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A contribution to the ecology of the whitefishes Prosopium cylindraceum and Coregonus clupeaformis of… Sandercock, Frederick Keith 1964

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CONTRIBUTION  TO  THE  ECOLOGY  'Prosopium cylindraceum OF  AND  ALGONQUIN  OF  THE WHITEFISHES  Coregonus clupeaformis  PARK,  ONTARIO  by FREDERICK KEITH SANDERCOCK B . S c , The University o f Toronto, 1962  A  THESIS THE  SUBMITTED IN REQUIREMENTS MASTER  PARTIAL  FOR OF  THE  FULFILMENT DEGREE OF  SCIENCE  i n the Department of . Zoology We accept t h i s t h e s i s as conforming to the required standard  THE  UNIVERSITY OF BRITISH October, 1964  COLUMBIA  OF  In the  r e q u i r e m e n t s f o r an  British  mission  for reference  for extensive  p u r p o s e s may  be  cation  of  written  Department  of  degree at  the  study,  copying of the  for  /  agree for  that  of •  not  per-  scholarly  Department  shall  of  make i t f r e e l y  or  t h a t , c o p y i n g or  f i n a n c i a l gain  Z7~  fulfilment  University  shall  I further  Head o f my  The U n i v e r s i t y of British/Columbia, Vancouver 8 C a n a d a Date  the  this thesis  permission...  9 /  Library  I t i s understood  this thesis  w i t h o u t my  that  and  g r a n t e d by  representatives.  this thesis i n partial  advanced  Columbia, I agree  available  his  presenting  be  by publi-  allowed  ii  ABSTRACT The d i s t r i b u t i o n of Prosopium cylindraceum (Pallas) and Coregonus clupeaformis (MLtchill) i n Algonquin Park, Ontario, suggested that there may be some i n t e r a c t i o n between these species.  In large lakes where both  species are present the C_. clupeaformis population i s always dominant; i n small lakes only, one species i s present.  During the summer of 1963  ecological relationships between these species were studied.  the  Lakes Opeongo  and L a v i e i l l e each contained both species, while i n Lakes Redrock and Happy I s l e only P. cylindraceum was  present.  G i l l nets were set at frequent i n t e r v a l s , t o determine the depth range occupied by the two species and t o provide material f o r stomach analysis and age and growth data.  Temperature and dissolved oxygen l e v e l s were  recorded regularly using standard limnological techniques.  The depth range  occupied by both species was not strongly correlated with the thermal structure or oxygen l e v e l of the lake. P. cylindraceum i n sympatric situations i n v a r i a b l y occupied shallower depth range than d i d C. clupeaformis. was absent P. cylindraceum  a  Where the l a t t e r species  were frequently found i n a wide range of  depths. P. cylindraceum from Lake Opeongo fed h e a v i l y on l a r v a l i n s e c t s and to a lesser extent on bottom-dwelling Crustacea.  C_. clupeaformis from the  same lake fed mainly on bottom-dwelling Crustacea plus some insects and molluscs.  P. cylindraceum- i n Lakes Redrock and Happy I s l e fed almost  e n t i r e l y on plankton Crustacea.  Zooplankton was of importance as a primary  food source f o r w h i t e f i s h . Age and growth data have shown that there i s a d i r e c t correlation  iii  between the r e l a t i v e importance of plankton i n the d i e t and the rate of growth of the f i s h . . F i s h from Lakes Redrock and Happy I s l e had a much higher growth rate i n both length and weight than the two species i n Lake Opeongo.  In the l a t t e r lake C. ..clupeaformjs grew f a s t e r than P. c y l i n d -  raceum. Large lakes with adequate zooplankton production w i l l support both P. cylindraceum and C_. clupeaformis. but the better adaptation of C..clupeaformis t o plankton feeding may account f o r i t s greater success as indicated by i t s wide d i s t r i b u t i o n , large numbers, and high rate of growth.  viii  ACOOWLiiDGEMENTS I wish t o thank Mr. N.V. Ifertin, d i r e c t o r of the Harkness Memorial F i s h e r i e s Research Laboratory, Algonquin Park, Ontario, f o r h i s continuing guidance throughout a l l stages of t h i s study. Also Mr. K. Loftus, head of F i s h e r i e s Research Branch, Ontario Department of Lands and Forests, f o r providing a l l the necessary f a c i l i t i e s and equipment, without which the problem could not have been undertaken. I am indebted t o Dr. G.C. Lindsey, I n s t i t u t e o f F i s h e r i e s , University of B r i t i s h Columbia, who supervised the writing of the t h e s i s , and whose c r i t i c i s m s and advice have proven invaluable. I.E.  Dr. N.J;. Wilimovsky and Dr.  E f f o r d c r i t i c a l l y reviewed the manuscript and made many h e l p f u l  suggestions. The author wishes t o express h i s thanks t o the I n s t i t u t e of F i s h e r i e s , University of B r i t i s h Columbia, and The Fisheries Association of B r i t i s h Columbia f o r t h e i r f i n a n c i a l assistance.  iv  TABLE  OF CONTENTS Page  ABSTRACT  . i i  LIST  OF TABLES  LIST  OF FIGURES.  .  .y .vii  ACMOWLEDGEMENTS  viii  INTRODUCTION.  1  DISTRIBUTION.  3  LAKE  DESCRIPTIONS....  METHODS DEPTH FOOD  OF  OBTAINING  .9 FISH  ....i.l5 .17  DISTRIBUTION. HABITS,  ................ .17  Opeongo Lake Happy I s l e Lake and Redroek Lake. AGE  AND  GROWTH  Lengths-weight r e l a t i o n s h i p . Calculated growth..;....."." Growth i n Length Growth i n Weight.  SUMMARY  APPENDIX.  28 . .29 .3.0 .34 37 .40 44  DISCUSSION  LITERATURE  .27  ••••56 CITED...............................  .. .58 .62  V  LIST  OF  TABLES Page  I.  II.  III.  IV.  D i s t r i b u t i o n records of P. cylindraceum i n Ontario excluding Algonquin Park.  .7  D i s t r i b u t i o n of P. cylindraceum and C. clupeaformis i n Algonquin Park.  8  A l i s t of a l l food items found i n the stomachs analysed, along with a comment on t h e i r r e l a t i v e abundance. Equations f o r length-weight r e l a t i o n s h i p .  .22  ......30  V,  Length-weight Lake.  r e l a t i o n s h i p of P. cylindraceum from Redrock ........ . 3 1  VI.  Length-weight Lake.  r e l a t i o n s h i p o f P. cylindraceum from Happy I s l e 7 . . . . v . . . . . . . v........ 3 3  VII.  Length-weight Lake.  relationship of P. cylindraceum from Opeongo  V I I I . Length-weight  relationship of G. p.1np<aaf<yi»mi a f r o m Opwnnflft  Lake.  ..33  .7...................................34  IX.  Relation between standard length and magnified (x35) s c a l e diameter of P. cylindraceum from Redrock Lake.  35  X.  Relation between standard length and magnified ( s 3 5 ) scale diameter of P. cylindraceum from Happy I s l e Lake  .35  XI.  Relation between standard length and magnified ( x 3 5 ) scale diameter of P. cylindraceum from Opeongo Lake.  35  XII.  Relation between standard length and magnified ( x 3 5 ) scale diameter of C. clupeaf ormis from Opeongo Lake.  36  XIII. Equations f o r length-scale diameter r e l a t i o n s h i p XIV. Calculated standard length at the end of each year of l i f e of each age group of P. cylindraceum from Redrock Lake XV.  37  ....38  Calculated standard length at the end of each year of l i f e of each age group of P. cylindraceum from Happy I s l e Lake  38  XVI. Calculated standard length at the end of each year of l i f e of each age group of P. cylindraceum from Opeongo Lake.  39  XVII. Calculated standard length at the end of each year of l i f e of each age group of £. clupeaf ormis from Opeongo Lake.  39  vi Page XVIII. Summary of the calculated growth i n length of w h i t e f i s h from Lakes Redroek, Happy I s l e and Opeongo XIX. Summary of the calculated growth i n weight of whitefish from Lakes Redroek, Happy I s l e and Opeongo XX. XXI.  Levels of food consumption by the major fi3h species i n four Algonquin Park lakes. The food of P. cylindraceum and C. clupeaformis from three Ontario lakes.  42 .42 .51  ...62  vii  LIST  OF  FIGURES IMS.  1.  2.  Map of Ontario showing d i s t r i b u t i o n of Prosopium cylindraceum .. Map of Algonquin Park showing d i s t r i b u t i o n of Prosopium cylindraceum and Coregonus clupeaformis.  5 .. 6  3.  Contour map of Opeongo Lake, Ontario  4.  Contour map of Happy I s l e Lake, Ontario.  5.  Contour map of Redrock Lake, Ontario  6.  Contour map of L a v i e i l l e Lake, Ontario.  7.  Depth d i s t r i b u t i o n of Prosopium cylindraceum and Coregonus clupeaformis i n Opeongo Lake.  18  Depth d i s t r i b u t i o n of Prosopium cylindraceum i n Lakes Happy I s l e and Redrock.  19  Summary of the depth range occupied by sympatric p a i r s of whitefish.  20  8. 9.  10 .......11 13 .......14  10.  Bimonthly food index values f o r P. cylindraceum and C. clupeaformis i n Opeongo Lake. ...............................24  11.  Bimonthly food index values f o r P. cylindraceum i n Lakes Happy I s l e and Redrock.  25  12.  Summary of food index values.  26  13.  Length-weight r e l a t i o n s h i p of whitefish from Lakes Redrock, Happy I s l e and Opeongo, based on calculated Weights.  .32  Calculated growth i n length of whitefish from Lakes Redrock, Happy I s l e and Opeongo.  .41  Calculated growth i n weight o f whitefish from Lakes Redrock, Happy I s l e and Opeongo  .43  14. 15.  INTRODUCTION During the course of an aquatic faunal survey of Algonquin Park, Ontario, i t became apparent that the d i s t r i b u t i o n of the Coregonine  fishes  contained some unusual features. The lake whitefish, Coregonus clupeaformis ( M i t c h i l l ) i n t h i s area occurs i n almost a l l lakes that are s u f f i c i e n t l y deep to support a cold-water species. However the d i s t r i b u t i o n of the round whitefish Prosopium cylindraceum (Pallas) i s more r e s t r i c t e d and r e f l e c t s i t s rather sporadic North American d i s t r i b u t i o n on a smaller scale. An examination of the lakes i n which these species occur revealed the following: ( l ) that both species may occur separately i n r e l a t i v e l y small lakes (one-half square mile i n area) i n which the maximum depth does not exceed sixty f e e t ; (2) that where these species occur together the lakes are f o r the most part greater than f i v e square miles i n area and have a maximum depth of over one hundred feet.  I t was also observed i n the study  area that i n lakes where both species are present C. clupeaformis i s much more common than P. cylindraceum. Cooper and F u l l e r (1945) determined some of the aspects of the. ecology of the aboye species i n Moosehead Lake, Maine.  Studies on other sympatric  p a i r s of whitefish have been made by Godfrey (1955), Lindsey (1963), and Fenderson (1964).  S i m i l a r investigations by Svardson  (1953), Lindstrom  and Nilsson (1962) and Nilsson (1958) have been made on European species of whitefish. Due to the commercial importance of C. clupeaformis a large number of papers have been published on t h i s species, many of which deal with certain aspects of t h e i r ecology.  Hart (1931), Qadri (1961), Watson (1963) and  2  others have described the food h a b i t s , age and growth and other f a c t o r s . Kennedy (1943) examined the C. clupeaformis populations of Lake Opeongo, Algonquin Park, but r e s t r i c t e d h i s work primarily to morphology. Although P. cylindraceum i s widespread, i t i s only recently that much work has been done on t h i s species.  Other than Cooper and F u l l e r ' s  (1945) paper, only Kennedy (1949), Rawson (1951), B a i l e y (1963) and Mraz ( 1 9 6 4 ) have made d e t a i l e d studies on the round w h i t e f i s h . The l a t t e r  two  confined t h e i r work to Lakes Superior and Michigan r e s p e c t i v e l y . Papers by McKugh (1939, 1940), Northcote  (1957), S i g l e r (1951) and  others have dealt with the related form,.the.mountain whitefish, P. w i l l i a m s o n i . while Eschmeyer and B a i l e y (1955) have treated the pygmy whitefish, P. c o u l t e r ! . In view of the p e c u l i a r i t i e s i n the l o c a l d i s t r i b u t i o n of C. clupeaformis and P. cylindraceum. plus the f a c t that so l i t t l e was known about the food habits of P. cylindraceum. a study was begun to determine the ecological' r e l a t i o n s h i p e x i s t i n g between these f i s h e s .  The study  was  confined e s s e n t i a l l y t o four lakes, Opeongo, L a y i e i l l e , Happy I s l e and Redroek, a l l of which are located i n Algonquin Park.  In the f i r s t  two  lakes, Opeongo and L a v i e i l l e , C. clupeaformis and P. cylindraceum are both present, however i n Lakes Happy I s l e and Redroek P. cylindraceum i s the sole whitefish species. Other lakes were examined b r i e f l y during the summer months but the data presented here are based p r i m a r i l y on work completed on the above lakes. was  The information on depth d i s t r i b u t i o n , food habits and parasitism  obtained almost e n t i r e l y during the months of May t o September, 1963.  3  DISTRIBUTION C. clupeaformis i s broadly d i s t r i b u t e d over much of North America, frequently occurring i n such Large quantities as to make i t a commercially important species.  Smith (1957) has pointed out that the probable o r i g i n  of the Coregonus complex was i n north-central Europe and that C. clupeaformis i s merely the most easterly representative of t h i s group.  It i s  thought that the Coregonines were confined t o Northern Europe and Asia p r i o r t o crossing the Bering S t r a i t area i n the early Pleistocene. Although these f i s h are normally found only i n fresh waters t h e i r a b i l i t y to withstand high s a l i n i t i e s under certain conditions has been w e l l documented (Dymond 1933, Wynne-Edwards 1952, Walters 1955).  Periods of  g l a c i a l advances and r e t r e a t s with the associated p r o - g l a c i a l lakes undoubtably provided the means by which these f i s h moved i n an eastward d i r e c t i o n across North America  (Radfprth 1944).  The present range of t h i s species i s from the Yukon and northern B r i t i s h Columbia, across Canada t o Quebec, Labrador and New  Brunswick.  The southern l i m i t of t h e i r d i s t r i b u t i o n roughly p a r a l l e l s the Canadian United States border but also includes most of the states within the Great Lakes drainage system. Evidence suggests that the southern l i m i t of t h e i r d i s t r i b u t i o n has always been close t o that exhibited at present (Rostlund 1952),  For  although the waters of the upper M i s s i s s i p p i were probably cool enough to support t h i s species during the l a s t g l a c i a l advance i t i s assumed that other factors i n the environment must have proved unsuitable, f o r there i s no evidence t o suggest that whitefish ever occupied t h i s southern area. The northern l i m i t of t h e i r range i s poorly defined but extends close  4  to the edge of the Canadian Archipelago. The range of P. cylindraceum i n North America roughly p a r a l l e l s that of C. clupeaformis with the exception that the range does not extend further south than the Great Lakes.  The number of l o c a l i t i e s from which t h i s species  i s known i s f a r fewer than that of C. clupeaformis.  Only r a r e l y does t h i s  f i s h occur i n s u f f i c i e n t l y large numbers t o make i t of any commercial value. It appears to have o r i g i n a t e d i n the moutainous country of northwestern North America and. subsequently extended i t s range eastward across Canada and westward across A s i a and Europe (Smith 1957).  I t i s presumed that the  same means of dispersal was.utilized by Prosopium as by Coregonus. that of the p r o - g l a c i a l waterways. The d i s t r i b u t i o n of C. clupeaformis i s so wide i n Ontario that no attempt has been made t o indicate the innumerable inland lakes i n which i t occurs.  The d i s t r i b u t i o n of P. cylindraceum (Table I ) i s based mainly on  published reports and information obtained from d i s t r i c t o f f i c e s of the Ontario Department of Lands and Forests.  Although a l l known l o c a l i t i e s  i n which P. cylindraceum occurs are shown i n Figure 1., there i s no doubt that more w i l l be added at a l a t e r date as lake surveys are completed i n northern areas. Algonquin Park (Figure. 2.) i s s i t u a t e d on a height of land bounded by the Ottawa River, Georgian Bay, and Lake Ontario drainage systems. o g i c a l l y i t i s part of the Canadian S h i e l d .  Geol-  Extensive lake surveys of t h i s  area have been conducted by the s t a f f of the Fisheries Research Branch of the Ontario Department of Lands and Forests since 1948. For t h i s reason the knowledge of the d e t a i l e d d i s t r i b u t i o n q£ P. cylindraceum and C. clupeaformis i n Algonquin Park i s quite complete.  In the forty-one lakes i n which at  5  6  Figure 2.  Map of Algonquin Park showing d i s t r i b u t i o n of Prosopium cylindraceum and Coregonus clupeaformis.  7 TABLE I . Map Number  D i s t r i b u t i o n records of P. cylindraceum i n Ontario excluding Algonquin Park. Lake Name: (with location on lake f o r Great Lakes) SUPERIOR 'Apostle Island i s l e Royaie  Location:  Reference:  47°00'N, 90°30»W 48 00»N, 88 40'W  Bailey  44°00«N, 87°15'W  Mraz ( 1 9 6 4 )  4. 5.  HURON North Channel Dorcas Bay  46°00'N, 83°00'W 4 5 ^ 0 ' N , 81 40'W  D. Cucin (1)  6. •7.  ONTARIO Oakville Picton  43°25'N, 43°53'N,  Radforth ( 1 9 4 4 ) W.J. C h r i s t i e ( 2 )  1. 2.  3,  8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27.  MICHIGAN ; Sturgeon Bay Ship Canal  LIMERICK PAPINEAU Algonquin Park CLEAR LA CLOCHE MOCCASIN • "? RANGER TORRANCE • CLOVE' MEGISAN GORD : COMO DOG PUKASKWA HELEN POLLY NIPIGON ST. "JOSEPH WINISK BIG TROUT :  44°55'N, 45°20'N, .for l i s t 45°28«N, 46°0?!N, 46°45'N, 46°55'N, 47°I3»N, -47°15?N, 47°15'N, 47°19!N, 47°55>N, 48°25«N, 48°02 N, 49°05'N, 49 08'N, 50°00«N, 51°05'N, 52°55'N,. 53°45'N, ,  O  79°40'W 77°00'W  (1963)  77°38'W Tweed D.O. ii 77°50«W of l o c a l i t i e s see Table I I 78°55'W Parry Sound D.O. 82°04'W D. Cucin (1) 82°33'W Sault Ste. Marie D.O. 83°35'W '.. •. I I • . -•' " 83°31*W II ' 83 29'W tt 83°31*W 83°32«W 83°30!W Chapleau D.O. .84°15'?W K.H. Loftus ( 3 ) f ••• ti 85°50>W 88°15'W R. Ryder ( 3 ) 88°15'W II • S' 88°30*W Dymond ( 1 9 2 6 ) 90 40.'W R. Ryder (3) 87°20'W il ' - • 90°00»W 0  M  1  o  Ont. Dept. of Lands and Forests Research S t a t i o n s : (1) South BayMouth* Manitouiin Island. ( 2 ) Lake Ontario Research S t a t i o n , Picton, Ontario. (3) Southern Research S t a t i o n , Mapie, Ontario. D.0.=  D i s t r i c t O f f i c e , Ont. Dept. of Lands and F o r e s t s .  8 least one of these species i s known there are only seven l o c a l i t i e s i n which P. cylindraceum and C. clupeaformis occur sympatrically (Table I I ) .  TABLE ' " v  :  I I . D i s t r i b u t i o n of P. cylindraceum and C_. clupeaformis i n Algonquin Park. ' • "  Both species present: Map Number: 1. 2. 3* 4. 5. 6.  7.  Lake Name:  BLACK BEAR VICTORIA BOOTH OPEONGO BIG CROW LAVIEILLE CATFISH  Location: 45°38'N, 45°37'K, 4539'N, 45„42'N, 45°50;'N, •45 53,'N, 4 5 56»N,  78°44»W 78°02«W 78^12 «.W 7 8 . 2 2 «W 78„26»W 78 15>W 7 8 33'W  45 35'N, 45°35% 45_39'N, 45°41'N, 45~45'N, 45°46'N, 45146'N, 45°48'N, 45°46'N, 4 5 46'N,  78 28'W 78 26'W 78 06»W 78 00»W 78°30»W 78^08'W 78°28'W 78°12'W 78°32W 78 55'W  45 31«N, 4536 »N, 4537'N, 45°39'N, 45°36'N, 45^40 «N, 45°46»N, 45.47'N, 45°44% 45°46<N, 45°48'N, -45 49'N, 45°52>N,  78"41«W 78^44»W 78 42'W 78"38'W 78 23»W 78^08«W 78.24'W 78^08»W 78°40'W 7838'W 78 40'W 78°36»W 78 30'W  0  Drainage System:  OXTONGUE RIVER OPEONGO RIVER  •v '•  •  CROW RIVER II  0  PETAWAWA  RIVER  One species present: Prosopium cylindrac eum 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.  TWO RIVERS KEARNEY CROTCH ALSEVER HAPPY ISLE ANIMOOSH REDROCK DICKSON MERCHANT ROSEBARY  D  0  MADAWASKA  RIVER  II  OPEONGO II  RIVER  II  CROW  RIVER  II  n  PETAWAWA  RIVER  II  Coregonus clupeaformis 18. 19. 20. 21. 22. 23. 24. 25. 26. 27.  28. 29. 30.  SMOKE TEPEE LITTLE JOE BURNT: ISLAND SPROULE BRIDLE PROULX ALLURING WHITE BIG TROUT LONGER LA MUIR HOGAN  0  OXTONGUE  RIVER  II  Q  0  «'  OPEONGO RIVER, n  CROW  RIVER  •'.. n -  PETAWAWA RIVER .  it  n II  ti  9  Coregonus clupeaformis  31. 32.  33. 34. 35. 36. 37.  38. 39. 40.  continued:  GRAND ST. ANDREWS CEDAR LAURA WASKIGOMOG ERABLES MAPLE •• WILKES KIOSHKOKWI LAUDER  45  53'N, 77 50»W  PETAWAWA  ii ii it  45 50;«N, 77 41'W 46 01»N, 78 30»W 46 04*N, 78 36»W 45 57*B, 79 02«W 46 00'N, 78 48»W 46 0 1 % 78 49'W 46 00% 79 OO'W 46 05% 78 52'W 46 08% 78 50'W  LAKE  RIVER  AMABLE DU FOND RIVER II  II II  it II  DESCRIPTIONS  Opeongo Lake (Figure 3.) i s the largest lake i n Algonquin Park, with an area of 20.5  square miles.  The lake i s divided into three major basins,  the South, North and East Arms, the l a t t e r having an a d d i t i o n a l basin associated with i t .  These Arms are interconnected by a narrow channel and  shallow s i l l s (ten f e e t ) .  Despite the shallowness of the s i l l s there i s an  a c t i v e exchange of f i s h between the basins p a r t i c u l a r l y during the periods when the basins are isothermal, i n Spring and Autumn.  A l l parts of the lake  are c l a s s i f i e d as o l i g o t r o p h i c , although i n recent years some eutrophication of the South Arm has occurred.  The shoreline i s rocky and precipitous i n  most areas with the occasional sandy beach i n protected bays.  As Kennedy  (1943) has pointed out, v i r t u a l l y a l l lake bottom at depths greater than f i f t e e n feet i s covered by a soft black ooze consisting of a mixture of organic debris and soft clay.  Maximum depth i n t h i s lake i s one hundred  and s i x t y f e e t . Happy I s l e Lake (Figure 4.)  i s located one and a quarter miles due  west of the North Arm of Opeongo Lake.  The t o t a l area of the lake i s 2.3  square miles, with a maximum depth of 138 feet.  The shore of t h i s lake i s  11  Figure 4.  Contour map of Happy I s l e Lake, Ontario f e e t , dots indicate n e t t i n g s i t e s . )  (Contour i n t e r v a l 20  12  quite rocky with a few sand beaches.  The l i t t o r a l zone i s not extensive  since large boulders dominate the narrow shallow-water dead t r e e s l i n e the shore area.  zone.  In some areas  The bottom materials i n deeper water consist  of organic debris and clay. Redrock Lake (Figure 5 . ) i s situated about one mile north-west of the North Arm of Opeongo Lake and i s separated from i t by a height of land. Martin ( 1 9 5 2 ) described the lake as having a. t o t a l area of 1 . 1 a maximum depth of 7 0 feet and a mean depth of 2 9 f e e t . zone l i n e s the shore area of much of the lake.  square miles,  A broad  littoral  Beyond the l i t t o r a l zone  there i s a narrow area of rocky bottom which gives way t o a soft mud  bottom  i n depths greater than f i f t e e n to twenty f e e t . Lake L a v i e i l l e (Figure 6 . ) , located eight miles northeast of Opeongo Lake i s the t h i r d l a r g e s t lake i n Algonquin Park, with a t o t a l area of 9 . 3 square miles and a maximum depth of 165 f e e t .  Much of the shoreline  of t h i s lake i s rocky with sand beaches i n protected bays.  The  littoral  zone i s broad i n many areas but the rooted vegetation i s quite sparse. Like the above lakes, the bottom at depths ..greater than twenty feet c o n s i s t s of black mud with a high organic content. During the course of the study c e r t a i n physical features of the above four lakes were measured.  Thermister readings were taken at weekly i n t e r v a l s  i n Lake Opeongo, but were recorded l e s s frequently i n the three other lakes. By June 1 5 t h a well-developed thermocline had appeared at the 2 0 to 3 0 foot l e v e l i n each of the lakes.  The maximum surface temperature of 24°C  reached i n a l l of the four lakes during the period J u l y 1 s t  was  to 7 t h .  Temperatures i n the hypolimnion were consistently i n the 7 - 10°C range. The e f f e c t s of temperature are discussed more f u l l y under the topic of  Figure 5.  Contour map of Redroek Lake., Ontario. feet, dots indicate n e t t i n g s i t e s . )  (Contour i n t e r v a l 15  Figure 6.  Contour map of L a v i e i l l e Lake, Ontario, f e e t , dots indicate n e t t i n g s i t e s . )  (Contour i n t e r v a l 20  15  v e r t i c a l d i s t r i b u t i o n of w h i t e f i s h . Measurement of the l e v e l of dissolved oxygen i n the four lakes was found t o be close t o saturation at a l l depths during the summer months and so d i d not appear t o be a c o n t r o l l i n g f a c t o r i n f i s h d i s t r i b u t i o n .  "'1 Lakes Opeongo and Happy I s l e are situated at the head waters of the Madawaska River, while Lakes L a v i e i l l e and Redroek are i n the upper reaches of the Petawawa River.  Both the Madawaska and the Petawawa Rivers drain  into the Ottawa River. METHODS  OF  OBTAINING  FISH  During the summer of 1963, netting at about weekly i n t e r v a l s was conducted i n Opeongo Lake.  Nets were also set i n Lakes Happy I s l e and Red-  rock at about monthly i n t e r v a l s over the period May to September i n c l u s i v e . The netting i n L a v i e i l l e Lake was conducted at i r r e g u l a r i n t e r v a l s during the summer months of 1962 and 1963.  The purpose of the n e t t i n g was t o  determine the normal depth range occupied by the f i s h as w e l l as to c o l l e c t specimens f o r age and growth data and stomach analysis.  Standard sets of  g i l l nets were used at various sites i n the above lakes, a l l of which were placed at r i g h t angles to the shoreline and over a variety of gradients. A standard set consisted of four hundred and f i f t y feet of net, t h i s being comprised of three, one hundred and f i f t y feet by s i x feet lengths of two inches and two and a half inches, stretched mesh, braided nylon nets.  A  single two and a h a l f inch monofilament net, f i f t y feet i n length and twentyf i v e feet i n depth was also used.  Previous work on g i l l net s e l e c t i v i t y i n  t h i s area had indicated that the greatest numbers of whitefish, as well as representatives of a l l size ranges were taken by the two inch and two and a  16  half inch mesh nets.  The inshore end of the net was held i n place by t y i n g  a twenty foot length of quarter inch rope from the f l o a t - l i n e to some object on shore.  Each gang of nets was anchored at the offshore end.  edge of the net rested on the bottom throughout i t s length.  The lower  Since the  two  species of whitefish had been shown e a r l i e r to be c l o s e l y associated with the bottom, no offshore diagonal or f l o a t i n g sets were used.  Some experiment-  a l use of a v e r t i c a l set i n f i f t y and one hundred f e e t of water proved quite unsuccessful. net, was  In t h i s case a s i x foot wide, two and a h a l f inch mesh nylon  suspended v e r t i c a l l y from the surface by two  styrene f l o a t s and  weighted at the bottom by a s i x foot length of galvanized pipe which also served to keep the net spread uniformly.  The only f i s h taken with t h i s net  were a few Leucichthys a r t e d i . In order to determine the depth at which any p a r t i c u l a r f i s h was soundings were taken along the length of the net s i t e .  As the net was  (from the inshore end) the number of f i s h per f l o a t i n t e r v a l f i v e f e e t ) was recorded.  caught, lifted  (approximately  In t h i s way the d i s t r i b u t i o n of the f i s h over the  entire length of the net could be determined.  These data were l a t e r p l o t t e d  on a s c a l e drawing of the net showing i t s p o s i t i o n r e l a t i v e to the bottom profile.  From t h i s p l o t the number of f i s h per f l o a t i n t e r v a l could be  converted d i r e c t l y i n t o the number per f i v e foot depth i n t e r v a l , and so give t h e i r d i s t r i b u t i o n i n respect to the bottom contours.  A l l of the net settings  were overnight sets, with an average duration of t h i r t e e n to fourteen hours.  17  DEPTH  DISTRIBUTION  By using a mesh s i z e known to take the largest numbers as well as the greatest size range of whitefish i t was possible to determine with reasonable accuracy the depth d i s t r i b u t i o n of both P. cylindraceum and C. clupeaformis. The method by which the depth of capture was determined has been outlined above.  I t has been assumed that the s u s c e p t i b i l i t y t o the nets was the same  at a l l depths and that the r e l a t i v e number i n a given depth zone i s i n d i c a t i v e Of the abundance of the f i s h at that l e v e l .  The bimonthly averages of d i s t -  r i b u t i o n f o r Opeongo Lake are based on several nettings and have been plotted along with the temperatures at various depths (Figure 7.). A noticeable feature of the depth d i s t r i b u t i o n i s the uniformity throughout the summer months.  I t i s not u n t i l the surface temperatures  approach 21°C that the zone of maximum abundance i s s h i f t e d downward from the 1 0 - 2 0 foot zone t o the 2 0 - 3 0 foot zone.  In the present study there  appears t o be no c o r r e l a t i o n between the observed depth of the f i s h and any p a r t i c u l a r isotherm. Similar r e s u l t s were observed i n Lakes Happy I s l e and Redroek f o r P. cylindraceum (Figure 8.). Depth d i s t r i b u t i o n data from other studies have been summarized (Figure 9.).  FOOD  HABITS  In order t o obtain information on the food habits of the whitefishes being studied, an average of twenty stomachs per species was preserved from each catch f o r l a t e r analysis.  The number of stomachs examined was as  18  Figure 7 .  Depth d i s t r i b u t i o n of Prosopium cylindraceum and Coregonus clupeaformis i n Opeongo Lake.  Aid-eu ssjprT. ur tuneaeopurxAo mnraTSsojjf j o uoxq.nqfjq.sTp uqctaQDEPTH  8.  c* . Q  IN  FEET  *  •  O  IU  .  O  Q  >  Oiu-M>  co O  »g  eanSfj  20  7  o  20  40  Q_  80  Q  100  120  I40 — 1  Figure 9 .  Summary of the depth range occupied by sympatric p a i r s of whitefish. ( 1 ^ Opeongo Lakej 2 — L a v i e l l e Lake; 3 Moosehead Lake, Cooper and F u l l e r , 1 9 4 5 J 4 = Okanagan Lake, McHugh, 1 9 3 9 ; 5 = Babine Lake, Godfrey, 1 9 5 5 ; 6 = Tacheeda Lake, McCart, 1963; 7 =• Cluculz Lake, McCart, 1 9 6 3 . )  0*  clupeaformis  P. cylindraceum  P. •wi.n.iamaoni  P. c o u l t e r i  21  follows; C. clupeaformis  Opeongo Lake  280  P. cylindraceum  Opeongo Lake  160  "  Happy I s l e Lake  120  "  Redroek Lake  80  The stomachs were removed by severing the oesophagus and the posterior section of the p y l o r i c sphincter. The open ends of the oesophagus and pylorus were e f f e c t i v e l y closed by a brass safety-pin which a l s o held an i n d i v i d u a l label.  The stomachs were then preserved i n 755^ a l c o h o l .  This manner of  preservation completely retarded any further digestion of the stomach contents. Subsequently the contents of each of the stomachs was i d e n t i f i e d and  counted.  A v i s u a l estimate of percentage of t o t a l volume was made f o r each type of food organism present.  The t o t a l volume of food material i n the stomach  was then measured by displacement i n alcohol.  Any non-edible m a t e r i a l such  as sand, pebbles, caddis-cases or hemlock needles, etc., that were found i n the stomachs were excluded from the volumetric a n a l y s i s .  Actual counts were  made on a l l organisms with the exception of some Cladocerans.  Where large  numbers of Cladocera were present, the volume displacement of a subsample (100 Cladocera) was determined and then compared with the t o t a l volume displacement of a l l Cladocera i n the stomach.  In t h i s way the approximate  number of Cladocera consumed could be calculated.  Table I I I outlines the  organisms that were present as food i n the 640 stomachs that were analysed. In most papers dealing with food studies on various species of f i s h , the measure of importance of a p a r t i c u l a r food organism may be given as the percentage volume, including or excluding the empty stomachs i n the sample,  22  TABLE I I I .  A l i s t of a l l food items found i n the stomachs analysed, along with a comment on t h e i r r e l a t i v e abundance ( C » common, F few, R ~ rare, A - a b s e n t ) . m  CRUSTACEA Cladocera Sida c r y s t a l l i n a Ophryoxus g r a c i l i s Eurycercus lamellatus Latona s e t i f e r a Daphnia so. Acantholeberis c u r v i r o s t r i s Bosmina sp.' Holopedium gibberum Leptodora k i n d t i i Polyphemus pedicuius  Coregonus  Prosopium  C c c c F R R R R R  C C C A C A A A A R  Amphipoda H y a l e l l a azteca  R  R  Copepoda Cyclops sp.  c  A  INSECTA c Ephemeroptera (nymphs) Odonata A Gomphidae Hemiptera Corixidae ( i n s t a r s ) F Neuroptera S i a l i d a e (nymphs) F Trichoptera (larvae) c Molannidae ' • c . Leptoceridae • c Phryganeidae R Coleoptera .Hymenoptera Formicidae (adults) Diptera Chironomidae (larvae and pupae) c Ceratopogonidae (larvae & pupae) R C u l i c i d a e (larvae and pupae; c Chaoborus sp. '  MQLLUSCA Amnicola limosa Valvata sincera Planorbula sp. Physa sp.  R  c F R A  C F A •  F '•. -  .  C • v  C '••'.:c '•' '• V"' R "'. '  A  C R  C A A R  23  MOLLUSCA continued: Heli8oma sp. Pisidium sp.  A c  R C  OSTRACODA  C  A  WATER  MITES  c  c  FISH Perca flavescens  R  R  or the percentage frequency of occurrence. However, as Godfrey ( 1 9 5 5 ) and others have pointed out neither of these values taken alone Is an adequate measure of the food intake, f o r example, " i f a single or few f i s h have ingested a large volume of some food organism, or when a l l or many f i s h have each consumed very small amounts of some organism" then either of the above values would be misleading.  One way of overcoming t h i s d i f f i c u l t y i s t o plot  graphically the percentage volume against percentage frequency as Korthcote ( 1 9 5 4 ) did i n h i s work on s c u l p i n s .  In t h i s way the importance of a food  organism may be determined by comparing the r e l a t i v e areas of the graphs. Godfrey ( 1 9 5 5 ) i n an e f f o r t t o minimize t h i s d i f f i c u l t y u t i l i z e d , a "consumption index" derived from the square root of the product of the number of f i s h i n the sample that consumed a s p e c i f i c organism times the average volume of that organism i n a l l stomachs.  The present author has used a  similar method i n deriving "food index" values ( F I ) . These values are found by taking the square root of the product of percent volume times percent frequency (Table XII) which has the advantage over the above method i n that I t r e s t r i c t s the range of values to between zero and 1 0 0 .  Thus the magnitude  of the value indicates the "rank" or r e l a t i v e importance of a food organism. Figures 1 0 . , 1 1 . ,  and 1 2 . , are a summary of the food index values f o r the  four populations studied.  Figure 10.  Bimonthly food index values f o r P. cylindraceum and C. clupeaformis i n Opeongo Lake.  25  R CYLINDRACEUM so  HAPPY ISLE LAKE  J  A AUG 16 31  l_-J P CYLINDRACEUM  REDROCK LAKE  2 o  Figure 11.  Bimonthly food index values f o r P. cylindraceum i n Lakes Happy I s l e and Redrock. „  26  Figure 12„  Summary of food index values. (Average bimonthly F.I. value of food items grouped by type; Misc. = miscellaneous, includes water mites, ostracods and f i s h . )  27  Opeongo Lake: In Lake Opeongo, both P. cylindraceum and C. clupeaformis are e s s e n t i a l l y bottom feeders, consuming bottom-dwelling crustaceans as well as insect larvae and molluscs (Figure 10}.  This pattern of feeding appears to be quite f i x e d  during the summer months.  In P. cylindraceum the emphasis i s decidedly upon  insect larvae.  In the l a t t e r part of May,  c a d d i s - f l y larvae are the most  important food organism with dragonfly naiads being somewhat l e s s so.  As the  summer progresses caddis-fly larvae become l e s s important and the emphasis i s shifted towards chironomid larvae and pupae, and t o a lesser extent the mayfly nymphs (mostly Hexagenia).  Only during June and J u l y are the bottom-  dwelling plankters consumed i n any quantity and even then t h e i r r e l a t i v e importance does not exceed that of the insect l a r v a e . As f a r as molluscs and other food items are concerned t h e i r importance t o i n d i v i d u a l f i s h may  be  s i g n i f i c a n t but t o the population as a whole, represent a rather minor element of the d i e t . The food habits of C. clupeaformis are however i n sharp contrast to those of the P. cylindraceum population.  Purely s u p e r f i c i a l examination of  the,stomach contents would indicate a marked s i m i l a r i t y between these species but as i n so many other food studies the detailed analysis reveals s i g n i f i cant differences.  During the l a t t e r part of May l a r v a l insects form a major  part of the d i e t of both C. clupeaformis and P. cylindraceum but there i s a d i s t i n c t difference.  The lake w h i t e f i s h feed almost e n t i r e l y on mayfly  nymphs, while the emphasis i n the round whitefish i s divided between caddisf l y larvae and dragonfly naiads. !  Beginning i n June and throughout the summer months, bottom-dwelling  Crustacea and other organisms such as ostracods and water mites make up a  28  major portion of the diet of the lake whitefish only.  In both species i t i s  i n t e r e s t i n g t o note the almost complete absence of any mid-water plankters i n the stomachs of these f i s h .  The reason f o r t h i s , i t i s believed, i s the  presence i n Lake Opeongo of the c i s c o , Leucicthys a r t e d i . (Clemens and Bigelow 1922,  A number of papers  Langford 1938b) have w e l l documented the plankton  feeding habit of t h i s species.  I t would seem then that the mid-water plankton  feeding niche i s being occupied by t h i s species.  Happy I s l e Lake-and Redroek Lake: In these lakes P. cylindraceum i s the only w h i t e f i s h species  present.  Stomach analysis of f i s h taken from these lakes during the summer months revealed a s i t u a t i o n quite d i f f e r e n t from that of Lake Opeongo.  As shown i n  Figure 11. the major element i n the d i e t of the round whitefish i s Daphnia longispina .  Although these f i s h do feed on insect larvae as w e l l , t h i s food  material i s of much l e s s importance compared to i t s r o l e i n the d i e t of round w h i t e f i s h i n Lake Opeongo. , The question then arises as t o whether the observed difference i s due to a lack of bottom fauna i n Lakes Happy I s l e and Redroek. Martin 1952)  stated that the bottom fauna of Redroek Lake was the r i c h e s t of  any lake studied by him i n Algonquin Park. 63.5  M i l l e r (1937$ i n :  Wood (1953) published a value of  i n d i v i d u a l organisms per square foot of bottom area f o r Redroek Lake.  S i m i l a r work by Webb (pers. com.)  gives values of 38 and 43 i n d i v i d u a l  organisms per square foot f o r Lakes Happy I s l e and Opeongo r e s p e c t i v e l y . Since the r e l a t i v e abundance of the bottom fauna i n Lake Opeongo i s i n t e r mediate between the values for Lakes Happy I s l e and Redroek, i t must be concluded that the plankton-feeding  habit of the P. cylindraceum populations  29  of the l a t t e r two lakes i s related t o some factor other than the a v a i l a b i l i t y of the bottom fauna as food.  AGE  AND GROWTH  F i s h collected by methods outlined above were measured i n the f i e l d tcu the nearest millimetre of standard length, t h i s measurement being defined by Hubbs and Lagler (1958) as the distance from the t i p of the snout to the posterior end of the v e r t e b r a l column. Fresh weights were determined by a spring balance t o the nearest 0.1 pound. The sex and state of maturity of the gonads were determined by gross examination;  Any f i s h captured that was judged t o be ready to spawn during  the f a l l of the same year was considered mature. Scales were removed from the l e f t side of the f i s h midway between the mid-dorsal l i n e and the l a t e r a l l i n e at a point below the o r i g i n of the d o r s a l f i n . by p l a c i n g them i n small envelopes.  The scales were preserved dry  P r i o r t o reading the scales, a few were  taken from the envelope, cleaned and dry mounted between glass s l i d e s . The s l i d e s were then placed on the stage of a Bausch and Lomb Microprojector, and the images of the scales (magnified x35) projected o n g r i d .  By p o s i t i o n i n g  the focus of the scale on the centre of the grid i t was possible t o accurately measure i n millimetres the annuli diameters along the dorso-ventral a x i s of the scale as suggested by Smith (1955).  The v a l i d i t y of age determination  from scales of Coregonines has been amply demonstrated i n numerous papers: Van Oosten (1923), Van Oosten and H i l e (1949), Eschmeyer and Bailey (1955), Bailey (1963), Mraz (1964) and others.  30  Length-weight r e l a t i o n s h i p ; In order t o express the length-weight r e l a t i o n s h i p of the whitefish b studied the general equation of a parabola, W » aL  was used, where W«=-  weight, L «= length, and a and b are empirically determined  constants.  The  values of a and b were derived from data c o l l e c t e d during the period May t o September, 1963.  Empirical weights and scale diameters are averages f o r 1 cm.  i n t e r v a l s of length.  As the differences i n weight between a male and a female  of a given length were small, the" data were combined without regard to sex or state of maturity. TABLE  IV.  Equations f o r length-weight r e l a t i o n s h i p . ¥ «• weight i n poundsj L * standard length i n cm. j t s = standard error of slope b at 95% confidence l i m i t s . o o S  b  P. cylindraceum Redroek Lake  l o g W=  -4.93656-H 3.3179 l o g L b + 0.3215  WHappy I s l e Lake  L *  5  3  3 1 7 9  l o g W = - 4 . I 6 9 6 O +- 2.7665 l o g L W~  Opeongo Lake  1.157 x 10~  6.767  xlO^L 2  7  6  6  b  0.3984  bt  0.1524  h±  0.1083  5  l o g W = -4.67478 +• 3.1122 l o g L W = 2.1146 x 10"  5  L ' 3  1  1  2  2  C. clupeaformis Opeongo Lake  l o g W a, -4.82693 +- 3 . 2 5 3 6 l o g L V ~ 1.4896 x 10~  5  L * 3  2 5 3 6  Using a standard l i n e a r regression a n a l y s i s , with length and weight data transformed t o logarithms, the equations representing each of the four  31  populations of whitefish were determined (Table I V ) . From the above equations the t h e o r e t i c a l weights f o r each u n i t of standard length were determined (Tables V - V I I I ) . are the basis f o r the curves shown i n Figure 1 3 . .  The calculated weights In the normal size range  of whitefish observed i n the three lakes studied, the length-weight  relation-  ship i s quite s i m i l a r , however i f the curves f o r the three populations of Prosopium are extrapolated t o a value equal t o the maximum s i z e of Coregonus observed i n Lake Opeongo, the differences become apparent.  In the larger  sizes a £ . clupeaformis of a given standard length from Lake Opeongo, w i l l be heavier than a f i s h of s i m i l a r length from any of the three populations of P. cylindraceum.  I t may also be seen that within the three populations of  Prosopium there i s a d i s t i n c t order.  The round whitefish from Opeongo Lake  are intermediate t o those from Happy I s l e Lake and Redrock Lake.  TABLE  V.  Length-weight r e l a t i o n s h i p of P. cylindraceum from Redrock Lake. STANDARD LENGTH (cm.) 26  2? 28 29  30 31 32 33 34 35  WEIGHT ( l b s . ) -  EMPIRICAL 0.56 0.61 0.78 0.83 0.94 1.09 1.13 1.25 1.34 1.53  CALCULATED 0.57 0.65 0.73 0,82 0.92 1.03  1.14 1.26 1.40 1.49  NUMBER of FISH 1 8 6 9 10 9 6 3 6 5  32  10 .  Figure 1 3 .  . • .  •  •  2.0  LENGTH \  30 ••'  IN C M .  40  50 .  .  ••  Length-weight r e l a t i o n s h i p of whitefish from Lakes Redroek, Happy I s l e and Opeongo, based on calculated weights. (Dotted sections represent extrapolations? 1 •= C. clupeaformis from Opeongo Lake j 2 = P. cylindraceum from Redroek Lake; 3 P• cylindraceum from Opeongo Lake; 4 = P. cylindraceum from Happy I s l e Lake.) =  33  TABLE VI.  Length-weight r e l a t i o n s h i p of P. cylindraceum from Happy Isle Lake. STANDARD LENGTH (cm.) 21 23 24 25 26  27 28 29 30 31 32 33 34  35 36 37  TABLE  WEIGHT (lbs.) EMPIRICAL  CALCULATED  NUMBER of FISH  0.29 0.39 0.44 0.49 0.59 0.62 0.68 0.83  0.31 0.40  1 1  0.45 0.50 0.56  5 5 1  0.62  2  0.68 0.75  8  0.85  0.82  0.92 1.03 1.05 1.16 1.19 1.30 1.47  0.91 0.99  1.08 1.17 1.27 1.37 1.48  5 11 10 10 11 11 16 10  2  V I I , Length-weight r e l a t i o n s h i p of P. cylindraceum i n Opeongo Lake. STANDARD LENGTH (cm.) 24 25 26 27  28 29 30 31 32 33 34 35 36 37 38 39  WEIGHT (lbs.) EMPIRICAL  CALCULATED  0.46 0.44 0.55 0.60 0.67 0.72  0.42 0.47 0,54 0.66 0.67 0.75  0.82 0.91 1.00 1.13 1.23 1.37 1.56 1.63 1.67 1.94  0.84 0.93 1.02 1.12 1.23 1.35  1.48 1.61 1.75 1.89  , NUMBER of FISH 3 3 6 17 13 13 11 21 19 17 11 8  4 4 1  i  34  TABLE  VIII.  Length-weight r e l a t i o n s h i p of C. clupeaformis from Opeongo Lake. STANDARD LENGTH (cm.) 16 17  18 19  20 21 22 23  24 25  26 27  28 29 30  31 32  33 34 35 36  37 38 39 43  44 45  WEIGHT ( l b s . ) EMPIRICAL  CALCULATED 0.12 0.15 0.18 0.22 0.25  0.13 0.14 0.16 0.22 0.28 0.31 0.37 0.41 0.47 0.53 0.61 0.64 0.77 0.79  0.30  0.35  0.40  0.46 0.53 0.60 0.68 0.76  0.85 0.95  0.90 1.07  23 8 7 2  1.30 1.43 1.57 1.73 1.89  3  3.08 3.31 3.57  4  2.66 2.23  3.17 3.69  33  4  1.26  3.32  2  10 7 4 10 34 38 37 42 28  1.06 1.17  1.24  "1.37 1.36 1.71 1.96 2.15 2.36  NUMBER of FISH  2  i  I  2 3 2 2 1 1  Calculated Growth; Preparatory t o making back calculations f o r the s i z e of f i s h at various ages i t was f i r s t necessary t o e s t a b l i s h the r e l a t i o n s h i p between body length and scale diameter.  The maximum scale diameter as well as the diameter of  each annulus was measured as outlined above. from scales used i n age determination.  Scale diameters were taken only  The mean scale diameter (magnified)  f o r each cm. of standard length was computed (Tables IX - X I I ) . were then p l o t t e d on a logarithmic  These values  scale and the l i n e of best f i t determined  35  TABLE  IX. R e l a t i o n between standard length and magnified ( x 3 5 ) scale diameter of P. cylindraceum from Redroek Lake. STANDARD LENGTH (cm.) 26  18.8  1  20.2 21.4  8 7 13 11  -22.8 22.7 24.3 25.3 25.5  .  27.8 27.9  13 11 6  7 7  X. Relation between standard length and magnified ( x 3 5 ) scale diameter of P. cylindraceum from Happy I s l e Lake. STANDARD LENGTH (cm.)  AVERAGE SCALE • DIAMETER (cm.)  21  15.2 17.3 17.6 17.6 20.4 18.6 21.3 21.4 21.9 22.3 21.8 22.7 23.3 25.3 26.9 28.8  23  24 25 26  27 28 29  30  31 32  33 34 35 36 37 TABLE  NUMBER of FISH  27 28 .2.9 30 31 , 32 33 34 35  TABLE  AVERAGE SCALE DIAMETER (cm.)  NUMBER of FISH 1 1 5  6 1 2 7  8 13 10 7 9 9 19 11 2  X I . Relation between standard length and magnified ,(x35) scale diameter of P. cylindraceum from Opeongo Lake. STANDARD LENGTH (cm.) 24 25 26  27  AVERAGE SCALE DIAMETER (cm.) :  15.4 16.1 19.2 18.7  NUMBER of FISH 3 3 6  17  36  TABLE  XI.  continued: 28 29 30 31 32 33 34 35 36 37 38 39  TABLE  20.0 20.0 20.9 21.1 21.6 23.0 24.2 24.5 24.1  14 13 12 21 19 17 11 8 4 4 1 1  27.0 25.4 29.5  XII. R e l a t i o n between standard length and magnified ( x 3 5 ) scale diameter of C. clupeaformis from Opeongo Lake, y STANDARD LENGTH (cm.) 16 17 18 19 20 21  22 23  24 25 26  27 28 29 30 31 32 33  34 35  36  37 38 39 43 44 45  AVERAGE SCALE DIAMETER (cm.) 10.7 11.7 12.5 14.7 14.2 14.5 15.4 15.2 16.9 17.0 19.6 20.0 21.4 22.2 21.8 23.4 24.9 24.4 25.4 22.9 27.7 26.2 28.5 29.5 31.7 34.1 30.0  .  NUMBER of FISH • 2 10 7 4 10 34 38 37 42 28 33 23 8 7 2 4 2 3 1 1 2 3 2 2 4 1  1  37  by regression a n a l y s i s .  The equations expressing the body length t o scale  diameter r e l a t i o n s h i p (Table XIII) are of the form, magnified (x35)  dorso-ventral scale diameters,  f i s h , and a and b are empirically determined  TABLE  XIII.  S *=• a L , where S = b  L = standard length of the  constants.  Equations f o r length-scale diameter r e l a t i o n s h i p . S = scale diameter (x35) i n cm. ; L = standard length i n cm. ; t s standard error of slope b at 955^ confidence l i m i t s . o  P.  cylindraceum REDROCK HAPPY  S = 0.2800 L  LAKE  ISLE  OPEONGO C.  fe  LAKE  1 , 2 9 7 7  S =0.7935 L ° *  9 7 3 9  b i 0.1951  1 1 6 9  b ± 0.1562  LAKE  S = 0.4638 L '  LAKE  1.0856 S = 0.5434 L  1  b t 0.1567  cluDeaformis OPEONGO  bt  0.1026  Growth i n Length; From the above equations the previous growth h i s t o r i e s were calculated (Tables XI? - XVII).  Examination of these values i n d i c a t e s some small  discrepancies, both random and systematic.  For instance, the random discrep-  ancies observed i n the back calculations of growth i n f i s h from Lakes Redroek and Happy I s l e are probably due t o the r e l a t i v e l y small sample s i z e .  However  i t appears that the discrepancies observed i n the growth h i s t o r y o f the two species of f i s h from Lake Opeongo are systematic i n o r i g i n . The  P. cylindraceum population of Lake Opeongo exhibit Lee's phenomenon  t o a marked degree.  This phenomenon was described by Lee (1912) as the  "apparent change i n growth rate from the calculated values of lengths of f i s h of d i f f e r e n t age a t corresponding years of t h e i r existence, by which i t appears  38  TABLE  XIV. Calculated standard length at end of each year of l i f e o f each age group of P. cylindraceum from Redrock Lake. AGE  GROUP  II III IV V VI VII AVERAGE CALCULATED LENGTH INCREMENT OF AVERAGE  TABLE  I  II  III  12.4 17.2 12.8 1 9 . 0 1 2 . 3 18.5 1 2 . 3 18.9 1 2 . 4 18.8 1 3 . 1 18.9  IV  V  VI  VII  NUMBER of  . 36.4"  FTSH 2 4 9 55 19 2  d  22.3* 2 3 . 4 26.8' 23.7 27.6 30.3 23.8 28.3 3 1 . 4 3 3 . 5 2 4 . 5 28.5 3 1 . 3 3 4 . 0  1 2 . 6 18.8 2 3 . 9 2 8 . 1 3 1 . 4 34.Q 3 6 . 4 -  12.6  6.2  5.1  4.2  3.3  2.6  -  XV. Calculated standard length at end of each year of l i f e o f each age group of P. cylindraceum from Happy I s l e Lake. AGE  GROUP  III IV V VI vii AVERAGE CALCULATED LENGTH INCREMENT OF AVERAGE  I 9.2 9.3 9.3 8.8 9.2  II  I I I IV  V  VI  VII  17.8 23.5* • 1 8 . 0 2 5 . 2 28.2 1 7 . 9 25.2 2 9 . 5 3 1 . 7 * 1 6 . 7 24.2 2 9 . 9 3 3 . 6 3 5 . 7 * 16.7 2 3 . 62 9 . 63 4 . 1 3 8 . 0 40.9*  9.2 17.4 2 4 . 6 2 9 . 7 3 3 . 9 3 8 . 0 4 0 . 9  9.2  8.2  7.2  5.1  4.2  4.1  -  size a t capture not included i n c a l c u l a t i o n of mean.  NUMBER of 11 24 54 20 3  39  TABLE  XVI. Calculated standard length a t end of each year of l i f e of each age group of P. cylindraceum from Opeongo Lake.  AGE GROUP  I  TV V VI VII VIII IX X XII  II  I I I IV  V  VI  VII VIII  IX  X  XI  XII NUMBER of  9.0 16.2 19.1 24.1* 5 8.7 15.5 20.3 24.1 26.5* 12 9.3 15.7 20.3 24.0 26.7 28.4* 30 9.2 15.4 19.8 23.3 26.1 28.2 29.3* 40 8.9 14.8 19.2 22.6 25.7 28.3 30.5 32.3* 40 17 8.9 14.7 19.2 22.4 25.7 28.3 30.5 32.4 33.7* 9 9.1 15.2 19.5 23.3 26.5 29.0 31.4 33.5 34.9 36.3* * 8.9 15.1 19.1 22.7 25.8 28.8 30.9 32.8 34.7 36.3 38.3 39.8* 2  A.C.L.  9.0 15.3 19.6 23.2 26.1 28.5 30.8 32.9 34.8 3 6 . 3 38.3 39.8  I.O.A.  9.0  TABLE  AGE  XVII.  GROUP  6.3  4.3  3.6 2.9 2.4  2.3 2.1 1.9  1.5 -  Calculated standard length at end of each year of l i f e o f each age group o f C. clupeaformis from Opeongo Lake.  I  II  I I I IV  V  VI  VII VIII  IX  X  XI  II III IV V VI VII VIII ix X XI  11.4 10.3 9.6 10.1 11.0 11.1 10.9 11.1 9.3 10.2  15.6"  A..C.L.  10.5  15.3 1 9 . 3 2 2 . 8 2 6 . 4 3 0 . 0 3 3 . 2 3 6 . 0 3 8 . 6 4 2 . 1 4 3 . 7  I.O.A.  10.5  NUMBER of FTftH  15.017.9 1 4 . 6 18.1 2 0 . 4 * 1 5 . 1 18.6 2 1 . 4 2 3 . 0 1 5 . 8 19.5 2 2 . 8 2 5 . 6 2 7 . 4 15.6 19.4 2 3 . 0 26.3 2 9 . 1 3 1 . 0 1 5 . 7 1 9 . 7 2 3 . 4 2 7 . 0 30.6 3 3 . 7 3 5 . 7 * 16.4 20.6 23.7 27.2 30.7 33.9 37.1 39.0*" 1 3 . 1 1 7 . 9 2 1 . 2 2 4 . 5 28.8 3 1 . 3 3 4 . 2 3 7 . 7 4 0 . 5 „. 16.6 2 0 . 4 2 4 . 4 2 7 . 5 3 0 . 7 3 3 . 7 3 6 . 6 3 9 . 4 4 2 . 1 4 3 . 7 #  4.8  4.0 3.5  3.6  3.6  3.2  2.8  2.6 3 . 5  -  A.C.L.™ Average Calculated Length; I.O.A. Increment of Average: * s i z e a t capture not included i n calculation of mean. m  4 14 26  28 35 16 9 3 2 3  40  that i n older and older f i s h less growth i s attained i n each year of t h e i r existence".  Although t h i s decrease i n calculated lengths i s not apparent i n  the age group I, or i n the oldest age groups, i t i s however quite obvious f o r f i s h i n the I I - V age groups. Examination of the calculated values f o r C. clupeaformis from Lake Opeongo indicates that they do not exhibit Lee's phenomenon but show what appears t o be a r e v e r s a l of t h i s tendency, that i s the lengths calculated from older f i s h seem t o increase i n s i z e as compared with lengths calculated from younger f i s h . The rate of increase i n length (Figure 14, Table XVIII) among the four populations studied i s quite d i s t i n c t .  The maximum s i z e reached by round  whitefish from either Redrock Lake or Happy I s l e Lake i s not as great as that i n either of the two species from Lake Opeongo, but i t i s achieved i n l i t t l e more than half the time. For example the largest f i s h collected i n Redrock Lake had completed i t s sixth annulus and had a calculated length of 34*0 cm.. A f i s h of similar s i z e from annulus.  Lake Opeongo would be just completing i t s ninth  The difference between the growth rate i n Happy I s l e Lake and  Opeongo Lake i s even more s i g n i f i c a n t .  A 38.0 cm. f i s h from Happy I s l e Lake  would have completed i t s sixth annulus but i n Lake Opeongo would have reached t h i s s i z e only a f t e r completion of the eleventh annulus.  Growth i n Weight; Calculated values f o r increase i n weight, derived from length-weight equations show p r e c i s e l y the same sort of pattern as demonstrated i n the length data (Figure 15, Table XIX).  The r a t e of growth i n terms of weight i s  much greater f o r f i s h from Redrock Lake and Happy I s l e Lake as compared with  41  AGE Figure 14.  Calculated growth i n length of whitefish from Lakes Redroek, Happy I s l e and Opeongo. (1 =- C. clupeaformis from Opeongo Lakej 2— P. cylindraceum from Redroek Lake; 3 *=* P. cylindraceum from Opeongo Lakej 4 =• P. cylindraceum from Happy I s l e Lake.)  42  TABLE  XVIII.  AGE GROUP  REDROCK LAKE P. cylindraceum  HAPPY ISLE L A P P. cylindraceum  OPEONGO LAKE P. cylindraceum C. clupeaformis  Average Increlength" ment (cm.)  Average length (cm.)  Average length (cm.)  12.6 18.8 23.9 28.1 31.4 34.0  I II 111 IV V VI VII Vltl IX X  TABLE  12.6 6.2 5.1 4.2 3.3 2.6  9.2 17.4 24.6 29.7 33.9 38.0  Increment  9.2 8.2 7.2 5.1 4.2 4.1  9.0 15.3 19.6 23.2 26.1 28.5 30.8 32.9 34.8 36.3  Increment  9.0 6.3 4.3 3.6 2.9 2.4 2.3 2.1 1.9 1.5  Average length (cm.) 10.5 15.3 19.3 22.8 26.4 30.0 33.2 36.0 38.6 42.1  Increment  10.5 4.8 4.0 3.5 3.6 3.6 3.2 2.8 2.6 3.5  XIX. Summary of the calculated growth i n weight of w h i t e f i s h from Lakes Redroek, Happy I s l e and Opeongo.  AGE GROUP I II III IV V VII VIII •' IX X  Summary of the calculated growth i n length of w h i t e f i s h from Lakes Redroek, Happy I s l e and Opeongo.  REDROCK LAKE P. cylindraceum  HAPPY ISLE LAKE P. cylindraceum  Average weight (lbs.)  Average weight (lbs.)  0.05 0.20 0.43 0.74 1.07 :  .. ' > ; • ,  Increment 0.05 0.15 0.23 0.31 0.33  0.03 0.18 0.48 0.80 1.16  Increment 0.03 0.15 0.30 0.32 0.36  OPEONGO LAKE P. cylindraceum C. clupeaformis Average weight (lbs.) 0.02 0.10 0.22 0.38 0.71 0.91 1.12 1.31 1.51  Increment 0.02 0.08 0.12 0.16 0.17 0.20 0.21 0.19 0.20  Average weight (lbs.) 0.03 0.11 0.23 0.39 0.95 1.33 1.73 2.16 2.87  Increment  0.03 0.08 0.12 0.13 0.32 0.38 0.40 6.43 0.71  43  AGE Figure 15.  Calculated growth i n weight of whitefishes from Lakes Redroek, Happy Isle.and Opeongo. ( l = C. clupeaformis from Opeongo Lakej 2 = P. cylindraceum from Redroek Lakej • 3 •= P. cylindraceum.. from Opeongo Lake; 4 •= P. cylindraceum from Happy I s l e Lake* )  the whitefish from Lake Opeongo.  I t i s p a r t i c u l a r l y i n t e r e s t i n g to note the  close s i m i l a r i t y i n the growth history of C. clupeaformis and P. cylindraceum i n Lake Opeongo e s p e c i a l l y during the f i r s t 4 - 5 period the growth rates diverge.  years, however a f t e r t h i s  Comparing the rates of growth f o r the  three populations of P. cylindraceum i t i s important to note how much slower the growth rate i s i n f i s h from Opeongo Lake.  In t h i s lake, a weight of 1.5  pounds i s reached only a f t e r ten years of growth, whereas i n Redroek Lake and Happy I s l e Lake the same weight i s reached i n l e s s than half the time.  44  DISCUSSION One of the most noticeable features of the d i s t r i b u t i o n of whitefish i n Algonquin Park i s the apparent r e l a t i o n s h i p t o lake s i z e .  Routine  sampling  indicates that lakes with a t o t a l surface area of more than 5 sq. mi. and a maximum depth of more than 100 feet frequently contain two or more species of w h i t e f i s h , while r e l a t i v e l y small l a k e s , those l e s s than one-half of a square mile i n area, possess no more than one whitefish species. Work by Godfrey (1955) showed s i m i l a r r e s u l t s . I t i s obvious though, that i t i s not s t r i c t l y the p h y s i c a l dimensions of the body of water involved but i s r e l a t e d t o the presence or absence of a p a r t i c u l a r factor i n lakes of d i f f e r e n t s i z e s .  Whether a given body of water  w i l l support one or more species of f i s h , e s p e c i a l l y closely r e l a t e d ones, w i l l l i k e l y be r e l a t e d t o the a v a i l a b i l i t y of food, or space, or some other habitat requirement.  As Odum (1953) has pointed out the larger the habitat  s i z e the greater the number of niches available and hence the greater the number of species i t w i l l support. One i n t e r e s t i n g aspect of the sympatric occurrence of P. cylindraceum and C. clupeaformis i s that the l a t t e r species i s almost i n v a r i a b l y the more successful one.  The sole exception to t h i s appears t o be the f i n d i n g s of  Cooper and F u l l e r (1945) i n Maine.  In Opeongo Lake i t was estimated that the  lake whitefish outnumbered the round whitefish i n the order of s i x t o one, and were found t o have a higher r a t e of growth. An e s s e n t i a l part of the present study was t o determine i f possible the presence of any i n t e r a c t i o n between the above two species. Attempts t o determine the temperature preferences, i f any, f o r the two species met with rather poor success.  Although a s l i g h t seasonal downward s h i f t d i d occur, the  45  f i s h d i d not appear to be confined to a narrow temperature zone as might be expected. Qadri ( I 9 6 I ) observed i n h i s depth d i s t r i b u t i o n data f o r 1954,  that the  G. clupeaformis of Lac La Ronge, Sask., did not migrate downward but appeared to stay up i n the warmer water throughout the summer.  However i n the years  1948, 1949, 1950 and 1953 a d i s t i n c t downward migration was observed.  The  f i s h appeared to be following the 18°C isotherm with maximum concentrations occurring at the 12°C isotherm.  No explanation f o r the 1954 data was  offered.  Other studies such as that by Kennedy (1943) have not observed t h i s rather d i f f u s e v e r t i c a l d i s t r i b u t i o n i n regard to temperature but found i t t o be more d i s t i n c t .  Kennedy noted that the common w h i t e f i s h of Opeongo Lake d i d  not move above the 18°C isotherm and that they seemed to be "concentrated at about 15°C". I t would appear then that under certain conditions a species that i s normally considered a cold-water form may be found i n a zone of high temperature.  An example of t h i s i s t o be found i n the work by Martin (1952) on the  lake trout of Redrock Lake.  He observed that the trout were most frequently  found below the 18°C isotherm, but noted that they were also " i n much shallower water than i t i s commonly believed the species w i l l enter at t h i s time". Since most of the depth d i s t r i b u t i o n data i n the above papers and i n the present study are based on overnight sets, i t i s p o s s i b l e that those f i s h caught i n areas of high temperature do not r e f l e c t t h e i r normal d i s t r i b u t i o n , but represent the temporary excursion of some i n d i v i d u a l s i n t o the epilimnion. The presence of t e r r e s t r i a l insects and the emerging adult stages of some aquatic forms i n the stomachs of these f i s h would seem t o support t h i s idea. According t o Cooper and P u l l e r (1945) these excursions may be more frequent  46  than i s r e a l i s e d . They stated that "the designation of even surface waters as 'non-trout • i s probably erroneus'', due t o the fact that salmon and trout were observed feeding at the surface during the midsummer when the lake temperature exceeded 21°C. However on the basis o f the present  study and the work of others i t may  be assumed that the d i s t r i b u t i o n of these cold-water whitefish species i s below the 18°G isotherm i n a s t r a t i f i e d lake, and and that those f i s h caught i n shallower depths were taken only during periods of feeding a c t i v i t y .  This  assumption could be tested by extensive netting on a d i e l basis. Another i n t e r e s t i n g feature of the depth d i s t r i b u t i o n of Coregonus and Prosopium i s the range of depth occupied by each of the species,  i n a number  of cases where two species of whitefish occur sympatrically i t may be demonstrated that the maximum depth range of the former i s consistently greater than that of the l a t t e r . relationship:  The following are some examples of t h i s  i n Opeongo Lake during the summer months, _C. clupeaformis  was  caught i n a l depths ranging from 0 - 8 0 f e e t , while P. cylindraceum was found only between 10 - 55 f e e t . r e l a t i o n s h i p i s observed.  In L a v i e i l l e Lake an almost i d e n t i c a l depth range During the summer of 1962, extensive netting i n  t h i s lake showed that i n the months of May and June C_. clupeaformis  were  frequently caught at depths t o 55 feet while the maximum depth at which P. cylindraceum was taken was 45 f e e t .  In July 1963 the r e s u l t s were again  s i m i l a r : lake whitefish down t o 75 f e e t , and round whitefish down t o 55 f e e t . Other studies i n sympatric pairs of whitefish show comparable r e s u l t s . Cooper and F u l l e r (1945) observed a maximum depth of 120 feet f o r lake whitefish and a maximum of 75 feet f o r round whitefish i n Moosehead Lake, Maine.  McHugh (1939) i n h i s work on Okanagan Lake, B r i t i s h Columbia, found  47  that C. clupeaformis were caught i n depths ranging from 20 feet to 138 f e e t , whereas the mountain w h i t e f i s h , P. w i l l i a m s o n i . were never taken at depths over 50 f e e t . B.C.,  Godfrey (1955) studying the above two  species i n Babine Lake,  observed much the same type of d i s t r i b u t i o n ; the lake whitefish ranged  from the surface to 70 f e e t , but only one mountain whitefish was  captured i n  more than 55 feet of water. McCart (1963) also found an apparent s h i f t i n depth range when three species of whitefish were present.  In Tacheeda Lake, B.C.,  ranged from the surface to 40 f e e t j C. clupeaformis  P. williamsoni  down t o 55 feet while  the pygmy w h i t e f i s h , P. c o u l t e r i . ranged i n depth from 35 feet to over 100 feet.  In Cluculz Lake, B.C.,  a similar type of d i s t r i b u t i o n was  P. williamsoni and C. clupeaformis  observed;  from the surface to 35 f e e t , while  P. c o u l t e r i were caught only between 35 and 125  feet.  In two other  British  Columbia lakes, McLeese and MacLure, where P. c o u l t e r i i s the only whitefish present, the apparent depth range was respectively.  between 15 to 70 f e e t and 15 to 50 f e e t  Since the presence of the other two  appeared t o have a depressing  species of whitefish  e f f e c t on the pygmy whitefish i t was  concluded  by McCart that the absence of t h i s species i n the upper l e v e l s of Lakes Tacheeda and Cluculz, "may  be l a r g e l y the r e s u l t of competitive  exclusion by  the other two whitefish".  (A summary of the above data i s shown i n Figure  9.)  Examination of the depth d i s t r i b u t i o n data f o r Lakes Happy I s l e and Redrock (Figure 8 . ) suggests that P. cylindraceum may when i t i s the sole whitefish species  also range over greater depths  present.  Just what b i o l o g i c a l s i g n i f i c a n c e of t h i s r e l a t i o n s h i p i s can only be l e f t to speculation. between the two  It i s possible that the difference i n depth d i s t r i b u t i o n  species i s simply due to a preference by P. williamsoni or  48  P. cylindraceum f o r the l i t t o r a l and s u b l i t t o r a l zones, although the l a t t e r have been recorded at depths greater than 175 feet i n Lake Michigan (Koelz 1929).  On the other hand t h i s difference may be due i n fact to some i n t e r -  action between the two species as McCart has suggested.  I t appears that a  d e f i n i t e answer t o t h i s problem i s not possible u n t i l more i s known about the biology of these species. Another i n s i g h t into the e c o l o g i c a l r e l a t i o n s h i p between P.  cylindraceum  and C. clupeaformis can be gained by detailed a n a l y s i s of the food habits of the two species. Much has been written about competition between f i s h species (Larkin 1956, Lindstrom and Hilsson 1962 and others) but only r a r e l y can i t be accurately demonstrated.  One of the basic problems, as Larkin has pointed  out, i s the d i f f i c u l t y i n determining the a v a i l a b i l i t y and the l i m i t s of a p a r t i c u l a r resource, l i k e food, that i s possibly being competed f o r .  By  d e f i n i t i o n , i n t e r s p e c i f i c competition i s the i n t e r a c t i o n between two species that have demands on the same resources of the environment i n excess of the immediate supply. Whether such an i n t e r a c t i o n exists i n the present study i s open to question.  However one t h i n g i s certains  as. much as P. cylindraceum and C_. clupea-  formis consume e s s e n t i a l l y the same organisms, they do so either at d i f f e r e n t times of the year or else i n vastly d i f f e r e n t quantities.  Compare f o r example  the consumption of chironomid larvae and pupae during the month of J u l y (Figure 10.).  In the f i r s t h a l f of the month, chironomid larvae are an  important food item to C. clupeaformis whereas i n P. cylindraceum the emphasis i s on chironomid pupae. of  In the l a t t e r half of the month when the consumption  chironomid larvae and pupae by C. clupeaformis i s low, the values f o r  these food items are high i n P. cylindraceum.  This and other examples  49  i l l u s t r a t e the d i s t i n c t difference i n the food habits of these two Lake Opeongo.  species i n  Nilsson (195$) a l s o demonstrated s i m i l a r food relationships  with other species of sympatrically occurring whitefish. In general then, P. cylindraceum feed mainly on l a r v a l i n s e c t s while C. clupeaformis feed p r i m a r i l y on l i t t o r a l and bottom-dwelling Crustacea. As has been discussed previously the Cisco, Leucichthys a r t e d i , occupies the mid-water plankton feeding niche.  Also present i n Lake Opeongo are lake  trout, Salvelinus namaycush. which i n t h i s lake are e s s e n t i a l l y piscivorous i n nature^ Redrock.  Compare t h i s s i t u a t i o n with that found i n Lakes Happy I s l e and I t has been noted e a r l i e r that neither Leucicthys a r t e d i nor  C. clupeaformis are present i n either of the above lakes.  I t would appear  then that P. cylindraceum has shifted i t s feeding habits to occupy the niche normally held by the other two species.  Likewise the t r o u t i n these lakes  appear to have shifted away from t h e i r normal piscivorous habit to a mixed d i e t c o n s i s t i n g of f i s h , insects and plankton.  Martin (1952) stated that t h e  diet of S. namaycush i n Redrock Lake was as follows; 7Q# (frequency of occurrence) f i s h , 53# i n s e c t larvae, and 8% plankton Crustacea.  Baldwin (1948) i n  h i s study on S. f o n t i n a l i s of the same lake, found that i n the early summer months the frequency of occurrence of insects i n t h i s species was 31# while during July and August the perch f r y comprised almost 98^ of the t o t a l volume. Preliminary work on the lake t r o u t of Lake Happy I s l e shows an even greater s h i f t away from the piscivorous habit (frequency of occurrence of f i s h i n lake trout stomachs i s about 30j£). One might ask what would be observed i f only the lake t r o u t were present. Martin (1952) studied the ecology of a lake trout population i n t h i s type of situation i n Louisa Lake.  This lake i s located i n the south-central area of  50  Algonquin Park and i n limnological features i s not unlike the four lakes examined i n the present study.  Analysis of. lake trout stomachs during the  period May 2 0 t h to October 31st showed that plankton had a frequency of occurrence of 73$ while insects and f i s h had values of 25% and 23$ r e s p e c t i v e l y . In the cold-water  species of the above four lakes there appear to be  d i s t i n c t niches based on food, habits (Table XX) which may be occupied by a p a r t i c u l a r species i n one lake and by another species jLn a second lake.  It  i s not known i f s i m i l a r r e l a t i o n s h i p s are present between the warm-water species.  The v a l i d i t y of comparisons such as that between the t r o u t and white-  f i s h i s open to question, due to a lack of information about so many other factors.  For example the plankton feeding habit of the Louisa t r o u t i s possibly  the end result of being forced i n t o t h i s niche by the absence of forage f i s h such as the w h i t e f i s h .  In the other lakes the a v a i l a b i l i t y of a food type  not be the same, r e s u l t i n g i n food habit d i f f e r e n c e s . Only by  may  experimental  feeding under conditions such as those described by Fabricius and Lindroth (1954) might a more conclusive answer be provided f o r t h i s problem. :;  Another aspect of the feeding habits of whitefish yet t o be considered i s  the conspicuous absence of copepods i n the d i e t of round w h i t e f i s h .  In many  lakes, i n c l u d i n g those studied i n Algonquin Park, the numerous species of copepods make up a s i g n i f i c a n t part of the planktonic Crustacea.  These forms  are generally found quite uniformly distributed i n a l l regions of the lake, with the possible exception of the deep water zones (Langford 1 9 3 8 a ) .  In view  of the fact that such large q u a n t i t i e s of plankton are consumed by round whitef i s h , p a r t i c u l a r l y by those f i s h i n Lakes Happy I s l e and Redroek, the absence of copepods i n a l l stomachs i s s u r p r i s i n g . The small size of the copepods would seem to preclude any s e l e c t i v e feeding against these organisms, yet work  51 TABLE  XX.  Levels of food consumption by the major f i s h species i n four Algonquin Park lakes.  LAKE  Salvelinus sp.  LOUISA  S. namaycush P 732 "(F) i 252 (F) f 23% (F)  SPECIES Coregonus Prosopium cylindraceum clupeaformis  -  Leucichthys artedi  -  -  -  -  'CD HAPPY ISLE  S. namaycush p 88% (FI) P 5 $ .(F) i 21$ '(F) i 33% (FI) f 30%' (F) (2)  REDROCK  S. namaycush p 70$ (F) i 53% (F) f 8% (F) (1) S. f o n t i n a l i s  P 75% (FI) i 34^ (FI)  -  i 98% (V) f 315 (F)  (3) OPEONGO  S. namaycush i 1035 .(F) f 80$ (e)  p 282 (FI) P 532*(FI) i 80% (FI) i 442 (FI)  p 902 (E)  (4) (1) Martin (1952); (2) Martin and Sandercock (unpub.); (3) Baldwin (1948); (4) Fry and Kennedy (1937)°° (F) =• percent frequency of occurrence; (V) = percent volume; (FI) = food index value; (E) = estimated value; *- = mean value f o r period June 1st t o September 1st; - - species not present i n lakes p ^.plankton; i = i n s e c t s ; f = f i s h .  52  by McHugh (1940) showed s i m i l a r r e s u l t s i n t h e f o o d h a b i t s o f P.  williamsoni.  A l t h o u g h r o u t i n e p l a n k t o n sampling g e n e r a l l y i n d i c a t e s t h a t t h e s e p l a n k t e r s o c c u r q u i t e randomly, i t has been o b s e r v e d i n l i t t o r a l t h a t t h e r e i s f r e q u e n t l y a "bunching"  of plankters.  and s u b l i t t o r a l zones  I t i s possible that there  is  some k i n d o f a v o i d a n c e r e a c t i o n t o t h e s e " c l o u d s " o f copepods on t h e p a r t  of  Prosopium. a r e a c t i o n t h a t i s n o t e x h i b i t e d i n Coregonus; i n f a c t C y c l o p s  sp. were f o u n d t o rank t h i r d i n importance e a f o r m i s o f Opeongo L a k e .  I t i s equally possible that  manner o f f e e d i n g , o r o f s i t e , may The  f a c t remains  among p l a n k t e r s as f o o d i n C.  clup-  s l i g h t v a r i a t i o n i n the  a l s o account f o r t h e observed  differences.  t h a t P. c y l i n d r a c e u m does n o t n o r m a l l y f e e d on copepods w h i l e  t h e o p p o s i t e i s t r u e f o r C. c l u p e a f o r m i s . S i n c e C y c l o p s s p . a r e w e l l known as t h e i n t e r m e d i a t e h o s t s f o r a v a r i e t y of  p a r a s i t e s , i t i s o f i n t e r e s t t o examine t h e p a r a s i t i c fauna o f P.  raceum and £ . c l u p e a f o r m i s o f A l g o n q u i n Park. a list  cylind-  Bangham (1940) p u b l i s h e d such  f o r t h i s a r e a and i n d i c a t e d t h e f r e q u e n c y o f o c c u r r e n c e o f each o f t h e  parasites: Coregonus c l u p e a f o r m i s % 10 f i s h  examined.  Protocephalus l a r u e i Faust ( i n 9 f i s h ) L e p t o r h y n c h o i d e s f h e c a t u s ( L i n t o n ) ( i n 3) Crepidostomum c o o p e r i Hopkins ( i n 2) S p i n i t e c t e c t u s g r a c i l i s Ward and Magath ( i n l ) Prosopium c y l i n d r a c e u m % 10 f i s h  examined.  Crepidostomum f a r i o n i s ( M i l l e r ) ( i n 6) P r o t o c e p h a l u s l a r u e i F a u s t ( i n 4) Crepidostomum c o o p e r i Hopkins ( i n 2)  Subsequent work by Bangham and Venard about t h e d i s t r i b u t i o n o f p a r a s i t e s ;  (1946) r e v e a l e d two o t h e r f e a t u r e s  f i r s t that Protocephalus l a r u e i i s only  f o u n d v e r y r a r e l y i n P. c y l i n d r a c e u m , and second t h a t Crepidostomum f a r i o n i s  53  may occasionally be found i n C. clupeaformis.  These f i n d i n g s have been  confirmed more recently by Dr. R.S. Freeman, Ontario Research Foundation (pers. com,), who has been working i n the same area.  Freeman (1961)  demonstrated experimentally that Cyclops bicuspidatus i s probably the most important intermediate host i n the l i f e cycle of Protocephalus l a r u e i .  This  then would explain the presence of t h i s p a r a s i t e i n £. clupeaformis and i t s great r a r i t y i n P.  cylindraceum.  The f l u k e , Crepidostomum -farionis, i s by f a r the most important parasite found i n the round whitefish population of Algonquin Park.  According to  Dogiel et a l (I96l) the p a r a s i t e i s most probably acquired by consuming infected l a r v a l Ephemeroptera.  This however, raises the question of host  s u i t a b i l i t y since more Ephemeroptera are consumed by £. clupeaformis than by P. cylindraceum and yet the incidence of parasitism i s much higher i n the l a t t e r species.  This problem.also i n v i t e s further study.  A comparison of the age and growth data of the round whitefish from the three lakes studied can be made with the work by Bailey (1963) and Mraz (1964) on Lakes Superior and Michigan r e s p e c t i v e l y .  The growth rate of the round  whitefish studied by Bailey was comparable to that of the same species from Lake Opeongo.  Another s i m i l a r i t y i s the presence i n both populations of Lee's  phenomenon. However as Bailey has suggested,, there i s a strong l i k e l i h o o d that the observed discrepancy i n the back calculations i s due simply t o the s e l e c t i v i t y of the nets used. to  G i l l nets of a given s i z e always have a tendency  select only the l a r g e r , faster growing f i s h of the younger age groups.  For  t h i s reason i t i s possible that the back calculations from these younger f i s h i n the sample are an over-estimate of s i z e , rather than from older f i s h being an  under-estimate.  the figures derived  54  The fast r a t e of growth of round whitefish from Lakes Redrock and Happy I s l e i s similar t o that found by Mraz i n the whitefish of Lake Michigan. In these three populations no evidence of Lee's phenomenon was observed*  The  growth data f o r C. clupeaformis from Opeongo Lake showed a r e v e r s a l of Lee's phenomenon, that i s , there was an apparent increase i n the c a l c u l a t e d lengths from older f i s h as compared with younger f i s h .  Kennedy (1943) observed the  same apparent increase i n calculated lengths, but demonstrated that t h i s relationship was merely a function of sample s i z e . The growth patterns of the whitefish from Algonquin Park r e f l e c t the previously described differences i n food habits.  There appears to be a d i s t i n c t  c o r r e l a t i o n between the amount of plankton eaten and the rate of growth.  For  example, of the four populations of whitefish studied, the P. cylindraceum of Happy I s l e Lake, consume the l a r g e s t amount of plankton; the  highest growth r a t e .  from Opeongo Lake.  they also have  At the lower end of the scale are the P. cylindraceum  Here i t was observed that these f i s h fed p r i m a r i l y on  insects and only to a small degree consumed any plankton. was only h a l f that of the f i s h from Happy I s l e Lake.  Their growth rate  The growth rates of  round whitefish from Redrock Lake and the lake whitefish from Opeongo Lake are  intermediate between the P. cylindraceum of Happy I s l e and Opeongo Lake,  as are the consumption l e v e l s of plankton. Studies by Cooper and F u l l e r (1945) i n Moosehead Lake, Maine, demonstrate a similar r e l a t i o n s h i p between food and growth r a t e .  In t h i s lake the P.  cylindraceum reach a weight of one pound i n t h e i r tenth year of growth, whereas the  slowest growing f i s h i n the present study, the P. cylindraceum from Opeongo  Lake, reach t h i s same weight before t h e i r eighth year. Stomach analysis of round whitefish from Moosehead Lake showed that these f i s h fed e n t i r e l y on  55  l a r v a l insects and s n a i l s .  I t appears then, that the a v a i l a b i l i t y o f plankton  as a food source f o r whitefish i s of prime importance t o t h e i r r e l a t i v e success. Since C. clupeaformis  are better adapted to plankton feeding than the  P. cylindraceum, by v i r t u e of the large number of f i n e g i l l rakers, i t i s not s u r p r i s i n g that i n any s i t u a t i o n where £. clupeaformis  and P. cylindraceum  occur sympatrically that the lake whitefish are almost invariably the dominant species*  56  SUMMARY The d i s t r i b u t i o n and r e l a t i v e abundance o f Prosopium c y l i n d r a c e u m and Coregonus c l u p e a f o r m i s ( M i t c h i l l ) i n Algonquin P a r k , O n t a r i o , t h a t some i n t e r a c t i o n may  be present between t h e s e two  f o u r Ontario l a k e s :  first  two  l a k e s P.  t h e l a t t e r two  s p e c i e s was  In the  c y l i n d r a c e u m and C. c l u p e a f o r m i s o c c u r s y m p a t r i c a l l y .  In  l a k e s o n l y P. c y l i n d r a c e u m i s p r e s e n t . depth range of t h e  s p e c i e s and a t t h e same time sample stomachs t o determine  food h a b i t s .  S c a l e samples p l u s l e n g t h and weight d a t a were c o l l e c t e d i n t h e In  conducted  Opeongo, L a y i e i l l e , Redrock and Happy I s l e .  G i l l n e t s were s e t a t r e g u l a r i n t e r v a l s t o determine two  suggested  species.  A s t u d y of t h e e c o l o g i c a l r e l a t i o n s h i p o f t h e s e two in  (Pallas)  t h e presence  field.  o f C. c l u p e a f o r m i s i t appears t h a t P. c y l i n d r a c e u m occupy  a s h a l l o w e r depth range.  When t h e l a k e w h i t e f i s h a r e absent t h e round  f i s h a r e found i n a wide range o f A d e t a i l e d examination  o f .640  white-  depths. stomachs was  made.  P. c y l i n d r a c e u m  from  Lake Opeongo were found t o consume mainly l a r v a l i n s e c t s p l u s some bottomdwelling Crustacea.  G  c l u p e a f o r m i s from Lake Opeongo f e d m o s t l y on bottom-  d w e l l i n g C r u s t a c e a but a l s o i n c l u d e d a v a r i e t y o f o t h e r bottom organisms. d i e t o f both p o p u l a t i o n s o f P.  The  c y l i n d r a c e u m f r o m Lakes Redrock and Happy ,Isle  c o n s i s t e d p r i m a r i l y o f p l a n k t o n i c and b o t t o m - d w e l l i n g  Crustacea.  The growth r a t e f o r t h e f o u r p o p u l a t i o n s o f f i s h appeared  quite d i s t i n c t .  The r a t e o f i n c r e a s e o f b o t h l e n g t h and weight o f t h e P. c y l i n d r a c e u m Lakes Redrock and Happy I s l e was  from  much g r e a t e r than t h a t o b s e r v e d f o r t h e  w h i t e f i s h p o p u l a t i o n s from Lake Opeongo.  two  However when C. c l u p e a f o r m i s i s  p r e s e n t , as i n Lake Opeongo, t h e growth r a t e of P. c y l i n d r a c e u m i s markedly reduced.  57  It i s concluded that the better adaptation of C. clupeaformis to plankton feeding may i n part account f o r i t s success and at the same time provide an i n s i g h t i n t o i t s dominance over P. cylindraceum.  58  LITERATURE  CITED  B a i l e y , M.M. 1963. Age, growth and m a t u r i t y o f round w h i t e f i s h o f t h e A p o s t l e I s l a n d s and I s l e R o y a l e r e g i o n s , Lake S u p e r i o r . Fish. Bull., U.S. F i s h and W i l d l i f e S e r v i c e , Department o f I n t e r i o r , 6_3_(l)s 63=75. Baldwin, N.S. 1948. A s t u d y o f t h e s p e c k l e d t r o u t , S a l v e l i n u s f o n t i n a l i s ( M i t c h i l l ) i n a Precambrian l a k e . M.A. T h e s i s , Department o f Z o o l o g y , U n i v e r s i t y o f Toronto. Bangham, R.V. Fish. Soc,  1940. P a r a s i t e s o f f i s h o f Algonquin P a r k l a k e s . 20s 161-171.  Bangham, R.V. and C.E. V e n a r d . l a k e s . Pub. Ont. F i s h . Res.  T r a n s . Am.  1946. P a r a s i t e s o f f i s h o f Algonquin P a r k Lab., No. 53, pp.'33-46.  Clemens, W.A. and N.K. Bigelow. 1922. The food o f c i s c o e s ( L e u c i c h t h y s ) i n Lake E r i e . Pub. O n t . F i s h . Res. Lab., No. 3, pp. 41-53. " Cooper, G.P. and J.C. F u l l e r . 1945. A b i o l o g i c a l s u r v e y o f Moosehead Lake and Haymoch Lake, Maine. F i s h . S u r v e y Rept. No. 6, Maine Department o f I n l a n d Game and F i s h e r i e s , 160 pp. D o g i e l , V.A., P e t r u s h e v s k i , G.K. and I . I . P o l y a n s k i . f i s h e s . Edinburgh, O l i v e r and Boyd, 384 pp. Dymond, J.R. 1926.  The f i s h e s o f Lake N i p i g o n .  1961.  Pub. Ont.  Parasitology of  F i s h . Res. L a b . ,  No. 27, pp. 1-108. Dymond, J.R. 1933. Qoregonine f i s h e s o f Hudson and James Bays. B i o l . , N.S., 8s 1 - 1 2 . -  C o n t r . Can.  Eschmeyer, P.H. and R.M. B a i l e y . 1 9 5 5 . The pygmy w h i t e f i s h , Coregonus c o u l t e r i i n Lake S u p e r i o r . T r a n s . Am. F i s h . S o c , 84_s 161-199. F a b r i c i u s , E . and A. L i n d r o t h . 1 9 5 4 . E x p e r i m e n t a l o b s e r v a t i o n s on t h e spawning o f w h i t e f i s h , Coregonus i a v a r e t u s L . , i n t h e stream aquarium o f t h e H o l l e l a b o r a t o r y a t R i v e r I n d a l s a l v e n . R e p t . I n s t . Freshw. R e s . D r o t t n i n g h o l m , 21% 1 0 5 - 1 1 2 . Fenderson, O.C. I 9 6 4 . E v i d e n c e . o f s u b p o p u l a t i o n s o f l a k e w h i t e f i s h , Coregonus clupeaformis„ i n v o l v i n g a dwarfed form. T r a n s . Am. F i s h . S o c , 93(2)s 7 7 -  94. Freeman, R.S. 1 9 6 I . Annual r e p o r t o f t h e O n t a r i o Research F o u n d a t i o n , Department o f P a r a s i t o l o g y . F r y , F . E . J , and W.A. Kennedy. 1 9 3 7 . Report on t h e 1936 lake t r o u t i n v e s t i g a t i o n , Lake Opeongo, O n t a r i o . Pub. Ont. F i s h . Res. Lab., No. 54, pp. 3=20.  59  Godfrey, H. 1955. On t h e e c o l o g y of Skeena R i v e r w h i t e f i s h , Coregonus and Prosopium. J . F i s h . Res. Bd. Can., 12.(4)s. 499=542. H a r t , J . L . 1931. The f o o d o f t h e w h i t e f i s h Coregonus c l u p e a f o r m i s ( M i t c h i l l ) i n O n t a r i o waters, w i t h a note on t h e p a r a s i t e s . C o n t r . Can, B i o l . , N.S.  6(21)s 447-454. Hubbs, C.L. and K.F. L a g l e r . 1958. F i s h e s o f t h e Great Lakes r e g i o n . B u l l . Cranbrook I n s t i t u t e o f S c i e n c e , 26s 213 PP«> r e v i s e d e d i t i o n . Kennedy, W.A. 1943. The w h i t e f i s h , Coregonus c l u p e a f o r m i s ( M i t c h i l l ) , p f Lake Opeongo, Algonquin P a r k , O n t a r i o . Pub. O n t . " F i s h . Res. Lab.,,No.  6 2 , pp. 2 3 - 6 6 .  Kennedy, W.A. 1949. Some o b s e r v a t i o n s on t h e coregonine f i s h o f Great Bear Lake, N o r t h West T e r r i t o r i e s . B u l l . F i s h . Res. Bd., 82s 1-10. K o e l z , W. 1929. Coregonid f i s h e s of t h e G r e a t Lakes. F i s h e r i e s , 43.(2)s 2 9 7 - 6 4 3 .  B u l l . U.S.  Bureau o f  Langford, R.R. 1938a. D i u r n a l and s e a s o n a l changes i n t h e d i s t r i b u t i o n o f the l i m n e t i c Crustacea of Lake N i p i s s i n g , O n t a r i o . Pub. Ont. F i s h . Res. Lab., No. 5 6 , pp. 1=142. L a n g f o r d , R.R. 1938b. The f o o d of the Lake N i p i s s i n g Cisco, L e u e i c h t h y s a r t e d i (Le S u e u r ) w i t h s p e c i a l r e f e r e n c e t o t h e u t i l i z a t i o n , o f t h e l i m n e t i c Crustacea. Pub. Ont. F i s h . Res. Lab., No. 57* pp. 1 4 3 - 1 9 0 . L a r k i n , P.A. 1956. freshwater f i s h .  I n t e r s p e c i f i c c o m p e t i t i o n and p o p u l a t i o n c o n t r o l i n J . F i s h . Res. Bd. Can., 1,2(3)* 3 2 7 - 3 4 2 .  Lee, R.M. 1912. An i n v e s t i g a t i o n i n t o t h e methods of growth d e t e r m i n a t i o n in fishes. C o n s e i l permanent i n t e r n a t i o n a l pour 1 e x p l o r a t i o n de l a mer. Pub. de C i r c . 6 3 . 5  L i n d s e y , C.C. 1963. Sympatric o c c u r r e n c e of two s p e c i e s of humpback w h i t e f i s h i n Squanga Lake, Yukon T e r r i t o r y . J . F i s h . Res. Bd. Can., 2 0 ( 3 ) s  749-767. L i n d s t r o m , T. and N.A. N i l s s o n . 1962. On t h e c o m p e t i t i o n between w h i t e f i s h s p e c i e s . I n : E x p l o i t a t i o n of n a t u r a l a n i m a l p o p u l a t i o n s . E d i t e d by E.D. LeCren and M.W. Hodgate, O x f o r d , B l a c k w e l l S c i . Pubs., pp. 3 2 7 - 3 4 0 . McCart, P.J. I 9 6 3 . Growth and morphometry of t h e pygmy w h i t e f i s h , (Prosopium c o u l t e r i ) i n B r i t i s h Columbia. M.Sc. T h e s i s , Department o f Zoology, U n i v e r s i t y o f B r i t i s h Columbia 98.pp. s  McHugh, J . L . 1939. The w h i t e f i s h e s C. c l u p e a f o r m i s ( M i t c h i l l ) and P. w i l l i a m s o n i ( G i r a r d ) of t h e l a k e s o f t h e Okanagan V a l l e y , B r i t i s h Columbia. B u l l . F i s h . Res. Bd. Can., 5j>s 3 9 - 5 0 .  60  McHugh, J . L .  1940.  Food o f t h e Reeky Mountain w h i t e f i s h .  J . ..Fish. R e s .  Bd. Can., j>(2): 131-137. M a r t i n , N.V. 1952. A s t u d y o f t h e l a k e t r o u t , S a l v e l i n u s namaycush. i n two A l g o n q u i n Park, O n t a r i o , l a k e s . T r a n s . Am. F i s h . S o c . , 81: 111-137. Mraz, D. 1964. Age and growth o f t h e round w h i t e f i s h i n Lake M i c h i g a n . T r a n s . Am. F i s h . S o c , 23.(1): 46^-52. N i l s s o n , N.A. 1958. On t h e f o o d c o m p e t i t i o n between two s p e c i e s o f Coregonus i n a North-Swedish l a k e . Rept. I n s t . Freshw. R e s . D r o t t n i n g h o l m , 3_?J 146-  161. N o r t h c o t e , T.G. O b s e r v a t i o n s on t h e comparative e c o l o g y o f two s p e c i e s o f f i s h , Cottus a s p e r and Cottus r h o t h e u s . i n B r i t i s h Columbia. Copeia 1:  25-28. N o r t h c o t e , T.G. 1957* A r e v i e w o f t h e l i f e h i s t o r y and management o f t h e mountain w h i t e f i s h , Coregonus w i l l i a m s o n i G i r a f d . F i s h . Management D i v . , B r i t i s h Columbia Game Commission. Mimeo., 6 pp. Odum, E.P. 1953. Fundamentals o f e c o l o g y . Saunders Co., 384 p p .  P h i l a d e l p h i a and London, W.B.  Q a d r i , S.U. 1961. Food and d i s t r i b u t i o n o f l a k e w h i t e f i s h i n Lac L a Ronge, Saskatchewan. T r a n s . Am. F i s h . S o c , £0(3): 303-307. R a d f o r t h , I . 1944. Some c o n s i d e r a t i o n s on t h e d i s t r i b u t i o n o f f i s h e s o f O n t a r i o . C o n t r . R o y a l O n t a r i o Museum, No. 25, 116 p p . Rawson, D.S.  1951.  S t u d i e s o f t h e f i s h o f G r e a t S l a v e Lake.  J . F i s h . Res.  Bd. Can., 8(4): 207-240. R o s t l u n d , E . 1952. Freshwater f i s h and f i s h i n g i n n a t i v e North America. U n i v e r s i t y o f C a l i f o r n i a P u b l i c a t i o n s (Geography), V o l . 9 , pp. 1-313. Smith, S.B. 1955. The r e l a t i o n between s c a l e diameter and body l e n g t h o f Kamloops t r o u t , Salmo g a i r d n e r i kamloops. J . F i s h . R e s . Bd. Can., 12(5):  742-753. Smith, S.H.  1957.  E v o l u t i o n and d i s t r i b u t i o n o f t h e c o r e g o n i d s .  J . Fish.  Res. Bd. Can., 1^(4)s 599-604. S i g l e r , W.F. 1 9 5 1 . The l i f e h i s t o r y and management o f t h e mountain w h i t e f i s h , Prosopium w i l l i a m s o n i ( G i r a r d ) i n Logan R i v e r , Utah. Utah S t a t e A g r i c u l t u r e C o l l e g e B u l l . , 3_4_2s 1 - 2 1 . S v a r d s o n , G. 1953. The coregonid problem; V. S y m p a t r i c w h i t e f i s h s p e c i e s of t h e l a k e s I d s j o n , S t o r a j o n , and Hornovon. F i s h . Bd. Sweden, Rept. I n s t . Freshw. R e s . D r o t t n i n g h o l m , 3JfcS 141-166.  61  Van  Van  Oosten, J . 1923. The whitefishes (Coregonus clupeaformis). A study of the scales of whitefishes of known ages. Zoologiea, New York, 2(17)? 3 8 0 412.  Oosten, J . and R. H i l e . 1949. Age and growth of the lake whitefish, Coregonus clupeaformis ( M i t c h i l l ) i n Lake E r i e . Trans. Am. F i s h . Soc.j 22 s 178-249.  Walters, V. 1 9 5 5 . Fishes of western a r c t i c America and eastern a r c t i c Siberia? taxonomy and zoogeography. B u l l . American Museum of Natural History, 106(5)s 2 5 7 - 3 6 8 . Watson, N.H,F. 1 9 6 3 . Summer food pf lake whitefish, Coregonus clupeaformis ( M i t c h i l l ) , from Heming Lake^ Manitoba. JV F i s h . Res. Bd. Can., 20(2)% 279-286. Wood, K.G. 1953. The bottom fauna of Louisa and Redrock l a k e s , Algonquin Park,'Ontario. Trans. Am. F i s h . S o c , 82s 203-212. Wynne—Edwards, V.C. 1952. Fresh-water vertebrates of the A r c t i c and Suba: B u l l . F i s h . Res. Bd. Can., No. 94, pp» 1-28.  62 APPENDIX  TABLE  XXI.  The f o o d o f P. c y l i n d r a c e u m and C. c l u p e a f o r m i s from three Ontario l a k e s .  Prosopium FOOD  c y l i n d r a c e u m : Lake Opeongo MAI 15 - 3 1 JUNE 1 - 15 FI %V %V %F J6F FI ITEM  12.2 4.1 2.5  Sida Ophryoxus Eurycercus Polyphemus Hyallela Ephem. Odonata Sialidae Triehop. Coleop. Chiron. L. C h i r o n . P. Chaob. L . Chaob. P.  1.6 31.4  100 50  13 40  64.3  100  80  2.1  100  14  Amnicola Valvata Pisidium Helisoma Physa  0.8  50  6  Hydracar. Perca  39.0 39.0 34.2  21 13 9  6.0 0.1 0.1 8.9  36.6 2.4 2.4 46.3  20  52.5 7.2 0.8  75.6 75.6 7.3  63 23 2  15 X X  1.1 0.3 0.4 0.1 3.6  9.8 12.2 9.8 7.3 2.4  3  0.2  7.3  1  3 2 2  JUNE 16 - 30 %V %¥ FI  22.1 42.9 1.1 . 2 0 . 0 1.7 42.9  31 5 9  0.1  2.9  X  5.4 15.1 0.2 9.8 1.4 11.3 20.1 0.1  28.6 2.9 2.9 37.1 2.9 51.4 57.1 5.7  13 7  X  25.3 0.1 0.7 0.2  44.4 11.1 22.2 11.1  34 1 4 2  21.5  22.2  22  25.4  18.2  22  0.1  44.9  33.3  3.9  8.5 24.9  18.2 63.6  13 40  25.4  62.5 40  13.8 21.8  9.1 11 36.4 28  0.5 5.9 0.3  11.1 77.8 11.1  2 21 2  21 .4 45.5 8.3 63.6  31 23  0.8 66.2  37.5 5 50.0 58  14.1 25.4  24.2 19 30.3 28  %F  FI  10  3.5 3.5  6.3 6.2  13  1  16.1  0.5 11.1 0.1,  2.9  X  0.0 11.5  5.7 2.4  X  X  0.3  11.1  2  0.6  6.3  2  9.1  12  2.5  3.0  3  3.8  6.1  5  1.9  3.0  2  0.6  3.0  1  Coregonus FOOD  clupeaformis Lake Opeongo MAY 15 - 3 1 JUNE 1 - 15 FI %F %F $V %V ITEM FI  6  AUGUST 16 - 3 1 #V %F FI  FI  X  19 2 24 34  AUGUST 1 - 1 5 %y %¥ F I  %¥  Sida Ophryoxus Eurycercus Latona Daphnia Acantho. Bosmina Holopedium Leptodora Hyallela Cyclops  2.8 5.7 3.0 12.6  0.1  3.9  X  0.4 0.2 3.9 0.1 0.1 1.7  29.7 48.6 37.8 52.7 4.1 1.4 8.1 2.7 41.0 50.0  9 17 11 26  JUNE 16  6.4 5.4 13.2 2.3  - 30  %¥  FI  50.0 47.4 55.3 15.8  18 16 27 6  JULY 1 - 15 %V %F i F I  16.1 1.8 7.1 0.1  1 X  JULY 16 - 31 %Y %F FI  6 1 . 9 3 2 . 18.0 60.0 47.6 9 1.6 30.0 7 1 . 4 23 43.-5 40.0 9.5 x 0.0 2.5 0.1 2.5  33 7 42 x x  AUGUST 1 - 1 5 %V %F FI  10.0 31.6 0.2 8.8 0.4 5.3 0.1 3.5 0.1  19 1 1 x  3.5  6 X X  9  31.5 0.1 9.1  26.3 2.6 68.4  29 X  25  6.6  81.0 > ' 2 3 . 3.7  52.5  14  2.0  33.3  8  AUGUST 16 - 3 1 %V %F FI  35.2 0.2 0.8 3.5 0.0 0.2 0.1  50.0 10.0 3.3 15.0 3.3 11.7 6.7  0.3 3.3 0.1 3.3 5 . 9 48.3  42 2 2 7 x  2 x X X  17  63  TABLE  XXI.  continued:  Coregonus clupeaformis : Lake Opeongo MAY 15 - 3 1 JUNE 1 - 15 %V %F FI %V %¥ FI FOOD ITEM Ephem. Corixidae Sialidae Trichop. Coleop. Formicidae Chiron. L. Chiron. P. Chiron. A. Chaob. L. Chaob. P.  95.3 0.0 1.9 0.0  Amnicola Valvata Pisidium Planorb.  0.7  Ostracods Hydracar. Perca  1.1 0.3  0.5  0.1  76.9 3.9 19.2 3.9 26.9 11.5  19.2 7.7  19.2  86 X  12.4 1.9  37.5 22.6  21 6  9.0  0.7 0.1 10.1 1.6 2.2  22.6 1.4 5.4 46.9 43.2  4  1.4  7 9 10  0.4 5.2 2.4  2.6 63.2 39.5  0.2 0.3  8.1 1.4  1  1.1  23.7  X  29.9 1.2 2.4  37 3 7  o.i  46.9 8.1 19.9 4.1  0.5 5.6  .28.4 72.6  4 20  6 X  6 2  4 2  2  Ephem. Odonata Trichop. Chiron.. L.. Chiron. P. Chaob. L.  88.5  88.0  88  0.9  8.8  3  4.3 0.3 5.5  12.0 8.8 88.0  7 .2 2  Amnicola Pisidium  0.3  Hydracar.  0.2  4.0 4.0  1  X  4.7 93.8  1.3 0.2  50.0 75.0  25.0 25,0  18.4 15.8  JULY 1 ' - . 15 FI %F  %V  13  JULY 16 - 31 2v  %¥  FI  AUGUST 1 - 15 . %'V %F FI  AUGUST 16 - 3 1 %F JbV  3.4 0.8  9.5c . 4.8;  6 2  0;1 0.3  2.5 2.5  X X  2.2 0.3  3.5 3.5  2 1  5.2 0.5  6.7 6.7  2.1  4.8.  3  0.1  5.0  X  0.6  3.5  2  10.0 1.7 5,0 55.0 20.0 3.3 15.0 1.7  3.3  7.9  18 10  17.0 1.1  6 1 . 9 - . 33 6 33.3  4.3 2.9  42.5 30.0  4. 9  11.2 3.2  33.3 26.3  19 9  5  0.7 1.6  14.3 .. 3 28.6 7  1.5 1.9  17.5 15.0  5 5  1.6 0.9  u .o 14.0  5 4  0.3 0.2 16.7  7.5 2.5 45.0  2 X  27  1.1 1.2 9.2  7.0 5.3 17.5  3 3 13  1.6 0.2 10.3  8.3 1.7 36.7  20  0.1 4.9  2.5 52.5  0.1 8.2 47.4  10.5 38.6 5.3  X  16  18 16  1.3 7.9  36.7 45.0  7 19  X  5  1.6  6 2  4.8  3  3.5  36.8  11  36.8  57.1  46  0.2 5.7  7.9 55.3  1 18  0.0 3.1  19.1 76.2  X  X  15 84  JULY 16 - 3 1 2v %F FI  15  AUGUST .16 - 3 1 %V %F FI  ' 2.0 41.1 28.4  10.0 45.0 85.0  5 3 49  20.2 0.7 4.8 70.6  41.2 11.8 35.3 74.3  .4.9  15.0  9  1.3  11.8  • 4  0.9 4.0 14.7  10.0 50.0 80.0  3 14 34  8.6 5.8 1.8  29.4 29.4 23.5  16 13 7  3.0 0.6 0.4  6 2  1.6 0.3 2.0 20.0 2.2 0.4 0.6 0.1  5  X  Prosopium cylindrac eum : Lake Happy I s l e JUNE 16 - 30 MAY 16 - 31 2v %F FI %F FI %M FOOD ITEM Sida Ophryoxus Eurycercus Daphnia  JUNE 16 - 3 0 • %V %F FI  10.0 5.0  6 2  5.0  1  1.5 .  0.1  11.7  5;9  -29 313 72  X  4  X  3 33 7 1 3 X  4 X  Prosopium cylindraceum : Redrock Lake JULY 16 - 31 AUGUST 16 - 3 1 J feV %F FI %! FI  i  4  X  82.6  89.5  86  62.6  81.0  71  2.1 2.1 5.1 0.1 5.1 2.8  5.3 5.3 10.5 5.3 10.5 15.8  3 3 7  0.5  4.8  2  X  4.5 32.1  9.5 38.1  7 35  7 7  0.2  9.5  1  0.1  9.5  X  

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