No. 7

THE SPAWNING AND EARLY LIFE HISTORY OF THE WHITEFISH.COREGONUS CLUPEAFORMIS (MITCHILL), IN THE BAY OF

QUINTE, ONTARIO

BY

JOHN LAWSON HART

Uniaersity of Toronto

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ABSTRACT

The spawning run of whitefish is described in respect to the details of themigration and sex ratio, age and size, and breeding characters of the fich. Aninvestigation of the eggs in the spawning grounds by the use of a pump indicatesthat the proportion of eggs to be fertilized is high but that there is a high mor-tality during the development. Many whitefish eggs are eaten on the spawninggrounds by the common perch (Perca f,aaescens). For the first time there isrecorded the capture of a complete series of whitefish young of the year. Basedon this material are descriptions of the stages of the young from twelve milli-metre to eighty millimetre stages and the characters differentiating whitefishfrom cisco. The rate of growth of the fry is slow at first but is much acceleratedin the latter part of May and until the end of July. The food from the firstconsists of Entomostraca, chiefly Bosmina, Daphnia and Cyclops. The firstmovement of the newly hatched fry is inshore close to the surface. Later theyform schools and finally take to deeper water. Records of physical conditionsin the habitat of young whitefish are recorded. Consideration of the food andother habits and the concentration of predaceous species where young whitefishare abnormally abundant leads to the recommendation that hatchery fry shouldbe widely distributed in shallow water.

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The Spawning and Early Life History of the Whitefish, CoregonusclupcaJormis (Mitchill), in the Bay of Quinte, Ontario

By JonN Lewsox HlnrUniversity of Toronto

CONTENTS

Introduction 3S p a w n i n g . . . . . . . . . . . . . . . . . . . . . . . . . 8Development of the eggs. . 13

Development and habits of the fty. . . . 18

Conservation of the whitefish fry . . . 42

Summary and conclusions. . 45

Relerences. 47

INTRODUCTION

The catch of whitefish, Coregonus clupeaformis (Mitchill), in Canada is of

more value than that of any other freshwater fish, being practically always ofgreater value than that of ciscoes (Leucichthys spp.) or lake trout (Cristivomer

namaycush). In the fisheries of Ontario the whitefish occupies first place only

occasionally. This is due to the relatively greater importance of the lake trout

and to rather marked fluctuations in all three species.Fluctuations such as those referred to may be of considerable magnitude in

the whitefish, occur irregularly and originate from unknown causes. To control

or even foretell the direction of these changes in the fishery were a matter of great

economic importance. To accomplish this, it is necessary to have a thoroughunderstanding of the complete life history and interrelationships of the species.

It is with this in mind and in the hope that subsequent investigators may beprovided with useful information that the present paper has been prepared.

SvsrBlrerrc Posrtrox oF THE SpBcrBs

Jordan and Evermann (1896) recognized two species of whitefish in central

and eastern North America, Coregonus clupeaformis (Mitchill) and Coregonuslabrad,oricus (Richardson), both species occurring in the Great Lakes. In Jordanand Evermann (1911), however, Coregonus albus Le Sueur is assigned to the lake

Erie whitefish and the whitefish of the other Great Lakes considered as being

Coregonus clupeaformis (Mitchill) and this statement occurs: " Possibly Coregonusalbus is merely an 'ontogenetic species,'its peculiarities being due to the con-

dition of food and water in lake Erie." Koelz (L929) considers this last sug-gestion as being the true interpretation, for he places in the one species, CoregonusclupeaJormis (Mitchill), all the whitefish of the Great Lakes.

In view of the known variability of the genus, the certain knowledge that

body form is modified by conditions in captivity (Koelz lg29), and the evidencecited by Dymond and Hart (1927) for Coregonidae, and Hubbs and Whitlock(1929) for Dorosoma cepedianum, that body proportions may be altered in definite

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directions by difierent conditions, it appears advisable until specific differenceshave been established by biological studies to consider as one species all theforms and races of Coregonus found in central and eastern Canada.

Owing to the intergrading forms in the old world, European taxonomistsusually consider as the one genus, Coregonus, the group of forms similar to thosedistinguished on this continent as Coregonus and Leucichthys (Jarvi 1929;etc.).In the present discussion Hubbs (1926) and Koelz (1929) are followed both inmaking that distinction and in separating from Coregonus the round whitefishand Rocky Mountain whitefishes, Prosopium spp.

Coregonus belongs to the group Coregonidae. Recent American taxono-mists (Koelz 1929) have regarded this group as being of family rank. Europeanand some of the older American students (Regan 1914; Gill 1895) however,consider the differences between the Coregonidae and the salmons as being in-sufficient to warrant their being placed in separate families and have referred tothis group as a subfamily, Coregoninae, in the family Salmonidae, of the Isos-pondylii.

GBocnapnrcAl DrsrRrBUTroN

The genus Coregonus is distributed very generally throughout the northernhemisphere (Meek 1916). In North America C. clupeaforncis extends from theArctic to the northern United States of America and from the Rocky mountainsto the Maritime Provinces.

In Hudson and James bays considerable catches are made of whitefishwhich are indistinguishable from the Great Lakes form (Melvill and others 1915;Couch 1922; Skaptason 1926). Sea run members of the genus are found inEurope which, like the Hudson bay form, are anadromous.

Hrstonrcer axo EcoNoMIC IMpoRTANCE

Tlre whitefish in Canada has played and is still playing a part of great im-portance in the opening up of the sparsely inhabited regions of the north. Hearne(1911) has numerous references to the dependence of the explorer on whitefishand other fish. Preble (1908) says:

" Whitefish of one or more species are found in nearly every lake and stream throughout thenorth. Some of the species are anadromous. The average weight of those taken is from 2 to 4pounds, but in some lakes they attain a weight of 8, 12 or even 20 pounds. ,ts a food fish pro-bably none surpass it. . . . So important are whitefish as an article of diet that the sites of many,perhaps the majority, of trading posts, as well as the wintering stations of a number of exploringexpeditions, places which have become famous in Agctic literature, have been selected with aview to the local abundance of this fish."

Buchanan (1920) in discussing conditions at Fort Du Brochet in northwesternManitoba says:

"What food the natives subsist on is also food for their dogs. The year round the nativeand dog community at Fort Du Brochet and of many Far North Posts live almost exclusively onfish with the addition in winter of what deer meat the Cbribou migrations provide. Raw fish,fresh from the water in summer, or f.rozen in winter, is the chief dog food the year round and onthis they thrive. And, in this respect, it is certain that the fish on which the dogs of the outer-most Posts are fed has played an important part in retaining, perhaps even in developing, thefine physique which the breed obtain along the trails of the Ffinderland, for the fish of the pure

cold waters of northern lakes are of surpassing excelleqce."

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and then he continues to give the details of the capture and preservation in thefall of large numbers of whitefish for the winter's supply.

Trappers say that working dogs fed on meat lose weight and strength butthat dogs fed on fish, and this means whitefish largely, endure the rigours of thetrap line without ill effects. In consequence the whitefish is of direct importanceto the fur trade.

As has already been pointed out the direct economic value of the whitefishis very considerable. The average catch in Canada for the years 1913 to 1928inclusive was 7,915,145 kg. (174,500 cwt.) with an average annual valuefor this period of 91,650,000. The average value for the years 1925 to 1928 was

$2,135,000.For the ten years from 1918 to 7927 the whitefish fishery was the sixth most

valuable of Canadian fisheries. In 1928 it was superseded in this position bythe rapidly growing pilchard industry.

Sreusrrcs on CercnBs FoR THE GnBer Ler<Bs

The annual catches of whitefish made in the Canadian waters of the GreatLakes are shown in figure 1. The data for the polygons have been obtained fromthe Reports of the Department of Marine and Fisheries of the Dominion ofCanada from 1878 to 1910 and the Reports of the Department of Game andFisheries of the Province of Ontario, 1911 to 1928. Barrels were considered toweigh 91 kg. (2001b.) and fish to weigh 907 gm. (21b.) each.

Increased quantity and efficiency of fishing equipment make it inadvisableto assume a direct quantitative relationship between the size of the catch andthe size of the stock from which it is drawn without a thorough examination offishing efforts producing the catch.

Fishing effort itself is difficult of estimation. Improvements and differencesin tackle, increased knowledge of fishing grounds and fish habits by the fisher-men, the effects of weather and changes in the habits of the fish, the probabilitythat increased fishing effort is likely to be the result of increased abundance offish as much as a cause of increased catch, all unite to make an analysis of theeffectiveness of fishing effort a most difficult one.

Owing to insufficient data a complete analysis is impossible in the presentdiscussion and a detailed consideration of what information is available would bemerely an added complication. Accordingly the subject of fishing effort isdismissed with the observations that in the past fifty years the number of boatshas increased irregularly to approximately double the number in 1877 and thatthere has been an accompanying improvement in the efficiency of the tackleused in primary operations. Increases in the amount of fishing equipment havebeen associated with increased catches but have not been of sufficient magnitudeto wholly account for them.

Two points worthy of mention are illustrated by these polygons. The firstof these is the great increase in catch and presumably in the abundance of fishin lake Erie and lake Ontario which has occurred in spite of the continuance ofheavy fishing.

The second point of interest is the continued high production of whitefishby lake Huron. This may be related to the large "whitefish area" of lake

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coo

300

)oo

L A K E S U P E . R I O R

)oo

5oo

II)oo

Il /

L A K E H U R O N

,oo

)oo

)oo

_,^n-_ra^_

L A X E E R I E

LAKE ONTARIO

t877 tEgo lgoo lglo n2o 1928

FrcunB 1. Catch of whitefish in the Canadian waters of the Great Lakes. 1877-1928.Unit of measurement is 45.36 kg. (cwt.).

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Huron pointed out by Reighard (1910) but is on the whole out of propo.tionto it.

These observatioqs would suggest that the magnitude of the whitefish catchis not controlled solely either by the area of the feeding ground of the adult fishor by previous overfishing as suggested by Reighard (1910). Biological factorsare doubtless of great importance.

The rise noted in the catches of lake Superior in the years between 1918and 1923 is due to the inclusion for those years of fish taken in lake Nipigon,which has been separately plotted in figure 1 for most of that period.

Pnnvrous Wonx

As no records of the regular capture of young whitefish, C. clupeaformis,are to be found, it is concluded that no previous work deals directly with thematter of the present paper. Accordingly no formal review of any literature isattempted and the results of previous investigators are introduced in the sec-tions with which their work was associated.

MerBnler,s

The investigation of spawning and of the development of the fry of thewhitefish has been for the most part carried out in the bay of Quinte (see figure 2).Much of the material collected there was taken in association with and withthe help of Dr. A. L. Pritchard who was at that time engaged in a study of thecisco in the same locality.

FRINCT-TDWARD COUNTY

LAKtONTARIOMY OT QUINTI ffiCION

t0 fytt€S

5CALE

Frcune 2. Bay of Quinte region, lake Ontario, where the whitefish investigation was carried on.

Observations and collections made in the baymented by less systematic collections in two other

of Quinte have been supple-places. These localities are

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lake Nipigon and a small lake in the southeast corner of Shakespeare island (lakeNipigon) henceforth in this report referred to as Shakespeare Island lake.

Through the kindness of Dr. Carl L. Hubbs I have been allowed to examinethe young whitefish in the Museum of Zoology, University of Michigan.

Acruowr,plcMENTS

The present research has been carried on in part under a bursary and ascholarship of the National Research Council of Canada" To it I express mygratitude.

Much of the expense of the operations in the field has been borne by theBiological Board of Canada. For its financial assistance and other courtesies Iam very grateful.

The research has been pursued chiefly in the Department of Biology,University of Toronto. The financial assistance given me by the departmentand the advice and facilities extended to me by Dr. B. A. Bensley and themembers of the staff has been invaluable. For their assistance and particularlythat of Professor J. R. Dymond and Professor W. J. K. Harkness I am deeplygrateful.

I am indebted to the city of Toronto for the use of the diving apparatusused during the investigation and to the Department of Marine and Fisheriesand the Department of Game and Fisheries for the courtesies shown me ina[owing me the use of the facilities of the Belleville hatchery. I am especiallygrateful to Mr. H. H. MacKay of the latter department for his courtesy inallowing me the use of part of his data.

Dr. Carl L. Hubbs has shown me many kindnesses in lending specimensand in other ways. It is with pleasure that I acknowledge these.

Dr. D. S. Rawson and other graduate students in the Department of Biologyhave given assistance in various ways. I am very grateful to them and to Dr.A. L. Pritchard for the co-operation afforded me in his conduct of the ciscoinvestigation.

SPAWNING

TnB SpewNrNG MrcRATroN

In the bay of Quinte the spawning migration of adult whitefish occurs duringOctober. Fishermen take whitefish in greatly increased quantities at the timeof the spawning run, but in the bay of Quinte region this increased catch is nottaken until the fish are actually in the bay and approaching their spawninggrounds. The assumption is therefore that the fish in their movements towardthe bay do not swim as close to the bottom as they do during the rest of 'the year.Fishing in the open lake too does not show greatly increased catches until thefish are actually on the beaches to spawn.

Further evidence for this suggestion is found in the " rail fence" method offishing which has proven most successful during the migration. This methodof fishing consists of setting the nets in a zig-zag line along the upper part ofthe sublacustrine slope forming the channel of the bay of Quinte. The result of"

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such a set is to get the net as far into the centre of the channel and as close to

the surface of the water as possible. Such settings are reported to take more fish

on the windward shore.A consideration of the speed at which pulses of heavier catches pass up the

bay leads to the conclusion that the speed of migration is in the neighbourhood

of five or five and a half kilometres (three or four miles) a day.

OnoBn oF THE Annrvar- oF THE FISH

Mr. J. Oakes, under whose direction the hatchery pound nets were operated,

repofts that the first run of fish frequently contains a preponderance of

small males of 30.5 to 33 cm. (12 to 13 in.) in. length. However, this is not the

case in every season and the exact nature of the run varies considerably.-

The late Capt. Geo. Mclvor stated that the same early run of males is found in

lake Nipigon. Fishermen say that male fish are generally the first on the spawn-

ing ground and the last to leave.

NerunB oF THE SpewNtNc Run

SBx nerro

It is a matter of considerable difficulty to determine the sex ratio with

certainty. In hatchery operations in order to assure a plentiful supply of males

a large proportion of them are returned to the retainers of the hatchery pound

nets after stripping. Fish of both sexes which are not ready to be spawned are

also thrown back to ripen. Consequently the only figures which are unvitiated

by human interference are those to be obtained on the first day of spawn taking

and include only ripe fish. Such figures, obtained on October 31, 1926, showed

724 ripe males and 351 ripe females. Under the conditions of the investigation

it was impossible to sex green fish. These figures, therefore, do not necessarily

indicate that males were more numerous as much as that they are ready to

spawn at an earlier date than the females. This is indicated by the figures

obtained on November 4 for the same nets, when the fish taken were: males

756, females 479, unripe 235, spent 15. The rise in the proportion of females

occurred in spite of the return of ripe males to the retainers.The proportion of males and females taken in gill nets is no more reliable

as a measure of the true sex ratio than that of the pound net fish. This is due

to the disparity of the sizes of males and females, a difference which is quite

marked. This is well shown in table I.The most reliable d,ata at hand on sex ratio are those obtained during a

systematic netting of whitefish in Shakespeare Island lake. The gang of nets

used in this work consisted of 45.72 m. (50 Vd.) each of nets of 3.17 cm.(1| in . ) 3 .81 cm. (1* in . ) , 5 .08 cm. (2 in . ) , 5 .71 cm. (2f , in . ) ,6 .35 cm. (2\ in . ) ,

6 .97 cm. (2t in . ) , 7 .62 cm. (3 in . ) ,8 .89 cm. (3+) , 10.16 cm. (4 in . ) , 11.43 cm.(4| in . ) , 12.05cm. (af in . ) and12.70 (5 in. ) s t retchedmesh. Al l f ishmatureornot-30.5 cm. (12 in.) in length or over-were considered. The danger of intro-

ducing errors due to mistakes in diagnosing the sex is obviated by discarding

fish of the smaller sizes. The figures obtained in this vr'ay were, males 238 and

females 205. The preponderance of males is small but is probably significant.

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Pearl (1916) found the sex ratio in lake Erie whitefish to be 386 males to455 females.

TasLB I. Size distribution of mate and female whitefish taken in pound nets set in the bay ofQuinte, November 2, 1926.

Length Number Length Number

cm d t9

29.835.6-37.438. 1-40 . 040 .H2 .543.245.0

(11*)(r4-14'-)(15-15i)(16-16*)(L7-r7Z)

45.747.648. 3-50. I50.8-52.753.3-55.2

(r8-18i)(1e-let)(20-20Z)(2r-2r+)

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The length has been measured from the tip of the snout to the fork of the tail.

Foerster (1929) found the sex ratio in the sockeye salmon (Oncorhynchusnerka) to vary from year to year. Some such condition may obtain in thewhitefish.

AcB erqo SrzB

Some fish begin to spawn in their fifth year, a few mature specimens of thatage of both sexes having been taken. By far the greater proportion of the catchis composed of fish in older age groups. In the fall of 1925 more fish appearedto be in their seventh and eighth years than in any other years.

The sizes of the fish forming the spawning run are illustrated in table I.

EpscnrprroN oF SpAwNTNG FrsH

During the spawning season most whitefish assume a breeding dress con-sisting of nuptial tubercles on the head and rows of elliptical pearl organs on thesides (Bensley, 1915; Koelz, 1929; and others). The small males, 35.6 to 38.1cm. (14 to 15 in.), show a greater development of these breeding characters thanany other fish in the run and have the following differences from the non-breedingconditions.

The scales in the five rows on each side of the lateral line and the lateralline scales themselves each bears a single, pale tubercle or pearl organ. On thecaudal peduncle the number of rows of modified scales may be reduced. Evenbeyond these limits scales bearing pearl organs may be found but they are ofirregular distribution. A11 dorsal scales in the anterior five rows are finelytuberculate and in this region two small additional pearl organs may occur onthe same scale. Except for the end of the snout and a tract between the eyeand the nostril, the sides and top of the head are covered with fine tubercles.On the cheeks and operculum these are larger and more sparsely placed. Belly,mandible and branchiostegals are smooth.

Hesrrs oF FrsH rN THE Spl.wrrNc RUN

On reaching the locality of the spawning grounds the fish usually remain

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offshore for a short time, during which they are taken by the fishermen on the"soft bottom" at depths between 9 and 15 m. (30 and 50 ft.).

Fish taken during their spawning migration have not been examined, buttheir habits of swimming off the bottom would indicate that they are not feedingactively at this time. Spbcimens captured in the government pound nets inthe early part of the season as well as those taken in gill nets set on the spawninggrounds never show full stomachs. Frequently some stomach content is found,but this usually consists of whitefish eggs which are probably taken incidentallyto the respiratory movements of the fish on the spawning grounds.

DBscnrptroN oF THE SpewNrNc GnouNns

The spawning ground under investigation 1ryas a reef known as the HogsBack. This is one of .a series of rocky shoals in Big bay to.the north of Bigisland. It is about 183 m. (200 yd.) long by 9 m. (f0 yd.) wide with thelong axis running north and south. It is separated from Big island by atrough some 15 m. (50 ft.) wide with gently sloping sides and a maximumdepth of about 1.5 m. (5 ft.). The depth at the inner end of the Hogs Backis between 30.5 and 61 cm. (1 and 2 ft.) and gradually increases to from 183 to213 cm. (6 to 7 ft.) at the outer end. On the north and east the shoal falls offsuddenly to a depth of from 366 to 549 cm. (12 to 18 ft.) and a sandy bottom.The shallow rocky nature of the bottom is continued to the west for a kilometre(half a mile) or more. The neighbouring shore of Big island is sandy and gravelly.The Hogs Back and the neighbouring shoals are favourite sites for whitefishnets during the spawning season. Some spawning is supposed to take place onthe sand bottom.

At the height of the spawning season of. L927 a descent in a diving suit wasmade on the outside of this reef. The bottom was found to be covered for themost part with flat stones from 5 to 91 cm. (2 in. to 3 ft.) in size with occasional"hard heads." All were covered by a thin layer of fine silt. Between thecrevices were found more silt and large numbers of clams, snails, insect larvae

and isopods. The tessellated darter, Boleosoma olmstedi (Storer), was frequentlyobserved. Sphaerium, Pisid'iurn, Goniobasis, Arunicola, Mancasellus, Gammarusand Heragenia were common also. In the crevices and under stones whitefisheggs were found. They extended over a considerable range of depths but wereobserved most commonly at a depth of about 244 cm. (8 ft.). None were

observed below a depth of 457 cm. (15 ft.).Actual spawning has not been observed. The accounts of this phase of the

life history in the l.iterature and the accounts of the fishermen are equally diverse(Milner, 1874; Downing, 1910). Personal observation has confirmed the

opinion that during the whitefish spawning season there is considerable jumping

and playing of fish in the shallow water and that this takes place for the mostpart at night.

FecuNorrv

Milner (1874) gives figures for the number of eggs produced by a whitefish.They were obtained by weighing the ovaries and then counting the eggs of a

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definite fraction. From the number of eggS in the fraction the total number ofeggs was readily calculated. He found that fish of moderate size produce 24,250to 26,455 eggs per kg. (11,000 or 12,000 eggs per lb.) of f ish. Kendall (1903)reports a similar figure.

The number of eggs produced by bay of Quinte whitefish was calculated byactually stripping the fish and estimating the eggs produced. As estimated bythis method the number of eggs produced was found to be between 8,500 and14,500 per kg. (4,000 and 6,500 per lb.) for fish of ordinary sizes. Some ofthese fish may have been partly spawned out but the fact that there is a sig-nificant difference either in race or in technique is attested by the highest valueobtained by the stripping method being 18,500 eggs to the kilogram (8,400to the pound) of fish-

An examination of fish spawned out by spawn takers showed that therewas considerable'variation in the amount of spawn remaining in them. Somefish-apparently those which were not quite ready to spawn-contained con-siderable numbers of eggs. Others and many of the gill net fish captured latein the season contained only a few score eggs. Possibly the difference betweenthe methods of Milner and Kendall and those of the present investigationaccount for the lack of agreement in the results.

The spawn remaining in fish after stripping by spawn takers may representa considerable loss in hatchery practice.

TnupBneruRE AND TrruB on SpawNrNc

Neither the temperature nor dates of spawning are constant from year toyear, nor does there appear to be a reciprocal effect.

In the present investigations there has been no consistent taking of tempera-tures on the spawning grounds, but it has been found that temperatures takeninside the hatchery correspond very closely with those taken at the nets andon the grounds. Moreover, it is found that at the time at which spawn is takenin the hatchery pound nets, fish are taken on the spawning grounds and manyof them are spawning freely. It seems reasonable therefore to assume that thetemperatures taken at the hatchery during the spawn taking season can beconsidered indicative of the temperatures at which spawning takes place natur-ally. Following are the dates at which spawn taking was begun and the watertemperatures on that day for several years.

1922 Oct. 31 7.8" C.1923 Nov. 5 7.8" C.1924 Nov. 3 8.3" C.

1925 Oct. 26 4.5o C.1926 Nov. 1, 5.5o C.1929 Nov. 2 10.0" C.

Trials with the reversing thermometer indicate that bottom and surface tem-peratures at this season are equal or approximately so.

It is apparent that spawning takes place about the beginning of Novemberat temperatures ranging from 4.5o C. to 10.00 C. It is possible that very lowwater temperatures as in 1925 induce spawning at an earlier date than usual.

The duration of spawning is a week or ten days although stragglers may

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remain on the spawning grounds for a considerable period after the main spawningrun has started for the open lake.

Fishermen set nets in the channels immediately after the main spawningrun to take whitefish on their return to the open lake.

DEVELOPMENT OF THE EGGS

DBscnrprtox op rsB Ecc

Eggs immediately after being pressed from the fish are small spheres withdiameters between 2.3 and 2.4 mm., the yolk occupyipg the whole of the egg.They immediately begin to absorb water and increase greatly in size during thefirst few hours. At the end of 24 hours the diameter is 3.0 to 3.2 mm. and ab-sorption is practically complete. Absorption takes place in eggs independent offertilization. At this time fertilized eggs show about four cells in the embryonicdisc which rests on top of the yolk. The yolk is 2.3 mm. in diameter and containsa number of small and medium-sized oil globules. The yolk and on it the em-bryonic disc float freely in the perivitelline fluid which separates them from theturgid egg envelope.

Pnoponrror.r on Eccs FpnrtrtzBo

Hatchery operators and others (Milner, 1874; Downing, 1910) have assumedthe proportion of eggs fertilized under natural conditions to be very small.Such evidence as has been collected in the present investigation is not in agree-ment with that assumption.

The impossibility of using an Ekman dredge or drag dredges for the recoveryof eggs on spawning grounds such as that already described is apparent.The apparatus used for the recovery of the eggs from the Hogs Back consistedof a large sized bilge pump with a considerable length of hose 3.17 crn. (li in.)in diameter attached to the intake. The distal end of this hose was fixed to aIong pole with which the stones were turned over and the crevices exploredwhile pumping was in operation. By the use of this apparatus immediately afterthe close of the spawning season of 1927 twenty-nine whitefish eggs were pumpedto the surface.

The eggs so obtained were placed in running water for three weeks at theBelleville hatchery. During this time they were attacked by Saprolegnia withthe result that even after they had been treated with 10 per cent. acetic acid(Nussbaum 1883) it was a matter of considerable difficulty to determine whetheror not development had begun. However, it was found that all of those eggswhich were least affected were alive as well as a number of those in which it wasnecessary to make some dissection to make any determination. Considering asfertile only those eggs in which it was possible to find the embryo with certainty,it was found that 18 out of the 29 eggs, or 62 per cent., were fertile. As it ispossible that a'considerable proportion of the doubtful material was fertile, thisfigure may be low.. In 1928 this experiment was repeated under slightly different conditions,

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Mr. Clayton Sprague of Demorestville tended eggs procured in the same wayfor a short period before placing them in the acetic acid solution. [n this ex-periment all of 125 eggs were found to be fertile.

During the spawning season of. 1927 one egg was caught in a wire clothtray designed for the taking of normally spawned eggs. After three weeks inrunning water it was found to be fertile.

Such data as is of certain accuracy point to there being a very high per-'centage of fertilized eggs on the whitefish spawning grounds. None of it confirmsthe suggestion that only one per cent. are fertile.

There is, however, the possibility that there is considerable variation in theproportion of eggs fertilized in different years and on different spawning grounds.

Monrer,rry op Eccs DUB ro Arrecxs sv FtsH

The mortality occurring in whitefish eggs in nature can be considered as

that due to destruction by being eaten by fish and other animals, and that

occurring in ova undisturbed by larger creatures.

In order to investigate the destruction of whitefish ova by fish the stomachcontents of a number of them were examined. The fish whose stomachs wereexamined in 1926 were taken from the Provincial Government pound nets

operated in the bay of Quinte in the interests of the hatchery. The material

examined in 1927 was captured in gill nets of various mesh set on and about

the spawning grounds. The round whitefish, Prosopium guad'rilaterale, wereobtained off Brighton and were supplied by Mr. Quick of that place. The

number of each species of coarse fish examined is roughly in proportion to theabundance of the species on the spawning grounds. The results of the analysesfollow:

C. clu peal ormis (M itchill)

Of 18 specimens examined Nov.4,L926,15 contained food (in small quan-

tities) and 12 of these contained a few whitefish eggs. Of 10 specimens examinedNov. 9-15, 1927, 6 contained food and 5 contained whitefish eggs. (Average of

.7 eggs for each fish c<intaining them.)

Leucichthys artedi (Le Sueur)

Three specimens 28 to 30.5 cm. (11 to 12 in.) in length examined Nov. 4,

1926, were found to contain 2,0 whitefish eggs in all, but very little other contents.

Milner (1874) cites evidence showing the cisco to feed extenEively on white-fish eggs. Pritchard (in press) states that whitefish eggs are eaten by ciscoes to

some extent on the spawning grounds.

P ros o pium quod'rilalerale (Richardson)

Five specimens were examined Nov. 5, 1926. One of these contained 30eggs of the lake trout, Crist'ioorner nalnaycush (Walbaum), but no whitefish eggs

were found. Other stomach contents were found for the most part tobe Physa sp.

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Cato stomus commer s onii (Lac6pdde)

In 1926 thirteen specimens, 33 to 43 cm. (13 to 17 in.) in length wereexamined and found to contain no whitefish eggs. Amphipods, isopods, chiro-nomid and other insect larvae and molluscs constituted the stomach contents.ln 1927 six specimens were examined and found to contain no fish eggs.

It would appear that as far.as whitefish ova in the bay of Quinte are con-cerned the popular accusation that the sucker eats eggs lacks foundation. Thereis, however, no doubt that occasionally eggs are taken by this species (Ellis andRoe, 1917; and Reighard, 1920). Stewart (1926) reports the absence of eggsin the stbmachs of suckers taken on the spawning grounds of trout, and Bajkov(1930) found no whitefish eggs in the stomachs of suckers taken on the whitefishspawning grounds.

Ameiurus nebulosus (Le Sueur)

Of 14 stomachs of bullheads between 25 and 33 cm. (10 and 13 in.)in length examined in 1926 four contained whitefish eggs. One of these hadeaten approximately 125 eggs to the extent of about 30 per cent. of thestomach contents. In the others the number eaten was inconsiderable. Therest of.the food consisted of molluscs, insect larvae and crustaceans. In 7927no bullheads were taken on the Hogs Back. This species is of too rare occurr-ence on the natural spawning grounds to be responsible for the destruction ofmany eggs.

Villariu s lacustris (Walbaum)

One specimen examined in 19)6 contained no fish eggs. One large specimenexamined in 7927 contained 2 whitefish eggs. This species is of rare occurrenceand is probably an inconsiderable factor in affecting the mortality of whitefisheggs.

P erca f,aaescezs (Mitchill)

Twenty-one specimens ranging in length from 18 to 25 cm. (7 to 1O in.)examined Nov. 2-7, 1926, all contained whitefish eggs, averaging over 200eggs per fish. Of the 35 other fish of this species examined 27 containedwhitefish eggs. Of 75 specimens examined Nov. 8-15, 1927, two w.ereempty, 44 contained whitefish eggs, averaging between 30 and 35 each, and3 contained cisco eggs. Other stomach contents were: isopods, fish remains,gastropods, crayfish and pelecypods, amphipods, tessellated darter, and mayflynymphs.

Leach (1923) reports the perch as being destructive of whitefish eggs.As perch are very numerous in the bay of Quinte and as the evidence here

presented shows that whitefish eggs are a preferred diet with them, it appearslikely that they may constitute an important factor in the mortality of thewhitefish eggs. The abundance of this species on the spawning grounds is shownby the capture of 80 of them in 45.7 m. (50 yds.) of 5.08 cm. (2-in.) gilt netover night.

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Perch taken on November 21 about the Hogs Back contained almost no

whitefish eggs although the eggs of the later spawning cisco, Z. artedi, constituted

most of the stomach contents. It may be that a large proportion of the accessible

whitefish eggs had been eaten by this date.The stomachs of a number of other species were examined, but no eggs were

found. In the list the name of each species is accompanied by the year and the

number of fish examined. 1926 Lepi.sosteus osseus (Linnaeus) (3); 1926 Moxos-

toma rubreques (of Hubbs and Brown, 1929) (3); 1926, 1927 Moxostoma aureolum(Le Sueur) (of Hubbs and Brown, 1929) (2);1927 Notropis hudsonius (Clinton)

(2); 1926 Eupomotis gibbosus (Linnaeus) (2); 1926 Ambloplites rupestris (Rafi-

nesque) (3) ; 1926 Pomoxis sparoides (Lac6pdde) (1); 1926 Lepibema chrysops

(Rafinesque) (1); 1926 Aplod'inotus grunn'iens Rafinesque (4).

The mud puppy, Necturus rnaculosus Rafinesque, which is reported to do

considerable damage to v/hitefish eggs on other spawning grounds (Downing,

1910; Leach,7923; Bishop, 1926), has not been found on the spawning grounds

of the bay of Quinte.From our evidence it would seem that the perch is a source of considerable

loss to whitefish eggs, but that other species, either due to their dietetic habits

or their scarcity on the spawning grounds, are not noxious in this respect.

Monrar,rrv oF EcGS RBuerurNc oN SPAwNING GRoUNDS

Evidence of mortality in eggs which remain on the bottom has been obtained

in two ways. The first of these ways consisted of pumping eggs from the spawning

beds, using the apparatus already described. On February 29 and March 1,

1928, holes were cut in the ice in several places, but eggs were obtained through

only two of them. One of these was directly on the Hogs Back in 107 cm-

(3* ft.) of water and produced 7 whitefish eggs, only one of which was living.

The other productive hole was over 244 cm. (8 ft.) of water on the outside of

the shoal. It yielded 9 whitefish eggs and 2 cisco eggs. One of the whitefish

eggs was eyed and apparently alive. The other 8 and the 2 cisco eggs were

dead. At this season of the year whitefish eggs have been eyed for some time;

accordingly the living ones are readily recognizable. Only 13 per cent. of the

15 whitefish eggs recovered were living.The mortality occurring during normal development was further investi-

gated by placing a number, approximately 1,300, fertilized eggs from the Belle-

ville Hatchery in boxes with a little earth and gravel and leaving these on the

bottom of the bay of Quinte through the winter. The sides and ends of these

boxes were 60.9 cm. (2 ft.) long and 20.3 cm. (8 in.) high and were constructed

of. 2.5 cm. (1 in.) wood. Top and bottom were made of wire cloth with mesh

approximately 1.41 mm. wide (18-mesh-to-the-in.). Over the wire cloth were

nailed heavy sheet-iron cleats, U-shaped in cross section, whiCh served both as

holdfasts and as a protection for the wire cloth. Hooks were placed on top of

the boxes to facilitate grappling them up in the spring,

Although five such boxes were made, it was found impossible to get them

by grappling. One, however, was obtained from 365 cm. (12 ft.) of water by

diving down and tying a line to it. In this box 470 dead eggs were found. As

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it is possible that a considerable number of eggs may have been crushed, thisfigure, representing a mortality of 36 per cent., is minimal for the experiment.However, the finding of many dead eggs in good condition is a fair indicationthat there has been no general disintegration of the dead eggs and that themortality represented by the experiment gives a true idea of the degree ofmagnitude of the percentage mortality.

As the results have been obtained from small amounts of material it isunsafe to draw conclusions as to the exact extent of the mortality. However, itappears justifiable to state that the mortality is heavy in eggs remaining on thebottom throughout the winter.

Pnvsrcer, CoNonloNs oN SpArilNrNc GnouNns

It has already been pointed out that temperatures taken in the Bellevillehatchery are found by direct comparison to closely parallel those taken on thespawning grounds. That this similarity between water temperatures in thehatchery and the bay of Quinte is continued throughout the winter is indicatedby two observations. First, the temperature of the water in the hatcheryrernains practically constant throughout the winter and is independent of thevicissitudes of the weather. Secondly, in 1928 the eggs in the hatchery beganto hatch in quantities about the same time as fry began to appear in the neigh-bourhood of the spawning grounds.

If the assumption that temperature in the hatchery can be accepted asthe same as temperatures on the spawning ground is correct, it can be statedthat the fertilized eggs start development at a'temperature between 4.5 and10.0 degrees Centigrade about the beginning of November. For the nextmonths they are exposed to a temperature falling by irregular stages to zeroand 1.0 degree Centigrade around the end of December. From then until theice breaks up at the end of March the temperature is uniformly between zero and.1.0 degree Centigrade. If the spring breakup is accompanied by much windthe temperature of the water may drop to zero Centigrade at that time. Tempera-tures taken through the ice of lake Simcoe by Rawson (1930) are in keeping withthis assumption.

The following spring temperatures were obtained between the time of thebreakup and general hatching:

1927 March 29Hatchery trough 0.0o C.

1928 April 6Hatchery trough 2.8' C.

April SHatchery trough 2.0' C.

April 7Hogs Back 2.7" C.

On February I, L928, determinations of oxygen and pH were made of watertaken through a hole in the ice over the Hogs Back.

Temperature 0o C.pH 7.5 cresol red02 9.7 parts per mille.

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On April 8, 1928, water at the hatchery dock at Belleville showed a pH of

7.4 to brom-thymol-blue and an oxygen content of 8.1 parts per mille at a tem-

perature of 4" C. The oxygen saturation was 91 per cent. (Roscoe and Lunt

1889).These determinations give no suggestion as to the reason for the observed

mortality in the eggs which have been found to tolerate temperatures between

0.3'C. and 4.0oC. and salinites from 0 to 3 parts per mille in experiments when

the pH range was between 8.0 and 8.4.ln the experiments rnentioned, eggs developing at 0o C. in York Springs

water, following a method developed by Dr. A. G. Huntsman and Dr. A. H.

Leim, showed a mortality of forty-five per cent. As the tested fertility of the

eggs was ninety-four pef cent., definite conclusions are inadvisable, especially

"i "ggr develop in the running water'of the hatchery jars at temperatures between

teri und 0.6o C. with such excellent results as ninety per cent. hatches. Tem-

perature alone therefore cannot be the lethal factor.

The pH, although lower than that found during the summer months, is still

well on the alkaline side.

DEVELOPMENT AND HABITS OF THE FRY

OespnverroNs oN Eenr,v Fnv

Observations of the occurrence and habits of newly hatched whitefish fry

have been made on several occasions.On March 29,1927, the bay of Quinte was not yet clear of ice, but in the

lee of the hatchery dock a small area of water was kept open by the current

from the hatchery sewer. lnto this open space a considerable number of newly

hatched whitefish had escaped before the retaining screens were put in place.

Observations showed that most of these fry were concentrated between 5 and

20.3,cm. (2 and 8 in.) from the surface. The swimming, which was spasmodic

and weak but definite, was accomplished by an exaggerated lashing of the tail.

The speed was determined to be at a rate of about 2.5 cm. (1 in.) a second.

One individual was observed to make an appafently purposeful and successful

effort to elude a pursuing Perch.Observations of whitefish fry in hatchery troughs showed that they tended

to swim against the current and that they do not show the negative photo-

tropism demonstrated by young lake trout under similar conditions.

At ten o'clock on the night of April 10, 1928, two whitefish fry were taken

over the Hogs Back. These fry are certainly of natural origin as the only plant-

ing made by the hatchery had been made on the same day ten miles away' They

were taken on the surface in a conical net made of No. 0000 grit gauze. This

net was about 91.5 cm. (3 ft.) long and had a circular mouth 61 cm. (2 ft.) in

diameter. Fry continued to be taken on the surface over the spawning grounds

off Big island until April 23. On this day for the first time fry were observed

close along the sandy shore of Big island within a kilometre of the Hogs

Back. A well defined tendency to concentrate in water of 30.5 cm. (1 ft.) or

less in depth was apparent and continued to be evident until May 7. On May

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2 a.nd 3 fry were beginning to show a marked tendency to school along theshore. This tendency gradually became better defined until toward the end of themonth when fry became rather scarce. Shore collections around Big island

were made with,a kitchen sieve having a diameter of approximately 13 cm.(5 in.). As the fry always kept close to the surface, within 10 cm. (4 in.) forthe most part, collecting was comparatively easy (Hart, 1929).

In order to be close to the commercial fishery the base was moved on May

7 to Prinyers cove.

Prinyers cove is an inlet off the bay of Quinte about l'2 km. (* of a mile)'long and 274 m. (300 yd.) wide. The northern shore of the cove is steep and

stony, dropping quite suddenly to a depth of. 12.2 m. (40 ft.) or even more

toward the mouth. The southern shore is, for the most part, gently sloping

sand or shingle. Toward the head of the cove a large bed of bullrushesgrows about the shores of a shallow, sandy bay, having an area of about 836sq. m. (1000 sq. yd.) and a maximum depth of about l2i2 cm. (4 ft.). The

deeper parts of the head of the cove were well stocked with aquatic vegetation.

Whitefish fry were taken on both shores of the cove and among the bullrushes,the shallow south shore providing the most consistent collecting.

Fry taken in Prinyers cove were found to be at a stage comparable with that

of the Big island fry. By May 15 fry were still swimming close to the surface

but were not concentrating close to the shore in water less than 30.5 cm' (1 ft')

deep, wandering freely into water 60 or 90 cm. (2 or 3 ft.) in depth. In the

reedy bay off Prinyers cove fry seemed to definitely seek the shelter of the

reeds. On May 23 very large numbers of fry on the north shore of the cove

were observed to attempt flight by swimming to the bottom on the approach

of a large boat. This change in behaviour appears significant in view of thefact that on May 26 a general tendency to swim deeper was observed and thatby the end of May whitefish fry were of very rare occurrence in shallow water.Some of the fry captured in Prinyers cove were taken by the use of the sieve.Most, however, were captured by a dip net made by wiring wire cloth 2'1 mm.

mesh (12-mesh-to-the-inch) to an iron frame 30.48 cm. (12 in.) in diameterfixed to a handle 91.5 cm. (3 ft.) long.

On July 26 three youlg whitefish were taken in a bottom haul at a depth

of about I5.2 m. (50 ft.) in the Adolphus reach. This is the only evidence

available from lake Ontario to indicate the habitat of fry of this size.

These young whitefish were taken in the net illustrated (figure 3). The frame

was of heavy iron. Runners were hollow and of galvanized iron and were wiredto the,frame so as to leave considerable play. The bag was constructed of

Frcune 3. Trawl used to capture young whitefish.

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.62 cm. (*-i".) mesh material and was fitted with a funnel. An additional weightin the shape of. a 22.7 kg. (50 lb.) steei bar was wired to the bottom of the framefor work in deeper water.

DrsrnreurroN oF THE Fnv rw eNn AnouND THE Bev or Qurvre

In addition to the fry seen at Big island near the Hogs Back and in Prinyerscove as described, fry of similar size were observed to be quite common in similarsituations along all the north shore of Big island and the south shore of Adolphusreach from Cressy rock to Pleasant point and less commonly at Trident pointand the lake shore near Pleasant point.

TnB CnpruRE oF WnnBnrsq Fnv rN LerB Nrplcott

Evidence as to the distribution of the young fry in lake Nipigon is rathercontradictory, for of 10 larvae captured 5 were taken in deep hauls (sup-posedly) and 5 in a shallow channel. Two explanations appear reasonable.Either the net used in making the deep hauls captured the fish when qear thesurface at the beginning or end of a haul, or it captured newly hatched fry

which had not yet made their way to the surface. It is scarcely probable thatthis difference in behaviour can be explained as a racial characteristic. All ofthese fry were newly hatched. The water temperatures where they were foundwere between 4.8o C. and 6.5" C. and the dates of their capture between May 31and June 4,1926.

On June 30, 1926, six postlarvae were captured in water 91.5 cm. (3 ft.) orless in depth among the Shakespeare islands, lake Nipigon. Their lengths rangedbetween l8 and 22 mm.

TnB CepruRE oF YouNc Wnrrpprsn IN SHAKESpEARE IsLANo Ll.xB

Between June 8 and June 13 consistent trawling on the bottorn of Shake-speare Island lake captured no young whitefish. On the latter date, however,1 specimen 26 mm. long was taken at a depth of 4.3 m. (14 ft.). On June 155 postlarval whitefish between 30 and 32 mm. were captured on the bottomat the same depth. Reference to the descriptions of fry stages and to the sectionon rate of growth of the fry will show that it was at approximately these sizesthat the young whitefish deserted the shallow water in Prinyers cove.

The contingencies of camping caused efforts at collecting to be ratherirregular thereafter. Nevertheless such efforts at trawling on the bottom aswere made were rewarded with a fair degree of consistency until June 29. Afterthis date only 1 young whitefish was taken alive, a fact possibly related totheir increasing size and agility in escaping our nets.

The fish were taken.between 3 and 9 m. (10 and 30 ft.) of water. Repeatedsurface hauls failed to yield specimens.

GnNener, CoNcrusroNs coNcERNTNG THE MovpuBnrs op rrre Fnv

Observations on whitefish fry in and around the Belleville hatchery, in thebay of Quinte and Shakespeare Island lake lead to certain provisional conclusionsconcerning their movements.'

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On hatching, whitefish larvad come to the surface over the spawning grounds,

where they remain for a few days but finally make their way, or are carried by

irregular currents, to the shore, where they tend to concentrate in water of

approximately 30.5 cm. (1 ft.) in depth. At this stage they begin to show a

tendency to school. With growth they venture into slightly deeper water, but

swim near the surface. When their total length approaches thirty millimetres, at

which time the dorsal pigment is generally dark, they sink to the bottom, seeking

water of medium depths. The meagre direct evidence for the last suggestiron is

supported by the occasional capture of whitefish of the year in seines (Hankinson,

1914, 1916; Kendall, 1903). Others have been taken by Ontario Fisheries

Research Laboratory parties as follows: lake Nipigon, South bay, Aug. 4, lg2l(1) ; Lone Wolf harbour, Aug. 11 and 12,l92l (3) ; Mclntyre bay, 1921 (3) ; Long

lake, Aug. 26, 7924 (L).In the Museum of. Zoology of the University of Michigan are solne nine

whitefish between 3.8 and 10.2 cm. (1$ and 4 in.) in length which have been

captured in seines.

Pnysrcer. CoNorrroNs IN THE Locar-rry OF THE CaprunB oF WHITEFISH FRY

A number of determinations were made of the physical conditions under

which whitefish fry were found. The results of these determinations (consisting

principally of temperature observations) follow:

Bay of Quinte (off Big island)

April 7, 1928: surface,2.7" C.Ap r i l 11 , ' 1928 : nea r Hogs Back : su r face ,4 .0o C . ;1 .5 m . (5 f t . ) , 4 .0 " C . ;bo t tom

3 .0 m . (10 f t . ) , 4 .0o C . ; a i r , 7 .5 " C .Apr i l 23, 1928: near Hogs Back: sur face, 4.7" C. ;bot tom 3.4 m. (11 f t . ) ' 4 .5 'C' ;

ait,7.8" C.;pH Cresol red, 7.9.May 3, 1928: surface 61 m. (200 ft.) from shore, 8.5" C.;surface near shore, 9'5"

C . ; a i r , 11 .0 ' C .May 5, 1928: near Hogs Back: sur face, 10.7 'C. ;bot tom, 9.5o C. ;a i r , 20.3o C.

Prinyers cove

May 16 , 1928 : su r face , 10 .1o C . ;2 .7 m . (9 f t . ) , 8 ' 2o C ' ; 7 .0 m . (23 f t . ) ' 7 .3 " C ' ;

9.1 m. (30 f t . ) , 6 .7 ' C.May 24 ,1928 : su r face , 13 .3o C . ;bo t tom 11 m. (36 f t . ) , 5 .9o C ' ; a i r , 12 .0 'C . ;

pH Phenol red, 8.2.May 31, 1928: sur face, 12.0o C. ; 4.6 m. (15 f t . ) , 11.0 ' C. ; bot tom 10.4 m. (34 f t . ) '

9.7o C.; air, I4.3" C.; pH Cresol red, 8.2.

June 9, 1928: sur face, 11.7" C. ; 4 .6 m. (15 f t . ) , 10.6o C. ; bot tom, 8.9" C. ; a i r ,

14.4" C.Aug.31, 1928: Adolphus reach, near Cressy: sur face, 19.1 'C. ;30.5 m. (100 f t . ) ,

10.2o C. ;bot tom 36.6 m. (120 f t . ) , 9 .7o C. ;a i r , 20.0" C'

Lake Nipigon

May29,1926: sur face,6.5o C. ; a i r ,22.0o C.

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May 31, 1926: 4.6 to 6.1 m. (15-20 ft.), 5.1o C.

June 5 , 1926 : 06 m. (2 f t . ) , 5 .1o C . ;6 .1 m . (20 f t . ) , 4 .8o C .

Shakespeare Island lake

June 15, 1926: sur face, 17.5o C. ;3 m. (10 f t . ) ,8 .7o C. ;bot tom 4.3 m. (14 f t . ) ,6 .70 C.

June 29, 1926: sur face, 18.5o C. ; 1.5 m. (5 f t . ) , L7.4" C. ;3.0 m. (10 f t . ) , 16.9o C. ;4 .6 m . (15 f t . ) , 12 .5 'C . ;bo t tom 6 .1 m . (20 f t . ) , 8 .3o C .

lu ly 25,1926: sur face,23.7o C. ; 1.5 m. (5 f t . ) , 22.3 'C. ;3.0 m. (10 f t . ) , 18.4o C. ;4 . 6 m . ( 1 5 f t . ) , 1 4 . 8 ' C . ; 6 . 1 m . ( 2 0 f t . ) , 9 . 1 " C . ; 7 . 6 m . ( 2 5 f t . ) , 6 . 8 " C . ;9.1 m. (30 f t . ) , 6 .1" C. ; 10.7 m. (35 f t . ) , 5 .4" C. ; 12.8 m. (42 f . t . ) ,5 .2o C.

DpscnrptroN on Srecrs IN THE DBvBLopuBNT oF YouNc Wrurnrrsn

Fish (1929) has described and figured the eggs and fry of whitefish. Muchof the material used was obtained from the New York aquarium and the Put-in-Bay hatchery, Ohio. In view of the differences observed between natural andcaptive whitefish as pointed out by Koelz (1929) and as is shown by the illus-trations in the Report of the Ontario Department of Game and Fisheries for1927 and the suggested racial differences between lake Ontario and lake Eriewhitefish accepted by Jordan and Evermann (f911) it appears as though it isnot unnecessary repetition to describe the various stages of whitefish fry ascaptured.

Descriptions of the newly deposited egg and the appearance after hardeninghave already been given. The following notes on developing eggs are based onmaterial from the Belleville hatchery. At the end ol 10 days the embryonicdisc is definitely elongated and by 20 days the primary vesicles of the brain aredistinguishable. By the end of 30 days the embryo is half way round the yolk.By 40 days optic vesicles showing pigment are well developed and the caudalthird of the embryo is free from the yolk which by this time shows coalescenceof the oil globules. Fin fold and pigment are both shown by the 64th day atwhich time the yolk is almost surrounded by the embryo. Pigmentation appearsto be as on hatching after Il7 days and the first fry to hatch appear around thel39th day. General hatching is in progress a few days later.

Figure 4 illustrates the main features of development to the time ofhatching.

The folloiving descriptions are of fish taken in the bay of Quinte exceptwhere otherwise mentioned. Measurements of some of the earlier specimensmay be influenced slightly by contraction of the yolk in preservation but it isbelieved that distortion of this kind is slight.

All measurements in the following descriptions are given in millimetres.Lengths are measured from the most anterior part of the head to the end of thecaudal fin. The terms melanophore and chromatophore are used interchange-ably. When other pigmentation is meant it is specifically mentioned.

The positions of various parts of the body are indicated by the distance inmillimetres from the most anterior part of the head.

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Egg or ha'Jcnrng JO Days

l M n

FrcunB 4. The whitefish egg at different stages of development.

April 10, 1928 (Figure 5, A)

Body fairly elongated, yolk sac large with one large oil globule toward the

anterior border, body slender behind yolk sac. Tail lophocercal, myotomes

plainly evident. Snout barely extending beyond eyes, mouth subterminal,

dorsal and ventral fin folds complete, vent raised in papilla. Choroid fissure

still very evident.

Length 12.7 .Head length 1.7Length to vent 8.0Yolk sac extends from 1.7 to 4.0

Head depth 1.2 below middle of eyeBody depth at yolk sac 1.4Body depth behind yolk sac 0.8Diameter of eye 0.7

52 D"y" 64 Qays 75 Days

83 Days 93Oazs I t3 Days

134 Dayr

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P'igmentation. General thin distribution of xanthophores concentratedanteriorly and particularly in the yolk sac region. Rather transparent.

Head. Between lines joining posterior third of eyes and occiput is a circulararea in which are a number of well developed melanophores, circ. 28. Twostraggling spots anterior to this. Ventral and lateral surfaces of head immaculate.

Body. Some ten melanophores in haphazard arrangement about occiputfrom which they are continued backwards in two more or less bilaterally sym-metrical lines 9n either side of the dorsal fin fold; symmetry becoming vagueposterior to vent; continuing to end of vertebral axis. Over yolk sac region afew melanophores in middorsal line. No melanophores on flanks.

A number of melanophores elongated in the direction of the long axis of thefish are scattered over the yolk sac tending to be more numerous toward the mid-ventral line. Laterally on the yolk sac are a few radially symmetrical largeand well developed melanophores showing a vague tendency to outline yolk sac.

On eithe. side of the ventral fin fold from the margins of the yolk sacextend poorly defined lines converging at the vent. This line consists of a numberof large superficial melanophores, beneath which can be distinguished a secondseries in the peritoneum. Behind the vent the lines are continued backwardson either side of the ventral fin fold to the end of the vertebral axis. A smallbreak in the line occurs in the tail fin region.

' Fins. Dorsal fin fold originating about 3.8, coming gently to maxima at

5.8 and 8.3; minima at 6.9 and 9.8. Maxima 0.3 and 0.4 respectively.Ventral fin fold on rising on posterior quarter of yolk sac continues at an

even width, 0.5, to the conically raised vent, to the anterior edge of which it isdefinitely recurved. Immediately behind the vent the fold makes its appear-ance, reaching a maximum of 0.4 before narrowing anterior to tail fin.

Caudal fin fold symmetrical. Width 1.4 mm.Pectoral fin relatively large, of ovate shape, consisting of an opaque axis

surrounded by a wide membrane of similar shape. No fin rays are distinguish-able. Insertion 1.8, length 1.5, width 0.9.

No sign of ventral fins.

April 17, 1928.

Body elongated. Yolk sac reduced but greatest depth still found at its level.

Length 12.8Length to vent 8.5Yolk sac extending from 1.8 to 3.5Head depth 1.2

Body depth at yolk sac 1.2Body depth behind yolk sac 0.8Diameter of eye 0.7Snout 0.2 ahead of anterior border of

evesPigmentaLion. Practically no changes from April 10, except for a few

pigment cells in the region where the caudal rays are to develop.

Fins. Similar to April 10.Dorsal fin fold beginning at2.5. Reduced maxima at 6.0 and 8.0. Minima

at 6.8 and 10.0. Width at maxima 0.3 and 0.5 respectively.

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Ventral fin fold as before, but not so strongly recurved at vent. Widthanterior to vent 0.4. Maxima behind vent 0.4 at 9.2.

The tail shows definite asymmetry with the epichordal portion propor-tionately larger. Width 1.7.

Pectorals. lnsertion 1.9, length 1.6, width 1.2.Ventrals not evident.Rays are not evident in any of the fins.There is no assurance that this specimen represents an advance of seven

days in development over that described for April 10. Even after April 24,newly hatched fry appeared to be joining the shore community. On April 24the proportion of newly hatched fry in the sample taken was large enough tocause a drop in the average size and to be quite noticeable in the field. (Seesection on rate of growth of fry.)

April24,1928

Body in general same as for April 17. Yolk sac further reduced. Firstindication of ventral fins.

Length 13.0 Body depth at yolk sac 1.2Length to vent 8.9 Body depth behind yolk sac 0.9Yolk sac 2.0 to 3.2 Diameter of eye 0.7Head depth 1.4 Snout 0.3

Pigmentation. Distribution of yellow pigment similar to that describedon April 11. However, the yellow is less evident on more advanced specimens.

Head. General arrangement of dorsal pigment similar but the melano-phores in the circular area mentioned for April 10, have increased in number toaboui 60, and others extend irregularly to the anterior border of the eye.

Some specimens show a few chromatophores near the posterior margin ofthe operculum.

Body. General arrangement as before, but anterior mid-dorsal melano-phores have disappeared except in immediate vicinity of occiput. A few smallchromatophores have appeared in the general line of the larger dorsal onesalready described.

Ventrally too the general arrangement of pigment is the same as previously.The melanophores.immediately posterior to the pectoral fins have increased innumber. Deep set melanophores already mentioned form a well marked "V"with the open end subtended by the yolk sac.

Fins. The dorsal fin fold is essentially the same as forApril 17. Risingat3.8, maxima at 6.3 and 7.7, minima at7.0 and 9.8.

Ventral firi fold as for April 17. Maxima behind vent at 9.4.Caudal fin as before.Pectorals. Length 1.6, width 1.2.

May 1, 1928'

Body elongated and the yolk sac is gone, but the ventral surface has asmooth raised portion in the yolk sac region. Vent still raised.

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Length 14.7Head length 2.0Length to vent 9.2Body depth 1.1

Length 15.0Head length 2.5Length to vent 10.5

Pigmentation. Head. Distribution of chromatophores between anteriorpart of eyes rather more general than before. Otherwise the same as April 24.

Body. Dorsally changed only in the presence of a sparse scattering of

melanophores caudally.Ventral pigment unchanged save for reduction in numbers of melanophores

on yolk sac region.Posterior to the vent an indefinite row of small chromotophores shows along

the central angle of the myotomes.

Fins. Dorsal fin fold commences at 4.0, maxima at 6.3 and 8.6, minima(the first sharply marked) at7.2 and 10.5. Maxima 0.5 and 0.4 respectively.

Ventral fin fold, rises at 3.8 and has maxima at 8.0 and 9.1. Minimum in

caudal peduncle region at 10.5. Maxima both 0.5.Caudal fin as previously.Pectorals. lnsertion 2.5, length 1.8, width 1.3.Ventrals still minute.

May 9, 1928 (Figure 5, B)

Body elongated. Yolk sac with very inconspicuous remnants only from

2.8 to 4.3? Vertebral axis turning dorsally posteriorly. Maxillary quite Well

developed and extending to middle of the eye. Snout very definitely anterior to

eves.

Head depth 1.4Diameter of eye 1.0Length of snout 0.3

Head depth 1.7Body depth 1.6Diameter of eye 1.1

Pigmentation. Head. Between the occiput and the lines joining theposterior thirds of the eyes, is a roughly circular, densely pigmented area with

large melanophores (circ. 60). Anterior to this is a vaguely defined region of

smaller melanophores extending to the anterior margin of the eyes. Scattered

melanophores on the snout.Scattered melanophores on the operculum.A very few small pigment cells are to be found on the lower jaw.

Body. Slight concentration of melanophores immediately posterior to

occiput continued posteriorly to the end of the vertebral column in two well

defined lines, each consisting of a row of large melanophores and many smaller

ones. There is a narrow well defined clear area in the mid dorsal line anteriorly,

but posteriorly the dorsal margin of the body is outlined by the two lines.

Along the middle angle of the myotomes posterior to the vent is a row of

small melanophores extending into the caudal area. The scattered melanophores

on the flanks are more numerous ventrallv.

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27

C

FrcunE 5. Whitefish. A. Big island. April 10, 1928. Length 12.7 mm.B. Prinyers cove. May 9, 1928. Length 15.0 mm. C. Prinyerscove. May 16, 1928. Length 14.9 mm.

A well defined group of pigment cells starts immediately posterior to andbetween the insertions of the pectoral fins, extends caudad to the point of originof the ventral fin fold and on each side of it to the end of the yolk sac region.In the yolk sac region are a few scattered chromatophores. Two lines of internalmelanophores form an elongated "V" with the open end in the yolk sac regionand the closed end immediately posterior to the vent. Caudal to this it iscontinued superficially on either side of the ventral fin fold. No pigment cellsoccur inside the "V".

Fins. Dorsal fin fold originates at 3.5, rising very gradually to greatestwidth of 0.6 at 7.8. A second maximum of equal size occurs at 10.0. Minimumin caudal peduncle at 12,5.

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The ventral fin fold begins in the middle yolk sac area increasing gradually

to a width of 0.6 at 4.5, which is nearly constant until the sharp break at thevent. Rises sharply from vent to 0.6 maximum at LL.z. Much reduced from

12.7 to 12.8.The caudal fin expands dorsally and ventrally from'12.8: rnaximum width,

1.8 at 14.0. Some 13 rays are evident in the hypochordal part of the tail. Smallmelanophores are scattered between them.

Pectorals are broadly rounded. Insertion 2.5, length 2.0, width 1.3. Opaque

axis about 0.6 mm. in length.Ventrals minute. Insertion 7.2.

May 16, 1928 (Figure 5, C)

Length 14.9. One of the smaller speci-mens of the collection

Length to vent 11.0Head depth 1.9

Body depth 1.8Diameter of eye 1.2Snout 0.3

P'igmentation. Head. Circ. 80 melanophores in the pigmented cranial

region described for May 9. The scattered melanophores anterior to this

extend to the eyes on either side. They are larger medially, reaching the pre-

maxillary, extending along it and the maxillary.Two sparse rows extend along anterior edge of the mandibles. Small scat-

tered pig'ment cells posterior to it extend as far as the isthmus.Scattered chromatophores on the sides of the head are concentrated at the

posterior and ventral borders of the eyes and the posterior angle of the operculum.Body. Unaltered from May 9, except for slight increase in scattered

pigment cells ventrally and laterally.

Fins. The dorsal fin fold is first evident at 4.5, but is very narrow to 6.0where it rises sharply to a width of 0.6 at 8.0. This is the site of the dorsal fin

in which 11 rays can be distinguished. Notched sharply at 8.8, rising gently to0.4 at 11.0 at the site of the adipose. Gently notched at the caudal peduncle

with a minimum at 13.8.The ventral fin fold rises quite abruptly in the middle of the " yolk sac area"

at 5.6, attains a width of 0.5 which is retained to the sharp notch at'the vent.

Rises sharply behind vent at 11.1 to a maximum at 11.8 in anlage of anal fin of

which 12 rays are apparent. Notch in caudal peduncle deepest at 13.0 (width

0 .1 mm. ) .Rays are distinguishable developing from the upturned vertebral axis of

the tail fin, which is markedly asymmetrical. Pigment cells are radially arranged

between the rays. Width 1.7.Pectorals. Insertion 3.2, length 1.9, width 1.2.Ventrals. Insertion 7.7., length 0.3, width 0.3.

May 20, 1928.

Fry elongated with the greatest depth of the head behind the eyes. Body

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mtapering gradually to caudal peduncle. No sign of yolk sac, and other larvalcharacters have largely disappeared. The choroid fissure is now apparent onlyas an indentation in the lower margin of the iris. Mouth showing tendency toadult character with premaxillaries almost vertical. Tail condition definitelyintermediate between a homocercal and lophocercal character. Operculum notyet completely covering gills.

Length 19.8Length of head 3.5Length to vent 13.7

Head depth 2.3Body depth 2.1Diameter of eye 1.3

Pigmentation. There are indications of guanin deposits in the abdominaregion although the colour is still a translucent yellow green.

Head. Some increase in the pigmentation in the premaxilla marks thechief change from the condition described for May 16.

Three rows of small pigment cells are found on the mandible. One, scarcelydeveloped, on the inside of the terminal portion; one distinct, on the outside ofthe terminal part, and the third distinctly outlining the lateral backward pro-longations of the mandibles. A very few scattered chromatophores on the mid-ventral line anterior to the isthmus.

Marked concentration of pigment cells on the angle of the operculum. Rowof chromatophores along the ventral margin of the eye. Scattered pigment cellson maxillary and upper part of head posterior to eye.

Body. Although there is some retention of the general character of pig-

mentation, as described for May 16, the addition of many melanophores ofvarying sizes dorsally has rendered definite rows indistinguishable. Pigmenta-tion is somewhat denser on the caudal peduncle and occiput.

Ventrally the appearance is slightly changed from that of May 1.6, by anincrease in density of the deeply set "V", increase in the mid-ventral pigment

for 2 mm. posterior to the pectoral insertions, and an increase in the diffuse pig-

ments posterior to the vent.The line of pigment lying in the angle of the myotomes is becoming in-

creasingly evident.

F,ins. Those parts of the dorsal fin fold which are not in the neighbourhoodof developing fins are very much reduced in width. The dorsal fin rays number 12and extend to the edge of the fin fold.

Dorsal f in fold rises at 6.5. Maxima at 10.0 and 14.3. Minima from 11.2to 12.2 and 16.0 to 17.0. Width at maxima 0.7 and 0.8 respectively.

Ventral fin fold essentially unchanged, rises at 7.0, maximum behind ventat 14.5. Minimum between 16.0 and 16.7. Greatest width before vent 0.7,behind vent 0.6. Twelve anal rays are apparent and extend two-thirds of thedistance to the margin.

The junction of the lophocercal and developing rayed part of the tail ismarked by a distinct notch, the latter at this stage extending most posteriorly.Eight rays are apparent on either side of the new axis. Pigment arranged asbefore.

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Pectorals. Insertion 4.0, length 2.0,Ventrals. Insertion 10.0, length 0.4.

May 24,1928 (Figure 6)

Length 20.9Length of head 4.0Length to vent 14.1

width 1.7. No rays distinguishable;Slight indication of rays.

Head depth 2.3Body depth 2.3Diameter of eye 1.4 (horizontal)

Pigmentation. Silvery guanin deposit shown from opercula to the caudalpeduncle, and from the ventral surface to a little above the lateral line. In thelower part-of this area the silvery sheen dominates the other colours, but on bothsides of the lateral line the silver hues are combined with other colours to produce

a pinkish purple iridescence. Dorsally this in turn shades into an apple green'

The transparency which characterized the early fry has practically disappeared.

Head. Increase in pigmentation between-eyes and in snout. Dorsal surfaceof maxillary outlined, considerable colour on the premaxillary.

Pigmentation on mandible intensified by the fusion of the two terminal lines:

Some increase in the mid-ventral pigmentation.

Eye surrounded by a row of small pigment cells. Sprinkling of pigment cellsover dorso-lateral srrface of the head.

Body. Similar except for slight increase in scattered melanophores. Thelateral line of pigment reaching to within 4 mm. of the head.

B

FrcuRE 6. Whitefish. Prinyers cove. May 21, 1928. A. Length 20.9 mm.B. Length 21.5 mm.

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Fins. Dorsal fin fold completely reduced except near fins., Dorsal insertion

(anterior margin of first ray) 9.8 mm. Adipose maximum et 15.0, width 0.8.

iroportionate size of adipoie very large in comparison with adult specimens.

Ventr.al fin fold as befoie. Rises 8.0, width 0.6. Very narrow On caudal

peduncle. Anal insertion 14.5, width 0.7. Rays extending practically to the

margin of the memtirane.Caudal fin as on May 20, with three well defined notches-one in the fin,

antero-dorsal to the end of the primitive axis, one separating the lophoc-ercal and

rayed portions of the caudal membrane, and one representing the notch of the

developing homocercal tail. Twelve rays extend to the margin of the membrane.

Unrayed parts of the membrane increase on the caudal peduncle.

Pectorals. Insertion 4.2, length 2.0, width 1.6. Vagud indication of rays.

More pigment showing on axis.Ventrals. lnsertion 10.3, length 0.4.

May 27, 7928

Length 22.3Length of. head 4.2Length to vent 15.0

Length 21.2Length to the end of the vertebral

column 19.2Length of head 4.2

Depth of head 2.4Depth of body 2.6Diameter of eye 1.5

Length to vent 14.1Head depth 2.5.Body depth 2.6Diameter of eve 1.4

P,igmentation. No changes in essentials, but diffuse melanophores scattered

in most regions except belly'

Fins. Dorsal fin fold still more reduced.Dorsal insertion 10.9, fin extending to 12.5. Dorsal height 0.9.

Maximum of adipose at 11. Height 0.7'

Ventral fin fold insertion 7.5.Anal base from 15.2 to 17.2. Anal height 0.9.

Primitive part of the caudal fin much reduced, the two notches having dis-

appeared. Rays 24.Pectorals. Insertion 4.5, length 1.9, width 2.0. Rays definitely indicated.

Ventrals. Insertion 10.7, length 1.7. Rays apparent.

June 1, 1928 (Figure 7A)

Two specimens were taken, 21.2 and 27.6'

In form similar to that taken May 27 with larval characters practically

disappeared. The mouth is distinctly inferior, showing a resemblance to the

adult form.

Pigmentation. Head. The same well defined pigment areas are to be

found in the head which is altered in the rather more diffuse distribution of

melanophores and in the establishment of three pairs of well marked, clear

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B

FrcunB 7. Whitefish. Prinyers cove. A. June 1, 1928. Length 27.6 mm.B. June 1, 1928. Length 21.2 mm.

tracts. One pair separates the eyes from the surrounding row and includes thenares anteriorly. A second pair by an omega-shaped line divides the spacebetween the eyes into thirds, diverging posteriorly; the base of the omega is alittle posterior to the anterior border of the eyes. The remaining pair are lesswell defined and extend backwards from the upper junction of the operculumwith the head proper. There is rather more pigment on the isthmus than des-cribed for May 27.

Body. There is a general distribution of melanophores over the body, nopart being free except the belly region between the vent and 7.0. There is aconcentration along the dorsal surface posteriorly on the caudal peduncle, thisincreasing toward the tail fin. Well defined lines mark the tail fin and the angleof the myotomes.

Fins. Dorsal fin 9.0 to 11.3, height 1.5. Remnant. of fin fold anterior toinsertion.

Adipose fin maximum at 15.5. No sign of fin fold between this and dorsal.Ventral fin fold similar to last. Origin 7.5, maximum width 0.6. In

27.6 mm. specimen the only sign of either fin fold is a broad flap immediatelyanterior to the vent.

Anal f in 14.5 to 16.5, height 1.1.Caudal fin. Width 3.7.Pectoralb. Insertion 4.1, length 1.7, width 1.9.Ventrals. Insertion 9.6, length 1.7.

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June 15, 1926 (Shakespeare Island lake)

Specimens taken on this day showed a general reseinblance to the adult inall but coloration, the absence of scales, the form of the adipose, and the presenceof a small remnant of the ventral fin fold anterior to the vent.

Length 34.2Standard length 28.9Head length 7.2Length to vent 22.0Head depth 3.5Body depth 5.3Eye 2.2Snout 2.7Dorsal insertion 13.7 to 17.5

Dorsal height 3.3 (?)

Adipose maximum at 19.5Anal insertion 22.1 to 24,7Anal height 2.0Caudal width 7.0Pectoral insertion 7.0Pectoral length 4.0Ventral insertion 15.3Ventral length 3.4

Pignentation. Flanks and head with distinct silvery sheen in most places.Dorsal surface of head generally covered with melanophores which are larger

in two very dark elliptical areas between the posterior margins of the eye.Mandible and chin sprinkled with melanophores; Heavier distribution of melano-phores on dorsal and posterior borders of the eye. Eye silvery with a concen'tration of melanophores dorsally.

Except for the belly all of the body is at least sparsely sprinkled with chro-matophores which are much more closely placed dorsal to the lateral line andincrease in number toward the mid-dorsal line. One prominent row of largechromatophores extends throughout the length in the dorso-lateral region.Anal base outlined.

Dorsal and caudal fins with many melanophores between the rays.

June 28, 1926, Shakespeare Island lake (Figure 8 of one for June 29)

Length 45.4. Scale papillae showing prominently along the flank from thehead to the caudal peduncle.

FrcuRE 8. Whitefish. Shakespeare Island lake. June 29, 1926. Length 45.4 mm

July 18, f926 (Shakespeare Island lake)

. Length 54.0. Fully scaled.

July 24,1926 (Shakespeare Island lake)

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Larval characters entirely gone.throughout.

Length 69Standard length 57Head length 14.2Length to vent 42Head depth 8.0Body depth 13.0Diameter of eye 3.8Snout 3.0Dorsal insertion 25.5 to 34.2

34

Adipose fin assumes adult shape.

Dorsal height 10.8Adipose insertion 47.5Anal insertion 44.5 to 51-5Anal height 4.7Pectoral insertion 13.3Pectoral length 9.5Ventral insertion 28.7Ventral length 10.0

Scaled

Pigmentation. In white belly and dark back this specimen resembles thosetaken on June 15th from which it differs in the increase in the number of scatteredpigment cells and in the dbsence of the two prominent rows of chromatophoresobservable in that specimen.

July 26, 1928, bay of Quinte, Adolphus reach (Figure 9)

Fully scaled individual resembling adult in coloration and general form.No chromatophores on belly or fins on ventral surface of body.

Length 83.8Standard length 70.5Head length 18.0Length to vent 53.0Head depth 11.0Body depth 14.0Diameter of eye 5.2Snout 3.3Dorsal insertion 33.5 to 41.5

Dorsal height (?)Adipose insertion 58.0Anal insertion 54.0 to 62.5Anal height 7.2Pectoral insertion 15.5Pectoral length 11.2Ventral insertion 37.2Ventral length 11.5

FrcunB 9. Whitefish. Adolphus reach. July 26, 1928. l.ength 83.8 mm'

DlrprnBNcrs BETwEEN WnrrBrrsn AND Crsco Lenvlp AND PosTLARVAE

The only fish in the bay of Quinte with which the whitefish larva is likelyto be confused is the larval cisco, Leucichthys arted.i. In the early stages the two

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species are distinguishable by the greater amount of yellow pigment in thewhitefish, in which species it not only makes the yolk sac yellow but is quiteplentifully distributed over the head and the anterior part of the body. Thereis practically no yellow pigment on the body of the cisco, and even the yolk sacis very pale. The distribution of melanophores on the dorsal part of the headand the body of the whitefish is also much denser at all stages. The bilateralsymmetry in the arrangement of the melanophores of the dorsal part of thebody found in the whitefish is not observable in the cisco.

From the evidence it appears that the cisco hatches some three or four weekslater than the whitefish, but possibly owing to higher water temperature doesnot go through the preliminary long period of slow growth, and accordinglythe size relationships between the two species are practically constant, thewhitefish averaging about three millimetres longer until May 24th, when the sizesbegin to diverge (Pritchard, in press). As Hankinson (1914) found, the twospecies school together.

Throughout early life the whitefish is more robust than the cisco.By the time the whitefish has reached a length of 20 mm. the mouth has

reached the adult form sufficiently to make specific diagnosis on this basis alone.

TnB GnowrH oF WnrrBprsn Fnv

In order to investigate the growth of the whitefish fry the lengths of all of

FrcunB 10. Rate of growth and size distribution of young whitefish in the bay of Quinte.

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the fry in each collection were measured. The collections made after May 8

*"." Ji-rid"d before they could be examined, but the major part of each days

catch was available. Before that date all the fish in each day's collection were

measured. The fish caught each day have been divided into half millimetre size

groups. The numbe, oifirh in each size group and the curve representing the

I.r..ug" growth rate, based on these figures, are shown in figure 10'

It will be observed that the growth rate is at first slow, continuing at an

approximately even rate until about May 10' From May 10 until May 25

the growth fate seems to be accelerated. From May 25 until the end of July

the growth continues evenly at a much increased speed as compared with that

up to May 10.The slow growth rate evidenced in the earlier collections is possibly due in

part to the addition to the stock of newly hatched fry. That this is not the

i.rly .u,r." is indicated by the continuance of the slower growth into May, well

after the appearance of the last newly hatched fry'

The acceleration of the growth does not appear to be directly associated

with the start of feeding or the temperature of the water'

TnB Eppscr oF HATcHTNG TIME oN THE LBNcrrr oF THE FRY

The average size of whitefish fry taken in the bay of Quinte on April 10,

l l and 12 (1928) is 12.11.2 mm. (probabte error by the approximate formula

of Peters). The average size of eight newly hatched fry taken in lake Nipigon

between May 31 and June 4is743!.2. This is of interest in connection with

the findings of Hall (1gtb) that whitefish fry hatching at four months are4to 5 mm.

longer than those hatching earlier. Eggs deposited in the bav of Quinte hatch at

about t*"r,ty-three *eek. (Nov. 1 to Apr. 10); those deposited in lake Nipigon

hatch in some twenty-eight weeks [Nov' 15 (Dymond 1926)' to May 31]' As

winter and spring temperatures in the bay of Quinte closely approach zero

Centigrade, it is concluJed that the difference in developmental time is due to

lower water temperatures for the month immediately following spawning in. lake

Nipigon. It is io be inferred from Dymond and others (1928) that some ice is

found in lake Nipigon during December, and that water temperatures are

correspondingly low.

Tnn Fool op YouNc WrrrBr.rsn

Pnevrous woRK

The food of whitefish fry has already been made the subject of several

studies. These investigations have been along two lines' The first of these

has been to examine the stomachs of young fish seined in the natural habitats,

and the second has been to make observations on the effects of feeding fry in

captivity.-:L X".rartt (1903) suggests that whitefish between the lengths of 11'7 and

24,! cm. (4.6 and 0.5 i".)1re attracted by offal. Hankinson (1914, 1916) ieports

;h" fil t[io".i.r.rriefly of the entomosi....n., Bosmina longirostris, Diaptomus

ashland,i, and Cyclops viridis (var. parcus?)'

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Clemens and others (1923) record the stomach contents of two whitefish4.8 and 5.8 cm. in length as consisting of chironomid adults 50 per cent., Hydra-carina 25 pet cent., insect larvae 15 per cent., and plankton forms.

Forbes (1882a,1882b, I882c,1884, 1886, 1888) in a series of experiments inwhich he fed hatchery fry on natural plankton found that under these conditionsthe first food taken by preference consisted of small Entomostraca particularlyCyclops and D'iaptomus. His finding that under starvation conditions somevegetable material was taken probably elucidates the discovery by Parker(1888) of diatoms in the stomachs of fry which had been lowered to the bottomin a crate. The inference that whitefish fry are first surface feeders and thendrop to the bottom, drawn. by Mellen (1923) from observations on aquariumfish are of interest in connection with the present observations on feed-ng.

It is to be inferred from the table of contents of his paper that it was amethod similar to that of Forbes which Bajkov (1930) applied. He foundBosmina long'irostris to be the dominant organism in the food (seventy per cent.)with Ch'irononnlts sp., Cyclops, Diaptomus and Chydorus the other importantfood organisms. Diatoms constituted between three and four per cent. of thefood.

NlBrHoo

In the present study the problem has been approached only by the directmethod adopted by Hankinson, Clemens and others.

SouncBs oF MATERTALS

The data on the food of whitefish of the year have been obtained from foursources. Mr. H. H. MacKay, of the Ontario Department of Game and Fisheries,has been kind enough to allow the use of data obtained by him in analysing thestomachs of a number of young whitefish obtained in lake Nipigon. Throughthe courtesy of Dr. Carl L. Hubbs it has been possible to examine the stomachsof a number of young whitefish from lake Superior in the Museum of. Zoology,University of Michigan. The other analyses have been made of stomachs ofwhitefish taken in Shakespeare Island lake and the bay of Quinte.

Mnrnon oF PRESENTATToN

Analyses of stomach contents for bay of Quinte whitefish fry are presentedin full. The rest of the data has been summarized. Figures in parenthesesindicate the actual numbers of organisms occurring in the intestinal tracts of thespecimens examined. "x" indicates the mere presence of the organisms.

In most cases Daphnio indicates Daphnia longispina; Holopediurn is Holo-pedi,um g,ibberum; Bosmina, Bosm,ina longirostris; Graptoleberi,s, Graptoleberistestud,inaria; Leplod,ora, Leptodora ki,ndti,i; Potyphemus, Polyphemus pediculus.The ostracods recorded from the bay of Quinte whitefish are Cypria,' probablyCypria obesa. No attempt has been made at the specific determination of thecopepods.

Of 40 young whitefish taken in the bay of Quinte iri 1928r six,-(l taken

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April 17, I on April 20, and 4 on April 24), showed the yolk sac quite large'digestive tract unexpanded and with no organic contents. Two taken on May 8and one on May 19 contained no identifiable stomach contents; and one takenMay 28, 27 mm., containing nothing. The following is a record of the stomachanalyses of the 31 others.

May l, 14 mm.-Cyclops (6) 95/s, nauplius (1) |Vo; 73 mm.-Cycl,ops (1)

LO07o, Zygnema-trace; 13.5 mm.-Cyclopr (9) IO0To; 13 mm.-Cycl,ops (7)

7 5To, unidentifiable 25/q.

May 4, 13 mm.-Bosmina (L0) 8570, Cycl'ops (2) I5%; L4 mm--Bosm'ino(r) 2070, Daphn'ia (r) 80%.

May 8, 15 mm.-Chironomid larva (1) 700/e;14 mm.-Cyclops (2) 10074

May 9, 16 mm.-Daphni'a (L) 7070, small Cladocera (1) 5/s, Cyclops (7)

25Vo.May 15, 16 mm.-Bosmina (L) 30To, Cycl,ops (l) 70%.

May 16, 17 mm.-Young Cladocera (4) \O/s, Cycl'ops (l) L|/s, crustacean

remains 40/s;76 mm.-Cyclo|s (2) 90/e, nauplius (f) 10%.

May 18, 18 mm.-Daphn'i'a (l) 20To, Bosmina (2) L57o, Cyclops (2) 25Vo,

unidentifiable 40/s.

May 19, 17 mm.-Daphnia (2) 20To, Hol,oped'ium (3) 2070, Cycl'ofs (I0)

40/s, chironomid larva (l) 20%.

May 20, 16 mm.-.Elolopeitium (l) 6070, Cyctops (L) 2070, unidentified 20%;

20.5 mm.-Cyclops (6) 2070, chironomid pupae (2) SOVo; 17.5 rnm'-Bosmino(20) lOTo, Cyctops (7) 6070, Cladocera and copepod remains 1516, chironomid

larva (1) l\/s.

May 21,18 mm.-Bo srnina (20) LOTy, Cyclops (6) 2570, Diaptomus (l) 1570,

chironomid pupa (l) 45/s.

May 23,19 mm.-Daqhnia (l) 5/6, Hol'oped'ium (2) ll/s, Bosmina (5) ll/s,

Cyclops (20) 5070, crustacean remains 257o; 19 mm.-Holoped'ium (l) 7570,

Bosruina (2) t|To, Cyclops (5) 3570, Diaptomus (L) t\To, unidentified 20le'

May 24,19 mm.-Daqhnia (l) 60/s, Cyclops G) aOVo;2O mm.'-Holopedium(4) 25Vo, Cyclops (3) 2570, Canthocamptus (l) 25/s, chironomid larva (l) 25%'

lr/lay 25, CycIoPs (7) 100%.

li/:ay 26,23 mm.-Cyctops (L) L\/s, chitonomid pupae (2) g0%'

May 28, 23 mm.-Daphnia (2) lots, Hol'oped,ium (5) 20To, Bosmina (7) 2070,

Cyclops (3) l0To, crustacean rcmains 40/s.

May 30, 28 mm.-Bosmina (5) 2070, Cycl,ops (2) LDTT, crustaceair remains

45/s, insect remains (l) 257o;28 mm'-Bosrnina (4) 1570, Cyclops (2) L0Vo,

crustacean remains L57o, chironomid pupae (30) 60%.

June 7, 35 mm.-Bosmhta (15) 7570, Cladocera remains and unidentified

25%.July 26, 80 mm.-Eggs probably molluscan (300) 100%; 84 mm'--Ostra-

coda, trace, chironomid larvae (S) 2OTo, eggs (200) 807o;88 mm.-Bosmina (L)

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5/s, Eurycercus (17) l\/s, Cladocera remains LO/6, Cyclops (2) \Vo, Ostracoda(50) 5070, unidentified 2016.

The following records of analyses of stomach contents of fish taken inShakespeare island lake in 1926 show the dates taken, the length of each fishand the percentage each organism formed of the total contents.

June 13, 27 mm.-Bosmina x, Cyclops 10070.

June 15, 28 mm.-Cyctops 70/6, adult Tipulidae 907o; 28 mm.-Daphnia75/6, BosminalS/s,adultTipulidae l|/e;30 mm.-Cyclops \O/e,adult Tipulidae507o;30 mm.-Cyclops 93/e, adult Tipulidae 5To;32 mm.-Cyclops 100/s.

June 28, 43 mm.-Daphnia 30/6, Bosmina 20/s, Insect temains 50/s;43 mm.-Bosmina 40/p, Cyclops 20/6, adult Hymenoptera 407o; 43 mm.-Daphnia 2016, Bosmina 20/6, unidentified copepods x, chironomid larvae 70/s,insect remains 40/e, vegetable remains l|/s.

June 29, 46 mm.-Daphnia 5/6, Bosmina 80/s, Cyclops lU/s, insect remains57o.

July 18, 59 mm.-Daphnia 90/s, Leptodora 5/p, Corethra latvae 5/6.

July 24,65 mm.-Daphnia 80/6, Leptodora 5/6, Diaptomus 5/6, Corethralarvae 10/6.

TesLB II. The food of 40 young whitefish 21 to 33 mm. long, taken in lake Nipigo n, July 4,1924.

Organisms

Daphnia.B o s r n i n a . . . . . . . : .A lono. .Graptoleber,is.Polyphemus.Unidentified Cladocera. . . .Cycl,ops.Asellus.C h i r o n o m i d p u p a e . . . . . . . .C h i r o n o m i d l a r v a e . . . . . . . .Chironomid adults.. . . . . . .Collernbola.Thysanura.Insect larvae.Insect remainsHydrachnids.Asplanchna.Rotifers.Flatworms.Codonella.Cl,ad.ophora.Higher plant remaino.. . . .Intest inal parasites,, . . . . .Not identified

Number of stomachscontaining organisms

1810

III4

39I

19o3612o

I4141I681

Average per cent.in all stomachs

3 . 31 . 0

0 . 12 . 8

69 .8

lo.22 . 71 . 9t . 2

0 . 10 . 5

0 . 1

0 . 5

1 . 5

0 . 6

Largest per cent.in any individual

o

100100

5035

1009050J O

410

20

25

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Tenrn III. The food of young whitefish taken in lake Superior and now in the Museum ofZoology, University of Michigan

Organisms

Marqrtette county

July 3, 19272I-27 l:rl:r. 11 specimens

Whitefish pt.Aug.8 , 1913

50-71 mm. 6 specimens

Greatestper cent.

Bosmina.Acropterus.Eurycercus.Unidentified Cladocera. .Cycl,ops.Gammarus l,imnaeus. . . . .Chironomid larvae. . . . . .Chironomid pupae.. . . . .Insect remainsUlothr'itc.Vegetable remains. . . . . .Not identified

2

1

4

t716251 t

27

o l

63

n

65r00

xx

60

2J

1

45

10030

x

50

111

Lake Superior, Whitefish pt., Aug. 12,I9L3,50 mm.-Bosmina x, Diatomus 10, copepods 5, insectremains 75, not identified 10.

Whitefish bay, June 12, 1923,27 mm.-Eurycercus x, Diaptomus 5, chironomid larvae 5, chiro-nomid pupae 75, vegetable remains x, not identified 15; 30 mm.-Chironomid larvae 25,chironomid pupae 75.

Presque isle, July l, 1923,39 mm.-Cyclops 100.

CourrrBncBuENT oF FEEDTNG: MoRpHoLocrcAL CONSIDERATToN

Careful examinations of the fry captured in the bay of Quinte showed thatuntil April 24 no food had been taken and that up till this time the anterior endof the digestive tract was much compressed by the yolk sac through the dorsalpart of which it passed as a slender cord to expand immediately behind it. Nocollections were made between April 24 and May 1. By the latter date mostof the specimens seemed to be feeding on the smaller Entomostraca and in themajority of cases the yolk material had largely or entirely disappeared. Withina week there appeared to be established the feeding habits which continued untilearly, June when the fry disappeared. The young whitefish taken on July 25had evidently been feeding on the bottom.

Suuuany oF FINDINGS

The results obtained by the examination of the stomachs of bay of Quintefry are in striking agreement with those obtained for fry from Shakespeare Islandlake, lake Nipigon, table II, and lake Superior, table III, in the noticeablescarceness of small plankton organisms found. Cladocera, copepods and insectsform the bulk of the food in all cases.

This confirms the conclusions of Forbes in his research on the food of the

Nutnber

containingorganisms

Averageper cent.

in a l l

Greatestpef cent.

xx

l)

10

810

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young whitefish, in which another method was. used, and the observations of

Hankinson (1914, 1916).On the bay of Quinte material examined, it proved impossible to demon-

strate the raptorial teeth such as those described by Forbes (1884). Such

tubercles as were occasionally to be found on the lower,jaw were unpointed and

of irregular occurrence.There is little evidence of a sharp break in the type of food taken at the

time the whitefish deserts the surface of the shallow water. In the case of fish

taken in deep water, plankton organisms seem to dominate the food rather

than bottom organisms, although the latter are not uncommon. Bottom organ-

isms, especially chironomid larvae, seem to be more important in the food of

Iake Superior and lake Nipigon whitefish fry than in that of fish of the other

bodies of water investigated.

'CoNcrusroNs

These findings would suggest that hatchery operators should make definite

efforts to plant the fry where there is an abundant supply of crustacean food.

Until the detailed distribution of plankton has been thoroughly worked out it

seems justifiable to recommend provisionally that the fry be planted as close as

possible to the habitat they naturally seek.

Assocrarns AND CoMPETIToRS

The associates of the whitefish fry at Big Island appeared to be chiefly

ephemerid nymphs, tessellated darters Boleosoma nigrum, and a small un-

identified fish larva, possibly Perca flaaescens.In Prinyers cove the associates were rather more numerous. Besides various

insect larvae and Notonecta sp. there were Leuc'ichthys arted'i, Hyborhynchus

notal,us, Notropis hud,sonius, Perca flattescens afid Boleosorna nigrum.

The closest relationship exists between the young whitefish and the young

of Leucichthys arted,i as they school together indiscriminately and come into direct

competition for food. With the more or less carnivorous minnows (Clemens and

others, 1923, Allin, 1929, and examinations of specimens taken in the bay of

Quinte) there is no doubt some competition for food. The perch and tessellated

darter are both bottom feeders during the summer in the bay of Quinte and

occupy such different strata of water that although the same general type of

food is often taken, there can be little direct competition.The fish taken with the young whitefish on July 26, 1928, were Perco4sis

om.'isco-maycus and Pung'it'ius pungitius. Of these the latter is largely a plankton

feeder, but the former appears to obtain most of its food on the bottom (Clemens

and others, 1923) and no doubt enters into competition for food with whitefish

at this stage.

EuBrrrBs oF YoUNG WnrtBprsu

In the spring of. 1927, large numbers of whitefish larvaeBelleville hatchery before the retaining screens had been put

escaped frdm thein place. These

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fry appeared to keep in the immediate vicinity and became objects of interest toa number of yellow perch, Perca flaaescens, and. ciscoes, Leucichthys arledi, whichcollected in the neighbourhood. On April 4, several of each species werecaught in a piece of 6.3 cm. (2* in.) mesh gill net, and the stomachs examined.

The stomachs of 15 perch about 20.3 cm. (8 in,) long contained thirty-fivehundred whitefish fry, and 12 ciscoes about 25.4 cm. (10 in.) in length containedthirty-three hundred whitefish fry. This would indicate that these species werevery destructive of whitefish fry.

In May, 1928, however, eyidence to the contrary was obtained. Gill netsset in parts of Prinyers cove where whitefish and cisco fry were abundant, tookconsiderable numbers of perch, but although over one hundred stomachs wereexamined no fry were found in them. The fact that the stomach contents con-sisted largely of isopods and insect larvae and that all the perch captured atthis time were within 20.3 cm. (8 in.) of the lead line of the net, would'indicatethat they occupy an entirely different stratum of water from the surface swim-ming whitefish fry.

The great mass of the cisco run leaves the bay of Quinte immediately afterspawning. In localities where naturally hatched whitefish fry were found to beplentiful, adult ciscoes were so rare as to escape our gill nets entirely.

Others of the larger species of fish appear to be sufficiently rare in theselocalities to warrant the assumption that their destruction of young whitefish isnegligible.

The conditions referred to in the neighbourhood of the Belleville hatcheryindicate the necessity for extreme care in the distribution of fry. Otherwisethe results of an excellent season's hatchery operation may be lost. The widedistribution of fry obtained by the technique of distribution now employed bythe hatcheries seem to meet the requirements and should be continued andenlarged upon.

MoRTAT:ITY oF WHITEFISH FRY

No dead whitefish fry were observed at Big island or Prinyers cove. Suchnegative evidence cannot be regarded as of great significance in establishing asmall mortality by starvation or disease.

PenasrrBs oF THE FRy

In the records of stomach analysis made by Mr. MacKay (table II), it willbe observed that some twenty per cent. of the fry examined had intestinalparasites. The stomach of one young whitefish of similar size taken on June 26,1926, showed a number of plerocercoids of Proteocephalus sp. It is possible thatthis was the parasite found by Mr. MacKay.

The only parasite found in any of the Bay of Quinte fry was a glochidiumon the pectoral fin of one specimen.

CONSERVATION OF THE WHITEFISH FRY

TnB DrrrrcuLTrES oF A CoNSERvATToN Pnonr-pM

The discussion of the conservation of the whitefish must of necessity involve

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the consideration of many factors of which the value and significance are as yetunknown. Legislation intended to further the conservation of the whitefishhas been well intentioned enough but has been promulgated without an adequateunderstanding of the facts of life history essential to the formulation of d trulycomprehensive policy of fisheries exploitations. It is freely admitted that upto the present no great additions have been made to our knowledge of the factorsgoverning whitefish abundance, but it appears that a stage has been r€achedwhere there may be profit in a frank discussion of the difficulties in solving theproblems connected with whitefish abundance.

TnB Assurr,lprroN oF A CRITTcAL Pnnroo rN A DETERMTNATIoN op AsuxoeNcn

It has been generally assumed, and probably correctly, that the failure orsuccess of any one year's reproduction in school spawning fish is due to somecritical period during development. Hjort (1914) in his work on the herring,concluded that this period came in the first feeding stages of the young andshowed that a dominant year class might result from a mediocre "spawning".Until very recently the tacit assumption of most hatchery work in coregonoidand salmonoid fishes has been that this critical stage has existed between thetime of the deposition of the unfertilized egg and hatching. This assumption,though plausible enough, must be regarded as unproven.

TnB MonrAr,rrrr uNDER NATURAL CoNorrtoxs

In the present paper is presented evidence for the belief that there is a veryheavy mortality in the developing eggs from two types of causes. The first classof mortality is that occurring in eggs which spend the winter on the spawninggrounds and amounts to fifty to eighty-five per cent., if the meagre evidencecan be relied upon for quantitative accuracy. The second type of mortality isthat due to the eggs being eaten by perch. The common occurrence of thisspecies and the extent to which whitefish eggs are found in their stomachs wouldindicate that this loss may be very great. Owing to the meagreness of the infor-mation available concerning the percentage mortality of eggs remaining on thespawning grounds and the lack of quantitative data concerning the absoluteamount of eggs eaten by perch or deposited on the spawning grounds, it is im-possible to estimate the proportionate mortality of the eggs. It is probably overninety per cent. Further research along the lines of the work described in thepresent paper appear indicated. (Foerster (1929a) found that in the sockeyesalmon 1.05 per cent. of the eggs deposited reached yearling stage.)

TnB Hercnpnrps

In the hatcheries a large proportion of the mortality described is avoided.This is shown by the regular reports of hatching of eighty-five or ninety-five percent. of the eggs handled.

In estimating the importance of whitefish hatcheries, however, it is necessaryto form some estimate of the proportion of fry produced by the hatcheries tothe numbers produced naturally. The average annual catch of whitefish in lake

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Ontario for the ten years from 1918 to 1927 was approximately 861,820 kg.(1,900,000 lb.). Assuming that this figure represents one-quarter of the adult

whitefish population and that fifty per cent. of this population consists of females,

the total weight of females left to spawn naturally will be 1,292,73I kg.(2,850,000 lb.). They would produce some 28,500,000,000 eggs (Milner,1874,

Kendall 1903). Assuming one per cent. of these to hatch successfully the

number of fry produced would be 285,000,000, a number which is roughly equal

to the distribution of fry from lake Ontario fish hatcheries. If, and this again

is problematical, such a doubling of the number of fry hatching would double

the number of adult fish produced the hatcheries would certainly justify them-

selves.The number of assumptions in the last paragraph must be emphasized.

Until the real values of the quantities to which arbitrary values have been

assigned in the preceding paragraph can be stated with certainty the worth of

the hatcheries can only be guessed. The'"post hoc ergo propter hoc" attitude

of the earlier enthusiasts (Clark, 1910; Reighard, L910) must be avoided.

TnB CoNsTDERATToN oF THE Fooo op Fnv es A LIMITING Facron

So far this discussion has accepted the assumption of the hatchery operator

that the critical stage in the life history of the whitefish is previous to hatching.A consideration of an alternative assumption that the critical stage is after the

absorption of the yolk sac and the critical factor the supply of suitable entomos-tracan food leads to very different conclusions concerning the influence of the

factors previously discussed. If the food of the postlarval whitefish shouldprove te be the limiting factor, mortality of eggs due to the activities of perch

and due to other causes would probably be beneficial in their tendency to reduceharmful competition on the part of the whitefish fry and the effects of hatcherieswould be definitely detrimental due to their influence in the opposite direction.

If the supply of food of the fry or yoqng of the whitefish should be shownto be the limiting factor in their abundance, a possibility suggested by Forbes(f884), the greatest productivity of the Great Lakes is not to be attained by pro'

ducing large quantities of fry and catching the fry as they reach maturity.Rather, the fishing industry and hatchery policy should be so regulated that thenumbers of fry should not exceed the number for which there is an adequate foodsupply and that the amount of adult growth should be made as large as poss-ible.

RBcoiuuBNnATIoNS

In view of the lack of information of the factors governing the survival ofwhitefish eggs and fry, recommendations concerning hatcheries, general'fisherypolicy, elimination of enemies and competition, etc., would be out of order.

One conclusion concerning hatchery practice does appear to be warranted,Fry from hatcheries should be sparsely distributed in shallow water along agently sloping shore which need, not be in the neighbourhood of natural spawninggrounds. . Such practice would result in fry being placed in the type of localitywhich they appear to seek, under conditions where they would not be in com-

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petition among themselves for food and distributed sufficiently widely to avoidbecoming the'object of undue notice of predaceous species.

If it should ever prove advisable to reduce the numbers of perch in the bayof Quinte a 5.7 cm. (2i in.) stretched mesh gil l net would be suitable for thepurpose. Trials with test nets of graded sizes have shown that a net of thissize takes perch in large numpers, but takes only about five per cent. of fishwhich are under 17.8 cm. (7 in.) and too small to be marketable.

SUMMARY AND CONCLUSIONS

The common whitefish, Coregonus clupeaform,is (Mitchill) occurs throughoutthe Great Lakes. For the purposes of the present discussion this species is con-sidered to be the whitefish of all central and eastern Canada.

The whitefish has played a most important part in the opening up of sub-arctic Canada, and in the pursuit of the fur trade.

The value of the Canadian whitefish fishery is greater than one and a halfmillion dollars annually. It is the most valuable of the fresh water fisheriesand the sixth or seventh most valuable of all Canadian fisheries.

Owing to the influence of a number of factors whose magnitude cannot beestimated, statistics of the catch in a fishery cannot be regarded as providinga direct index of the abundance of the stock.

Statistics presented show marked positive fluctuations in the numbers offish captured in spite of continued heavy exploitation of the fishery.

The Canadian waters of lake Huron have provided more whitefish thanthose of any of the other Great Lakes.

An understanding of the causes of these fluctuations would be a greateconomic advantage.

Material for the study of spawning and the fry was collected in the bay of

Quinte at Big island and Prinyer's cove. Accessory material has been collectedat lake Nipigon and Shakespeare Island lake.

The spawning migration of whitefish in the bay of Quinte occurs in October,The fish swim off the bottom and do not feed actively at this time. Male fishare the first to migrate and the first on the spawning grounds. There is usuallysome time between the arrival of the fish at the neighbourhood of the spawninggrounds and actual spawning.

Differences in mortality, habits and size make sex ratio difficult of deter-mination. The best information available indicates that males are slightly morenumerous.

The smallest spawning fish are about 35.6 cm. (14 in.) in length. Fromdata collected in 1925, it would appear that although some spawning fish arein their fifth year, the bulk of the spawning run consists of fish in their seventhand eighth years. In that year the majority of the fifth year fish were males.

Spawning whitefish assume a definite breeding dress of nuptial tuberclesand pearl organs. Males are more strikingly modified in this way than females.

One of the spawning grounds of the bay of Quinte is a shallow, rocky shoalcalled the Hogs Back. The eggs of whitefish were found on it in the crevicesbetween the stones.

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An examination of the number of eggs produced by whitefish by stripping

them showed a much smaller production than that quoted by investigators

who counted the eggs in the ovary. The loss of eggs owing to incompletestripping may be considerable in hatchery practice.

The time of spawning is usually the first week in November. The tempera-ture at which spawning begins varies from 4.5" C. to 10.0" C.

Contrary to previous assumption the proportion of eggs to be fertilized innature is high-between sixty-five and one hundred per cent. The proportion

may be subject to considerable variation.Large numbers of whitefish eggs are destroyed by other fish, particularly

the perch, Perca fl,avescezs (Mitchill). The sucker, Catostomus cornmersonii(Lac6pdde), has not been found to eat whitefish eggs.

There is a heavy mortality occurring in eggs on the spawning grounds duringdevelopment. The information available is not sufficiently extensive to estimatethe proportion of eggs surviving to hatching.

The temperatures on the spawning grounds during the developmentalperiod of the eggs are between 0.0o C. and 0.8" C. An adequate supply of oxygenappears to be present.

In 1928 hatchittg occurred about the middle of April. Newly hatched fryare active swimmers and keep near the surface.

Schooling tendencies are evident within two weeks of hatching at whichperiod fry tend to concentrate in shallov4 water under 45.7 cm. (18 in.) in depth.

About four weeks after hatching fry venture into water of 9l'5 to 122 ctn.(3 or 4 ft.) in depth, but always rerriain close to the surface.

By the end of May young whitefish become scarce inshore, and finallydisappear entirely. The capture of three on the bottom in 75.2 m. (50 ft.) ofwater at the end of July suggests that they were on the bottom in water ofmedium depth.

Descriptions of the eggs and fry at different stages are given. Whitefishfry are distinguishable from their close relatives, the ciscoes, Leucichthys orled'i(Le Sueur), by the greater amount of black and yellow pigment of the whitefish,the greater size at corresponding stages, and the greater robustness at correspond-ing lengths. Later fry are distinguishable by the inchoate adult characters.

The growth of whitefish is at first slow and the apparent growth rate isprobably diminished by the addition to the stock of newly hatched individuals.The continuance of the slow rate till May 10 (1923) indicates that this is notthe sole cause. A much increased growth rate holds for May 18 till the endof July. Average lengths on hatching on April 10 to 12, May 15 and May28 were respectively I2.2 mm., 15.7 mm., and 22.5 mm.

Some evidence is presented to show that the relationship between time ofdevelopment and the length of the newly hatched whitefish larva found by Hall(1925) occurs under natural conditions in the whitefish.

Most whitefish fry had started to feed by May 1, in 1928, at which timethe yolk sac was absorbed. The food from the first consists of Entomostraca.Later food may include insect larvae and amphipods, as well as Entomostraca.

The chief associates of the whitefish young are the young of the cisco,

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+7Leucichthys arteili. With it there is direct competition for food. Other associ-

ates may compete to unknown extents.There is evidence for the belief that whitefish fry are not extensively preyed

upon by other species. Negative evidence that mortality due to starvation and

disease is small must be regarded as of little value.Parasitism of fry does not appear to be common in the bay of Quinte.The formulation of an adequate conservational policy is impossible without

a complete knowledge of the life history of the whitefish and its relationships

with other forms.A judgment of the value of the hatcheries in increasing the abundance of

whitefish depends upon our knowledge of the critical period in the life history

of the species.It is provisionally recommended that planting of hatchery fry be made

close to gently sloping shores, and that the fry be widely distributed. These

conditions are fairly well met by the methods in use at present.

If the reduction of the numbers of perch should be proven advisable, fishing

with 5.7 cm. (2f, in.) stretched mesh gill nets is recommended.

REFERENCES

Alr-tw, A. E. Seining records and food of the intermediate stages of lake Eriefishes. Bul,I. Bufalo Soc. Nat. Sci., L4, 188-194. 1929.

B.l;rov, A. A study of the whitefish (Coregonus clupeaJormis) in Manitobanlakes. Contr. Canail. Biol'. Fish., N.5..V,443-455. 1930.

BBnsrBv, B. A. The fishes of Georgian bay. contr. canail. 8io1,.,1911-1914,Fasc. II. 1-51. 1915.

Brsnoe, SnBn:ueu C. Notes on the habits and development of the mud puppy

Necturus maculosus (Rafinesque). Bul'I'. N.Y. St. Mus.,268,61pp. 7926.BucneNex. Aucus. Wild life in Canada. Toronto. 264 pp. 1920.Cr,Anx, FneNr N. A plan for promoting the whitefish production of the Great

Lakes. Bull'. U.S. Bur. Fish.,28,635-642. 1910.

cr,BueNs, w. A. and others. The food of lake Nipigon fishes. unia. TorontoStud.. Biol.,22. Pub. Ont. Fish. Res. Lab., L6,171-188. 7923.

Coucg, Jonm H. The rate of growth of whitefish (Coregonus a|bus) in lake Erie.

[Jniv. Toronto Stuil. Biol,.,2O, Pub, Ont. Res. Lab.,7,97'707. 1922.DowNrNc, S. W. A plan for promoting the whitefish production of the Great

Lakes. Bul]. U.S. Bur. Fish',z$, 627-633. 1910.DvuoNo, J. R. The fishes of lake Nipigon. [Jnia, Toronto Stuitr- Biol'.,ZTt

Pub. Ont. Fish. R.es. Lab., 27, 1-108. 1926.DrnroNo, J. R. and J. L. Hent. The fishes of lake Abitibi (Ontario) and ad-

jacent waters. (Jniv. Toronto Stud'. Biol'.,29, Pub. Ont. Fish. Res. Lab.,28,3-19. 1927.

DvlloNo, J. R. and others. A faunal investigation of the lake Nipigon region,Ontario. Trans. Canail. Inst., tB (2),233-237. 1928.

Er,r,rs, M. M. and G. C. RoB. Destruction of log perch eggs by suckers. Cope'i'a,47,69-7L.

2tL

1917.

Con

trib

. Can

. Bio

l. Fi

sh. D

ownl

oade

d fr

om w

ww

.nrc

rese

arch

pres

s.co

m b

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itory

Ser

vice

s Pr

ogra

m o

n 11

/12/

14Fo

r pe

rson

al u

se o

nly.

48

Frsn, M. P. Contributions to the earlv life histories of lake Erie fishes. Butt.Bufalo Soc. Nat. Sci., t4,136-187. 7929.

Fonnsron, R. E. An investigation of the life history and propagation of thesockeye salmon (orucorhynchus nerka) at cultus lake, British columbia.No. 2. The run of 1926. Contr. Canad.. Biol. Fish, N.5., V, 3g-b3. Ig2ga.

An investigation of the life history and propagation of the sockeyesalmon (Oncorhynchus nerka) at Cultus lake, British Columbia. No. 3.The downstream migration of the young in 1926 and 7927. Contr. Canad,.Biol. Fish.,N.S., V, 57-82. L929b.

Fonnes, S. A. The food of young whitefish Coregonus clupe,iformis. Butt. U.S-F,ish. Contm., t, 19-20. 1882a.

On the food of young whitefish (Coregonus). Bull. U.S. Bur. Fish., l,269-270. t882b.

An inquiry into the first food of young lake whitefish (CoregonusclupeiJorm'is). Bull. U.S. Bur. Fish.,t,402-403. 1882c.

The first food of the common whitefish (Coregonus clupeiformis Mitch.)-Bull. Il l. St. Lab. Nat. H,ist.,1, 1876-1883, 95-109. 1884.

The first food of the common whitefish (coregonus clupeiforrnis Mitch.).Rep. Bd. IU. St. F,ish.,L886,139-149. 1880.

Studies of the food of fresh water fishes. Bull. ilL. St. Lab. Nat. Hist..2, 433-473. 1888.

Grrr, T. The differential characters of the Salmonidae and the Thymallidae.Proc. U.S. Nat. Mus., L7, l l7-122. 1895.

Her,r,, A. R. Effect of oxygen and carbon dioxide on the development of thewhitefish. Ecology,6, 114-116. lg2;.

Hlur<rNsoN, T. L. Young whitefish in lake Superior. Science, N.S., 40, 2Bg_240. 7974-

Results of the Shiras expeditions to whitefish point, Michigan: Fishes.M'ich. Geol. Biol. Surv.,20, Biol. Ser. 4. 1916.

Henr, J. L. The capture of young whitefish in the bay of euinte. science,N.S. ,70, 284. lg2g-

HnenNn, S. A journey from Prince of wales' fort in Hudson's bay to the' northern ocean in the years 7769,7770, I77L, and 1722. New editionwith introduction, notes, and illustrations by J. B. Tyrrell, M.A. TheChamplain Society, Toronto. xv and 437 pp. 1 9 1 1 .

HJonr, Jonam. Fluctuations in the great fisheries of northern Europe viewedin the light of biological research. Rapp. Cons. Erplor. Mer. Copenh.,20,228 pp. 1914.

Hunns, C. L. A check list of the fishes of the Great Lakes and tributary waters"with nomenclatural notes and analytical keys. Misc. pub. Mus. Zool.Univ. Mich.,15, 177 pp. 7926.

Hunns, c. L. and D. E. s. BnowN. Materials for a distributional studv ofOntario fishes. Tians. Canad; Inst.,L7r 56 pp. 1929.

HuBBs, c. L. and S. c. wnrrl-ocx. Diverse types of young in a singre species of. fish, the gizzard shad. Pop. Mich. Acad. Sc.i. Arts and. Letters,l0, 461-

482.

2r21929.

Con

trib

. Can

. Bio

l. Fi

sh. D

ownl

oade

d fr

om w

ww

.nrc

rese

arch

pres

s.co

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epos

itory

Ser

vice

s Pr

ogra

m o

n 11

/12/

14Fo

r pe

rson

al u

se o

nly.

49

Jinvr, T. H, IJber die Arten und Forrnen'derActa, Zool. fenn.,6,259 pP.

Coregonen s. str. in F'innland., 1529.

JonoeN, D. S. and B. W. EvnnMANN. The fishes of north and middle America:

descriptive catalogue of the species of fishlike vertebrates found in the

waters of North America, north of the Isthmus of Panama. Billl' U.S.

NaL Mus.,47, ( l ) , lx and 1240 pp, 1896.A review of the salmonoid fishes of the Great Lakes, with notes on the

whitefishes of other regions. Bull. U.S. Bur' Fish.,29, 4L pp. 1911:

KnNter-r, W. C. Notes on some fresh-water fishes from Maine, with descrip-

tions of three new species. Bull. U.S. Fish. Com.,22' 353-368. 1903.KoBr-2, W. Coregonid fishes of the Great Lakes. Bull. U.S. Bur. F'ish.,43,

297-643. 1929.

LgACH, G. C. Artificial propagation of whitefish, grayling and lake trout.

Rep. U.S. Com. Fish.,1923, App. III, 32 pp. 7923-

Mnor, A. The migrations of f ish. London, vii i and 427 pp. 1916.

MBr-r-sN, I. M. The whitefishes (Coregonus clupeaform'is) reared in the New

York aquarium. Zoologica, 2, 375-379. 1923.Mnlvu-l-, E. D. and others. Reports on fisheries investigations in Hudson and

James bays and tributary waters in 1914. Rep. Dept. Naaal Serv., t9t4,

Ottawa, 85 pp. 1915.Mrr,nnn, J. W. Report on the fisheries of the Great Lakes; the result of in-.

quiries prosecuted in 1871 and 1872. Rep. U.S- Com. Fish., 1872 and1873, 1-78. 7874.

Nusseeuu, M. A simple test to learn if fish ova are impregnated' Bull. U.S.Fish. Cornm.,II, 347-348. 1883.

Penr<en, J. C. Some experiments with the fry of whitefish. Trq.ns. Amer. Fish.Soc., t7, 67-69. 1888.

PnaRl, Revuoxn. Notes on the proportion of the sexes in whitefish. ReP.Mich. Acad.. Sci., t7, (1), 76. 1916.

PnBer-B, E. A. A biological investigation of the Athabaska-Mackenzie region.

U.S. Dept. Agric., North Amer. Fauna,27' 1908.

Pnrrcnano, A. L. Spawning habits. and fry of the cisco (Leuc'ichthys arted,i)

in lake Ontario. Contr. Canad'. Bi,ol. F'ish., N.S. VI. (9) (in press).

RewsoN, D. S. The bottom fauna of lake Simcoe and its r6le in the ecology of

the lake. (Jn,iv.Toronto SLud.. B'ioL.34, Pub. Ont. F'ish Res. Lab.,40, 1930.

RnceN, C. T. The systematic arrangement of the fishes of the family Sal-monidae. Ann. Mag. Nat. H'ist.,13' 405-408. 1914.

RuGuAnl, Jacon. The breeding behavior of suckers and minnorvs' Biol. Bull,.

Woods Hole,38, l -32. 1920.

RErcnann, Paur,. A plan for promoting the whitefish production of the GreatLakes. Bull. U.S. Bur. Fish.,z9, 645-684. 19f0.

RoscoE, Srn H. E. and J. LuNr. On Schutzenburger's process for the estimationof dissolved oxygen in water. J. Ch'em. Soc., 55, 552-576. 1889.

Sr<erresox, J. B. The fish resources of Manitoba. Industrial Development Bd.Man. , Winnipeg,4S pp.

219

1926.

Con

trib

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. Bio

l. Fi

sh. D

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Ser

vice

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14Fo

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al u

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50

StrwAmn N. H. Development, growth and food habits of the white sucker,Catostomus comrnersonii Le Sueur. Bul,l. U.S. Bur. Fish,, 42, 147-184. t926.

Wurte,xrn, H. Early history of the fisheries on the Great Lakes. Rep. Mich.St. Bd. Fish Cernrn., 10, 172-181. r893.

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