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^^ 1653 East Moin Strvct
Rb RochMt»r. N«« York 14609 USA
(716) *a2 - 0300 - Phon«
(716) 28a- 5989 - Fo«
SPECIAL
APPENDED REPORTS
BY
PROFESSOR E. E. PRINCE
Dominion Comnilnnimn'r nf Fisherif.s, Oltnirn.
1. EGGS AND EARLY LUE HISTORT OF THE COD. HADDOCK AND MACKEREL.
8. MIGRATIONS OF SEA FISH.
1907-8
OTTAWA
GOVERNMENT PRINTINU BUREAU
1909
"^*^^^^^^^^'^P^^^*jf^'" ■
fk - .>;'■
i»»i. •■>^7^
SPECIAL
APPENDED REPOKTS
PROFESSOR E. E. PRINCE
Dominion Commissioner of Fisheries, Ottawa.
X..PTT OFE HISTORY OF THE COD. HADDOCK AND MACKBBEL-
1. BOOS AND EABLT LIFE HlSluni v^r
, MIGRATIONS OF SEA FISH.
1907-8
OTTAWA
GOVERNMENT PRINTING BUREAU
1909
CONTENTS.
I.— Tub Eoob and Lire Hmtoit or thi Cod, IIaddock and Mackiieu
Prevtiling ignorance respecting the life hittory of important commercial fiihea — Digest
of reaearchet by Prof. Mcintosh and Dr. Maaterman— Prof. O. O. Saru' rcaearchea
— The fisbea named produce amall floating eggr, minute young, which come inihore
—Later atages prefer diverse habitats— Six stages in each specie*— Cods' eggs
described— Number of egga produced— Spawning areas— Warmer waters preferred
— Embryonic development — Larval and post-larval feature* — 40-day cod inshore —
Small cod 2-6 inches long on rocky shores— Mature in third year— Haddock
resembles cod in development— How they differ— Haddock 1-3 inches long in
mid-water — Later reroaii in open sea — 'Mark' on shoulders at IJ-inch stagr—
Near the bottom at 4 inches — Later habits of haddock— Mackerel produces floating
eggs containing an oil-globule — Quantity of eggs smaller than in cod and haddock
— Size reached by mackerel — Spawning in May and June — Sch<H}lp decimated by
purse-seines — Later the spent fish recover and are fnt in the fall — Si«e ol the egg
— Appearance of fr, -First drawing made in Ireland — Mr. Holt's detailed
descriptians — Larval and post-larval stages — Schools inshore — Abundance of
' tinkers ' in bays — Adult stages.
n.— The MraRATiONS or Sea Fish.
Practical importance of fish migrations in the sea — Experiments planned at Marine
Biological Station, St. Andrews— Bird migrations are analogous— Different type*
of migration — Transportation of floating eggs and fry in the sea— Later move-
ments of young fish — Curious anomalies in marked fish — Individual wanderers —
Johnstone's and Schmidt's experiments with plaice in Irish Sea and Iceland —
Long distances exceptionally traversed — Inshore and off-shore migrations — Views
of Professor Mcintosh— Young cod larv» carried to colder areas and remain there
— Cod of li inches descend to bottom — Cod under 2 feet wander little — Mature
cod really local in habitat — Spencer Baird's and Nielsen's views — Mackerel form
local varieties — Natural restoration after depletion i* not rapid- Food attracts fish
to localities — Physical conditions are influantial — The Gurnard (Trigla) an excep-
tion— Anadromous fishes wander little from their rivers, shad, salmon — Migration
of birds and fishes compared — Fishes influenced by currents — Dr. Bell Dawson on
compensating circulation in Gulf of St. Lawrence — Seines take fish which refuse
bait — Main fishery for cod, mackerel, &c., should be after spawning, when the fish
have recovered — Fish hatcheries of small avail for sea fishes generally.
10364-1
I.— THE EOOS AND LIFE HISTORY OF THE COD, HADDOCK AND
MACKEREL.
BY raoriUOB BOWABO B. PBIMOB. OOMMUaiOXBa or rnilBBlBa, OTTAWA.
Complaint hat been made that publtthed inveatigationa on fiah Ufa and fith habitt,
for popular information have been too exclusively devotnl to frpch water fish and to
ansdromous ipeciea. The salmon, trout, whitefiah, black bass and pike-perch or doi*
have been fully treated in reports and papers for general readers. The cod, haddock
and mackerel are three examplea of fishes that are of the highest commeroial import-
anne and about them rea<lily acceasible publications are wanting. It mnst also b*
added that scientific and technical knowledge concerning the life history of fishes
inhabiting the deep sea is leaa full and complete than ia the case with river and lake
fiahes and species like the salmon that spend only a portion of their time in freah
water. A considerable mass of information exists respecting the cod, mackerel and
haddock, but to lea-n about the spawning peculiarities, habits of th(> young, rate of
growth, food at different stages and migrations, it is necessary to conault difllcult
technical treatises and to read scientific jrurnals which arc not readily acceasible. Ona
of the very few books for general readers published in London in 1807 is the beautifully
illuatrated work on Britiah Marine Food-Fishes, by ProfeMor W. C. Mcintosh and
Dr. A. T. Maaterman.
Little waa generally known about 'he eggs and life history, the growth and migra-
tiona of sea fishes used for food when I began their special study in 1885 at St
Andrews, Scotland, under the gruidance of Professor Mcintosh, though it was already
known, and bad been known to specialists for nearly twenty years that cod, haddock
and mackerel were wholly unlike the sea herring, and fresh water fishes, both in regard
to the nature of their spawn, the features of their breeding, growth and early migra-
tiona.
Profeaaor O. O. Sa'-a had begun investigations in the course of which be secured
■mall floating eggs, like minute pellets of glaas, but so light and buoyant 'Hat they
floated near the surface of the sea. The waters surrounding the Lofoten Islands, the
famous fishing grounds of the Norwegian cod-fishermen, were filled with these small,
almost invisible, floating eggs. Later Dr. Sars discovered other egg* much resembling
cod's eggs, which proved to be the very similar eggs of the haddi'>ck, and loter he obtained
the eggs of the mackerel, also floating, rather larger than cods' eggs, and exhibiting a
new feature, viz.: a glistening oil-globule. Dr. A. W. Malm, of Goteburg, likewise
found the oggs of the haddock and mackerel and described them, while Alexander
Agassiz, and the early scientific staff of the TTnited States' Fish Commission 'Dr.
J. A. Ryder, Dr. R. E. Earll aud other:'*) confirmed previous discoveries and extended
them very considerably. So inadequately was the importance of Sars' amazing dis-
coveries realized by biologists and by the general public that at the Great International
Fisheries Exhibition in London, in 18S3, his drawings and descriptions of these floating
fcoa-fish eggs ottracteo little attention on the whole. On my many visits to that famoua
and in some respects unsurpassed flsheries exhibition, I never failed to re-examine
Dr. Sara' drawings with the accompanying detailed descriptions placed alongside,
and on no occasion did I observe brother scientists or interested spectators paying
much attention to that unique exhibit. The specimens and drawings were not only
unique, they were, from a fisheries point of view, epoch-making. In the official
catalogue of the exhibition it is interesting to note that they were carefully described.
&
10364— li
Owing to this epecial interest I quote from the catalogue the following notice: Pro-
fewor O. O. Sars, development of cod {Oadua morrhua) eriilained by n aenea of fif^-
aiz coloured drawings on seven plates, made by the exhibitor during his visits to the
Lofoten Islands in the years 1866-69.' There were shown 66 accurately drawn figures,
Nos. 1-24 showing the ovary, early ovum and first segmentation stages; Nos. 26-36,
the formation of the young fish in the egg, and the features of the hatched larva and
young cod up to one inch in length; Nos. 37-6!?, later stages of young post-larval cod,
and Nos. 53 to 66, later codling up to adult cod, 20 and 33 inches in length.
The collection was not an imposing display and was overshadowed by the larger
and more striking objecU displayed in the various sections and galleries, and sent
from all quarters of the globe. At the conferences, which were held frequently during
the eight or nine months of the exhibition's existence, and which I attended diligently,
in order to listen to the great masters in the science of fish and fisheries, very scant
reference was made, so far as I can recall, to the astonishing and revolutionizing
character of Dr. Sars' specimens, and their importance as practically bearing upon
the preservation and welfare of the fishing industries in the sea.
At the commencement of my researches I found that the field was regarded as
virgin and practically untouched, so little was generally known about the eggs and the
broeding peculiarities of the marine food fishes, which form the staple commodities
in the great fish markets of the world. When Professor Mcintosh and myself read
at the British Association and at the Royal Society of Edinburgh the results of our
investigations, they were regarded by the biologists as very novel and of altogether
peculiar interest and importance. Full and adequate studies, in continuation of the
pioneer work of Dr. G. O. Sars and Dr. A. W. Malm, had not been made of the lilfe
histories of the marketable food fishes in the sea. Indeed, until I studied mackerel
eggs in the spring of 1893 on the s.s. Fingal, and made drawings of the young fry
immediately after hatching, no one had seen or sketched the mackerel in its first
stages, and those published subsequently by a very able English authority showed
colouration and other features not observed by me in the Irish mackerel eggs obtained
during the oflBcial fishery cruise under H. M. Inspector W. Spotswood Green, in the
year named.
The researches above referred to, with later investigations by other workers have
shown that:
(1) Cod, haddock and mackerel produce spherical eggs which are typically pelagic,
i.e., small in size, extremely delicate in structure and appearance, of glassy transparency
and so buoyant as to float freely near the „urface of the sea.
(2) The young larvaj emerging from these eggs are as minute as mosquitos or
midges, very buoyant and transparent, frequenting the superficial strnta of the open
sea, and carried helplessly about by the tides and currents, during the earliest part
of their life.
(3) The young fishes, as soon as thoy cease to feed on their stock of food yolk, and
actively capture food, migrate in schools incalculably vast, from the open waters, where
they are first congregated and find safer areas inshore, often quite close to the shallow
beach or the tidal rock-pools.
(4) The later post-larval and adolescent stages are marked in each species by
features in their migrations and habits which are not uniform but diverse, and
distinctive of the several species.
In the following summarized account I shall describe in each of the four named
species :
(1) The mature ovum and its deposition.
(2) The hatching of the ovum and larval migrations.
(3) The features characteristic of the early larval stages.
(4) The post-larval or pre-adolescent stages, often embracing curious develop-
mental transformations.
(5) The maturer stages, not yet adult, and migrations.
(8) The adult condition and habitat? in the sea.
The egg of the cod is a spherical buoyant pellet 1-38 to 1-39 mm., or a little a /er
three-fifths of an inch in diameter, nnd of such colourless transparency as to be
practically invisible in the water. On the Banks of Newfoundland and off the Can-
adian Labrador, as also off the Lofoten Islands and the southwest shores of Iceland,
these doatinfr eggs may occur in quantities beyond the grasp of the human mind.
Their incalculably vast myriads dancing like microscopic soap-bubbles in the sen may
indeed impart a dull milky aspect to the surface waters as though a filmy stratum of
mucilage floated along the surface of the sea, as described by Norwegian fishermen
over forty years ago.
Each female cod produces an enormous number of eggs. Indeed, M. Petit weighed
the ovary of a specimen and calculated that at least nine millions of eggs wore con-
tained in a single large fish. The female cod is, contrary to the rule in most fishns,
smaller than the male when full grown. The fish congregate near the surface of the
sea at the spawning time, which is during the months of midwinter. October to
December, or even so late as February and May. Off the coast of Labrador nnd around
the Magdalen Islands the spawning schools crowd so .'■ ickly that a vessel mny be
impeded in her progress, striving to pass through them. No well defined areas in the
sea can be distinguished as cod spawning groimds; but the regions in Canada and
Northern Europe vary from two to two hundred milrs frnm the shore. Much df^pends
on the nature of the coast and the character of the currents and tides ; but it has bren
determined that the parent cod have a preference for wnrmer rather than colder areas,
though the young fry are found to flourish, some months after hatching, in water of
extreme frigidity as off the north coast of Iceland. The eggs scatter widely and in
areas of low specific gravity they may descend to a depth of many fathoms, though
the roost favourable areas are those in which they float within one or two fathoms of
the surface, and in extreme calms may form a smooth film quite at the surface. All
the eggs are not deposited at once, but those which lose the creamy white opacity of the
maturing ef^s and acquire a clear glassy transparency like translucent gum, glide to
the posterior end of the ovary and are shed. While the ripe female cod scatter their
eggs near the surface, the male fish congregate below, and the streams of minute
sperms which they eject like jets of creom. ascend and fertilize the eggs. Few eggs
probably escape fertilization, as the tests in the Jfarine Laboratory, now the Oatty
Marine Station, at St. Andrews, Scotland, proved. Dr. Schmidt, in a recent report m
the cod in Iceland states that ' when maturity approaches, and the fish is preparing for
reproduction, it becomes much more sensitive to external conditions. This results in
the undertaking of the second great migration of its life, which having regard to the
object may be called the spawning migration, and which ends in the warm water on
the south and west coasts. The proportion of the sexes on the spawning grounds has
not been determined, as has been done in the case of the salmon and certain other
fishes; but Sars noticed in Norwegian waters more female fish near the surface than
male fish.
The eggs are helplessly wafted about in the water, and in a period varying from
one week to four weeks, according to the temperature, the young fish, less than one-
sixth of an inch long (4 mm. or -lO in.) emerge into the open sea, floating back down-
wards and exhibiting four black transverse bands along the slender worm-like body.
Within two or three days the young fish have vigour enough to swim in the right
position, progressing by sharp wriggling motions. A swollen ball of yolk protrudes
from the under side and upon that fluid yolk the fry feeds. By the end of the first
week the yolk-sac has nearly disappeared and the fish is slightly longer and appears
deeper in the body owing to a long fin along the back having grown in height. About
this time (being now over 5 mm. in length, or '195 in.) the eyes appear bright and
silvery, a black patch appears at each side of the body and the two first cross bands
of dark colour break up, but the second and third bands still remain, and the little
fish descends to some depth to what is known as the mid-water habitat. Minute crab-
life copepods now form the main food of the larval cod and these, when undergoing
digestion, turn pinkish or red. Hence this red food visihle through the transparent
walls of the young fish impart to it a reddish hue. Later, when 6-6 nun. long
(•226 in.) the last two bars have disintegrated, black spote appear on the head and
along the middle of the under surface, while a greenish yellow tint faintly appean
oyer the little fish. All this time the breast fins have been actively used like delicate
fans, but the second pair or ventral fins now bud out, yellowish tints appear, and a
length of -332 in. or 8-26 mm. is attained at this time, viz., the third week. A little
later, when the cod is -375 in. or 9-42 mm., hard rays appear and strengthen the back
fin, the anal fin and the tail fin, and the shape of the head is no longer blunt and
rounded, but more pointed and cod-like. The mouth opens to the front instead of
upwards, as in the earlier stages, and a little barbule or feeler appears at the tip of
the chin. Myriads of these baby cod now move shorewards, and a month or five weeks
later, in May, June and July, when the fish are over 40 days old (-586 in. or 14-8 mm.
long) they crowd the inshore waters. They rapidly reach a length of an inch, and in
company with green cod, pollock, &c., form schools in the rock pools and in shallow
inlets. The cod is distinguishable by the more marked reddish hue of the top of the
head, by the pearly lustre of the sides variegated with eight or nine irregular dark
blotches along the sides and back, while the belly is silvery. Black spots appear on the
two back fins and on the first anal fin below, but none on the tail fin, though a U-shaped
band occurs marking the root of the tail.
Dr. Schmidt found that small cod in the North Sea, off the Scottish coast, were
much paler in colour than the larval cod of more northern waters. Sars was the first
to describe the cod at 2 inches (50-8 mm.) in early August amongst alpe along rocky
shores, and states that by October they are 4 or 5 in. long, and a month later as much
as 6 to 10 inches long. Their colour varied, being reddish yellow on rocky shores and
greener or grey on sandy spots. When a year old, say in February or March, the young
codling may be a foot in length (304 8 mm.) and in the coiirse of the season they
forsake the shore and migrate seaward. In their third or fourth year the cod is mature
and they are then two feet or more in length and develop spawn.
HADDOCK.
In many respects the haddock resembles its congener the cod, yet, a careful study
of their eggs, life history, habits and external features shows innumerable differences
and even contrasts. Their localities for spawning are much the same as those of the
cod, being out in the open sea from five tc twenty, or even sixty, miles from land. The
female haddock is universally smaller than the male, and the size of the egg is really
the largest of the early pelagic or floating eggs. It is not readily distinguished from the
spherical, transparent, buoyant eggs of the cod, biit is larger, viz., 058 in. in diameter,
or 1 -458 mm., and the number produced is far less than in the case of the cod viz : a
quarter of a million to two million eggs. Haddock scatter their ova in the sea from
January to the end of May, and the time of hatching varies from one to three weeks.
The newly hatched fry are smaller than Ihosc of the cod, viz., 14 in., or 3-5 to 4 mm.,
and they swim helplessly, ventral side upwards, being incommoded by the yolk sac or
ball of fluid food which nourishes them for several days. There is no trace of the
cross-bars so prominent in the cod, but irregular black spots occur about the shoulder,
and a row on each side from the abdominal area to the tail and along the ventral line
of the muscular body. After floating about for a week near the surface of the sea
they appear to make for deeper water near the bottom and red-blood has been observed
at that age. It is interesting to note that in these minute floating larval fish there is
no red blood for some time, a delicate colourless fluid being driven by the heart over
the transparent body. The jaw is turned sharply upward until the eleventh or twelfth
day, when the movable lower jaw opens direct to the front. The lateral abdominal
patch of colour is even more marked and dense and along the lower border of the fleshy
tail a TOW of black stars is a marked feature. In May the young haddock from 1 inch
•9^2172?
to 8 inches in length abound in mid-water, neither at the bottcmi nor near the eurfaoe
of the Bea. They remain 20 to 40 milsa out at sea, and do not migrate close inshore
like the cod and the pollock and green cod. Sara described the haddock as stouter and
more compact in form than the cod of the same age. The ventral pair of fins are first
noticed in the fish at an inch in length, when the sides of the body are sparsely spotted
with black dots, the head and shoulders included, and the specks of black colour extend
over the fins; but the under surface of the fish is pale and silvery. When about one-
fifth longer, i.e., m inch long (20 mm.) the larval haddock still keeps to deep water,
and the two ventral fins appear exceptionally long, while the unpaired dorsal and anal
fins are largely developed, but there is still no regular cross-bar or checker pattern
similar to that of the cod. On reaching a length of H inches (39 mm.) minute scales
appear, and the characteristic ' thumb ' mark or black patch behind the shoulder is
quite distinctly visible. The barbule on the tip of the chin appears, but is shorter
than in the case of the cod, and the mouth is smaller in proportion to the size of the
fish. There is no dappled appearance ns in the cod, and no duaky or speckled colora-
tion as in the green cod or pollock. When an inch longer (2| inch, i.e., 60-46 mm.)
the haddock ' mark ' is darker and more definite, the pectoral fins are yellowish brown
and speckled, uniform specks of black extend all over the head and body, the eyes
are of a metallic silvery colour and tho lower jaw and the mental barbel are smaller
than in the cod. In contrast to the cod, no haddock appear to frequent the shore up
to this age. Specimens 80 mm., i.e.. 3i inches long, exhibit a warm copi>ery sheen
such as is so frequently observed in the large full grown haddocK. Professor Mcintosh
in his account of the haddock, states that the bottom trawl at the end of July has
secured haddock of 4 inches (101-1 mm.), and they are taken also on baited hooks, but
before that stage none have been secured otherwise than in the mid-water net or in
the stomachs of predaceous fishes. At that size they are no doubt about five months
old. Later specimens six or seven months old, 6 inches long, have been secured, and
in November and December they measure over 7 inches in length, while the following
May and June they reach a length of at least nine inches and cannot be less than
thirteen to nineteen months old. Thus the haddock shows rapid growth during its
first summer, no less than an inch per month ; but in winter its growth is slower. In
the third year the haddock reaches the mature stage and is developing spawn. After
spawning they are often found inshore feeding voraciously on eggs of other fishes
attached to rocks, &c., and they are much more gregarious in their habits than cod,
but are not abundant so far north as the related species named.
MACKKBEL.
Widely differing from the cod and haddock in all the features which are regarded
as important in the eyes of the naturalist, the mackerel ranks with the two valuable
food-fish named on accoimt of its importance economically, and on account of its pro-
duction of minute delicate floating eggs. The salmons' eggs arc large and heavy, and
the eggs of the herring are dense and cling together like hard glassy i>ellets; but
the eggs of the mackerel are extremely transparent and delicate and float buoyantly
near the sea's surface. Professor G. O. Sars and Dr. A. W. Malm first described the
egg, and it was my good fortune, as already stated, to be the first naturalist to hntch
out and make scientific drawings of the young larval mackerel, when with Mr. Spots-
wood Green, investigating the west Irish fishing grounds on the ss. Fingal. The
female mackerel produces on an average probably a quarter of a million eggs. As
Drs. Jordan and Evermann say : ' The mackerel egg is exceedingly small, it being
only Vu of an inch in diameter. The eggs average about 40,000 to the fish, but 200,000
have been taken from one fish. The largest mackerel would doubtless produce 1,000,000
eggs each.' Yarrel regards fish 14 to 16 inches long as large average specimens, such
weighing about 2 pounds; but he states that in 1849 a specimen 18 inches long and
weighing 2} pounds was caught on the English coast, and in November, 1866, one was
10
■old in London weighing 2 pounds 10 ounces; but in Canadian water* much larger
mackerel are frequent, and I myaelf aaw a Nova Scotia mackerel taken in May, 1898,
which was 22) inches long and weighed no lesa than 4i pounds. In May and June
the spawning schools move landward to spawn. They approach the Nova Sootian
coast and move into the Gulf of St Lawrence from a southeasterly direction. Up to
the middle of July they will not, as a rule take bait, and as Professor Hind pointed
out they lose all desire for bait when engaged in spawning. The deadly purse-seine
introduced into the Gulf of St. Lawrence by the American schooners captures these
spawning schools in immense quantities. Almost without exception these fish coming
into Pleasant Bay early in July and going up the north shore (Quebec) as far as
Pointe do Monti! about the end of July, are spawning or partly spawned. June and
July cover the period, though mackerel remain and feed in the Gulf and along the
Canadian shores until the end of October. The spawning and spawned fish are very
inferior, but the fall mackerel, having recovered and fed up, are firm and fat and
incomparably superior in every respect.
The eggs produced by the mackerel are small translucent spheres over %Bth of an
inch in diameter (-038 in. or 1-22 mm.), and exhibit in the midst of the clear contents
a cloudy, almost colourless globule ^oth of an inch in diameter (-32 or -33 mm.). No
globule appears in the eggs of the cod or haddock, bat the ling, the gurnard and other
fishes exhibit in the egg a so-called oil globule. In about six days the young fish
hatches out and at first, a few sparse specks of yellowish colour are seen near the eyes.
The yellow specks later appear mingled with black dots on the globule and over the
head and body, and form an irregular lino along the back. These spot?, says the well
known Irish fif hery authority, Mr. E. W. L. Holt, are blue black, not dead black. The
younir mackerel which I had under observation for over a week until accidentally
killc' Sy a cloud of hot soot showered upon them from the smoke stack of the steamer,
sho .< •) } other colours excepting yellow and black, but it has been stated that bright
grecii • ...inent occurs on the fifth day on the tail, and behind the eyes and on the
globule. On the ninth day after hatching a length of -19 in. or 4-88 mm. is reached
and the ball of food yolk is used up. The eyes have a bright blue metallic appearance,
and on the sides, the upper abdominal pigment is very marked, but there are few spots
on other parts, and no cross bands or serial patches. By the tenth or eleventh day the
larval appearance is gone and the post-larval stage is fully attained. Mr. Holt com-
pares the mackerel larva at this stage to the grotesque post-larval Cottus or sea-
skulpin. At this time the schools of young come inshore and vast numbers may be
seen in Northumberland Straits, off Prince Edward Island, and in the Bay of Chaleur
off the Bonaventure coast in August and September. Dunn, the well known English
observer, speaks of young mackerel 3 inches long in bays and shallow inlets. In
November, when 6 or 7 inches long, they move into deeper water, and are not observed
until they reappear as ' tinker ' mackerel, 8 or 9 inches long, abounding in harbours
and bays. Sars held the opinion that a one-year old mackerel was as long as the finger,
that at the end of the second year it wis the size of a herring, and that in the third
jear it is full grown, though mai authorities give the mackerel another year and
declare a mature spawning mac! be in its fourth year. For the first two years
the young mackerel frequent opei. -ter near shore, and as Proffssor Mcintosh, of
St. Andrews, Scotland, says, the lengths 4 inches, 8 inches and 11 inches probably
correspond with successive years in the life of the mackerel.
While the mackerel schools along the various portions of the lengthy Atlantic
coast of Canada have not been separated into local races or such differences noted as
in European seas, yet there is no doubt that each area on the coast has its own stock
and that the mackerel does not migrate over long distances, but largely confines its
movements to coming into shallow waters from deeper water and vice vena.
n
n.— THE MIGRATIONS OF SEA FISH. WITH SOME RESULTS OF MARK-
ING FISH.
BY PBOFESSOB EDWARD E. PRINCE, DOMINION COMMISSIONER OF FlSIIEttlES, OTTAWA.
The migrations of sea fish' are of importance in connection with the commercial
utilization of marine fishery resources. Their determination is beset by peculiar
difiiculties, and the systematic marking of considerablo numbe.-s of the most valued
food fishes on the plan adopted by the Marine Biological Board of Canada, to be carried
out in successive seasons on the Atlantic coast of the Dominion with the Marine
Laboratory at St. Andrews, N.B., as the principal station, is the first step towards
deciding the seasonal movements of the schools of fish upon which Canadian fishermen
depend for their catches. Just as the study of bird migrations occupied ornithologists
for over a hundred years, and the accumulation of observations and the tabulation of
ascertained facts has resulted in some approach to a satisfactory understanding of the
remarkable movements of the feathered tribes over the surface of the earth, though
much remains still to be discovered, so the thorough understanding of the wander-
ings of the finny tribes taking place in an element which hides them more securely
from continuous observation than the heights of the atmosphere hide the feathered
tribes, is a subject that only the patient collection of facta, and their ascertainment
both by ordinary practical as well as by scientific experimental methods can enable
us to arrive at complete and adequate results. The movements of fishes in the sea
vary according to the period of life of each species. Nay, even the epps, before giving
birth to the young fish, are the subject of migratory movements and add to the com-
plexity of the subject in many species. Shore fish, which produce floating eggs, like
the cod, haddock, mackerel and many flat fishes, are distributed over wide areas before
they hatch out. The young fish, after hatching, are under the influence of tides and
currents which effect migratory movements and transport thorn over great extents of
sea. Later, the effects of temperature, salinity, movements of the air (winds) and of
the water, are felt by the schools of small post-larval fishes, and later still the occurrence
of food is a most potent factor in leading fish to take long journeys, while at maturity,
besides the quest for food, the spawning instinct is powerful in causing them to move
from one area to another.
The methods of marking fish are important, but owing to the variety of devices
adopted by different observers in Europe and on this continent I shall deal with the
subject of modes of marking fish in a special paper in the journal of the Biological
Stations of Canada, Part III. of which appears at an early date. The mode of marking
is one of more serious moment in the work of deciding the migrations of fishes than
may, at first sight, appear. Observers have found, for example, that while a large
number of fish have been found to move over a limited area in some definite directior
single individuals or three or four individuals have taken to roaming, and in a sho'
time have migrated to very long distances in the most diverses directions.* Thus in Mi
James Johnstone's experiments in the Irish sea, with the valuable flat fish the plaice
(,Plalessa), out of 35 fishes marked and liberated on the Lancashire coast, about 40
miles northwest of Liverpool, one wandered past the Isle of Man round the Mull of
Galloway to Corsewall Point, near the southwest comer of Ayrshire, a distance of 110
miles, while another was recaptured near Dundalk, in Ireland, having traversed a
•The irritation caused by the tag may in some cases keep the fish continually on the
move, just 89 the minrabing herds of Barren Ground caribou, annoyed by the constant at-
taciw of large deer flies in suuiiiier, never c^ase tu move uuward over long Jistaucar.
distance of more than 120 miles, the former occupying over 14 months in the journey,
while the latter took between nine and ten months to cross the Irish sea, whereas most
of tliem were recaptured within a few months at distances of eight to twenty or thirty
miles from the spot where they were marked and placed in the sea. Similar peculiar
wanderings have been noticed in the United States' experiments with lobsters, rare
examples wandering upwards of a hunudred miles from thee locality of liberation.f Dr.
Johs. Schmidt, in his experiments with Icelandic plaice, foimd that moet of them in
10 or 11 months (July, 1905, to May and June, 1906), moved 200 miles; one plaice
reached a point about 280 miles, one about 250 miles and two about 220 miles from
Vopnafjordhr, where they had been placed in the water, the one travelling the longest
distance (from July to January following) in six months time. There is, however, an
inshore and offshore movement, apart from definite lengthy linear migrations, mainly
connected with spawning. Thus small flat fishes which very early in the yeav frequent
the shallow inshore grounds move with the approach of summer and, as they grow
larger, move into deeper water. Most fish in their early life after their larval life is
over ii»id they have assumed the form of the adult, though their dimensions are small,
exhibit this habit of leaving the shallows. This movement is no doubt connected with
a change in feeding habits as well as with a view to greater security and protection
from enemies. In all experiments with marked fish there is a preponderance observed
in the fish taking some definite direction. Johnstone's experiments showed, in the
North Woles plaice, a movement westward along the northeast shore of Anglesey, a
migration similar to that observed at two stations further north, viz. : off the Kibble
Estuary and off Lancaster Bay, where the migration west and southwest was marked.
Professor Mcintosh was the first observer to indicate the main facts, viz. : the migration
of the floating eggs innards, the hatching of the young and their distribution over the
inshore shallows, after drifting it may be for over a month in the same direction as
the eggs, and then after reaching maturity, moving into deeper water. In the deeper
waters the plaice move as in the Irish sea, or off the Scottish shores, westerly; but
must, of course, vory on other shores with the geographical contour of the different
localities. Indeed, as Schmidt shows, adult plaice liberated on the north coast of
Iceland moved westward more than a hundred miles, while other batches of adult
plaice, deposited on the east coast of Iceland, all migrated southwards. Tho authority
named decided that the reason of this definite migration was to reach areas of warmer
water ' with the exception of the few retaken close to where they were liberated, none
of the plaice were retaken on the east coast. It is only right down in the south ....
that the most were retaken.' Moreover the plaice from the north moved much slower
than those from the eastern station, due, it may be, to the rougher and more irregular
nature of the shore and the bottom. A similar west and south movement of the cod
was also observed by the Danish authority referred to. By this movement of the adult
cod warmer areas are reached suitable for the hatching of the floating eggs. But after
hatching the small cod, not more than Wh or %th of an inch in length, are borne by
currents north and east so that these cold northern areas are crowded with cod fry
and pass their first winter in those trigid surroundings. Schmidt found as early as
April (in 1904) vast swarms of young cod ' whilst the south and southwest coasts of
Iceland are washed throughout the whole year by warm Atlantic water, this is not the
case on the caai; and north coasts, where the influence of the polar water is felt.' Few
cod fry are found in the warmer south and southwest waters where the spawning
takes place, but they abound in the cold northern areas where the temperature rarely
rises for most of the year above freezing point There they remain until a year old or
even two years old. Young cod when 1} or li inches long are no longer found
swinmiing at the surface, but seek the bottom, and when from IJ inches to 2 inches
in length crowd inshore and abound in rock pools, and when 8 or 9 months old (6 to 10
inches lonp move out agoin to greater depths.- When about a year old they are a foot
long, and di not migrate until they are mature and ready to breed, usually when nearly
tSee my spnoinl B»pcrt, 1967, p. Izi.
tt
2 feet in length. Up to that time they are stationary and only migrata to warmer areai
in the early part of the year, January to April, for spawning purposes.
The recent experiments of the Marine Biological Association, England, shows that
in the cod marked on the steamer Huxley most of them appeared not to have wandered
far, these being below 2 feet in length. As the brief note in the recent journal of the
association states : —
' The report is based on tlio 252 cod marked on the Iluxley and the 42 recaptures
recorded up to the date of writing. Mfjst of the recaptures, constituting 13 per cent
of the healthy fish liberated, took place within six months of liberation.
'The fish below 60 om. (24 in.) in length remained in water of depth similar to
that in which they were first caught, and had not travelled far. Most of those which
Lad moved some distance from the liberation point were recaptured south or west of it.'
Now in the Atlantic waters of Canada the cod taken in June and July and on to
September or later are the cod which have spawned in deep water and resort to
shallow inshore waters for food or find it on the rough and rich ground known as the
banks. The fishermen speak of the cotl moving north after the capelin and the
swarming of immense schools of large cod on the Labrador shores is due to the presence
of the smelt-like capelin upon which they feed and grow fat. These coast migrations
during the summer months are limited and, we may almost say, with the late Professor
Hind, that the 'schools of cod frequenting a particular coast may be said to be
indigenous to it.' The late Professor Spencer Baird came to the same conclusion:
' The cod ' he says (U. S. Comm. Rep., 1889) ' is a local fish, nnd the different schools
have their different habitats.' Nielsen, in his report (Rep. Newfoundland Fish Comm.,
1889), expresses the opinion that the cod is a local fish as well as the salmon, and
indicates with some detail that each group has its local resort and the local varieties can
be readily distinguished, a George's Bank fish being known from any other kind of cod
on the other ' banks.' So can a Cape St. Mary's fish be distinguished from any other
kind of cod in Newfoundland, and a Trinity Bay fish from a Placentia fish.' The ^iew
has even been expressed that in the sea, as in salmon and shad rivers, each area or
locality has its own local variety of the same ppecies, and Professor Baird went so far
as to assert that deep sea fisheries depleted in any particular locality will rot be
restored. ' No fish ' he ventured to declare ' will come from surrounding localities to
take the vacant place. Fish bear a particular relation to particular spots and fishing
out one locality is thus like emptying a keg of lard, the space left does not become
again occupied.' Valid objection may be justifiably raised to a view so extreme as
that, but it is nevertheless tnie that in different localities the same species of fish may
exhibit distinctive features, and demonstrate the existence of local races. Even so
migratory a fish as the mackerel, if we accept Professor Garstang's views, shows marked
local variations, so that different areas may be said to be peopled by different local
races.
The floating eggs of most sea fishes of value for food purposes may be earned over
great distances as already pointed out, end the young larval and post-larval stages
are similarly transported from one area to another so that local varieties must cross
each others' borndaries and interdignte or intermingle, nevertheless the fact is that in
some localities valuable fish have been so persistently destroyed that their almost total
depletion has been accomplished and their former abundance, even after many years,
has never been restored. The cod fisheries on many parts of the Atlantic coast of
Canada have been destroyed, an<? the mackerel, once abounding all along the eastern
shores of the Dominion, have become largely a thing of the past, while the once
maivellous shad fisheries of the Bay of Fundy are not one-thousandth the value and
extent they were 30 or 40 years ago. The disappearance of fish may be the result of
many and various causes, but the restoration by incoming schools from other non-
depleted areas is either very slow, or does not take pl-ce to any appreciable degree.
Fish may migrate from an accustomed locality to another new locality, attracted there
by more abundant food, and the disappearance of fish and decay of important fisheries
may often be traced to that caiwe. It has even been claimed that the decline 18 or 20
year* ago of the Gulf of St Lrwrence mackerel fisheriea ia due not merely to the whole-
sale destruction of the schools of fish just before spawning, but to the increasing
scarcity of the food which brought them into the inshore waters. Lobsters were form-
erly incredibly abundant and each summer the inshore waters were alive with incredibly
vast numbers of the surface swimming fry of the valuable crustacean. Those crowded
young lobster fry were the chief food of Ihe mackerel, and with the destruction of the
lobsters and consequent scarcity of the free swimming young, the mackerel found their
food gone and they sought food elsewhere. This may be true in a certain degree, and
the svdden and unexpected appearance of large schools of mackerel last season supports
it. The balance of nature once seriously disturbed has wide and lasting effects. But
the physical conditions in the sea may change, currents and particular peasonal streams
may so vary as to affect the salinity and temperature of the water. Tcmpcrnture is a
potent factor in determining the movements of fish.* Thus, as Dr. Wemvss Fulton, ten
or eleven years ago announced, the gurnanl (Trigia), an esteemed food fish in Britain,
moves inshore from deeper water about the end of March and in April and especially
in. Jfay. Most of them are breeding fi-oh and they spawn from April until July or
August, thus seeking the warmer inshore waters at the spawning time. Temperature
brings in these adult fish, but large numbers of small immature gurnards also move
inshore from May onwards. With them it cannot bo the spawning instinct, but must
be due to the increasing temperature and possibly also to a greater nlenitudo of food.
The gurnard thus presents a feature quite the reverse of that of the cod. in the young
stage!", for the small gurnards appear to be moat sensitive to a higher temperature and
forsnke the deeper, colder water; whereas the cod, in its young stages, spends its first
year at least in the most frigid surroundings in the waters of northern Iceland. While
cod, linddoek, plaice, Ac, seek the deeper waters and spawn offshore, the gurnard moves
closer into shiillower water to commence spawning in April and Mav. But nnndromous
fishes, winch annually ascend rivers, like the smelt, stri|)ed bass, shnd. alewife or
gnpperemi mid snlmnn. nro not content to move into shallow inshore areas of the sea
they pass up into the brackish waters of rivers, like the smelt, or useend. like the
striped l).ias, (o tidal limits, or move further up entirely above the influence of the
tide, like the shnd and gaspereau, or like the salmon migrate hundreds or even thousands
of miles to the head-waters of the noblest and longest continental rivers. ' L.-nving
their home m the far deep, the shad, in beginning their annual piljrrimape.' savs a
popular writer on the migration of the shad, ' rise to the surface, and then direct their
course landward, the earliest emigrants l)eing those in which the propagntive function
19 n-ost advanced. Pursuing their way over the comparative shallowa tlmt widely
fringe our continent, and joined by oth^r communities bent upon the same devoted
errand, they giither in our estuaries and cbout the mouths of our rivers, and there they
linger until the effluent waters are warmer than those of the sea.' The opinion prevails
that the schools of shad resorting to a certain river are the fish originallv hatche<l in
that river, and attracted by some peculiarity in the water flowing out of the mouth of
their native slrenm, and influenced by the degree of temperature favourable for their
entrance into fresh water, return once more to the upper waters. Thus in the Bay of
Fundy the spawning fish in the St. John river are not the schools native to the
Annapolis or the Avon of Minas Basin, nor are any of these fish which were hatched
from eggs deposited by parent fish in the Stewiacke, Shubenacadie or the Petitcodiac
nvers. WTien shad were taken from the Atlantic to the Pacific bv the United States
Fisheries Bureau, certainty was felt that the shad planted in the Sacramento would
return to that river only. As the writer already quoted says:—
were
«>mp
sever
a failure.
u
' Until the Pacific coast plantings it was assumed that the shad inrnriably returned
to the stream that gave them birth, and this, as a rule, is perhaps correct. The con-
diti.ms of the California coast evidently operate, however, to the diffusion of the fish,
they having in many instances established themselves in rivers far from the Sacra-
mento. This movement may be due to the balmy Japanese current, the Gulf Stream
of the Pacific, which laves its northeastern shore and agreeably tempers its climate.
Influenced by its genial flow and pursuing its track, the shad have wandered northward.
and, if they maintain their advance, as they probably will, their ultimate establishment
in the river system of Asia may be regarded as assured. Owing to various favourable
conditions, the shad not only multiplies rapidly in its new abode, but in some localities
has modified its habits, being found in varying abundance throughout the year. More-
over, it attains an exceptional size; seven and eight pound fish are common in Cali-
fornia, but are almost unknown with us, and there have been exposed for sale in the
Ban Francisco market shad of a weight as high as twelve and thirteen pounds. This
superiority in size is not unlikely due mainly to a less actively prosecuted fishery, for
shad of equal weight were known to our fathers. The heaviest fish are probably the
growth of a number of years, and an exhaustive fishery that each season leaves but few
survivors necessarily tends to eliminate the larger individuals.'
It is reported that some of the shad resulting from the stock originally p'.aced in
the Sacramento have been captured in Alaska, and certainly in the Frawr river. Rivers
inlet and even the Skeena river, in British Columbia quite a number of shad have
been taken by the salmon fishermen, several hundreds in all. How does this affect
the prevalent theory that such fish are true to their own native river? There is
abundant evidence that salmon return to their own rivers. This is seen in the
differences almost sufficient to justify the establishment of sub-species, difference not
only of external form, and of internal characteristics of the flesh (texture, colour. &c.),
but of anatomical and skeletal features. A Godbout salmon of the north shore ia
distinguishable at once from the typical Restigouche salmon, while neither resemble
in size and conformation the salmon of the Miramichi. The Peticocliac salmon are
different from the St. John River fish, so that one may say of the Canadian salmon
rivers of the Atlantic shore that a different variety of Salmo solar is characteristic of
each of these rivers. Certainly, as Professor Starr Jordan has said, nearly all salmon
return, as a general proposition to the region in which they were spawned, but that
famous authority qualifies the opinion by indicating that the schools may also resort to
other rivers to which they were not native, and adheres to his original view expressed
in 1880. He says: ' It is the prevailing impression that the salmon have some special
instinct which leads them to return to spawn in the same spawning grounds where
they were originally hatched. We fail to find any evidence of this in the case of the
Pacific coast salmon, and we do not believe it to be true. It seems more probable that
the yonng salmon hatched in any river mostly remain in the ocean within a radius
of twenty, thirty or forty miles of its mouth. These, in their movement about in the
ocean may come into contact with the cold waters of their parent rivers, or perhaps
of any other river, at a considerable distance from the shore. In the case of the
quinnat and the blueback, their 'instinct' seems to lead them to ascend these fresh
waters, and in a majority of cases these waters will be those in which the fishes in
question were originally spawned. Later in the season the growth of the reproductive
organs leads them to approach the shore and search for fresh waters, and still the
chances are that they may find the original stream. But undoubtedly many fall salmon
ascend, or try to ascend, streams in which no salmon was ever hatched. In little brooks
about Puget Sound, where the water is not three inches deep, are often found dead or
dying salmon, which have entered them for the purpose of spawning. It is said of the
Russian river and other California rivers, that their mouths, in the time of low water
in summer, generally become entirely closed by sand-bars, and that the sahnon, in their
eagerness to ascend them, frequently fling themselves entirely out of water on the
beach.'
M
Tha oonclMion is thm lUtod that it i» rather • Mreh for frnh water •imply
ratter than a desire to -reach their natire head-waters which impels the salmm to aot
-!l. M *P[J** , °' ~""^ ***" '• ^ •n«logy of the migration of other animals.
V^S^Alt ^if":f?* *" '''*•?'* ^ ^^ Profes«)r Alfred Newton, of Cambridge.
iLngland, dUd not hesitate to speak of the ' pertinacity with which birds return to their
accustom^ breedinff places and the force of this passionate fondneM for the old home.'
tIJiot of Birds. IK 666). No doubt the parenU are in most cases the birds which return,
"r^iTi^'V' •*'"*"•" ^ understand the case of a pair of stone-curlews ((Edicnemiu)
wbicb bred for many years on the same spot, as Newton stated, even after the surround-
ings had bron completely changed, an original barren rabbit warren having become a
thick end flourishing bush or planUtion. That it is the same pair of birds which
return in such cases is difficult to prove, but as Newton pointed out. the altematire
raises much greater difflcnlty ' for then we have to account for some mode of com-
municating precise information by one bird to another.' But the young as well as the
parents are prone to return to the orijfioal haunts, as it has long been known that
birds of prey drive away their offspring from their own haunU. ' The practice, how-
ever. «aid Newton. ' is not limited to birds of prey alone, but is much more universal
(op. ctt. p. 654). There is much ground for believing that one of the main causes
of migration in fishes is due to an hereditary tendency, an ' instinct' it may be called,
for want of a better term, which is so strong, that even temperature of the surrounding
water is less potent as a stimulus, and apart from the question of food and of breeding
this tendency to move over geographical areas with unerring certainty as to time and
direction is one of the most perplexing and powerful that the scientific student can
contemplate. It is true that, as Profeswr Hind stated, 'the question of inshore and
off^ore mackerel fishing grounds becomes, in a great measure, reduced in the Gulf
of St. Lawrence, to the different conditions of marine climate which prevail where the
Labrador current is the controlling agent, or where the Gulf stream asserts its power
and iiifliipnce during the summor season,' but an iiihorent tendency exists also.
Dr. W. Bell Dawson has for successive seasons covering a number of years carried
on elaborate and accurate investigations in the Gulf of St. Lawrence, and though it is
early yet to attempt any generalizations between the results of these current and tide
observations, and the movements of the great schools of fish in the Gulf, such as cod
haddock and mackerel. The general result, however, is to show that the outflow from
the Gulf 18 compensated by an inflow both in the Stroits of Belle Isle and Cabot
straits and that the changes effected by this compensating circulation are what may be
called superficial rather than deep-water. At greater depths than 60 or 60 fathoms
these important currjnts have probably little or no effect. As Dr. Dawson has reported •
' In reviewing the movements of the water, with a view to tracing the general circula-
tion of the Gulf, it is the principle of the balance of flow which is the moat evident
Wherever a current of a constant character occurs, there is a corresponding retuni
current to make up for it. Thus in Cabot strait, the outflowing water in the Cane
Breton current is balanced by the inflow at Cape Ray; the northeastward current on
the west coast of Newfoundland is balanced by the contrary direction of the move-
ment on the opposite shore; and we have fairly good indications of a return flow to
compensate for the Gaspe current.
' It is this balance of flow which points to the nature and direction of the circula-
tion of water in the Gulf. If we begin to trace it from Cabot strait, where the balance
between the gulf and the ocean takes place, the inflow at Cape Ray appears to diffuse
itself more or less widely over the central part of the gulf, but it regains its strength
further north on the west coast of Newfoundland, and makes a deep bend into the
northeastern angle of the gulf, and returns westward along the north shore On
reaching Cape Whittle, it still makes westward; and, whether as an actual set or bv
displacing water which comes more directly from Cape Ray, it appears to work around
the eastern end of Anticosti, and so compensates for the outflow of the Gasp^ current
from the eatuary of the St. Lawrence. This current after rounding the Qasp6 coast,
17
inakM MotheMtward m • general Mt or drift aeroM the gulf to the wcatem side of
Cabot atrait; and iU waters there leave the gulf in the outflow of the Cape Breton
eurrrat.
' It alto appears that the whole of the balance or compensation in the gulf currents
takes plaoe at the surface and in ordinary underniurrents, which do not probably
extend to a greater depth than some 50 or 60 fathoms. There is nothing, therefore, to
show tho nncesiity for any appreciable moTement in the deep water from 60 to 80
fathoms downward, which lies in the deep channels of the gulf. Wheiv direct observa-
tions hare been obuined, this deep wster appears to lie quiescent, without any move-
ment that can be detected.'
But to the ordinary mind the outflow of such a vast river as the St. Lawrenoe, the
largest river in North America, must appear to profoundly affect the gulf waters, both
aa to salinity, temperature, 4c.; but Dr. Dawson has pointed out that the 'volume
discharged by the St. Lawrence has been measured above Lake St. Peter at different
aeasong; and with the addition of the Richelieu, St. Maurice, Soguenay, and other
tributaries along its estuary, the total volume of fresh water di»oharge would probably
amount in all to 340.000 cubic feet per second. This volume of fresh water will mingle
with sea water for which we may assume a density of 10340, as this may be taken to
represent either the mean density of Atlantic coast water to a moderate depth, or the
density of the Salter water in the gulf itself. Under these conditions!, the fresh water
of the St Lawrence would be sufficient to furnish a stream of water reduced to the
lower density of 10230 which would be twelve miles wide and 68 feet deep, and moving
with a speed of one knot per hour. This would represent the average density of the
Gaspfi current, and would probably be an approximation to its average speed and its
volume;' but the outflow known as the Gssp<g current is immenoely greater than the
volume of the St. Lawrer.ce river outflow. As Dr. Dawson has estimated ' such a
current has n volume forty-three timus greater than the St. Lawr- .'•e river. The
volume of the Cape Breton current also, is probably much the sa hese outflows
must therefore be replaced by a return movement at the entranci the lower St.
Lawrence; somewhere in the Anticosti region, and also by a return flo.v from the ocean
into the gulf area ; as the discharge of the St Lawrence furnishes less than 3 per
cent of the amount required in either case.'
The north shore current as well as the current flowing direct from Cabot strait
must bo taken into account in explanation of this vast volume of outflow. Dr. Dawson
indeed has pointed out that while ' the volume of fresh water from the St Lawrence'
as already explained, may be sufficient to dilute the sea water to the low density found'
in the Oaspfi current or in the corresiionding current flowing outward through Cabot
strait, the total volume of water which actually leaves the gulf is vastly greater than
the volume of fresh water which it receives from the St. Lawrence river. The volume
so leaving the gulf must, therefore, he replaced by water which enters it from the ocean
' The current which usually makes inwards on the east side of Cabot strait, may be
sufficient to compensate for the outflowing water of the Cape Breton current; although
It w also possible that the outflow from the gulf may be partly made up for, by the
difference of flow in the inward direction through Belle Isle strait; which in some
years may be considerable in the early spring. The relation of the current in this
strait to the gulf as a whole, has already been explained; as well as the probable
amount of inflow at Cape Ray, in continuation of the general westward tendency of the
water along the south coast of Newfoundland. The quiescence of the deep water in
Cabot strait has also been pointed out, in this connection.' The general result of these
counter currents, as affecting the distribution of floating ova and young of cod, had-
dock and mackerel, would appear to be that the spawn is kept inside the gulf limits
and not swept out into the open ocean, while the young fish are probably carried in
circular courses in local areas, never very distant from the hatching areas.
I have the materials well advanced for a report on the results of this
sysUm of currents on the distribution of floating ova which vast schools of cod and
m^^rcl dapodt in tha inrfM* waton. Th« moroBMito of tha aarly fiy mnat of
naeaidty tw monoMajpin and Taatly laia aaaj to aaoartaln than ia tha eaaa on tha aorth
and waat ahona of loaland or tha oomapondinc Noraa ihoiaa in both of whioh ladooa
alaborata aeiaaUflo raaulta hara bean publiahad.
It la wdl known that apawnin* flah rafuaa to laadily taka bait and tha aarlj
aehoola of cod oaptunNl in Juna hara alraady apawnad, lonia of tham prababb a month
?h-'liK*!?! ?''''*r"7'*['* ^./'" '^' ••P*''*ny ^ «*«P wat., lUh. ai« undoubtadly
tta Ml that hara taft tha ahallowar watara aud tha aurfaoa waton to faad on tha ri^
fauna on th. floor of tha laa. Nor ia it rary diflarant with tha macltaral which aarir
in Juna are distended with ripe apawn, and refuaintf to taka bait, aa aU apawninc »A
do, were merc.JeMly ilaughtered by purte-teinea, ke. By the end of July apawninc ia
orer. and the fiah commence to feed up from that period, thoufh their condition U not
larourable for a month or more, or not until the flrat ten or twelre daya of Aucuat
Such being the fact, rcfardin* the gulf mackorel and cod it is eaty to aea that both
ttoeaeflaheriei can be restore.! where decaye<l. or presenred permanently when the
5.i!!l'Tn li*^/]'".^ maintained by a. far a. poasibla securing that tha main
flahery shall be after the spawning is over, and if poasibla •♦tar the flah hare been
feeding for three or four weeks and hare recorered their condition. Inahore flahing
for cod rery early in the scMon ia not to be encouraged, and early deatruetion of the
apawn.ng schooU of mackerel is likewise unjustifiable. The millions of spawn produced
by one female cod or mackerel indicates how easy restoration is, if only a .uffldent
number of .pawners be allowed undiaturbed to perform their spawning function™ The
eggs and yminflr aiv of courw dwitroyed in quantity by their natural enemiea. and theae
are, therefore produced on a large sc^le. but the balance of nature is such that if not
too aenouily disturbed by .uch extorminatinir instruments as the c«hau.ting nurse-
seme swwpmg lu complete "chool. of spawning fl,h. there ia no fear for the wntinued
abundance of such marine fish. The aid of fish culture and the operation of mariw
flah hatchene. being too problematical and uncertain to aolre the difliculty the m«.
taction of the breeding «,hoola when they migrate and reach their sinS Z^7.
the only sure and safe step on which reliance can be placed. 'P"^"* «>«" i»