dealers use the sea otter's fur as the standard
of excellence against which all other furs are rated.

Very shortly after the sea otter's discovery, the massacre began, first by
Russians in the north and later by West Coast Indians and the Spaniards of
California. Killing them was a simple matter. About all one had to do was walk
up to them and club them to death. Upon the first blow of the club the otter
yvould in amazingly humanlike fashion lie down, cover its eyes with its forepaws,
and submit itself to the punishment. In the water, mothers with cubs were very
easilv taken since they would under no circumstances leave their young. It took
only about eight years to exterminate the St. Paul herd of the Pribilof Islands,
and by as early as the mid-1800's the sea otter existed only as a pitiful remnant
over its wide range. The length of time taken for this job of near extinction was
only about a third of the time that it took to equally reduce the American bison.
The price of a single pelt rose from $6 to $7 in 1785 to $2,500 in the 1920
fur boom.

The mother is verv protective toward her pup, cradling it when fleeing an
enemy, and, when asleep, she floats on her back, holding the pup in her arms.
Sea otters can make sounds variously described as "whimpering" or "crying" in
fright and "crooning" to young.

The sea otter feeds in kelp, from the shore to 30 miles out to sea, on
crustaceans, molluscs, sea urchins, and some fish. It can dive to 300 feet with the
aid of its paddlelike hind feet, but it mostly feeds at depths of 30 to 100 feet.
After di\'es of a quarter of a minute or up to four or five minutes, the otter
surfaces, floats on its back, and eats the morsels off the platter of its chest.

Thev niav be seen today in scattered bands throughout much of the former
range. Herds are making a comeback in Monterey Bay.

Seals: Suborder Pinnipedia

These animals are sometimes separated from the carnivores as a full order,
but this is probably not justified since they are clearly derived from carnivores
and closely related to them, the chief difference being the flipperlike limbs. There
are three families, all of which have fish- or mollusc -eating habits, and most of
which are of northern seas. They bear young and sleep on land, sometimes
gathering in large groups in definite rookeries to do so. The huge bulls gather
the cows into large harems for mating.

All members of this group are intelligent, swift in the water, and of large
size. Thev certainly could be dangerous if molested but are usuallv trusting
in the water and allow close approach. Swimmers have met the California sea
lion under water and found it to be curious but a little too large for comfort.
In the presence of pups they are probably dangerous. Young seals, however, are
docile and friendly. The huge walrus, which the swimmer will probably never
meet, is definitely a dangerous fellow.

EARED SEALS: Family Otariidae

These are the familiar seals and sea lions of the fur industrv, San Francisco's
Seal Rock, circuses, and zoos. All of them are of rich brown color and have

312

UNDERWATER GUIDE TO MARINE LIFE

Fig. 189. The California sea lion, Zalophus californianus, is an inveterate circus
performer. Under water, the irascible males or females with pwps can he dangerous.
Otherwise, this is an intelligent, friendly, and playful animal.

small external ears. All can stand erect on the large fore-flippers (used for
propulsion under water in a winglike manner), and all can rotate the rear limbs
forward so as to be able to move fairly rapidly on land. They are found in the
North Pacific and in the South Pacific but not in the warm waters in between.

CALIFORNIA SEA LION: Zalophus califomiamts

Size: Bulls up to 8 feet in length. Cows up to 6 feet in length.

Weight: Bulls up to 500 to 620 pounds. Cows up to 300 pounds.

Distribution: Southern Mexico to northern California.

Identification: As in other species of the family, the bull is thick-necked, heavy-
shouldered, and much larger than the slim cow. The bull also has a high
forehead. The color is a yellow brown (darker when wet) to almost black.

Habits: This is a very playful animal, gregarious and active. In the water, the
tendency on the part of the swimmer would be to play with them, but all except
the very small ones are liable to get a bit rough. They probably would not attack
a swimmer if left unmolested and if not in the presence of the pups (which are
cared for and defended by the females, but which may be killed by the bulls).
This species does not gather into large harems for breeding. The loud honking
bark is familiar and is uttered when feeding, playing, or as a warning. Adults
cat about twelve to fifteen pounds of fish and squid a day, although the males in
rut take no food at all.

Similar Species: The valuable fur seal, Callorhinus nrsiuiis, is about the same

THE RE-ENTRANTS

3B

size as the California sea lion. It breeds on the Pribilof Islands and may reach
south to California in winter. It has a dense yellow-brown underfur which
California sea lions lack. Its only enemy is the voracious killer whale.

The huge Steller's sea lion, Eumetopias juhata, reaches a weight of 1,800
pounds or more and a length of over 12 feet (bulls). Its voice is a long roar. The
distribution is from the Farallon Islands off San Francisco to the Bering Strait.

SEALS: Family Phocidae

These seals have no external ears and cannot turn their rear flippers forward
for locomotion on land. These are the most aquatic of the Carnivora. Progression
on land is very clumsy, hardly being more than a squirming or wriggling, in
which the body is dragged ineffectually by the small front flippers. In water,
however, they are swift and graceful fish-eaters. Propulsion in the water is by
means of the rear flippers which are used in undulating fashion like the fin of
a whale or fish. These seals do not usuallv congregate to breed (the elephant
seal does). The single pup is born, a little ball of white fur, in some secluded
place on shore or on ice in summer. Most are of arctic or cold temperate
distribution.

HARBOR SEAL (hAIR SEAL, LEOPARD SEAL, COMMON SEAl) : PhoCU vitlllma

Size: Up to 5 feet (for both sexes).

Distribution: South from the arctic to the Carolinas and Baja California.

Identification: Color is yellow-gray, spotted with dark, indistinct blotches.
Some are dark brown, spotted with yellow.

Habits: These are the common seals of our temperate coasts. They are friendly
and engaging, especially as pups, and, if tamed early enough, could make fine and
engaging swimming companions. They can utter a coarse bark. They eat about
ten pounds of fish, squid, and crustaceans a day near the bottom. The killer
whale, large sharks, polar bears, and man are its chief enemies. They are agile
and speedy swimmers.

Similar Species: Few species of seals go south of the St. Lawrence and Alaska.
The gray seal, Halichoerus grypus, is a large seal, the bulls reaching 6 to 9 feet
and 800 pounds and the cows reaching 6 feet and 700 pounds. The gray seal
resembles the harbor seal in coloration, and it shares the same common names,
but it is heavier and less active. It ranges south to Maine and straggles to
New Jersey.

Harbor seal.

314

UNDERWATER GUIDE TO MARINE LIFE

Fig. 191. Elefhant seal.

The West Indian seal, vionachus tropicalis, is nearly extinct and should be
looked for. Very little is known of it. It is brown above and pale below, and
trusting and sluggish in habits. Formerly it occurred in the West Indies north
to Florida. Any seal seen in that area should be reported to the United States
National Museum in Washington, D.C., or American Museum of Natural
History in New York City.

The elephant seal, Mironnga angiistirostris, is the largest of living Carnivora
in length and weight. Bulls reach 18 feet and 5,000 pounds. The cows are two-
thirds as large. The major herd now known is one on Guadalupe Island near
San Diego, where it is protected by law. This herd has spread to establish new
colonies on several surrounding islands. Formerlv it occurred ovev the entire
West Coast from Mexico to British Columbia. The name is derived from the
male's inflatable snout and its huge size. Its food probably consists of fish and
invertebrates, caught at night. By day they bask on shore and can be approached
closely. Its valuable oil was the cause of its near extinction by man.

Sea Cows: Order Sirenia

The head and mustache of a walrus, flippers of a seal, lack of hind limbs, and
odd, spatulate tail (on the manatee) identify the two living members of this
order, the Indo-Pacific dugong and the manatee of the Gulf of Mexico and the
West Indies. It is thought that these animals gave rise to the mermaid tales of
a few years ago. The scientific name gives credence to the fable by being adapted
from "sirens," the voluptuous singing maidens that so tempted Ulysses. Sea cows
are reported to be able to whistle, but they do it through their unmaidenlv,
valvelike noses. If former voyages had not been so protracted in length, it would
otherwise be difficult to imagine how a sailor, even a hot-blooded one, could
confuse a maiden and a sea cow.

Both species have been much reduced. The dugong is in special danger of
extinction.

MANATEES: Family Trichechidae

MANATEE (sEA cow) : Trichecluts viauatus

THE RE-ENTRANTS 315

Fig. 192. Sea cow.

Size: Up to 12 feet. Averages 7 to 8 feet, probably when it is subadult.

Weight: Up to 1 ton. A male 7V^ feet long weighed 432 pounds.

Distribution: The West Indies, the Atlantic Coast of Central America and
Mexico, and the coasts of southern Florida. Summer extensions up the eastern
coast of Florida and thinly up the Texas coast. Range does not include northern
Gulf of Mexico.

Identification: Same as for the family.

Habits: This is a docile, sluggish vegetarian which browses on aquatic vegeta-
tion in shallow bays, lagoons, river mouths, and rivers. The upper lip, with its
stiff bristles, gathers the food. Manatees travel singly or in small family groups.
They are hard to see because of a predilection for turbid water, but otherwise
they should not be too difficult to approach under water. Upboiling on the water's
surface in series indicates their direction and progress as they swim in shallow
rivers or bays. The ribs of manatees are remarkably heavy and dense and
probably aid in keeping the animals submerged. Fossil manatee ribs, black
and subcylindrical, are not uncommon objects on some Florida beaches. The
manatee has been much persecuted for its oil and flesh and deserves vigorous
enforcement of the Florida law which protects it. (There is a $500 fine for
killing or molesting a manatee.)

Whales, Dolphins, and Porpoises: Order Cetacea

The origin of whales is unknown although thev have been in existence for
nearly the entire Cenozoic Era (the age of mammals). They form the most
fishlike of the re-entrants but are immediately distinguishable from all fishes
by the horizontal tail flukes and the movements of the tail, which are up and
down rather than lateral. These animals suckle their young in the sea, but they
alter the normal mammalian suckling pattern. Instead of the young suckling
from the mother, a feat that would be difficult under water, the female pumps
milk into the calf by muscular action. This process is very quick. Occasionally,
a mother whale and calf will somehow miss connection, and gallons of rich
milk flow into the water, turning it white. The nostrils are on the top of the head
and form the blowhole which may be opened and closed by a valve. The spout
of large whales is the result of the exhalation of air and water vapor from this
blowhole. All cetaceans are carnivorous, but the size of prey varies greatly. These

316 UNDERWATER GUIDE TO MARINE LIFE

animals possess no sense of smell and probably hunt their fish or plankton prey
chiefly by sight or taste. Their intelligence is high as a group, that of the bottle-
nosed dolphin being comparable to that of a dog.

Whales have been much reduced by whaling. Supposedly, international law
regulates the yearly catch, but this law unfortunately shows few signs of
restoring former whaling grounds. Most of the smaller dolphin species are rare
and if seen, especially if they are stranded on beaches, should be reported to
the nearest scientific institution.

The habits of most of these animals are very poorly known. Good accounts
of many of them are found in Norman and Eraser (1938). Their distribution
is world-wide in all seas. The larger ones are more typical of cold waters where
the plankton is concentrated.

Whalebone or Baleen Whales: Suborder Mysticeti

These are the most gigantic of all living things and, indeed, the largest
animals that have ever lived. The suborder name refers to the fact that they
have no teeth. Instead, baleen or whalebone, a horny epidermal derivative, hangs
down in plates from the palate. This is used to strain plankton from sea water.
A huge mouthful of water and plankton is taken into the mouth. The tongue
presses up against the baleen plates and expels the water through the screen of
baleen which holds the plankton. Then the plankton is swallowed. Such huge
animals, it might be supposed, could not possibly find enough plankton to eat,
but marine crustaceans, especially krill (euphausians) and copepods, become
amazingly plentiful in summer in cold seas. So thick does the water become
with them that powerful ships are slowed to half their speed when traveling
through such water. The baleen whale's spout, which is thrown vertically
upward, is double because of the paired blowhole.

BLUE WHALE (SLILPHUR-BOTTOM WHALE, RORQUAl) :

Balaenoftera musculus

Size: This is the largest animal that has ever lived. Averages 60 to 80 feet long.
Up to 103 feet.

Weight: At 76 feet it weighs 63 tons. At 89 feet it weighs 119 tons.

Distribution: All seas, but particularly arctic and antarctic waters.

Identification: The throat and chest have a series of longitudinal pleats. The
body is slender and tapering for a whale, and the top of the head flattened
and broad.

Habits: These are perhaps the swiftest of large baleen whales, said to be able
to attain 12 miles per hour. The young are 24 feet long when born and take
one year in gestation. This embryonic growth rate is astonishingly fast and
probably represents a record for any type of growth rate. These are not
aggressive animals and are probably quite timid. Their only enemies are parasites,
the killer whale, and man. The most destructive of these is man, but the most
fearful, to the human eye at least, is the killer whale.

Similar Species: The other common rorqual or ridge-throated whale is the
65-foot finback, Balaenoptera physaJiis, which has small flippers, a ridged back.

THE RE-ENTRANTS

iPERM WHALE

Fig. 193. Whales.

and a wedge-shaped head. The humpback whale, Megaptera nodosa, is stocky
of body and has very long, knobby flippers. It reaches 50 feet in length. Both
of these are found in both the Atlantic and Pacific Oceans.

The right whales (/xg. 193\ Euhalaena species, and the bowhead whale,
Balaena mysticetus, have no dorsal fins or throat ridges, but have huge heads with
arched mouths and broad, rounded flippers in contrast to the tapering flippers
of rorquals. Both are found in both the Atlantic and Pacific and reach 60 feet
or more. These are slower whales than ridge-throated whales and were so
persecuted by whalers that they are now rather rare. They are increasing
slowly under international protection.

The California gray whale, Eschrichtius glaucus (/ig. 193\ is a medium-sized
whale reaching 40 feet in length. It is gray in color and has a small head.
Formerlv it abounded on coasts, especially in lagoons and estuaries from Baja
California north to Japan. Now it is rare but is increasing under protection.
It is said to be so terrified in the presence of killer whales that it offers no fight,
merely lying on its back and hanging out its tongue, which is eaten by the
killers.

Toothed Whales: Suborder Odontoceti

These whales have teeth and never possess baleen. There is only one nostril
so the spout is single. Most of the species of the suborder are small, and a great
number of them are rare and very poorly known. Many of them eat squids,
but they are mainlv fish-eaters.

318 UNDERWATER GUIDE TO MARINE LIFE

SPERM WHALES: Family Physeteridae

There are only two species, one of which, the pigmy sperm whale, is small
and rare. The name "sperm whale" refers to the large reservoir of oil or spermaceti
that is found on the top of the head, giving it a squarish appearance.

SPERM WHALE (cachelot) : Physeter catodon

Size: Males reach up to 85 feet, but usually not over 60 feet. Females reach
up to one-half this length.

Distribution: Tropics to subarctic waters of all seas.

Identification: The shape of the huge head with the narrow, toothed lower
jaw is distinctive. The spout is low and directed forward.

Hahits: This is Melville's "Moby Dick." The sperm whale is able to sound to
great depths (to half a mile or more) and can stay under for as long as an hour
to hunt for its food, the giant squid. Scars of squid suckers and tentacle hooks
are to be found on its body, mostly about the head. The physiological strain of
such prolonged deep dives is tremendous and how the whale stands it is not
known. Formerly this whale traveled in large schools of a hundred or more,
mostly composed of cows and calves, with a few bulls. Now they are much rarer
and schools of fifteen to twenty are large. This is a swift whale, able to attain
12 knots. The sperm whale has no enemies except man. Even the killer whale
cannot attack it successfully. There is a report of a small group of killers attacking
a large sperm whale while the latter was basking on the surface. It soon woke
and maimed one of the killers in its jaws and was last seen pursuing the others,
which it probably could not catch.

Ambergris, the valuable perfume base, is taken from the intestine of this
whale. Sometimes it is found cast up on coasts. One mass weighing 924 pounds
was found cast up on an Australian beach and was valued at $120,000. Usually
the pieces found in whales weigh only a few ounces. This valuable animal is
being hunted at the present day, and it is a question how long it can stand
hunting pressure. It seems to be holding its own, but not increasing.

PORPOISES AND DOLPHINS: Family Delphinidae

There are many species of these interesting, very intelligent, small cetaceans.
(We must refer the reader to the Bibliography for all but three of them.) Many
species are quite rare and are of great zoological interest. Observations of them
in the sea would be of value. The term "dolphin" and "porpoise" are commonly
used interchangeably. "Dolphin" is also the name of a fish, Coryphaena. As used
here, however, it only includes the small, beaked members of this family.
"Porpoise" refers to the small beakless species. The larger species are known
by various other names and include the narwhal, beluga, grampus, blackfish,
beaked whales, and killer whales. Most of these are rare or of northern seas, and
some are not strictly of this family. All are very swift, agile, and active carnivores,
mostly on lish.

bottle-nosed dolphin: Tursio-ps tnmcatiis

Size: Reaches almost 12 feet, but 9 feet is large.
Distribution: Cosmopolitan in warm seas.

Identification: The color is a slaty, dark, bluish-gray. The beak is short, and
there is a high forehead.

THE RE-ENTRANTS

319

aoTTLE-NOSCO DOUPHIN

KILLER WHALE

Fig. 194. Porfoises and dolphins.

Hahits: This is the best known dolphin, both to swimmers and to inshore
seafarers. It is the only dolphin commonly seen in river mouths, bays, and beach
areas of the Atlantic Coast. It is less common on the Pacific Coast, perhaps
because the waters are colder there.

The favorite food of the dolphin is mullet, which it pursues by sight. It also
has been observed to dash into a school of these fishes and send one aloft with
a stroke of its tail. The mullet then falls into the dolphin's awaiting jaws.

Dolphins travel with great ease through the water and are among the fastest
of swimmers, capable of playing about ships' bows at 40 mph or a little over.
They breathe at the surface every ten to sixty seconds and are capable of a
six-minute submersion. Surprisingly enough, they drown rather easily if water
gets in the blowhole.

These are not only very speedy swimmers, but they are also very active
ones. Their mammalian warm-bloodedness and efficient circulation accounts for
this. Swimming in water takes great amounts of energy, so it is not surprising
to find that the blood of dolphins can hold much more oxygen than that of land
animals of equal size. Their sense of hearing is acute. They utter whistles, barks,
and clucks through the blowhole and communicate by these means. They also
whimper when injured.

Dolphins are much-fabled animals, long held in high esteem by sailors. This
is not without reason, for dolphins are the known enemies of sharks. It is a bit
hard to separate fact from fancy on this score, but dolphins have been reliably
reported to attack both hammerhead and tiger sharks in the sea and in captivity.
They harass sharks by punching them with their hard, bony snouts in a series

320 UNDERWATER GUIDE TO MARINE LIFE

of swift, jolting blows. Sometimes several dolphins maneuver the shark into
position so that another can strike a fatal blow in a tender spot like the region
of the gills. Dolphins are also known to have pushed drowning people ashore,
though stories of this sort are even more difficult to run down. The recognition
of a person in distress would take a very high degree of intelligence; the pushing
which we interpret as a rescue probably arises from the tendency of dolphins
to push or nudge surface objects. For instance, they are known to give newborn
young a push toward the surface to necessary air.

Most of what is known of dolphins is drawn from their behavior in captivity.
There, these swift and extraordinarily playful creatures with the built-in grin are
a constant source of amusement, taking well to captivity and their captors.
Excepting the primates, their intelligence is perhaps greater than that of any
other animal. Their brain is convoluted and a little heavier than man's. The
highly developed brain of dolphins accounts for their elaborate play. For example,
one poor pelican at Marineland in Florida was the object of frequent torment.
One dolphin would pluck a feather from it, which it would toss about or try
to balance on its nose as it swam. At other times, the bird would be the recipient
of rather violent spanks from below, to its great consternation. Dolphins
constantly nipped at the fishes in the tank and used to annoy a turtle by turning
it repeatedly on its edge (Williams, 1950). The dolphin's plav with people in
the tank was well intentioned, but it tended to be a bit rough at times. Dolphins
like to play catch. They will retrieve all sorts of objects, overshadowing retrieving
dogs by throwing the object back. One dolphin, having received a somewhat
overly dead mullet for food, threw it back, hitting an innocent lady bystander
in the face.

Dolphins live for forty years or a little more. Much of their time is occupied
with sex play, the ever-eager males seeming never to tire of chasing the females.
The females in return, in heat only a few times a year, never seem to tire of
eluding the males. The males form a hierarchy and fight among themselves for
the female's attention. McBride and Hebb (1948) record several examples of the
male's sexual ardor, one of which deserves mention. The penis "forms an efficient
hook, and a young male was seen on several occasions to swim down at consider-
able speed, scoop up an eel at the bottom of the tank, and swim zig-zag all the
way across the bottom of the tank with the eel wrapped about [it]."

When a female is giving birth, the normal companionship which dolphins
show toward each other is accentuated. At such times, thev band together and
are alert, for the blood occuring at birth attracts sharks, which are driven away
by these attendants.

Dolphins are truly masters of the seas, able to elude all pursuers except a
member of their own family, the killer whale. Swimmers will have fascinating
experiences with them under water and should carefully record what they see
because little is known of them out of captivity. Dolphins will not usually flee
a swimmer; in fact, they will often nudge a swimmer playfully.

COMMON dolphin: Delfhinns delfhis

Size: Up to 8 feet or more.

Distribution: Cosmopolitan in warm temperate and tropical seas, chiefly
offshore.

THE RE-ENTRANTS 321

Identification: The beak is fairly long and separated from the low forehead
by a groove. The back is almost black, and there are light markings of yellow and
white on the sides.

Habits: It is like the common dolphin but is shier. This is the dolphin
frequently seen at sea gamboling about ships' bows.

Similar Species: The little common porpoise (harbor porpoise), Phocaena
fhocaena Qfig. 196^, is a little, chiefly north temperate, coastwise species that
reaches only about 6 feet and 120 pounds. It has no prolonged snout and is
dark gray above and white below. It is very rare in the eastern United States
being occasionallv seen in Maine. It has been reported south to New Jersey in the
Atlantic. More common on the Pacific coast, it also ranges farther south.

KILLER WHALE (grampus) : Orcinus orca

Size: Males to 30 feet. Females one-half that size. The largest of the dolphins
and porpoises.

Distribution: All seas, but most common in cold waters.

Identification: The verv high, black dorsal fin is the best field character. The
mouth is large and bears very heavy cutting teeth. The snout is rounded and not
produced to form a beak. There are white marks above the eyes and the white
of the belly extends up onto the sides.

Habits: The intelligence, speed, voracity, size, and power of these animals
make them without doubt the most dangerous of all the sea's inhabitants.
Luckily, they are not really common. They travel in small bands of two to three
or even up to forty individuals and attack their prey cooperatively. The killer
whale's favorite food is seal. Porpoises and the largest whales are also eaten. Its
prey evidently must be moving to attract it. Sea otters are known to freeze in
their presence to avoid detection. The high swordlike dorsal fin once gave them
the name "swordfish " among some seafaring men. This name is now only used
to mean certain fish, but old seamen's accounts of swordfish attacking baleen
whales meant killer whales attacking baleen whales. The manner of hunting
seals shows great cunning. Seals commonly bask on ice floes. The killer, spotting
such a seal, will overturn the floe with its back and swallow the dislodged seal.
Baby walruses, taking refuge on the backs of their mothers are also jarred loose
and eaten. The remains of up to fourteen seals have been found in a single
large killer's stomach. Killers have been known to break floes under men. One
photographer, a member of the British antarctic Terra Nova Expedition barely
escaped with his life as a floe was shattered by killers just as he ran to safety.
The attacks on whales are even more spectacular and cunning. Several killers
will hold the flippers of a large baleen whale while others tear juicy hunks out
of the tender lips and tongue. This frequently kills the large whale. It is said
that California gray whales become literally petrified in the killers' presence,
lying on their backs, tongues out, awaiting their fate. Some reports also sav
that killers are able to use the high dorsal fin as a weapon. The authors do not
know about the truth of this statement. It is hard to say what a diver should do
in the presence of a band of killers. Freezing motionless, an action that would
probably be involuntary anyway, might be attempted— after you have taken a
picture, of course.

BIBLIOGRAPHY

Following is a list of works cited as well as recommended works for further
reference. Those considered by the authors to be particularly useful are marked
with an asterisk (*).

CHAPTERS 1 AND 2: ECOLOGY

*W. C. Allee, A. E. Emerson, O. Park, T. Park, and K. P. Schmidt
1950 Principles of Animal Ecology. Saunders, Phildelphia.
Barnett, Lincoln

1953 "The miracle of the sea." Part II of The World We Live In. Life Magazine,
February 9: 74-94.

1953 "Creatures of the sea." Part VII of The World We Live In. Life Magazine,
November 30: 79-108.

1954 "The coral reef." Part VIII of The World We Live In. Life Magazine,

February 8: 58-82.
*Carson, Rachel

1951 The Sea Around Us. Oxford University Press, New York.
*Cott, H. B.

1940 Adaptive Coloration in Animals. Methuen, London.
J. Y. Cousteau

1954 "To the depths of the sea by bathyscaphe." National Geographic Magazine,

July: 67-79.
*Elkman, Sven

1954 Zoogeography of the Sea. Sidgwick and Jackson, London.
*Elton, Charles

1935 Animal Ecology. Sidgwick and Jackson, London.
Hardy, A. C.

1953 "Some problems of pelagic life." In Essays in Marine Biology. Oliver and

Boyd, Edinburgh.
*Hesse, R., W. C. Allee, and K. P. Schmidt

1951 Ecological Animal Geography. Wiley, New York.
Jarmer, K.

1928 "Das Seelenleben der Fische." Miinchen, Berlin, Oldenbourg.
Lehrman, D. S.

1953 "A critique of Konrad Lorenz's theory of instinctive behavior." Quart. Rev.
Biol. 28: 337-363.

*MacGinitie, G. E. and N. MacGinitie

1949 Nattiral History of Marine Animals. McGraw-Hill, New York.
McDougall, W. B.

1918 "The classification of symbiotic phenomena." Plant World, 21: 250-256.
^Marshall, N. B.

1954 Aspects of Deep Sea Biology. Philosophical Library, New York.
Marshall, S. M. and A. P. Orr

1953 "The production of animal plankton in the sea." In Essays in Marine Biology.
Oliver and Boyd, Edinburgh.
Odum, E. P.

1953 Fiindamehtals of Ecology. Saunders, Philadel]ihia.

323

324 BIBLIOGRAPHY

^Russell, F. S. and C. M. Yonge

1928 The Seas. Warne, London.
*Sverdrup, H. U., M. W. Jackson, and R. H. Fleming

1942 The Oceans. Prentice-Hall, New York.
Verrier, M. L.

1928 "Recherches sur les yeux et la vision des poissons." Bull. Biol. Fr. et Belg.

Presses Universitaires de France. Supplement XI: 230.

CHAPTERS 3 AND 4: MAN AND THE SEA

^Carrier, R. and B. Carrier

1955 Dive. Funk, New York.
*Cousteau, J. Y.

1953 The Silent Worhi. Harper, New York.
^Phillips, C. and W. H. Brady

1953 Sea Pests. University of Miami Marine Laboratory. University of Miami Press.
*Schenck, H., Jr., and H. Kendall

1954 Undeuvater Photography. Cornell Maritime Press, Cambridge, Maryland.
*Schenck, H., Jr., and H. Kendall

1954 Shallow Water Diving and Spearfishing. Cornell Maritime Press, Cambridge,
Maryland.

CHAPTER 5: EVOLUTION

*Dobzhansky, T.

1951 Genetics and the Origin of Species. Columbia University Press, New York.
"^Mayr, E.

1942 Systematics and the Origin of Species. Columbia University Press, New York.
Romer, A. S.

1945 Vertebrate Paleofitology. University of Chicago Press, Chicago.
*Simpson, G. G.

1953 Major Features of Evolution. Columbia University Press, New York.
^Simpson, G. G.

1949 The Meaning of Evolution. Yale University Press, New Haven.
Schenk, E. T. and J. H. McMasters

1948 Procedure in Taxonomy. Stanford University Press, Stanford, California.
Twenhofel, W. H. and R. R. Shrock

1935 Invertebrate Paleontology. McGraw-Hill, New York.

CHAPTER 6: PLANTS

Blinks, L. R.

1954 "The role of accessory pigments in photosynthesis." In Autotrophic Micro-
organisms, Ed. by B. A. Fry and J. L. Peel. Cambridge University Press.

*Smith, G. M.

1944 Marine Algae of the Monterey Peninsida, California. Stanford University

Press, Stanford, California.
*Taylor, W. R.

1937 Marine Algae of the Northeastern Coast of North Auierica. University of

Michigan Press, Ann Arbor, Michigan.

CHAPTER 7: INVERTEBRATES

* Abbott, R. T.

1954 American Seashells. Van Nostrand, New York.

BIBLIOGRAPHY 325

*Borradaile, L. A. and F. A. Potts

1935 The Inx'ertebrata. Macmillan, New York.
*Buchsbaum, R.

1948 Aniuials Without Backbones. University of Chicago Press, Chicago.
*Hyman, L. H.

1940 The Invertehrates. Vol. 1. Protozoa through Ctenophora. McGraw-Hill, New

York.

1951 Vol. 2. Platyhelminthes and Rhynchocoela. The acoelomate Bilateria.

1951 Vol. 3. Acanthocephala, Aschelminthes, and Entoprocta. The Pseudocoelomate
Bilateria.

1955 Vol. 4. Echinodermata.
Continuing volumes to be published.
Klingel, G. C.

1944 "In defense of octopuses." In The Book of Naturalists, Ed. by William Beebe.
Knopf, New York.

* Mayer, A. G.

1910 Medusae of the World. Carnegie Institute of Washington, Washington, D.C.

* Mayer, A. G.

1912 Ctenophores of the Atlantic Coast of North America. Carnegie Institute of
Washington, Washington, D.C.
McGowan, J. A.

1954 "Observations on the sexual behavior and spawning of the squid, Loligo
opalesens, at La Jolla, California." Calif. Fish and Game, 40: 47—54.

* Miner, R. W

1950 Field Book of Shore Life. Putnam's, New York.
*Parker, T. J. and W. A. Haswell

1947 A Text-hook of Zoology. Volume I, 6th edition. MacMillan, London.
*Ricketts, E. F. and J. Calvin

1952 Between Pacific Tides. 3rd edition revised by J. W. Hedgpeth. Stanford Uni-
versity Press, Stanford, California.

Thompson, Sir C. W. and J. Murray

1887 Report on the Scientific Results of the Voyage of H. M. S. Challenger. Publ.
by order of Her Majesty's Government, Edinburgh.
*Young, J. Z.

1950 The Life of Vertebrates. Chaps. 2 and 3. Clarendon Press, O.xford.
Zim, H. S. and L. Ingle

1955 Seashores. Golden Nature Guide. Simon and Schuster, New York.

CHAPTERS 8 AND 9: FISHES

*Ackerman, Bill

1951 Handbook of Fishes of the Atlantic Seaboard. American Publishing Co.,
Washington, D.C.

Anglo-American Caribbean Commission

1945 Guide to Commercial Shark Fishing in the Caribbean Area. Kaufman,
Washington, D.C.

Aronson, L. R.

1951 "Orientation and jumping behavior in the gobiid fish, BatJiygohius soporator."
Amer. Mus. Novitates no. 1486.
*Barnhart, P. S.

1936 Marine Fishes of Southern Califortiia. University of California Press,
Berkeley, California.

326 BIBLIOGRAPHY

*Beebe, W. and J. Tee- Van

1928 The Fishes of Port-au-Prince, Haiti. Zoologica X: 1-279.
*Beebe, W. and J. Tee-Van

1933 Field Book of the Shore Fishes of Bermuda. Putnam's, New York.
Berlin, L.

1942 Les Angiiilles. Payot, Paris.
*Bigelow, H. B. and W. C. Schroeder

1948 Fishes of the Western North Atlantic. Vol. I. Lancets, Cyclostomes, and Sharks.

Mem. Sears Foundation for Marine Research, Yale University.

1955 Vol. II. Sawfishes, Guitarfishes, Skates, and Rays.
*Breder, CM., Jr.

1926 "The k)comotion of fishes." Zoologica 4: 159-297.

1938 A contribution to the life histories of Atlantic Ocean flying fishes." Bull.
Bingham Oceanographic Cofl. Peabody Mus. Nat. Hist., Yale University. VI, Art. 5.

1948 Field Book of Marine Fishes of the Atlantic Coast. Putnam's, New York.
Breder, C. M., Jr. and C. W. Coates

1933 "Reproduction and eggs of Pomacentrxis leucoris Gilbert." Amer. Mus. Novi-

tates no. 612.
Breder, C. M., Jr. and H. E. Edgerton

1942 "An analysis of the locomotion of the seahorse. Hippocampus, by means of

high speed cinematography." Ann. N. Y. Acad. Sci. 43: 145-172.

1946 "Do flying fishes really fly?" Travel and Camera, August: 73-76.
Briggs, J. C.

1955 "A monograph of the clingfishes (Order Xenopterygii)." Stanford Ich. Bull.
Nat. Hist. Mus., Stanford University. Vol. 6.
'Budker, P.

1947 La Vie des Piequins. Gallimard, Paris.
Coles, R. J.

1916 "Natural history notes on the devilfish, Ma}ita hirostris (Walbaum) and

MoUda olfersi (Miiller)." Bufl. Amer. Mus. Nat. Hist. 35: 649-658.
Crawford, R. W. and C. P. Powers

1953 "Schooling of the orange filefish, Alutera schoepfi, in New York Bight."

Copeia: 115—116.
Me Latil, P.

1955 The Underwater Naturalist. Houghton-Mifflin, Cambridge, Mass.
De Witt, J. W.

1955 "A record of an attack by a leopard shark QTriakis semifasciata^." Calif. Fish

and Game 41 : 348.
Fast, T. N.

1955 "Second known shark attack on a 'swimmer in Monterey Bay." Calif. Fish

and Game 41: 348-351.
Gill, T. N.

1907 "Life histories of toadfishes (Batrachoidids) compared with those of weavers

(Trachinids) and stargazers CUranoscopids)." Smithsonian Misc. Coll. 48: 388-427.

1908 "Angler fishes; their kinds and ways." Smithsonian Report no. 1907: 565-615.
'Gray, J.

1953 "The locomotion of fishes." In Essays in Marine Biology. Oliver and Boyd,
Edin])iirgh.

BIBLIOGRAPHY 327

Gudger, E. W.

1932 "Cannibalism in sharks and rays." Sci. Monthly 34: 403-419.
^Harris, J. E.

1953 "Fin patterns and mode of life in fishes." In Essays in Marine Biology.

Oliver and Boyd, Edinburgh.
Herald, E. S.

1953 "Spotted cusk eel, the strange fish that stands on its tail." Calif. Fish and

Game 39: 381-384.
"Jordan, D. S.

1905 A Guide to the Study of Fishes. Holt, New York.
"Jordan, D. S. and B. W. Evermann

1900 The Fishes of North and Middle America. Bull. U.S. Nat. Mus. no. 47,

Washington, D.C.

1908 American Food and Game Fishes. Doubleday-Page, New York.
*La Monte, F.

1946 North American Game Fishes. Doubleday, New York.
Ley, Willy

1951 "The story of the fish Angitilla." In Dragons in Amber. Viking Press, New
York.

Linton, E.

1907 "Notes on the habits of Fierasfer affinis." Amer. Naturalist 41: 1-4.
*Longley, W. H. and S. F. Hildebrand

1941 Systematic Catalogue of the Fishes of Tortugas, Florida. Carnegie Institute of
Washington, Publ. 535.
*Norman, J. R.

1931 A History of Fishes. Benn, London.
* Norman, J. R. and F. C. Fraser

1938 Giant Fishes, Whales and Dolphins. Norton, New York.
Orcutt, H. G.

1950 "The life history of the starry flounder, Platichthys stellatiis (Pallas)." Calif.
Dept. Nat. Res., Div. Fish and Game, Fish Bull. no. 78.
Phillips, C.

1952 "An observation of flight in the pompano." Copeia: 203.
*Roedel, P. M. and W. E. Ripley

1950 California Sharks and Rays. Calif. Dept. Nat. Res., Div. Fish and Game,
Fish Bull. no. 75.

Smith, J. L. B.

1951 "A case of poisoning by the stonefish, Synanceja verrucosa." Copeia: 207-210.
*Springer, S.

1943 "Sharks and their behavior with particular reference to eight genera impli-
cated in reports of attacks on man." Coordinator of Res. & Dev., USN Emergency
Rescue Equipment Section.

Ta Volga, W. N.

1954 "Reproductive behavior in the Gobiid fish, Bathygohins soporator." Bull. Amer.
Mus. Nat. Hist. 104: 427-460.

Townsend, C. H.

1929 Records of changes in color among fishes. N. Y. Zool. Soc.

Walford, L. A.

1937 Marine Game Fishes of the Pacific Coast from Alaska to the Equator.
University of California Press, Berkeley, California.

328 BIBLIOGRAPHY

*Young, J. Z.

1950 The Life of Vertebrates. Clarendon Press, Oxford.

CHAPTER 10: THE REENTRANTS

^Anthony, H. E.

1928 Field Book of North American Mammals. Putnam's, New York.
*Carr, A.

1952 Handhook of Turtles. Comstock, Ithaca, New York.
Carr, A.

1955 "The riddle of the ridley." Animal Kingdom LVIII: 146-156. Reprinted

from The Windward Road by Archie Carr, Knopf, 1955.
McBride, A. F. and D. O. Hebb

1948 "Behavior of the captive bottle-nose dolphin, Tiirsiops truncatus." Jour.

Comp. Physiol. Psych. 41: 111-123.
*Norman, J. R. and F. C. Fraser

1938 Giant Fishes, Whales and Dolphins. Norton, New York.
^Peterson, R. T.

1941 A Field Guide to Western Birds. Houghton Mifflin, Boston.

1947 A Field Guide to the Birds. Houghton Mifflin, Boston.
*Pettingill, O. S.

1953 A Guide to Bird Finding. Oxford, New York.
*Pope, C. H.

1949 Tttrtles of the United States and Canada. Knopf, New York.
*Pope, C. H.

1955 The Reptile World. Knopf, New York.
*Pough, R. H.

1953 Auduhoyi Guides: All the Birds of Eastern and Central North America.

Doubleday, Garden City, New York.
*Schmidt, K. P. and D. D. Davis

1941 Field Book of Snakes of the United States and Canada. Putnam's, New York.
Seton, E. T.

1953 Lives of Game Animals. For sea otter, see Volume II, Part II. Reissued from

1923 edition. C. T. Branford, Boston.
Williams, G.

1950 "Practical joker of the high seas." Saturday Evening Post, October 7: 32-33,
169-172.

INDEX

Reference to page numbers for figures is made in italics. Reference to color plates
is made in text under each species. Because of space restrictions, reference to
group and some species names have been omitted as in the following cases;

Example a Family Rachicentridae would be given by type genus Rachycentron.
Example h The red, black, and broom-tail groupers are indicated simply by the

word "grouper."
Example c All species of the genus Acropora (e.g. cervicornis, palmata') are

referred to by the genus name only.

abalone 21, 120, 121

Abudefduf 253

abyssal zone JO, 18-20

Acanthocyhium 210

Acanthurtis 265

Achirus 298, 299

Acipenser !80

Acropora 24, 102, 103

Adamsia 103, 114

adaptation (see evolution 68-73) 27-29

adaptive radiation 71

advertisement 43-45, 262, 302

Aerosoma 128, 129

Aetohates 139-173

Agardhiella 85, 116

Agarum 82, 83

Agnatha 132-135

Alaria 80, 83

albacore 210, 211

Albula 183

Alcidae 309

Alcyonium 96, 103

Alectis 219

alewife 216, 217

algae 16, 17, 23, 76-85, 79, 81, 82, 84

allmouth 300

Alopias 151

Alosa 185

Alphestes 230

alteration of generations 94, 95

Ahttera 267, 268, 268

ambergris 318

amberjack 213, 214

a-mi-kuk 310

Amniocoelrs 133

Ammodylus 206

Amoeba 87

Amphineura 119-121

Amphinomidae 109

Amphioplii.s 128

Amphioxns 21, 130, Ul

amphipod 116

Amphistirhus 252

Anacanthini 284, 292-294

anatomy, bony fish 178; shark and ray 136

Anarhichas 289

Anchoxnella 186

anchovy, striped 186, 186

anemone 21, 38, 44, 47, 53, 63, 100-104, 119

angelfish 34, 44, 64, 261-265, 264

Angelichthys 263

angler 21, 39, 40, 41, 44,' 45, 299-302, 300

Anguilla 191

Anistotrevnis 241, 242

Annelida 48, 107-111

Anomia 123, 124

Anseridae 309

Anledon 128, 130

Antenriiiriiis 301

Antherinidae 186, 202-203

Anthozoa 100-104

Aphrodite 108, 109

Aplysia 40, 44, 122

Apodes 73, 180, 190-195

Apogonichthys 223

Arachnida 117

A r bad a 128

Area 123. 124

Arcliiteclonia 120

Arcliiteulhis 125

Archosargus 244

arctic 15, 17

Arenicola 108, 111

Argentinidae 188

Argonaula 123, 125-126

Arthropoda 49. 107, 111-119

Ascopliyllum 80

Astarte 123

Asterias 128

Asterida 127

Astrangia 96, 103

Astrea 120

Aslro.scopus 283

Athecae 307

Axilostoma 193, 200

Amelia 96, 99

Autolytus 109

autotomy 44-45, 112, 127

Auxis 209

Aves 309

avicularia 106, 107

av\a 184

Ayresia 254

bacteria 3, 5, 36, 36
Bagre 1 95
bagre sapo 285
Bairdella 247
Balaena 317
Balaenoptera 316
Balanoglossus 130, 131
Balanus 113, 115
Balerwphyll'a 96, 104
Batistes. 26^

329

330

INDEX

104, 111, 125, 131, 300

banana fish 183

barbero 265

barnacle 21, 23, 32, 38, 113, 115

Barnea 123, 124

barracuda 40, 51, 65, 204, 205, 205

barriers to dispersal 27, 32

bass 223-234; black sea 226, 226; blue and gold
fairy 234; California kelp 225; California white
sea 248; channel 24S, 249; Gulf sea 226; midget
233, 233; rock 225; shortfin sea 248; silver 225;
spotted kelp 226; striped 34, 35, 224, 225

batfish 41, 44, 302, 302

Bathygobius 280

Bothystoma 239, 240

Batrachoididae 284-285

baya 229

Bdellostoma 135

Bdelloiira 105, 105

beau gregory 253

beche-de-mer 129, 130, 291

behavior 46-52

Belonidae 197-198

benthic subprovince 10, 18, 19-22

bergall 256

Berycoidei 207-208

big-eye 7, 234-235

billfish 197-198

bioluminescence 8,

birds 309

blackfish 255

blacksmith 254

blanquillo 282-283

Blennius 287

blenny 17, 21, 32, 34, 39, 287, 288, 255

blood 65, 86, 106, 142

bluefish 52, 21S, 219

blue-head 102, 257

boccacio 273

Bodianux 257

bonaci 229

bonefish 40, 1S2, 183

Bonellia 1 1 1

bonito 199, 210, 214

bore, tidal 12

boreal seas 15, 17

Bos.tea S4, 85

Boston blackfish 293

boxfish 64, 271

Branchioreriaritlnis 95

Brachiopoda 18, 123, 126

Brachydeiilerus 240

Brama 222

bream 240, 245, 245

Brex'oortia 185

brim 244

Bryopsis 78, 79

Bryozoa 18, 21, 23, 106-107, 106

bug, sand 114, 116-117

Bugula 106, 107

Bulla 120

bumper 216

buoyancy (see flotation and support) 2, 6

burbot 294

burro 240

Busycon 120, 121

butterfish 221, 222

buttcrfiy fish 39, 40, 43, 44, 68-73, 261-262

cabezone 276
cabrilla 225, 229, 231
cachelot 318
caesar 239, 239
Calamus 243, 244
Calanu.s 113, 115
Calappa 114

Calcarea 91-92

calcium 4, 23

Calliostoma 120

Callorhinus 312

Cancer 114

Canthidermis 264, 267

Canthigaster 271

canyon, oceanic 10, 10

capitan 256

Caprella in, 116

Carangidae 213-219

Caranx 205, 215, 216

carbon dioxide 5

Carcharias 141, 147

Carcharinus 138, 141, 155, I5G

Carcharodon 140, 148

cardinal fishes 222-223

Cardium 123

Carelta 306

Carnivora 309-314

carnivore 33, 34, 309-310

carrying capacity 33

Carybdea 96, 99

Cassiopeia 96, 100

Cassis 121

catalufa 234

catfish 64, 194, 195-196, 196

cavalla 210

Caulolatilus 283

Ccntropomus 223

Centropristes 226

Cephalochordata ,130

Cephalopholis 231, 232

Cephalopoda 125-126

Cephaloscyllium 146

Ceratium 88, 88

Cerebratulus 105, 106

cero 210

Cestus 104, 104

Cetacea 315-321

Cetorhinus 149

Cliaetodipterus 261

Chaetodon 262

Chaetognatha 106

Chaetoplerus 108, 111

Chalina 91, 93

Challenger 123

Chanos 184

characin 195

Cheilodipteridae 222-223

Chelonia 302-308

Chelonia 305

cherna 230

chien de mer 154

Cliilornycterus 271

chimaera 63, 64, 176

Chimaera 176

chirivita 263

chiro 182

chiton 119-121, 120

Cliloroscombrus 216

Ctioridrus 84, 85

chopa 246

Chorda 84, 85

Chromidcs 252-254

Chrornis 254, 255

Chrondrostei 179-180

chrysomoiiad 88, 88

chub, Bermuda 246

ciguatera 236, 266

Ciliata 88, 89-90

Ciona 131, 131

Cirripcdia 1 15

Citharictithys 297

Cladocera 113

INDEX

331

Cladofiliora 78, 79

tlam 18, 21, 48, 49, 64, 123, 124

clainacore 259

classification 73-75

cling fish 285-286

Clinocottus 277

Cliona 93

Clionopsis 123

Clupea 184, 185

cobia 44, 220, 220

cocino 266

cockeve pilot 253

cod 17, 292-294, 293

Codiiim 79, 80

Coelcnterata 47, 63, 93-104

Colobus 198

color 7, 25; and depth 8, 40, 54

coloration, adaptive 39-46, 41, 42, 262

color change 39, 40, 125, 179, 280, 287

Colymbidae 309

commensalism 38, 105, 118

community 15, 28, 30

competition 19, 25, 27

conch 121

conchfish 7, 121, 223

coney 231

conservation (see introduction) 304, 310-311, 316

continental shelf 9, 10, 20; slope 9, 10

Conns 122
convergence 71
convict fish 276, 276

Convoluta 105, 105
Copepoda 18, 113, 115

coral 4, 23-25, 30, 32, 63, 95, 96, 97, 100, 101, 102,
104, 255

Corallina 84, 85

Coral Hum 100, 102

corbina 248, 250, 251

cornet fish 201
coronado 213

Coryphaena 199, 221, 318

Cotius 276
cowfish 40, 42, 269

cowrie 121

crab 22, 23, 38-39, 41, 45, 72, 91, 95, 103, 105,
110, 113, 114, 117, 118, 118

crab-eater 220

crampfish 168

Crangon 114, 117

Craniomi 278-279

crayfish 72

Crepidula 120, 121

Creole fish, southern 232, 232
. Cribina 103

croaker 66, 246-251

Crustacea 19, 20, 21, 22, 44-45, 49, 112-117

Cryptocanthodes 289

Cryptochilon 121

cryptomonad 88, 88

Ctenodiscus 128

Ctenophora 104

cubbyu 251

cubby yevs' 220

cubomedusan 99

Cucumaria 128

cucuyo 266

cultiis cod 276

dinner 256

currents 12-14, 13, 16, 32

cusk 294

cusk eel 290-291

cutlass fish 211, 211

cuttlebone 125

cuttlefish 44, 125

Cuvierina 123

Cyanea 19, 99
Cyanophyta 78
Cyclops 115
Cyclostomata 133
Cynoscion 247, 248
Cypliorna 120
Cypraea 121
Cyprinodontidae 196-197

Dactylometra 96, 99

Dactylopterus 279

Dalatiidae 160

Daphnia 113

Dasyalis 139, 162, 170, 171, 172

dead man's fingers 96, 103

decapods 116-117

Decapterus 215

deep scattering layer (DSL) 35, 36

deep sea bottom 10, 10

Delphinus 319, 320

demoiselle 43, 252-254

Demospongiae 93

Denlalium 120

dentex 243

depth 6-7; and body form 11, 19-20

dermal denticle 136

Dermochelidae 307-308

Desmare.slia 80, 80

devilfish 174, 175.-176

devil's apron 82, 83

diablo 302

Diadema 127, 128

diatom 18, 19, 20, 77, 11-19.

dinoflagellate 88

Diodon 271

Diplectrum 233, 233, 234

Di plod us 245

Discocephali 282

discomedusan 99

disguise 45

dispersal 30-33

distribution 30, 30-33

doctorfish 265

dogfish 64, 146, 151, 159, 159

Doliolum 131

doUarfish 221

dolphin 199, 220, 221, 309, 315, 318-321, 319

dorado 221

Dormitator 281

drum, black 249, 249

dugong 314

dulse 84. 85

Dunaliella 78, 79, 87

Echeneis 282

Echinocardium 128

Echinodermata 18, 47, 126-130

Echiurus 108, 111

ecology, definition of 1

Ectocarpus 80, 82

eel 16, 22, 65, 190-195; rock 17, 288; slime 134;

wolf 290
celgrass 22, 76, 85, 305
eelpout 290, 291
Elagatis 214

electric shock 166, 107, 283
Electrophorus 167
Elops 182
Embiotocidac 252
Emmydrichthys 272
Engraulidae 186-187
Enhydra 310
enjambre 232
Ensis 123, 124
Enteromorpha 78, 79

332

INDEX

Entosphenus 134

Eolis 122

Epliippidae 261

Epinephelus 42, 227, 228, 230, 231

Epitoniiim 120

Eques 42. 251

Eretmochelys 305

Esihrichtius 317

escolar 64

Eubalaena 317

Eucinostomus 246

Eiiglenophyta 77

Eiimelopias 313

Eunice IDS, 109

euphausians 113, 116

Euplectella 91, 93

European weaver 44, 45

Eurythoe 109

Eusmilia 101, 103

Euspongia 90, 97, 93

Evadne 113

evolution 27, 38, 68-73, 69, 15, 132-133, 161-162

Exocoetidae 199

eye 8, 49, 112, 125, 138; camouflage 41, 70, 262

Fasciolaria 120

fatback 204 .

features of the sea 9, 10, 10

feeding mood ()5, 140, 142

feeder, chemical 52; filter 34; visual 52

Eihiila 93

Herasfcr 291

filefish 45, 64, 267-268, 268

fins, bony fish 177-178, 178; shark and ray 136, 138

fishes of the king 203

fishing frog 299, 300

fish lice 1 15

Fislularia 201

Elagellata 77, 87-89

flatfish 21, 40, 41, 294-299

flat worms 104-105

flea, beach 116; sand 113, 116; water, 113, 113

flight (see synentognaths 197-199) 217, 278

flotation 4, 9, 19

floinider 295-298, 297

fluke, blood 63, 104; northern 296, 296

flying fish 40, 199

flying gurnard 279, 279

food chain 28, 33-37, 36, 37

foraminiferans 23, 89

frogfish 301

fry, green 186, 187, 202

Fucinus 120

Fitcus 21, 80, 82

Fundidus 197

Cadus 293

gag 229

Caleichtliys 195

Caleorerda 137, 140, 141, 153

Galeoidea 145-159

Caleorliiniis 157

gambuso 156

Gaintnarus 113, 116

gar 197-198

garibaldi 253

C.arrupa 227

gases in sea 4-5

Gasterosteus 200

('•a\tropelecus 199

Gastropoda 121-122

gata 145

Caviidae 309

gene 68-69

Oenyonetnus 249, 250

Germo 210

Gerres 245

Geryonia 97

ghost fish 183

Gigartina 84, 85

Ginglytnostoina 137, 145

Girella 246

glass-eye 235

Globigerina 19, 88, 89

goatfish 207, 208

Gobiesox 286

Gobiidae 21, 39, 279-281

Gonionemus 96

Gonyaulax 88, 88

Gorgoncepltalus 103, 127, 128

Gorgonia 101, 102

gorgonian 45, 97, 98, 100-104, 102, 127, 193, 255,

264
Gramma 234
grampus 321
grande ecaille 181
Grantia 91, 92
grayfish 159
graysby 232
greenfish 246

greenling 17, 275-276, 275
grouper 41, 42, 66, 228-232
growth and adaptation 29
grimion 203

grunt 32, 66, 72, 238-242, 241
guacamaia 259
guaguanche 204
guitar fish 164-165, 165
Gulf Stream 14, 22, 24
gunnel 288
Gymnodinium 88
Gymnodontes 266
Gymnogongrus 84, 85
Gymnolhorax 73, 74, 194
Gymtiura 172

liaddock 293

Hacmulon 32, 240, 241

hagfish 134, 135

hake 292

halfbcak 198-199

halfmoon, California 246

halibut 17, 295, 295, 296

Halirhoerus 313

Halichondria 91, 93

Halirystis 96

Halimeda 23, 79, 80

Haliotis 120

Halobates 118, 119

hamlet 230

Haplodoci 284-285

Haplomi 196-197

liardhead 250

liarletiuin scrranid 42, 233

harvest fishes 221-222

hatchet fish 199

hearing (see behavior 46-52)

hcctocolylus 123, 126

Hemibranchi 199-201

Hcmichordata 130

Hemirhamphidac 198-199

Hrmihiplirw. 277

Henriiia 128

Hcjit ranch us 145

herbivore 8, 33, 35, 310

liermaphroditism, barnacles 115

Hermodice 108, 109

herring 17, 34, 35, 72, 184-187, 184

Heterodontidae 143-144

Heterosomata 294-299

INDEX

333

Heterostirhus 287

Hexatlinellida 93

Hexagrarnmos 275, 276

Hexanchus 144

hind 231

Hippa 21, 114, 116, 164

Hippocampus 201

Hippoglossus 295, 296

Hircina 92, 93

Hislrio 301

hogfish 256, 257

Holconoti 251-252

Hohnanthus 262, 263

Holocentrus 207

Holocephali 176

Holothuria 128, 129, 130

Homarus 117

Hoplopagrus 238, 2i5

horsehead 218

horse latitudes 12

hoiindfish 198

Hydractina 95, 7/-/

hydrogen sulfide 5

hydroids 21, 23, 63, 94-95, 9S, 118, 122

Hydrolagus 176

Hydrophidae 308-309

Hydrozoa 94

Hynnis 217

Hypomesus 189

Hypoplecturus 233

Hypoprion 141, 155

Hyporhamphux 198

Hypotremata 161-176

Hypsypops 253

ichthyocistn 205

inflation 146, 277

Iniomi 189

Insecta 119

instinct 47

invertebrate, definition 86

Iridio 257-258

Irish moss S4, 85

isabelita 263

isolation 27

isopods 116

Isospondyli 180-190

Istioplwrus 212

Isurus 141, 147

jack 213-219

jaqueta 253

jellyfish 2, 18, 19, 20, 63, 94, 96, 99, 104,

131
Jenkensia 186, 187
jewelfish 253

jewfish 29, 65, 66, 226-228, 227, 228
jocu 236
john-paw 231
jugular fishes 284-294
jumper 204

kalan 310

Katsuwomis 199, 211, 210

kelp 64, 80, 82, 83

kelp basses 16, 225-226

killifish 21, 22, 30, 196-197, 197

kingfish 210, 250

krill 34, 112-113, IH, 116

Kyphosus 246

Labroid fishes 254-260
Lachnolaimus 256
Lactophrys 42, 269, 269, 270
ladyfish 40, 182, 183

Lagocephahis 270

Lagodon 245

Laminaria 82, 83

Lamna 148

lampreys 133-134, 134

langouste 72

lateral line 48, 50, 65

laver 84, 85

law of the minimum 31, 31

leatherjacket 213, 21}

Leioslomus 249, 250

Lepas 11), 115

Lepidochelys 307

Lepidonotus 108, 109

leptocephalus 191, 192

Leplocephaliis 192

Leptosynapla 128

Lessionopsis 80, 83

Leucifer 114

Leucoselenia 91, 92

Leuresthes 203

Lihinia 114

life, abundance of 4, 13, 17, 18, 35, 36, 36, 316;

diversity of 27; origin of 26-27
Ligia 113

light 6-8, 18, 20, 31, 35, 39. 53-54, 58-59
limiting factors 6, 23-25, 30-31, 31, 32, 33
limpet 120, 121
/./«!(//(// 105, 118, 118
ling, squirrel 294, 294
ling cod 276
Lingula 72, 123, 126
lionfish 272, 274
IJtlorina 120, 121
lizard fish 189-190
Loboles 234
lobster 72, 114, 117
locomotion (see movement)
Loligo 123, 125, 126
lookdown 218
I.ophias 45, 300
Lophiomus 301
Lophobranchi 201-202
Lopholatilu.s 283
Loricati 271-277
loro 258, 259
lAitianiis 236, 237
l.ylocarpus 95, 96

machete 21 1

mackerel 32, 40, 41, 43, 72, 208-211, 215, 220

Macrocystis 82, 83

mail-cheeked fishes 271-277

Makaira 212

maki-maki 64, 266

Malacantlms 282

Malacostraca 116

Mammalia 18, 309-321

manatee 16, 309, 315

mangrove 22

man-of-war fish 38, 43, 220-221

Mania 175

mapo 280

margate 73, 240, 242

marlin 212

marsh grass 21

Mastigophora 77, 87-89

Meandra 102, 103

Medialuna 246

medico 265

medusas 93-104, 96

Megalopidae 181-182

Megaptera 317

Melanogrammus 293

Mellila 128

334

INDEX

menhaden 185, 1S6

Menidia 203

Menticirrlnis 247, 250, 251

Merluccius 292

mermaid's fish line 82, 83

merman's shaving brush 79, 80, 129

Mesichthys 180-181, 196-202

Metacrinus 128

Metridium 96, 103

Microciona 91, 93

Microgadus 293, 294

Micropogon 249, 250

Microspatlwdon 254

midshipman 285, 285

milkfish 183-184, ISJ

Millepora 95, 97, 255

miller's thumb 276

mimicry 45-46

Mirounga 314

Mneniiop.sis 121

Mobula 175

mojarra 73, 241, 245-246, 245

Molgula 131, 131

Mollusca 22, 48-49, 119-126

molly miller 280, 287

Monachus 314

monkfish 160, 161, 161, 300

Monocanthus 268

moonfish 218

Morone 225

moss animal 106-107

moss-bunker 185

mountains, oceanic 10, 10

movements, bony fish 177-179; and chumming 67;

invertebrate 46-49, 86-131; shark and ray 138-

139, 161-162
mud-belly 259
mud line 22
Mugil 204

mullet 35, 36, 184, 204, 204
Mutlus 208

Muraenidae 73, 193-195
Miirex 120, 121
mussel 21, 123, 124
Musteliis 152
mutation 69-70
muttonfish 236
mutualism 38-39, 91, 95
Mya 124

Mycteroperca 229, 230
Myliobatis 174
Myoxocephaliis 277
Mysticeti 316-317
Mytilus 123, 124
Myxine 135

Nassa 120, 121

Nalica 120, 121

natural selection 70

Naucrates 214

nauplius 1 12, 11}

nautilus, chambered 19

Nebalia in, 116

needlefish 197-198

nekton 18, 32

Nematistius 219

nematocyst 63, 94, 95, 99, 100, 103, 122

Nemertea 105, 106

Neotliunniis 210

Neptune's cup 91

Nereis 48, 48, 63, 107, 108, 109

Nereorystis 82, 83

Nerila 120

neritic province 10, 20-22

nerve fiber, giaitt 125

nervous system (see behavior 46-52) 48, 93-94,

132
niche 28, 33

nictitating membrane 152
nitrogen 3
Noctihica 88, 88
nohu, black 272
Nomeics 220
Notidanoidea 144-145
Noturus 195
nudibranch 91, 122
nuisance 253
numbers, and deep sea 35, 36, 36; of individuals

27, 33, 36; pyramid of 36, 37; of species 27;

and temperature 17
niuTibfish 168
Nymplwn 118

oarfish 19

Ohelin 95, 96

oceanic province 10, 18-20

ocean sun fish 19

ocellus 48

octopus 18, 21, 39, 40, 43, 44, 48, 49. 63, 66, 100,

125-126
Oryurus 208, 237
Odontoceti 317-321
Ogcoceplialus 302
oldwife 216, 259, 266
olfactory sense, fishes 48, 50, 140
OligapUtes 213
Oliva 120

omnivore 33, 34, 310
Oncorhynchus 187, 188
ooze 9, 19, 89, 122
opaleye 246
Ophichthys 192, 193
Ophidioidei 284, 290-291
Ophiodon 276
Ophiurida 127
Opsaniis 284
Orcinus 321
Oreaster 127, 129
Ortliopri.stes 242
Osmerus 189

Ostariophysi 180, 195-196
Osteichthyes 73
Ostracion 270
Ostracoda 113, 113
Ostracodermi 266
Ostrea 123. 124
Otariidae 311-313
Otophidium 291
oviparous 139
ovoviviparous 139
oxygen 4-5
Oxylebius 276
Oxyulis 257

oyster 18, 22, 31, 48, 64, 72, 123, 124
oyster drill 120, 121
'oysterfish 255

Padina 82, 83

paguala 261

Pagurus 114

palometa 216, 217

Palometa 222

Panulirus 114, 117

papagallo 219

Paratahrax 16, 225

Paratirlitliys 296

parallelism 71

Paranthus 232

parasitism 35, 39, 115, 132-133

I'arexocoetus 199

INDEX

335

pargo 235-238

parrotfisli 16, 53, 258-260, 260

I'alelln 120

peacock tail S2, 83

pcarlfish 38, 129, 291. 291

peclif i:)retre 273

I'ecten 12), 124, 294

Pfdiculati 299-302

pegador 282

Pelagia 99

pelagic subproviiice 10, 18, 19-20

Pelagot'liynis SO, 83

Pelagothiiria 128

Pelnmis 309

Pclecypoda 122-124

Peneus 114

Penicillus 79, 80, 129

Pennnria 95, 98

Pennatula 96, 103

Peprilm 221

Percesosces 202-206

perch 224, 225, 247, 247; surf 17, 252, 252

I'ercoidei 222-251

periwinkle 21, 120, 121

permit 217

pescado aziil 253

pescados del rey 203

peto 210

Pelrornetopon 231, 232

Petromyzon 134

Phaeophyta 80-83

Phalacrocoridac 309

Phanrrodon 252

Pharyngognathi 254-260

pharynx 109

Philonexh 123, 125

P}ioca 313

Phoraena 321

phoebe 233

P/(o/a 288

Phoronis 105, 107

phosphorus 3

Pliotocoryniis 39

photography 53-39

photosynthesis 4, 5, 6, 7, 33, 76, 78, 80, 83

Phyris 294

Phyllopteryx 201

Physalia 99, 221

Physeter 318

piciida 204

pigfish 242

pike 196-197, 223

pilchard 72

pilot fish 214, 214

Pimelometopon jiitlclier 256

pinfish 245

Pinna 123, 124

Pinnipedia 311-314

pintado 210

pipefish 22, 45, 201

plankton 6. 7, 9, 17, 18, 19, 20. 32, 33. 34-37, 64

Platichtliys 296

Platophrys 298. 298

Platyhclminthes 104-105

Platyrltinoidis 165

Plectognathi 64, 266-267

Pleiirobranchia 104, 104

Pleuronectes 296

Pleurotremata 139-161

Pneumatop}iorus 209

Poecilidae 196-197

Pogonias 249

poison 34, 64, 100, 122, 124, 125, 129, 169, 176,

195. 270, 272, 308
polka dot 231

Pollarliius 293

pollack 293

Polychaeta 108-111

Polychoerus 105. 105

polyclad 105, 105

Polynemus 206

polyp 93-104, 96

Polysiplionia 84, 85

Pomaranthus 262, 263, 264

Pomacentriis 262

Poniadasis 240

Pomalomus 219

pomfret 222

pompanito 21 7

pompano 73, 216, 217, 217, 222

pompon 242

population (")8

porcupine fish 43, 64, 271

pore cell 47

porgy 16, 242-245, 243

PoricJitliys 285

Porifcra 47, 90-93

porkfish 41. 241

Poronohn 221

Porphyra 84, 85

porpoise 66. 67. 71. 315, 318-321, 319

Portuguese man-of-war 19, 22, 38, 43, 63, 94,

99, 129, 306
Paste hi a 80, 83
prawn 114, 116
pressure 5-6
Priacanthns 235
priestfish 273. 273
Prionare 141, 154
Prionodes 42. 233, 233, 234
Prionolus 278
Pristis 164

prochordates 18, 126, 130, 131
Promicrops 227
Protococcus 78
ProtoMa 19. 86-90
province 15; benthic 10, 18; neritic 10, 18, 20-22;

oceanic 10, 18, 20-22; pelagic 10, 18
Pseudoceros 105
Pseudopleuronecles 297
pseudopodia 88, 89
Pseudopriacanthiis 235
Psendoscarus 259
Psolus 128
Pteria 123
Pterognathus 288
Pterois 272

pteropod 18. 19. 20, 122. 123
puffer 34. 64. 270-271
purple sail 96, 99
pycnogonid 118-119

queenfish 248

rabbitfish 270

rabirubia 237. 238

Rabirubia 238

race, human 69

rachiglossan 121

Rachycentron 220

radiolarian 18, 88, 89

radula 119. 121. 122

Raja 136, 139, 165, 166-167

ratfish 176, 176

ray 20, 21, 41, 44, 161-176; anatomy 136; butter-
fly 172, 772; cow-nosed 173, 174; eagle 63, 136,
139, 173-174, 173; electric 167-169; evolution
of 161-162; manta 34. 53, 175, 220; round
sting 40, 43. 170, 171; sting 63, 162, 169, 170,
171-172; torpedo 168, 168

336

INDEX

razorfish 257, 2^1

red fish 249, 256

red tai 243

red tide 63. 88

reef, atoll 24, 2'i; barrier 24, 25; fringing 24, 25

reef fish 254, 255

regeneration (see autotoiny) 89, 104-105

remora, shark 282, 2S2

Renilla 9), 106

repellent, shark 142

Reptilia 303-309

respiratory system, 108, 112, 122, 137, 304

rhabdocoel 105, 105

Rhacochilus 252

Rhegnopteri 205-206

Rhineodon 150

Rhinobatoidea 164-165

Rlunohatos 164

Rliinoptera 174

Rliizophora 22

Rhizopoda 89

rhizostome 99-100

Rhodophyta 83-85, S5

Rliodymenia 84, 85

ribbonfish 19, 42, 251

Rissola 291

robalo 223

Roccus 225

rock beauty 263

rock cod 273

rockfish 17, 225, 229, 230, 272-275

rockling 294

rock trout 275

rock weed 21, 80, 82

Roncador 249, 250

ronco 72, 238-242, 241

roosterfish 218, 219

rosefish 273

Rossi a 12)

Rotifera 106, 106

rudderfish 215, 246

runner 44, 214, 216

Ryplicus 233

sabalo 181

Sabellidae 111

Saccnlina 113, 115

Sagitta 105, 106

sailfish 39, 44, 212, 212

sailors choice 240, 241, 242, 245

sailor's purse 165

salenia 244

salinity 3, 14, 32

Salmo 187-188

salmon 187-188, 187, 188

salmon herring 184

Sal pa 131

salts 3-4

sand bug 21, 116; dab 297, 297; dollar 127-128,

128; fish 233, 282. 285; launce 206-207, 206
Sartodina 89
Sarda 210

sardine 72, 184, 185
Sardinella 185
sardincra 230

Sargasso Sea 7, 12, 13, 22-23, 191, 192
sargasso weed 1, 21, 45, 80, 80, 83, 268
Sargassum 22, SO, 83
sargassum fish I, 23, 45, 301
sargo 242, 245
saurel 215
saury 198-199
sawfish 65, 16}, 163-164
scabbard fish 211
scad, 214, 215

scale, placoid 136

scallop 48, 49, 125, 124, 294

scaly-fin fishes 261-265

scamp 229

Scaphopoda 122

Scarus 259, 260

scattering 53-54

Schilbeodes 195

schistosome 104, 105

schoolmaster 236

Sciaena 249, 250

Sciaenops 249

scissors 198-199

Sclerodermi 266

Scoliodon 156, 157

Scomber 209

Scomberesocidae 198-199

Scomberomorus 209, 210, 220

Scorpaeria 274, 275

Srorpaeniclttliys 276

scorpion fish 40, 41, 45, 63, 272-275, 274

sculpin 17, 40, 43, 275, 276-277, 277

scungill 120, 121

scup 243

Scyliorliinus 146

•Scyllis 108, 109

Scyphozoa 99-100

sea, origin of 26; and plasma 27; size of 2

sea basses 223-234; beaver 310; colander 82, 83;
cow 314, 514: cucumber 128, 130; fan 101, 102;
feather 96, 103, 130, 195; gooseberry 104, 104;
hare 122; horse 22, 45, 201-202; lettuce 78,
79; lily 130; lion 66, 311-313, 512; moss 38,
78, 79, 84, 85; mouse 108, 109; otter 83, 309,
310, 510, 321; palm 80, 83; pansy 96, 103; pen
100, 103; plume 102, 264; pumpkin 80, 83
purse 165; raven 277: robin 278-279, 278
serpent 192; slug 34, 40, 43, 44, 46, 91, 122
snail 17; spider 23, 91, 118, 118; squab 266
squirt 18, 119, 131; stridcr 118; toad 299
turtle 32, 66, 282, 304-308; trout 247-248
248, 275; urchin 21, 22, 47, 63, 66, 127-129
128; walnut 104, 104; wasp 96, 99; weed 76-85
whip 98, 102, 195

seabather's eruption 104

seal 35, 66, 309, 311-314, 515, 514

Scbaslodes 17, 273-274

selection (see evolution 68-73), 29

Selene 218

sennet 204

senorita 257

senses (see behavior 46-52) 138, 179

Sepia 44, 125

Sepioteiithis 126

sergeant fish 220, 223

sergeant major 43, 253

Seriola 213, 214, 215

Seriphus 248

Scrranidae 223-234
. Serrano 234

shad 185, 245

shadow elimination 41

shagreen 1 36

shark 51, 64, 139-161; angel 160-161; basking
19, 34, 66, 149, 149-150; bay 156; black-tipped
141, 155; blue 141, 154, 154; bone 149
bonito 148; bonnet IfS, 158-159; brown 156
bull 155; cat I4t)-I47; comb-toothed 144
cow 144, 144; cub 155; fox 151; frilled 19
Clreenland KiO; griset 144; ground 141, 155-
156, 156; gurry 160; hammerhead 139, 141,
158-159, 319: horned 144; Lake Nicaragua
155; lemon 141, 155; leopard 141, 142, 152,
155; mackerel 139, 140, 147-149; mako 41,
141, 147, 148; man-eater 140, 148; mud 144;

INDEX

337

nurse n7 , 145, 145; oil 157; pcrlo 145;
porbeagle 148; Port Jackson 13(3, NJ, 144;
requiem 152-158; sand 141, 146, 147; sand-
bar 156; seven-gilled 145; sharp-nosed 156,
157; six-gilled 64, 144; sleeper 160; soup-fin
157, n'; swell 146, 146: thresher 150-151,
151; tiger 137, 139, 140, 141, 153, 153, 319;
whale 34, 53, 66, 150, 150; white 36, 140,
148, 148; white-tipped 156; yellow 154, 155

shark sucker 44

sheepshead 244, 245, 256

shell 120. 121-122, 124, 124

shellfish 269

shore 21-22; slater 113

shrimp 23, 113, 116, 117

sierra, Mexican 210

silicon 4

Siluridae 195-196

silver fish 211

siher king 181

silversides 186, 202-203, 203

singing fish 285

Siphonophora 18, 99

Sipunculida 1 1 1

Sipuncuhis lOS

Sirenia 314

size, and danger 66; and refraction 56

skate 136, 139, 165-167, 165, 172

skipjack 198, 205, 210, 216

sleeper 281

slippery dick 255, 257, 257, 291, 291

smell (see behavior 46-52) 48

smelt 188-189, 189, 202

smoothhound 152

snail 18, 21, 22, 23, 48-49, 63, 120, 121-122

snake, sea 63, 308-309, 309

snakefish 190, 190

snapper 22, 39, 235-238

snook 223, 223

soapfish, two-spined 232, 233

Solaster 128

soldier fish 207

sole 45, 295, 297, 298-299, 299

Solea 45

Soniniosus 160

spadefish 261

Spanish flag 274

Sparisoma 258-259

Spartina 21

spearfishes 65, 66, 211-213

species 27, 30, 69, 73-74

Sphenodon 303

Spheroides 270, 271

Sphyraena 204, 205, 205

Sphyrna 158

spicule 63, 90, 91, 91, 93

spines 63-64, 136, 265

Spondylus 123

sponge 18, 21, 32, 39, 47, 63, 83, 90-93, 91, 92,
119

sponge seaweed 79, 80

spongin 90, 93

spot 245, 250

Sqitalus 159

Squamata 308-309

Squamipinnes 261-265

Squatina 160-161

squeteague 247-248, 248

squid 18, 19, 20, 21, 43, 44, 48-49, 48, 63, 66,
123, 125-126, 318

Sqiiilla 113, 117

squirrel fish 7, 32, 64, 207

starfish 17, 22, 47, 103, 122, 127, 128, 129, 130

stargazer 21, 40, 44, 283, 284

Stenopus 114, 117

Slenorhynchus 45, 110, 117

Slenolomus 243

Stereolepis 227, 228

stickleback, two-spined 200, 200

stingaree 171, 171

stonefish 272

strobilation 96, 99

Strom bus 121

Stromeidae 221-222

Strongylura 198

sturgeon 72, 180, 180

subarctic 15, 17

subtropics 15, 15-16

suckfish 282

suctorian 88, 90

support (see buoyancy and flotation) 2, 20

surf fishes 251-252

surgeonfish 265

surmullet 207-208

swell toad 271

swim bladder 6, 18-19, 178

swimmer's itch 63, 104

swordfish 212-213, 321

Sycon 47

symbiosis 25, 37-39, 89, 91, 103, 117

Sytnpliurus 299

Synanceja 272

Synentognathi 197-199

Syngnalln'i.s 201

Sy nodus 190

taenioglossan 121

Taeniotoca 252

tambor 273

tang 44, 255, 265

taste (see behavior 46-52)

tattler 223

tarpon 22, 40, 65, 66, 181. 181-182

Tarpon 181

tautog 255, 256

Tautoga 255

Tautogolabrus 256

taylor 219

Tedania 91, 93

teeth 64, 136, 137, 163

Teleostei 180-302

temperate seas 15, 16-17

temperature 6, 8, 9, 14, 15-17, 23, 32

tenpounder 182. 182-183

Terebratulina 123

Teredo 124

territoriality 33

Testudinata 302-308

Tetraodon 266

Thalassia 76, 129, 185

Tlialassoma 257

thermocline 9

thornback 165

threadfin 205-206, 206

thread fish 219

Thunnus 210

tide 11-12

tidepool 21

tilefish 283

toad 302

toadfish 40, 43, 64, 65, 284-285, 285

tomcod 293, 294

tom tate 239, 240

tonguefish 299, 299

tope 157

Torpedo 168

totuava 248

touch (see behavior 46-52)

toxoglossan 121

Trachinocephalus 190, 190

338

INDEX

Trachinotus 216-217

Trachinus 44, 45

Trachurops 215

Trachurus 215

trachyline hydrozoa 95

trade winds 12

treefish 274, 274

trench, oceanic 10, 10

Triakis 141, 142, 152

Trichechus 315

Trichiurus 211

Trichodesmium 78

triclad 105, 105

triggerfish 64, 264, 266-267

Triglidae 278

tripletail 234

tropic bird 309

tropics 15, 15-16

trout 187-188

trumpetfish 45, 193, 200

trunkfisli 268, 269, 270

Tuhularia 95, 96

tuna 32, 66, 210

Tunicata 19, 21, 23, 131

turbellarian 104-105

turbot 267, 295, 297-298

Turitella 120

Tiirsioln 318

turtle 32-33, 35, 73, 302-308, 305, 306, 301, 30S

turtle grass 76, 85, 129

Ura 114

Viva 78, 79

Umbrina 249, 250

Upeneus 207-208

upwelling 3, 4, 5, 13-14, 16, 17, 23

Uranoscopidae 283

Urohatis 171

Urolophus 139, 171

Urosalpinx 120, 121

vagility 32

valence 30, 31, 31

vaqueta de dos colorcs 263

Velella 96, 99

Venus 123, 124

Venus flower basket 91, 93

Venus girdle 104, 104

Vermetus 120

Verrunculus 267

vertebrate, definition 132

vieja 259

viperfish 187

viscosity 4, 9, 19

vision (see behavior 46-52) 40

viviparous 139
Vomer 218

wahoo 65

walrus 309, 311

water 2, 4, 6, 7, 8, 9, 19, 53; currents 12-14, 13

water striders 119

waves, light 7; oceanic 11, 12

weakfish 247, 248

Weberian apparatus 195

westerlies 12

whale 30, 32, 34, 66, 309, 315; blue 34, 316, 317;
bowhead 317; California gray 317, 317; fin-
back 316; humpback 317; killer 34, 35, 36,
64, 65, 149, 317, 318, 319, 321; ridge-throated
316; right 317, 317; rorqual 316; sperm 31,
34, 125, 317, 318; sulfur-bottom 316

whalebone 316-317

whelk 21, 121

whiff 298

whitebait 189, 202, 203

whitefish, ocean 283

whitey 282

whiting 250-251, 251, 292

wind II, 13

worm 4, 8, 18, 19, 21, 22, 23; acorn 130; arrow
18, 21, 105, 106; bristle 63, 108, 109; budding
108; burrowing 110-111; errant 109-111; fan
111; flat 105, 105; lug 111; marine 108-111;
mounds 110; palolo 108, 109; parchment 108,
111; phoronid 105, 107; ribbon 106; sand 48,
107, 108, 109; scale 108, 109; segmented 107-
111; ship 123, 124

wolf fish 65, 289, 289

wrasse 53, 102, 254-258

wry-mouth 289, 289

Xanthichthys 267
Xenopterygi 284, 285-286
Xestoleheris 113
Xiphias 212
xurel de castilla 216
Xyrichthys 258

yellow belly 253

Zalophus 312, 312

zapatero 213

Zapteryx 165

Zoarces 290

zone, definition 14; geologic 9-10, 10; light 7, 8,

18; mangrove 22; nitrogen 3; phosphorus 3;

substrate 10, 17-25; temperature 15, 15-17
zoochlorellae 89, 94, 100, 103, 105
zooxanthellae 38, 89, 94, 100
Zostera 76, 85, 305