The relation of shellfish to fish in Oneida Lake, New York

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'Volume XVII

August, 1918 Number 27

CIRCULAR NO. 21
THE NEW YORK STATE COLLEGE OF FORESTRY

AT

SYRACUSE UNIVERSITY

HUGH P. BAKER, Dean

The Relation of Shellfish to Fish in
Oneida Lake, New York

BY
FRANK COLLINS BAKER

Investigator in Forest Zoology, 1915-1917
Prepared under the direction of Chas. C. Adams

Published Quarterly by the University
Syracuse, New York

Entered at the Postoffice at Syracuse as second-class mail matter

TRUSTEES

OF
THE NEW YORK STATE COLLEGE OF FORESTRY

AT

SYRACUSE UNIVERSITY

Ex OFFICIO

Dr. JAMES K. DAY, Chancellor Syracuse University.

Dr. JOHN HUSTON FIXLEY, Commissioner of Edu-
cation Albany, X. Y.

Hon. GEORGE D. PRATT, Conservation Commis-
sioner Xew York City.

Hon. EDWARD SCHOENECK, Lieutenant-Governor. . Syracuse, N. Y.

APPOINTED BY THE GOVERNOR

Hon. CHARLES ANDREWS Syracuse, X. Y.

Hon. ALEXANDER T. BROWN Syracuse, X. Y.

Hon. JOHN R. CLANCY Syracuse, X. Y.

Hon. HAROLD D. CORNWALL Lowville, X. Y.

Hon. GEORGE W. DRISCOLL Syracuse, X. Y.

Hon. FRANCIS HENDRICKS Syracuse, X. Y.

Hon. HENDRICK S. HOLDEN Syracuse, X. Y.

Hon. Louis MARSHALL Xew York City.

Mr. EDWARD H. O'HARA .Syracuse, X. Y.

OFFICERS OF THE BOARD

Hon. Louis MARSHALL President.

Hon. JOHN R. CLANCY Vice-President.

Hon. HENDRICK S. HOLDEN.. . Treasurer.

[2]

FACULTY

OF

THE NEW YORK STATE COLLEGE OF FORESTRY

AT
SYRACUSE UNIVERSITY

JAMES ROSC'OE DAY, S. T. D., I). C. L., LL.D.,
Chancellor of the University.

HUGH POTTER BAKER, M. F., 1904 (Yale) ; D. Oec., 1910 (Munich),
Dean of the College; Professor of Silviculture.

FRANK F. MOON, B. A., 1901 (Amherst) ; M. F., 1909 (Yale),
Professor of Forest Engineering; Acting Dean.

MAULSBY WILLETT BLACKMAN, A. B., 1901; A. M., 1902 (Uni-
versity of Kansas); Ph. D., 1905 (Harvard),
Professor of Forest Entomology.

EDWARD F. MCCARTHY, B. S., 1911 (University of Michigan),
Professor of Forestry at The New York State Ranger School.

"NELSON COURTLANDT BROWN, B. A., 1906 (Yale); M. F., 1908

(Yale),
Professor of Forest Utilization.

J. FRED BAKER, B. S., 1902 (Michigan Agricultural College) ; M. F.,

1905 (Yale),
Director of Forest Investigations.

LEIGH H. PENNINGTON, A. B., 1907; Ph. D., 1909 (University of

Michigan) ,
Professor of Forest Patliology.

SEWARD D. SMITH, A. B., 1907; M. S. F., 1909 (University of

Michigan) ,
Director of The New York State Ranger School.

JOHN WALLACE STEPHEN, B. A., 1907; M. S. F., 1909 (University

of Michigan); M. Pd., 1915 (Michigan Normal College),

Professor of Silviculture.

* On leave of absence.

[3]

4- College of Forestry

CHARLES CHRISTOPHER ADAMS, B. S., 1895 (Illinois Wesleyan) ;

M. S., 1808 (Harvard); Ph. D., 1908 (Chicago),

Professor of Forest Zoology.

*SHIRLEY W. ALLEN, B. S., 1909 (Iowa State College),
Professor of Forest Extension.

HARRY P. BROWN", A. B., 1909; A. M., 1910; Ph. D., 1914 (Cornell

University) ,
Professor of Dendrologi/.

SOLOMON F. AGREE, B. S., 1896; M. S., 1897 (University of Texas) ;

Ph. D., 1902 (Chicago),
Professor of Forest Chemistry.

"REUBEN PARKER PRICHARD, B. S., 1907 (Dartmouth) ; M. F., 1909

(Yale),
Assistant Professor of Dendrology.

LAURIE D. COX, A. B., 1903 (Arcadia College) ; S. B. in Landscape

Architecture, 1909 (Harvard),
Assistant Professor of Landscape Engineering.

HOWARD ELAINE WAHA, B. S., 1909 (Pennsylvania State College),
Assistant Professor of Forest Utilization.

•HARRY HARRINGTON TRYON, A. B., 1912; M. F., 1913 (Harvard),
Assistant Professor of Forest Utilization.

ERNEST G. DUDLEY, A. B., 1908 (Leland Stanford Jr. University) ;

1908-1909 (Yale Forest School),
Assistant Professor of Forest Extension.

•WILLIAM A. GRUSE, A. B., 1913 (Johns Hopkins); A. M., 1915;

Ph. D., 1916 (University of Wisconsin),

Assistant Professor of Dendrological Chemistry.

(Fuller Fund.)

*ALFRED HUBERT WILLIAM POVAH, A. B., 1912; Ph. D., 1916

(University of Michigan),
Assistant Professor of Forest Mycology.

HIRAM LEROY HENDERSON, B. S., 1915 (University of Michigan),
Assistant Professor of Forest Utilization.

CARL JOHN DRAKE, B. S., B. Ped., 1912 (Baldwin- Wallace) ; A. M.,

1914 (Ohio State University),
Assistant Professor of Forest Entomology.

* On leave of absence.

The Relation of Shellfish to Fish in Oneicla Luke 5

*ALAN F. ARNOLD (Harvard),
Instructor in Landscape Engineering.

"CARL CHESWELL FORSAITH, A. B., 1913 (Dartmouth) ; A. M..
1914; Ph. D., 1917 (Harvard),
Instructor in Forest Technology.

HAROLD CAHILL BELYEA, A. B., 1908 (Mount Allison University) ;

M. F., 1916 (Yale),
Instructor in Forest Engineering.

MERLE R. MEACHAM, B. S., 1913 (Hiram College) ; B. S. in Ch. E.,
1914; Ch. E., 1916 (Purdue University); Ph. D. (New York

State College of Forestry),

Research Assistant in Dendrological Chemistry.
(Fuller Fund.)

ALVIN G. SMITH, B. S. (New York State College of Forestry),
Field Assistant in Forest Investigations.

WILFORD E. SANDERSON, B. S., 1917 (New York State College of

Forestry) ,
Field Assistant in Forest Investigations.

DON. M. BENEDICT, B. S., 1917 (University of Michigan),
Laboratory Assistant in Botany.

C. F. CURTIS RILEY, A. B., 1901 (Doane College) ; B. S., 1905 (Uni-
versity of Michigan) ; A. M., 1911 (Doane College) ; M. S.,

1913 (University of Illinois),
Special Lecturer in Animal Behavior.

ELEANOR CHURCH, B. L. E., 1916 (Syracuse University),
Librarian.

LILLIAN M. LANG,

Secretary to the Dean.

WALTER W. CHIPMAN, B. S., 1893; A. M., 1904 (Wabash College),
Assistant Treasurer.

EDNA E. WHITELEY, B. L. E., 1916 (Syracuse University),
Recorder.

* On leave of absence.

CONTENTS

PAGI;

Physical Characters of Om-ida Lake 11

Plant and Animal Habitats 13

Invertebrate Animal Life in Oneida Lake 14

Oneida Lake Shellfish 1(5

Shellfish as Food for Fish IS

Food Fishes Feeding upon Shellfish 1!)

Game Fishes that Feed upon Mollusk-eating Fish 20

Oneida Lake Fish that Feed upon Shellfish 21

Food of Young Fisli 22

Enemies of Fresh-water Shellfish 23

Parasites. . 23

Predatory Enemies 23

Shellfish as Parasites of Fish 24

The Supply of Fish Food Available in Oneida Lake, etc 27

Quantitative Studies in Oneida Lake 28

Abundance of Animals in Shallow Water 29

Animals on Different Kinds of Bottom 30

Herbivorous and Carnivorous Animals 30

Production of Fish 31

Conclusions 32

[6]

ILLUSTRATIONS

General view of the west end of Oneicla Lake, including Big

Bay.

Milton Point looking east. Frenchman Island in the distance.
A bouldery point with only Water Willow and Bulrush for
vegetation.

Fig. 3. A bay-like habitat north of Long Point, looking north. The
bottom is very sanely.

Fig. 4. Xickerson Bay, on the north shore near the outlet at Brewer-
ton. An example of a habitat with abundant vegetation.

Fig. 5. A mussel fisherman on the Mississippi River with his flat-
bottomed boat rigged with two crowfoot dredges, each 12
feet long, and used to catch mussels for the pearl button
industry.

Fig. 6. The larger snails living in Oneida Lake.

Fig. 7. Snails and finger-nail shells of special value as the food of fish.

Fig. 8. Seining fish on Long Island, a habitat favorable for shellfish.

Fig. 0. Collecting shellfish on the rocky shore of Frenchman Island.

Fig. 10. Four common clams or mussels living in Oneida Lake.

Fig. 11. Invertebrate animals on sand bottom, water four feet deep.

Fig. 12. Invertebrate animals on clay bottom, water four feet deep.

Fig. 13. Invertebrate animals on mud bottom, water ten feet deep.

Fig. 14. Invertebrate animals on boulder bottom, water 20 inches deep.

Fig. 15. A good habitat for fish and shellfish near Fitzgerald Point,
north shore of Oneida Lake, near Brewerton.

Fig. 16. Field laboratory at Brewerton, N. Y., at the west end of
Oneida Lake.

RELATION OF FISH AND OTHER WILD LIFE TO
FORESTRY

" Forestry means not alone the growing of a crop of trees from the
soil for the production of wood, but it includes as well the conservation
of water by the forest and the perpetuation of the animal life of the
forest where it is beneficial. Therefore, in all of its plans for investi-
gative work in forestry in the State, the College has considered not only
the value of the non-agricultural soils for the production of forests but
the life of the forests and the forest waters and the use of the forests
and the forest waters in the most reasonable and effective way. In con-
sidering the question of forestry in this broad, constructive way, the
College is 'not original but is merely using the same vision for the future
which has been used during the past century in such European countries
as Germany and France, who have made their forests so important a
part of their industrial and commercial development."

HUGH P. BAKER, Dean,

The New York State College of Forestry.

" Forests are more than trees. They are rather land areas on which
are associated various forms of plant and animal life. The forester
must deal with all. Wild life is as essentially and legitimately an
object of his care as are water, wood, and forage. Forest administra-
tion should be planned with a view to realizing all possible benefits from
the land areas handled. It should take account of their indirect value
for recreation and health as well as their value for the production of
salable material; and of their value for the production of meat, hides
and furs of all kinds as well as for the production of wood and the
protection of water supplies."

H. S. GRAVES, Chief Forester,

U. S. Forest Service.

[8]

PREFACE

The quotations 011 the opposite page state briefly the
relation of fish to the use of non-agricultural, forest lands
and waters, as expressed by representative foresters, and this
clearly outlines the policy of this College on such matters.

In addition to timber, forest lands and waters may be
used to produce fish, game and other plant and animal crops,
for which the region is suited, and in addition they may be
used for recreation. The diversified use of such forests is a
natural development which accompanies intelligent use of
natural resources. The proper management of waters is a
problem similar to that of the proper management of a farm,
of a business, or the care of forest trees, and each must be
based upon a detailed knowledge of the subject. The public
has not yet taken up very seriously the relation of fish pro-
duction to food, to recreation, and to the general economic
welfare of the community. There are conflicting interests
here which can only be justly disposed of, in part, after
careful, impartial investigation. It is to the solution of such
State problems that the College is devoting its energies.

The present publication by Frank C. Baker, Investigator
in Forest Zoology of the College of Forestry, who since the
completion of these studies has become Curator of the Nat-
ural History Museum of the University of Illinois, Urbana,
Illinois, has here summarized two detailed studies which he
made on the fish food in Oneida Lake during the years of
1915, 1916 and 1917. His investigations show the kind of
food eaten by fish, particularly the molluscan or shellfish
food, and the conditions and relative abundance of this food
in certain parts of the lake. Plants are shown to have much
influence upon the fish food, and the depth of water has also
a great influence. In general, the amount of fish food
declines with increasing depth of water, and sand bottom

[9]

10 Col ley? of Forexfri/

was found harboring the largest amount of such food.
Shallow waters are thus the most productive of fish food.

Upon studies of this character the College hopes to
accumulate evidence which will be a surer guide for increas-
ing the amount of fish in the forest lakes, ponds and streams
of the State, as well as for a better utilization of this
natural resource.

CHARLES C. ADAMS,
Professor of Forest Zoology.

DEPARTMENT OF FOREST ZOOLOGY.

THE RELATION OF SHELLFISH TO FISH IN
ONEIDA LAKE, NEW YORK

Bv FRANK COLLIXS BAKER

PHYSICAL CHARACTERS OF ONEIDA LAKE

The State of Xew York is justly notable for. its beautiful
lakes, which interest alike the tourist, the summer vaca-
tionist, and the fisherman. To the latter they are of peculiar
interest because of their large size and the abundance and
variety of the fish which they contain. The value of fish,
both for sport and as a food of great economic value, has
not been fully appreciated by either fisherman or the public
at large. There is apparently need for much education on
the possibilities of more, intelligent fish culture among the
public in general.

Much has been done for agriculture through many agencies
organized for the solution of its problems. The study of
the conditions governing the production of animals and
plants living in the water, especially fresh water, has not
been given as much attention as the subject deserves, so that
we are still ignorant of many important facts which are
necessary before the subject of aquatic culture can be prac-
ticed in a manner comparable to that of agriculture. In
aquatic studies it is of first importance that detailed infor-
mation be available concerning all of the fish of a body of
water, its plants, its animals, their relation to each other
and to the water in which they live, and the physical char-
acter of the body of water, including its surroundings.

Realizing that our present knowledge of this subject is
incomplete, the Department of Forest Zoology of The ISTew
York State College of Forestry, under the direction of Dr.
Charles C. Adams, has made detailed studies during the
summers of 1915, 1910 and 1917 of the relation of the mol-

[ HI

12 College of Forestry

luscaii food supply to the fish in the largest of the inland
lakes wholly within the Empire State — Oiieida — the
results of which are embodied in two reports by the author :
Technical Publication Xo. 4, " The Relation of Mollusks to
Fish in Oiieida Lake" (1916). and Xo. 9, "The Produc-
tivity of Fish Food 011 the Bottom of Oiieida Lake, with
Special Reference to Mollusks" (1918).

Oiieida Lake (Fig. 1) lies near the center of Xew York
State and is 27 miles east of Lake Ontario and 11 miles
north of Syracuse. It is easily reached from that city by
either steam railroad or trolley, the latter maintaining hourly
schedules between Brewerton and South Bay during the
summer months. The lake extends in an east and west direc-
tion and is 21 miles in length and 5.5 miles in greatest
width. Its maximum depth is 55 feet, which occurs near
Cleveland 011 the north side, the lake deepening very notably
toward the eastern end. The lake has an approximate area
of 80 square miles or 51,200 acres, and a shore line of about
65 miles. The areas bordering the shore are always shallow,
usually deepening gradually and forming submerged ter-
races. The points are usually bouldery or gravelly, while
the bays are sandy. Mud and clay are found in the deeper
bays and in the deeper parts of the open lake. The shallow
area bordering the shore and extending to a depth of six or
more feet is covered with a luxuriant growth of vegetation.
This fact is very significant when it is remembered that it
is this area with the vegetation that affords food and lodge-
ment for the snails, clams, insects, crawfish and other ani-
mals upon which the fish and other aquatic animals depend
in an important degree for food. Below a depth of twelve
feet little vegetation is found. Within a depth of twelve
feet there is an area equal to thirteen square miles or 8,343
acres, which affords feeding and breeding grounds for the
fish of this large lake. This body of water does not appear
to belong in the same class as the deep finger lakes, such as
Cayuga and Seneca, which lie in old river valleys formed
before the last glacial epoch, but seems to be a rather shallow
body of water left in a depression in the old post-glacial out-

Tlie Relation of Shellfish to Fish in Oneida Lake !•>

let, when the Great Lakes emptied into the Hudson river by
way of the Mohawk river.

PLAXT AXD AXIMAL HABITATS

To support a large plant and animal population a body of
water must provide varied and suitable conditions, and these
are found in Oneida Lake in abundance. Detailed studies
of the lake indicate that there are three primary types or
kinds of these habitats which are more or less distinct. The
first includes the points or headlands (Fig. 2) and some
portions of the shore which are shallow and have been swept
clean of the fine sand and clay, leaving the stones and small
boulders as a stony pavement, the stones ranging in size
from large gravel to huge boulders several feet hi diameter.
This type of habitat affords lodgement for many mussels,
which live in the sand between the stones, for a multitude
of snails which live on the rocks, and for crawfish, insect
larvse and leeches which live on, under and between the
rocks. The vegetation of such habitats consists of Water
Willow and Bulrush.

The second kind of habitat is found in sheltered bays and
in other partly protected spots where the force of the \vaves
is somewhat arrested. (Fig. 3.) The bottom is composed
of fine sand; the vegetation is abundant, consisting of
Pickerel-weed, Bulrush, Swamp Loosestrife, Bur-reed, the
Water Lilies, and a few Pond-weeds (Potamogeton). Many -
mussels live here, but the most important life is made up o£__
small clams, snails, insects, and small animal life which form
such a large proportion of the food of fish.

The third kind of habitat (Fig. 4) is found in the well
protected bays, where there is a mass of vegetation consist-
ing of submerged plants such as Pond-weeds, ITornworts,
Milfoils, Water Lilies, Pickerel-weed, Cat-tails, and Bur-
reed. The bottom is usually of fine clay or mud. Many
fragile snails as well as insect larvse inhabit this kind of a
habitat, which provides excellent food for fish and other
aquatic animals.

14 College of Forexfri/

The striking- feature of the plant life in many habitats is
the presence of large quantities of the water plants known
as filamentous alga-, which cover the bottom as well as the
higher plants like a thick blanket, and greatly modify the
natural character of the bottom. It seems probable that the
great wealth of animal life in pails of this lake is largely
due to the presence of this lowly plant, which provides a rich
food supply for the invertebrate animals.

Below a depth of twelve feet the bottom of the lake, as far
as examined, is covered with soft, black mud on which little
or no vegetation grows excepting a few species of alga>. and
animal life is consequently reduced in both number and
kind.

LSTVEBTEBKATE AxiMAL LlVK IX OxKIDA LAKI-;

The floor of this beautiful lake, in the bays and the
shallow areas bordering the shore, is carpeted with a great
variety of plants, many of which, like the feathery Water
Milfoil (Myrioplii/lhun), form miniature aquatic forests in
the bays and other sheltered places. The rocks, the plants
and the whole bottom in many places is covered with masses
of the delicate green water plants, the filamentous alga\

Among this wealth of plant growth many kinds of animals
live in great abundance. The alga1 are inhabited by the
young or larvte of flies, and small-jointed worms related to
the earthworms (Oligocha?tes), whose bodies are as green as
the color of the alga1 which they have eaten. Myriads of
little crustaceans, called Scuds or Water Fleas (Amphipods
and (Tadocera) dart about and thousands of fresh-water
Sowbugs (Isopods) crawl over the filmy masses of alga?.
The little spider-like mites (Ilydrachnids) actively search
the alga1 and weeds to prey upon the smaller animals. The
young or nymphs of Dragon-flies (Odonata) lie in ambush
among the alga* or bury themselves in the muddy bottom :
the young of May-flies, with their feathery gills attached to
the outside of their bodies, and the Caddis-fly larvae, with
their curious houses or cases made of grains of sand, snail

The Relation of Shellfish to Fish in Oneidu- Lttke 15

shells, bits of sticks, plants, etc., crawl over the bottom, the
caddis-fly larvae dragging with them the houses that protect
their soft bodies. Water bugs. Water Boatmen, beetles, both
adult and young, and many kinds of small snails complete
the variety of this wealth of animal life on the bottom (see
Figures 11-13).

On the rocky shores the clams live between the stones,
partly buried in the sand or gravel, and crawfishes of many
ages and sizes hide beneath the rocks ready to retreat from
foe or to pursue some prey ; on the stones many snails live,
associated with the young of May-flies (Heptagenia) , the
flat, disc-like larva or young of a beetle (Psephenus), and
the Spiral Caddis-fly larva (Helicopsi/clie) which makes its
case of sand grains so nearly in the form of a spiral snail
shell as to confuse, many years ago, one of America's fore-
most students of mollusks (see Figure 1-i). The stones on
many points of land are coated with sponges, which look
like great patches of green velvet through the water.

The plants, too, afford a resting place as well as a foraging
ground for many animals, and we find on the leaves of the
\vater-lilies the small limpit-like snails (Ancylus), the round
shells of the Orb Snails (Planorbis) and the Tadpole Snails
(Physa), associated with young and full-grown beetles,
aphids or plant lice, and the curious caterpillars of moths
(Nymphula) which make cocoons on the surface of the lily
leaves. If we examine the leaves of the bulrush, even in
water six feet deep, we find them covered writh the little
brown Hydras, the long tentacles of which are outstretched
to catch unwary protozoans or other minute animals that
may chance to drift that way. Many of the bulrush stems,
as well as the other plants, are encrusted with the little cases
of the moss-animals or bryozoans, appearing indeed as though
a browrn moss. Amid this great wealth of animal life it is
not strange that fish find an attractive environment where
food is 'plentiful and conditions are favorable for their
growth and breeding.

16 College of Forestry

OXEIDA LAKE SHELLFISH

The class of animals known as mollusks or shellfish (snails
and clams) are widely distributed and in many lakes and
rivers form a large and conspicuous part of the animal popu-
lation. Though popularly considered of little value except
as curiosities, this class of animals is of real economic
importance and value. On the Mississippi river, and other
streams of the Central West, the clams or mussels are sys-
tematically sought for their shells, from which much of the
pearl button material of commerce is obtained. In Illinois
and Iowa there are many factories which manufacture pearl
buttons and depend upon these clams for their raw material,
and the fishing of these shells furnishes occupation for many
men. Ixeceiitly, the supply of mussels has been threatened
with exhaustion owing to the unbusiness-like methods of fish-
ing and to conserve these animals the United States Bureau
of Fisheries has established, in part, a laboratory at Fair-
port, Iowa, for the study and artificial propagation of these
mussels. In addition to their shells the clams have fur-
nished many pearls of great beauty and large value. The
clams are usually obtained by means of a crowfoot dredge
which is a long bar of iron to which are fastened a number
of ropes bearing several four-pronged hooks made of heavy
wire. A fisherman's boat rigged up with two of these dredges
is an interesting sight (Fig. 5).

The shellfish of Oiieitla Lake, however, are at present of no
particular value for the manufacture of pearl buttons, nor
do they, as far as known, afford pearls of value. They do,
however, form a part of the food of such fish as the Channel
Cat, as well as of such mammals as the Muskrat, Mink and
Otter.

One of the most interesting and important discoveries
brought out in the investigations is that the shellfish or mol-
lusks greatly outnumber in individuals all of the other
(macroscopic) kinds of invertebrate animals living on the
bottom. In the quantitative computations to be described
later, it was estimated, 011 the basis of counting the animals

The Relation of Shellfish to Fish in Oneida Lake 17

on many small sample areas, that the shellfish of Lower South
Bay and vicinity numbered 4,70-i million individuals, and
that the other associated animals numbered 3,062 million
individuals. The shellfish, therefore, are 30 per. cent greater
in number of individuals, showing that the shellfish are a
very important group of aquatic animals.

Shellfish are mostly flesh producers, eating plant tissue
and plant debris, which is thus converted into animal tissue
which can be used by fish as food. The large clams or mus-
sels eat minute plants called diatoms and desmids, besides
the small particles of partly disintegrated vegetable matter
floating in the water, which the Danish naturalist, Dr. Peter-
sen, has called " dust-fine detritus.'*' Some small animals,
like the protozoans, are also included in the food.

As just stated, snails (Fig. 6) are for the most part vege-
tarians, feeding upon algse and the soft tissues of plants, usu-
ally the outer part or epidermis. Snails may be frequently seen
browsing over the rocks which are covered with long strings
of green algae (filamentous alga?) much as cows browse over
a pasture. The peculiar rasping file-like tongue is covered
with many hundred minute teeth which enable the animal
to scrape off the algse and to cut, with the aid of a horny jaw,
the soft covering of larger plants. Only a very few snails
are carnivorous and these include for the most part the pond
snails or Lymncea. Some of these have been known to eat
other snails, leeches, and small fish as well as other dead
animals, and they may thus be regarded in a measure as
useful scavengers. Careful records have shown that as many
as thirteen different kinds of plants in Oneida Lake are used
by snails as a food supply, and twenty-two kinds of snails
were observed to use these plants for food. A very few snails
seem to prefer dead or decaying vegetation, as the little
limpet snails, Ancylus, but the majority of snails prefer
living plant food.

Of the 197 species of fresh-water shellfish listed as living
in the State of New York, 92, or nearly one-half of the
species inhabiting the State, have been collected from Oneida
Lake. This number of species is believed to be greater than

18 College of Forestry

has been found in any similar body of fresh-water in
America. Of the 92 species found in the lake, fully 50, or
about one-half, are known to be eaten by fish.

The shellfish that are of the greatest value are the small
species that live among the vegetation or on the sandy
bottom, and are to the average person considered of no value
whatever. These include the little wheel-like Orb Snails
(Planorbis") which may be seen crawling over the plants
with their round shell carried perpendicularly on the back
of the animal, the little spiral snails (Amnicola) and the
broadly spiral shells, called Valva-ta. The young of the
Tadpole Snails (PJiysci) with their shiny shells, long-pointed
tentacles and pointed foot, and the young of the Pond Snails,
or Lymncca, with spiral shells and broad, flat feet, are also
favorite food for fish. The little clams or " finger nail "
shells, Sphcerium and Pisidium, are especially sought after
by many fish. A quarter of the food of such fish as suckers,
Dog-fish and Carp consists of the little bivalve shellfish
known as Sphcerium. The small snails and clams are shown
in Figure 7.

SHELLFISH AS FOOD FOR FISH

The examination of the stomach contents of fish has shown
that shellfish, snails and clams, form a large part of the food
of many species. Compared with their other kinds of food,
we find that shellfish bear an interesting relation to the com-
plete diet. Thus we find that on the average, fish consume
40 per cent of insects, 14 per cent of Crustacea (crawfish,
fresh-water sowbugs, scuds, fresh-water fleas, etc.), 20 per
cent of fish, 20 per cent of plants and mud, and 6 per cent of
shellfish. While the percentage of shellfish food is small for
the total number of fresh-water fish, it rises to large propor-
tions (24 per cent) when only the mollusk-eating species are
considered. In the different species the percentage of shell-
fish food ranges from 1 to 100 per cent, or from a trace to the
total food.

A study of the fish of Oneida Lake, together with what
is already known concerning the food of our freshwater fish,

The Relation of Shellfish to Fish in Oneicla Lake 19

indicates that of 225 species inhabiting the fresh waters of
the states of Illinois and Xew York, 4(5, or about one-fifth,
are eaters of shellfish to a greater or less degree. The average
amount of molluscan footl eaten by these 4G fish is about
one-fourth, or 24 per cent.

Among those fish that eat a large percentage of shellfish
food may be mentioned such common species as the Sheeps-
head, which eats 100 per cent, the Lake Sturgeon and
Spotted Sucker, which consume upwards of 90 per cent, the
Common Red-horse which is credited with G2 per cent, and
the Pumpkinseed Sunfish which eats about half mollusks.
or 51 per cent. The Common Sucker eats 30 per cent while
the valuable Whitefish consumes 26 per cent. The Bullhead,
a common bottom feeder, is credited with but 20 per cent.
Many of the fish mentioned are provided with especially
modified mouths containing, in some species, crushing appa-
ratus of more or less perfection, which appear as if they had
been modified by nature to include a diet of shellfish.

Some fish confine their diet to a few kinds of shellfish but
the majority of mollusk-eaters devour any shellfish available
that is of the right size. The large number of different
species or kinds of shellfish eaten by a single species of fish
is, however, interesting. Thus, the Pumpkinseed is known
to eat 18 different kinds of shellfish, the Whitefish, 17 kinds,
the Yellow Perch and the common Red-horse, each eight
kinds, and the common Bullhead, 11 kinds. Upwards of
50 different kinds of shellfish are now known to be eaten by
fish and this number wyill probably be greatly increased with
further study (Fig. 8).

FOOD FISHES FEEDING rroisr SHELLFISH

There are about twenty-five food fishes inhabiting the
waters of Xew York State that feed upon shellfish. These
include a majority of this class of fish and indicate the value
and importance of the shellfish as a source of food supply.
If we divide these fish into four classes, in the order of their
importance economically, we see at once the significance of

20 College of Forestry

the molluscaii diet. In the species of the first class, includ-
ing the most valuable fish, we find that the Whitefish eats
26 per cent, the Channel Cat, 15 per cent, and the Bluegill.
16 per cent. In the fishes of the second class, which are the
most numerous, the Round Whitefish consumes 26 per cent
of shellfish, the Red-mouth Buffalo, 3 per cent, the Round
Buffalo, 12 per cent, the Small-mouth Buffalo, 30 per cent,
the European Carp, 15 per cent, the Long-eared Sunfish,
16 per cent, the Pumpkinseed, 51 per cent, the Yellow
Perch, 8 per cent, and the White Perch, 90 per cent. In
the third class, which includes many valuable fish, we find
the Lake Sturgeon eating 90 per cent of shellfish, the Com-
mon Red-horse, 62 per cent, the Short-headed Red-horse. 50
per cent, the Yellow Bullhead, 5 per cent, the Common Bull-
head and the Black Bullhead, each 20 per cent, and the
Sheepshead, 100 per cent. In the fish of the fourth class
we find the Dogfish eating 25 per cent of shellfish, the
Spotted Sucker, 90 per cent, the Common Sucker, 30 per
cent, and the Toothed Herring and the Gizzard Shad, each
1 per cent. The general averages for these four classes are
19, 28, 50 and 29 per cent respectively.

GAME FISH THAT FEED UPON MOLLUSK-EATING FISH

Shellfish are not only of direct value as fish food, but are
also perhaps of even greater value indirectly. They are
food for certain other fish, which we may call " culls,"
which of themselves are of little or no recognized direct
importance as food, but which are of great value as food
for game and food fish. The shellfish eaten by these " culls ''*
thus become of food value second only to the larger fish.
In addition to these " culls " the game fish feed upon dragon-
fly nymphs, frogs, and other amphibians whose food includes
snails (Fig. 9).

Six game fish are especially noteworthy as eaters of
mollusk-eating fish. Pike and Pickerel head the list, the
Pickerel feeding upon Carp, Suckers, Carp minnows, etc.,
which consume 15 per cent of shellfish, and the Wall-eyed

The Relation of Shellfish to Fish in Oneida Lake 21

Pike feeding upon Carp minnows, Gizzard Shad, etc., which
are known to eat 7 per cent of shellfish. The Sand Pike, on
the other hand, feeds upon Catfish, White Perch, etc., which
consume upwards of 30 per cent of shellfish, this being the
largest amount of indirect molluscan food. The much es-
teemed game fish, the Large- and Small-mouthed Black Bass,
feed on Yellow Perch, Catfish, etc., which consume about
8 per cent of shellfish. The valuable Great Lake Trout feeds
largely on Whitefish, which eats 26 per cent of shellfish.
It is seen, therefore, that these six important game fish eat
indirectly 15 per cent of shellfish food, indicating again the
value of this class of animals in the economy of fish.

OXEIDA LAKE FISH THAT FEED TTPOX SHELLFISH

Of the fish inhabiting Oneida Lake eight are eaters
directly of shellfish the ratios being from 1 to 66 per cent.
The most voracious eater of shellfish is the Pumpkinseed
which has the largest percentage of those of any waters yet
examined, 66 per cent. This is 15 per cent higher than the
general average, which is 51 per cent. Next to the Pumpkin-
seed, the Common Sucker is the largest eater, consuming 30
per cent of shellfish. The Common Bullhead eats 10 per
cent while the Yellow Bullhead appropriates but 1 per cent
and the Yellow Perch 10 per cent. As stated above, the
basses and pikes should be credited' with a considerable
amount of shellfish food eaten secondarily, in their case
probably as much as 13 per cent.

It is of interest to compare the detailed food studies made
upon New York fish with those made by Forbes some years
ago. Forbes examined 1,221 specimens representing 87
species, of which 917 were adult and 307 were young. Of
the 87 species, 39 were shellfish eaters more or less, or
nearly one-half. Needham and the writer have made care-
ful examinations of 298 specimens representing 19 species
of New York fish, of which 10, or over half, are shellfish
eaters. In New York the sunfish appear to be large con-
sumers of shellfish, the Pumpkinseed eating 66 per cent, as

99

College- of Forestry

already stated, and the Long-eared Sunfish 05 per cent, as
recorded by Needham. The small number of Xew York
fish examined indicates that there is yet much to be done
before the food of the fish of this great State is well known.
The examination of waters abounding in fish, and the
examination of the stomach contents of fish caught in such
waters, indicates that there is a close relationship between
the conditions favorable for shellfish and the food of the
fish. From a knowledge of the animals of the body of water
one should be able to predict, within reasonable limits, what
the food of a fish in a given habitat will be. In other words,
we should expect a definite relation between the shellfish.
the fish, and the environment. The accuracy of such expec-
tation was shown by the examination of a specimen of the
Pumpkinseed which was caught on a sanely bottom on which
lived ten species of shellfish. When dissected, the fish was
found to contain in its stomach the shells of eight species of
these shellfish. Studies of this kind will ultimately give
information which will be of great value and importance in
the culture of food and game fish.

FOOD OF Yorxo Fisir

Fish in general vary their food with age. Thus the
Common Perch passes through stages which may be called
infancy, youth, and adult. During the first stage only the
smallest kind of food is taken, and this consists of the
minute animals known as Water Fleas (Entomostraca), and
the larvae of small flies. During the second stage the water
fleas are eaten at first but this diet soon gives place to the
larvae of insects. In the last or adult stage, the food consists
of shellfish, crawfish, insects and their larvae, and a few
fishes. Many of our fish pass through these stages and it
will easily be understood that a knowledge of the food of all
stages is necessary before the species can be thoroughly
understood.

Tlie Relation of Shellfish to Fish in Oneida Lake 23

EXEMIES OF FEESH-\VATER SIIELLFISIE

Parasites. Since the snails and clams are an important
element in the food of fish, it is of importance to know how
they can be protected and increased in number. We have
seen that the environment is favorable and that food is abun-
dant for them in Oneida Lake. Of unfavorable agencies we
know but little. Parasites are known to infest both clams
and snails to a marked degree but just how much mortality
is produced by this means is not known. Many of these
parasites spend but a part of their lives in shellfish while
the adult stage of the parasite is passed in birds, fish or other
vertebrate animals. The parasites may be worms and infu-
sorians. The Sheep Liver-fluke, which causes the death of
many sheep, lives for a time as a parasite in the respiratory
cavity of a small pond snail (Lymncea^). These parasites
are mostly confined to the liver, respiratory cavity, or genital
organs of the shellfish. It is probable that upwards of 20
per cent of mollusks are affected by these parasites.

Another agency affecting more or less seriously the life of
shellfish is the boring algae which perforate the shell, destroy-
ing the protective horny -outer covering or epidermis and
permitting the carbon dioxide in the water to dissolve the
substance of the shell (carbonate of lime). The effect of
such action by algse is usually indicated by a roughened or
worn condition of the shell. It is more apparent in clams
than in snails, in which the apex of the shell is usually
attacked. The constant effort on the part of shellfish to
repair the damage caused by this erosion is a drain upon
their vitality, and probably causes the ultimate death of
many.

Predatory Enemies. A number of animals prey upon
shellfish. These animals thus come into competition with
the mollusk-eating fish. This is compensated for, in a meas-
ure, by the fact that many fishes live on these animals
and thereby receive the benefit of the mollusks, though
secondarily. Among the animals feeding on shellfish may
be mentioned dragon-fly nymphs, horse-fly larvse, water bugs,

24 College of Forestry

the larvae of large water beetles, and crawfishes. Leeches
and the larger pond snails are large consumers of mollusks.
Frogs, salamanders, newts, the painted, snapping, and other
turtles, as well as many ducks and other water birds also
obtain a part of their daily food from this class of animals.
The Muskrat is a well-known depredator of the mussel beds,
and it is said that the Mink and Otter also eat clams
occasionally.

The amount of molluscan food eaten by these animals is
not definitely known, though in some cases it is probably
large. The nymph of one dragon-fly (Anax junius) has been
known to eat 15 per cent of snails (Amnicola). In the case
of the leeches, several are known to eat largely of snails,' and
one (Glossiphonia complanata) is called the Snail Leech,
and feeds largely on small snails.

Shellfish as Parasites of Fish. The .intimate relation
existing between the fresh-water clams (Fig. 10) and fishes
has but recently become understood, principally through
studies carried on by naturalists at the United States Bio-
logical Laboratory at Fairport, Iowa. The young of these
clams are known as glochidia and pass a part of their exist-
ence attached to some part of a fish.

The metamorphosis or transformation of the fresh-water
mussels or clams is quite as wonderful and as interesting as
that of the butterfly or beetle, and also quite as complicated.
In the female mussel the gills or breathing organs are modi-
fied to form a broad pouch or marsupium into which the eggs
are carried soon after being fertilized by the sperm, which
is taken in with the water through the lower siphon. After
a period of development the eggs become purse-shaped and
the gills are swollen and distended by the mass of young or
embryos. After the lapse of time, the length varying in
different kinds of mussels, the young are discharged into the
water and fall to the bottom where they lie with their two
shell valves widely open. The next stage is passed in a fish
or amphibian (usually the former) which becomes infected
by brushing or stirring up water currents at the bottom,
which enables the young to come into contact with the gills,

The Relation of Shellfish to Fish in Oneida Lake 25

fins, or tail, and upon which the young clam immediately
fastens itself. On this fish or other host the young clams
become imbedded in the skin, which entirely covers the
mussel embryo. After the lapse of a certain time (varying
from nine to 74 days in different species) the young, having
completed their transformation, break the cyst and fall to
the bottom, usually shaped, though very small, like mature
mussels. There are therefore four distinct stages in the
growth of a mussel: 1, the fertilized egg; 2, the glochidium
living in the brood pouch of a mussel; 3, the parasitic stage,
encysted in the skin of a fish or salamander; and 4, post-
glochidial development, with fully formed shell. Subse-
quent growth is principally in size. Unless the young mussel
drops from the fish to a suitable habitat it will not long
survive. A rocky or pebbly bottom seems to be the most
favorable to the growth of the young mussel and it is also
upon such locations that many adult clams are found.

Several interesting facts are now known concerning the
subject of mussel propagation. Two principal kinds of young
or glochidia occur: one, hooked, the other bookless. The
former attach themselves by these hooks to the fins or other
external parts of the fish, while the latter become encysted
in the gills of the fish. It is believed that the hookless type
are fixed to the gill by a fluid produced by the irritation of
the gill by the young clam.

It has also been ascertained that there is a long and a short
period of reproduction, the former having the eggs fertilized
from the middle of July to the middle of August and the
glochidia being carried in the brood pouch until the follow-
ing spring or early summer. In the short period the entire
breeding season is confined to about four months, extending
from the end of April to the middle of August, and the
glochidia are discharged as soon as they are fully developed.
The clams of Oneida Lake represent both long and short
periods, two species of clams representing the latter and
13 the former period.

This relation between fish and mussels is very significant
when we remember that such fish as the bullheads and other

2(3 College of Forestry

catfish feed upon clams or mussels. In Oneida Lake, nine
fish are known to lie susceptible to infection by mussel glo-
chidia. These are Green Sunfish, Bluegill, Strawberry Bass,
White Bass, Catfish, Yellow Perch, Large-mouth Black Bass,
Rock Bass, and Pumpkinseed. This subject has not the
economic significance in Oneida Lake, or, indeed, in Xew
York State, that it has in the Middle West, where the button
factories are dependent upon, the mussels for their raw
material.

Recent studies (C. B. Wilson, Bull. U. S. Bureau of Fish-
eries, Vol. 34, pp. 329-374,' 1916) on the small crustacean
parasites, known as copepods, which infest the gills and fins
of many fish, have shown that there is a definite relation
between these parasites, which are harmful to the fish, and
the young mussels or glochidia which apparently do the fish
no harm. It was found that where the gills were already
infected with young mussels they are practically immune
from attacks by the harmful copepod parasites, showing that
the presence of the glochidia is of advantage to the fish. At
the United States Biological Station at Fairport, Iowa,
where experiments on the artificial infection of fish by glo-
chidia have been conducted on a large scale, it has been
found that by infecting fish with the glochidia they may be
rendered immune for a time from the attacks of the copepod
parasites. It was also observed that where a fish wras carry-
ing the parasitic copepods it could not be infected with glo-
chidia. Parasitic copepods have been observed on the gills
of several species of Oneida Lake fish, and of the 50 species
of fish inhabiting this lake, 17 are known to carry copepod
parasites and 11 mussel glochidia, in other localities, and it
is apparent that the mussels, of which 12 species have been
found in Oneida Lake, are of considerable importance to the
fish life of these waters. It is possible that the presence of
these young mussels or glochidia has made the fish of this
lake more or less immune to the attacks of parasitic copepods.

The Relation of Shellfish to Fish in Oneida Lake 27

THE SUPPLY OF FISH FOOD AVAILABLE ix OXEIDA LAKE

The scientific study of the food relations of fresh water
animals is of comparatively recent date. One of the fore-
most students of the food of fish has stated that of all the
circumstances of life none affect it so powerfully and so
vitally as its food supply. A study of the food of any ani-
mal soon develops into a consideration of all the animals,
plants, and general agencies which affect the life of the
animal in any manner. Another noted student has said that
" barring enemies and artificial hinderances to increase, such
as overfishiiig, fish will multiply up to the limit of the food
supply, but can never overstep that limit. If the food supply
can be increased, an increase in the number of fish will
naturally follow." Failure to realize this law has probably
caused many failures in attempts to stock bodies of water
with fish.

But few studies of limited areas have been carried 011 in
this country for the purpose of ascertaining rather precisely
the amount of fish food in a body of water. In Europe,
however, the floating microscopic food in inland and marine
waters has been studied, but only one quantitative study of
the bottom animals of a lake has been seen. The most nota-
ble study of marine bottom food has been carried 011 at the
Danish Biological Station, under the direction of Dr. C. G.
Joh. Petersen, who realized that to understand fully the
conditions governing the habits of fish, especially as regards
their food, a knowledge must be gained of the variety and
amount of the possible food supply. In other words, a bio-
logical survey of the fish habitat is necessary. For the pur-
pose of carrying on this work, Dr. Petersen devised an in-
strument which he called a " bottom sampler." With this
apparatus it was possible to bring up from the bottom of the
sea a small sample of the bottom one-tenth of a meter square
(about four inches) with the bottom layers one to two milli-
meters (1/25 to 1/13 inch) thick, in their natural position.
A large number of these bottom samples were obtained, and
the animals in each were counted. By this .means it was
possible to find the average amount of food present in an

28 College of Forestry

area. In addition, the dried animal matter contained in this
Tinit area was weighed, so that it was also possible to deter-
mine the amount of animal matter in one square meter
(10%. square feet) of bottom. Petersen was able to ascer-
tain, by these studies and by the examination of the stomachs
•of fish and other animals, that the fish consumed about one-
tenth of an ounce (three grams) per square meter and the
whelks (snails) and starfishes, predaceous animals, about one-
fifth of an ounce (six grams) dry weight per square meter,
lie estimated that the total amount of dry matter on the
bottom was about one ounce (30 grams) per square meter and
that the bottom inhabiting animals consumed several times
their own weight in a year. The food supply was found to
reproduce itself several times during the year.

The fine material on the bottom in the area studied by
Dr. Petersen was found to be rich in organic matter, and
was found to be used as food by both fish and other bottom
inhabiting animals. This material is called " dust-fine
detritus " by Dr. Petersen, and is believed by him to form
a large part of the food of bottom-feeding animals. A con-
siderable amount of the same material is held in suspension,
and with the other floating minute animals and plants, called
the plankton, constitutes a food supply of large proportions.
This dust-fine detritus is largely the product of disintegra-
tion and decay of a marine plant called Sea Wrack
(Zostera).

Quantitative Studies in Oneida Lake. Investigations
comparable to those carried on by Dr. Petersen have not
previously been conducted in America, and the results ob-
tained by a similar study of Lower South Bay in Oneida
Lake is therefore of much interest. A somewhat similar
study has been made in the Swedish lake Vetter. This is
the only study of this character of the bottom of inland
waters of the world previous to those of Oneida Lake. An
area of 1,164 acres, including the bay and its immediate
vicinity, was carefully studied. A dredge was attached to a
long handle which scraped up an area about four inches
square or 16 square inches, in water up to six feet depth.

The Relation of Shellfish to Fish in Oneida Lake 29

For the deeper water, a larger dredge 16 inches wide was
used which was dragged over an area carefully estimated to
cover 64 square feet. The deeper water dredgings were
reduced and averaged to the equivalent of the small 16 square
inch unit scraped up in shallow water; each large dredging
equalling 48 of these smaller units. Upwards of 600 sepa-
rate samples of the bottom were collected and the contents
carefully sorted, the animals and plants counted and the
different species named by specialists. By collecting such a
large number of samples it was possible to reduce the prob-
able error made in taking samples and to calculate with a
considerable degree of accuracy the total number of indi-
vidual animals living in the bottom on the different kinds
of bottom in Lower South Bay and vicinity.

Abundance of Animals in Shallow Water. Many inter-
esting and significant features were brought out during this
investigation of lake bottom animals. It was computed that
over seven billion individual animals lived in the area of
1,164 acres. Of this life 88 per cent occurred in water
one to six feet deep; and only 12 per cent in all the water
deeper than six feet, or in round numbers, 6,786 million
individuals lived in water six feet deep, and 983 million
individuals in water more than six feet deep. From the
standpoint of area, it was found that a population of almost
seven billion individuals lived in 205 acres, in water six
feet deep, and beyond this depth a population of less than
one billion animals lived in 959 acres. Reducing this popu-
lation to acres we find that 33 million individuals live in one
acre in water less than six feet deep while but one million
individuals live in one acre in water more than six feet.
•This decrease in density of population is striking, showing'
that the greatest development of plant and animal life on
the bottom is found in water six feet or less in depth. When
we remember that fish are more abundant in this shallow
water, and that this is where most adult fish breed and the
young fish live, the significance of this richness of bottom
life is at once realized, and indicates that this is the most
important depth for the culture of fish even in large lakes.

30 CoUrge of Forestry

Animals on Different Kinds of Bottom. Another feature
brought out by the investigation was the relative abundance
of animal life on the different kinds of bottom. Sand bottom
(Fig. 11) was found to be the richest in number of indi-
viduals and boulders the poorest. If the sand be valued at
100 per cent, the other kinds of habitats will stand as fol-
lows: Sandy clay, 87 per cent; clay (Fig. 12), 66 per
cent: gravel, 57 per cent; mud (Fig. 13), 42 per cent; and
boulder. 36 per cent. Of the areas examined in the vicinity
of Lower South Bay, the sandy bottom between Frenchman
and Dunham Islands was computed to be the richest of all
the shallow areas examined, averaging about 110 million
individuals per acre. The poorest area in the vicinity of the
bay in animal life was found to be the boulder bottom (Fig.
14) along the shore, which averaged but four million indi-
viduals to the acre, or less than 4 per cent of the population
of the sand bottom. The reason for this paucity of the ani-
mals is the exposed character of the environment and the
small amount of plant food present.

Herbivorous and Carnivorous Animals. The great pre-
ponderance in number of animals feeding on plants (herbiv-
orous) and 011 fine ^particles of decaying plant material
(dust-fine detritus) on the bottom and suspended in the
water, over those animals that feed upon other animals
(carnivorous) is strikingly shown by these lake studies.
The herbivorous animals number about 7,743 million indi-
viduals while the carnivorous animals are calculated to
number not more than 23 million individuals, or about 3/10
of one per cent. This fact is important when it is remem-
bered that the herbivorous or plant-eating animals are
producers of flesh from vegetation and debris and the,
carnivorous animals are consumers of materials used more
extensively as fish food. But few fish (aside from the Carp)
feed extensively on vegetation. One of the significant facts
brought out in these investigations is that the presence of
filamentous algse in abundance profoundly affects the inver-
tebrate animals, providing a food supply of sufficient amount
to meet the requirements of a large population of small

The Relation of Shellfish to Fish in Oneida Lake 31

herbivorous animals, which in their turn, provide an abun-
dant food supply for the predaceous or carnivorous animals,
which are to a large extent fish.

Production of Fish. An attempt has been made to deter-
mine the number of fish that this rich store of animal life
will feed. To do this it was necessary to know the amount
of food eaten in a period of time, as in a day or twenty-four
hours. Studies of such marine fish as the Plaice indicated
that its digestive canal is emptied about once in twenty-four
hours. The Goby, a small European fish, is found to empty
its alimentary canal in about six hours, the fish seeking its
food in the daytime. These marine fish, however, may not
be altogether comparable to our fresh-water species and these
fish are principally suggestive of methods for work which
should be done on fresh-water fish.

During an investigation of the diseases of Oneida Lake fish,
many fish were caught in trap-nets, from which fish were
removed after intervals of 24, 48 and 72 hours. The results
of these studies suggested that the stomach may be emptied
in 24 hours, and the intestine in 48 hours. The percentage
of fish with empty stomachs increased rapidly with the time
interval of removing the fish from the net; 50 per cent
having full stomachs in the 24-hour interval, and about 13
per cent in the 48-hour interval. All had empty stomachs
in the 72-hour interval.

It is known that the digestive powers of fish become
slower in cold weather, and it is probable that between the
months of November and March fish eat about two-thirds or
less of the amount of food eaten during the warmer months
of spring, summer and fall. In the examination of the
stomach and intestines of Oneida Lake fish it was found that
011 the average a fish with a full stomach contained about
115 invertebrate animals. If we assume that this amount
is a daily average, and that fish eat this amount for nine
months of the year, then the invertebrate animal life on the
bottom of the 1,164 acres examined in Lower South Bay and
vicinity are calculated to furnish food for 337,500 bottom
feeding fish. Predatory fish like the Pike Perch consume

32 College of Forestry

a large number of fish. By using Illinois and Oneida Lake
data, a single individual of this game fish is calculated to
eat from 250 to 600 small fish in a year. When we remem-
ber that there are hundreds of individuals of the Pike Perch,
as well as other predatory fish, in Oneida Lake, it is at once
seen that the number of small fish in this lake must be very
large to supply these fish with food. It also follows that a
large number of invertebrate animals as well as an abun-
dance of vegetation for these smaller animals to feed upon
is necessary to provide food for these small fish. It has
been shown by these investigations that Oneida Lake meets
all of these conditions favorable for fish in full measure,
and these provide the essentials for a large and varied
population of food and game fish (Fig. 15).

Conclusions. A fresh water pond or lake has been com-
pared to a microcosm or miniature world. It is isolated
from the rest of the world and the animal life of the sur-
rounding country might be shut off without greatly modify-
ing the life of the water. This life has not reached the high
state of complexity that the life on the land has attained.
The life of the wrater is intimately related and bound together
so that it is quite likely that any agency that tends to influ-
ence any group would sooner or later upset the balance of the
whole community of animals.

It is when we come to study the natural history of a single
water animal that we realize how closely related this is to
all the other animals and to the environment in which it
lives. Thus if we wish to learn what we can concerning the
Yellow Perch we soon find it necessary to consider the other
animals that the Perch preys upon, as well as those which
prey upon the Perch. We learn that this fish feeds upon
insects, crustaceans, shellfish, and small fish. These animals-
in turn feed upon other insects, crustaceans, and plants, and
these in turn feed upon plants, mostly algse. The plants
feed upon the mineral and organic matter in the water and
soil. The physical environment, also, must be favorable in
order that the plants may find a suitable place in which to>
grow. And so in our study of this familiar fish we have

The Relation of Shellfish to Fisli in Oneida Lake 33

to consider the lives of the other inhabitants of the water in
which the Perch lives, as well as the whole physical and
plant environment, before we are able to understand the
natural history of this common fish thoroughly.

The studies carried on at Oneida Lake and elsewhere have
shown that the group of animals known as mollusks or shell-
fish have a vital relation to the fish fauna as well as to many
other animals, some of which bear an intimate relation to
fish. Recognizing the value of shellfish, it is evident that
the time is not far distant when these, as well as other ani-
mals of value as a food supply, wrill be artificially introduced
into waters where they were previously wanting or insufficient
in number. If the environment and other factors are favor-
able there will be 110 difficulties not surmountable that will
hinder this procedure. The day is evidently not far distant
when the fresh waters will be cultivated to the extent that
the land areas are nowr worked, as has been the case in
France and Germany, where ponds have been made artifi-
cially and stocked with fishes and their food. Food in the
form of plants, shellfish, insects, crustaceans, etc., will be
introduced where needed before the fish are planted, paral-
leling in a way the preparation of the land before the crop
is sown. Given a species of fish whose life history and
natural history is known, it is comparatively easy to prepare
the right kind of a habitat and the natural and suitable food.
Thus in the course of time we may hope to have a flourish-
iiif water culture or aquaculture, so that the streams, lakes
and ponds of forest lands may be made as productive in their
way of food, recreation and income as the forests are of
lumber, game and recreation (Fig. 16).

NOVEMBER 15, 1917.
Department of Forest Zoology.

2

COMMON AND SCIENTIFIC NAMES OF FISH
USED IN THIS CIRCULAR

Lake Sturgeon

Dogfish

Toothed Herring

(<i/zard Shad

(Jreat Lake Trout

Common \Vhitefish

Round Whitefisli

American Eel

Red-mouthed Buffalo

Round Buffalo

Small-mouthed Buffalo

Spotted Sucker

Common Sucker

Common Red-horse

Short headed Red-horse

Carp

Channel Cat

Yellow Bullhead

Common Bullhead

Black Bullhead

Chain Pickerel

Common Pike

Rock Bass

Strawberry or Calico Bass

Bluegill

Long-eared Sunfish

Pumpkinseed

Small-mouthed Black Bass

Large-mouthed Black Bass

Pike or Pike Perch

Sand Pike

Yellow Perch

White Perch; Sheepshead

Acclpenser rubicundus LeSueur
Amiatus calv-us (Linnaeus)
Hiodon teryisus LeSueur
Dorosoma ccpedianum (LeSueur)
Crist ivomer namycush (Walbaum)
Coregonus clupeaformis (Mitchill)
Coregonus quaclrilateralis Richardson
Anguilla chryso-pa Rafinesque
Ictiobus cyprinella (Cuvier & Valenciennes)
Ictiobus urus (Agassiz)
Ictiobus bubalus (Rafinesque)
M'inytrema melanops (Rafinesque)
Catostonnis commcrsonii (Lacepede)
Moxostoma aureolum (LeSueur)
Moxostoma, breviccps (Cope)
(hfprinus carpio (Linnaeus)
Ictalurus punctatiis (Rafinesque)
Ameinrus natalis (LeSueur)
AmeinniK ncbulositx (LeSueur)
Antciiinifi melas (Rafinesque)
ESO.T reticula t us ( LeSueur )
Eftox Indus (Linnaeus)
Ambloplites rupcstris (Rafinesque)
Pomoxis sparoides (Lacepede)
Lepomis pallid us (Mitcliill)
Lepomis megalotis (Rafinesque)
Eupomotis gibbosus (Linnaeus)
Micropterus dolomieu (Lacepede)
Micropterus salmoides (Lacepede)
Stizostedion vitreum (Mitchill)
Stizostedion cana dense (Smith)
Perca flavescens (Mitchill)
Aplodinotiis grunnicns (Rafinesque)

31

Fig. 1. — General view of the west end of Oneida Lake, including
Big Bav.

Fig. 2. — Milton Point looking east, Frenchman Island in the distance.
A bouldery point with only Water Willow and Bulrush for vegetation.

Fig. 3. — A bay-like habitat, north of Long Point, looking northwest.
The bottom is verv sandv.

Fig. 4. — Xickerson Bay, on the north shore near the outlet at
Brewerton. An example of a habitat with abundant vegetation.

Fig. 5. — A mussel fisherman on the Mississippi River with his flat-
bottomed boat rigged with two crowfoot dredges, each 12 feet long, and
used to catch mussels for the pearl button industry.

n

Fig. 6. — The larger snails* living in Oneida Lake. 1 and 5. Viviparous
Apple Snail ( 1 iri/xirii contectoides) ; jJ-S. Apple Snails (Cnmpcloma
inti'f/nini and Campelcma decision); !)-12, large Pond Snails ( Li/mmra
staynalis lilliaii(r) ; 13-20, Orb-snails (I'lanorbix Iricolris and I'lnnorbifi
binneyi) ; when young, these Orb-snails are eaten by several species of fish.
Campeloma and Vivipara furnish food for such fish as bullheads and catfish.

I

&

4

13

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17 18

441

19 io

10 II

J2

26

4 44

IS 2Z 2.3 24

' *

27 28

Z9 3°

35

37 38

39 40

43

FIG. 7.
(For description, see next pajre. )

Fig. 7. — Snails and finger-nail shells of special value as the food of fish.
Xos. 1-9, small Orb-snails (Planorbis defiectus, Planorbis parvus, and Planorbis
exactions) ; 10—15, Valvata Snails (Yalvata tricarinata and Valvata bicarinata
normalis) ; 16-18, fresh-water Limpet Snails (Ancylus fuscus, Ancylus paral-
lelus, and Ancylus tardus) ; 19-21, Amnicola Snails (Amnicola limosa and
Amnicola lustrica) ; 22-23, Bythinia Snails (Bythinia tentaculata) ; 24, Amber
Snail (Succinca avara) ; 25-28, Pisidium Clams (Pisidium variabilc, Pisidium
compressum Icevigatum, Pisidium compressum, and Pisidium cequllaterale) ;
29-30, Musculium Clams (Musculium securis and Musculium rosaceum) ; 31-33,
Sphffirium Clams ( Splicer ium striatinum and Sphcerium vermontanum) ; 34—36.
Tadpole Snails (Physa ancillaria warreniana and Physa Integra) ; 37-38, Pond
Snails (Lymncea columella chalybca and Lymncua columclla) ; 39-40, Snails

(Gillia altilis and Somatogyrus subglobosus) ; 41, Tadpole Snail (Physa
gyrina) ; 42, Slender Pond Snail (LymncKa haldemani) ; 43. Pond Snail (Lym-
n(Ka palustris) ; 44, the larva of a Caddis-fly which resembles a snail in form

(Helicopsyclie borealis) .

Fig. 8. — Seining fish on Long Island, a habitat favorable for shellfish.

Fig. 9. — Collecting shellfish on the rocky shore of Frenchman Island.

C\|

Fig. 11. — Invertebrate animals on sand bottom, water four feet deep. Area
dredged (54 square feet. The principal animals are '; finger-nail " shells (ttplid-
riitm, 1, Pisidium, 2) ; pond snails (Galba catascopium, 3) ; and small snails
(Amnicola, 4). Caddis-fly cases, mostly without the animal, are numerous
(Molanna and Lrptocell-a. 5). Head of Short Point Bay.

Fig. 12. — Invertebrate life on clay bottom, a 16 square inch unit, water
4 feet deep. The principal animals are fresh-water sowbugs (Ascllus, 1) ;
Caddis-fly larvae (Ar/rai/lca,2, Phryganeidac, 3) ; snails (Amnicola, 4) and
Scuds (Hyalella, 5). Southwest corner of Lower South Bav.

Fig. 13. — Invertebrate life on mud bottom, water 10 feet deep. Dredged from
area of 64 square feet. The principal animals are May-fly larvae (Hexagenia, 1) ;
Midge-fly larva; (Chironomus, 2); finger-nail clams (Pisidium, 3); snail shells
(Amnicola, 4) ; many empty cases of caddis-fly larvae are present (Molanna, 5,
Leptocella, 6). Middle of Short Point Bay.

Fig. 14. — Invertebrate life on a boulder measuring 6 x 4Vo * '^/2 inches,
water 20 inches deep. The characteristic animals are the snail (Gonio-
basis, 1) ; the beetle larva (Psephenus, 2) ; the spiral caddis-fly (Heli-
copsi/clie, 3) , and the May-fly larva (Heptayenia, 4) . Short Point. Lower
South Bav.

Fig. 15. — A good habitat for fish and shellfish near Fitzgerald
Point, north shore of Oneida Lake, near Bre\verton.

Fig. 16. — Field Laboratory at Brewerton, N. Y., at the west end of
Oneida Lake. The crowfoot dredge (at left of picture on the .door)
and other apparatus for collect ing shellfish are shown.

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