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Structural variation as related to the ecology of the redside shiner Richardsonius balteatus (Richardson)… Lindsey, Casimir Charles 1950

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n$o Hz STRUCTURAL VARIATION AS RELATED TO THE ECOLOGY OP THE REDSIDE SHINER Rlchardsonlus balteatus (RICHARDSON) by Casimir Charles Lindsey A Thesis Submitted i n P a r t i a l Fulfilment of the Requirements f o r the Degree of MASTER OF ARTS In the Department of ZOOLOGY The University of B r i t i s h Columbia A p r i l , 1950. STRUCTURAL VARIATION AS RELATED TO THE ECOLOGY OF THE REDSIDE SHINER Richardsoniua balteatus Richardson. By CASIMIR CHARLES LINDSEY ABSTRACT R. balteatus is extremely variable in number of anal rays. Counts of over 4000 specimens from 5^ l o c a l i t i e s in B r i t i s h Columbia varied from 10 to 21, with differences bet-ween means of d i f f e r e n t populations, d i f f e r e n t year classes and sometimes between the sexes. Variation i s shown to be controlled at least p a r t i a l l y by environmental factors during development; temperature i s an important factor* A mechanism for environmental control of f i n ray count is suggested. Variation also occurs In body proportions. Inflections in r e l a t i v e growth of body parts is demonstrated; v a r i a t i o n in proportions of these parts is probably due to environmental control of body size at I n f l e c t i o n . Pectoral and p e l v i c f i n s show heterogonic growth. Notes on l i f e history are given. The spawning period varies from 7 to 10 weeks, star t i n g bet-ween the l a s t week of May end the second week of June. Indiv-iduals spawn at d i f f e r e n t times and probably more than once per season. Smaller f i s h frequent shallower water. Few f i s h are older than k years and females l i v e longer than males. Relation of shiners to game species is discussed; shiners eat trout f r y , trout eat shiners, and shiners probably sometira compete with trout for other food. TABLE OP CONTENTS Page INTRODUCTION 1 ACKNOWLEDGEMENTS 3 LITERATURE ON THE SPECIES 4 LIFE HISTORY RANGE AND HABITAT 7 SPAWNING 9 EMBRYOLOGY 12 METAMORPHOSIS 15 ' GROWTH 17 SEX RATIO 19 MOVEMENTS 21 Size Differences 21 Night A c t i v i t y 22 Summer Range 23 Winter Habits 23 POOD RELATIONSHIPS 24 Relation to Game Species 24 Predation by Shiners 25 Predation on Shiners 27. Competition 28 Ecological Relations 29 STRUCTURAL VARIATION LITERATURE ON VARIATION IN PISH 31 ANAL RAY COUNTS 35 Counting Methods 35 Range of Variation 35 Page A r t i f i c i a l Introductions 36 Intra-population Variation 37 Summary of Adult V a r i a t i o n 38 VARIATION IN ANAL PIN BASE 39 Morphology of the Pin Base 39 Pin Base Proportion 41 PIN RAY FORMATION AND ECOLOGICAL FACTORS 43 Body Size at Ray Formation 43 Correlation with Temperature 43 Geographic Variation 45 VARIATION IN OTHER STRUCTURES 48 Relative Growth of Parts 48 Adult V a r i a t i o n i n Proportions 49 Vertebrae 50 Scales 52 CONCLUSIONS: A POSSIBLE MECHANISM FOR ANAL RAY COUNT VARIATION 52 Evidence f o r Environmental Control 52 Possible Causes of Intra-population Varia-t i o n 54 Hypothesis 55 General Application of the Hypothesis 58 SUMMARY 59a LITERATURE CITED 60 APPENDICES 6 7 3 ? i g . l . Adult redside s h i n e r , Cottonwood lake,1949. X 4/5 INTRODUCTION , i The redside shiner Richardsonius balteatus (Richard-lf®v son^-shows greater v a r i a b i l i t y i n number of anal f i n rays than almost any other fresh-water f i s h which has been studied i n North America. Ray counts of B r i t i s h Columbia specimens vary from 10 to 22. Shiners occur i n dense populations i n a wide vari e t y of stream and lake types from sea l e v e l to 7300 f e e t . £>8 large samples can be obtained from a number of d i f f e r e n t environments, the species lends i t s e l f to a study on i n t r a -s p e c i f i c v a r i a t i o n . In .addition, as the f i s h occurs together with various species of economic value, i t s ecology i s of p r a c t i c a l importance. ^ F i g . 1 shows an adult specimen.SA*- 1*JL,£-J The present study has been made along two l i n e s ; f i r s t , to investigate the l i f e h i s t o r y and relations with ce r t a i n other species, and second, to enumerate and i f possible explain some of the morphological v a r i a t i o n found. Data on l i f e h i s t o r y are presented f i r s t because, although somewhat diffuse, they form a necessary background to discussion of st r u c t u r a l v a r i a t i o n . Findings are based on f i e l d c o l l e c t i o n s and obser-vations made i n 1948 and 1949 i n various parts of B r i t i s h Columbia, and on experiments at the Summerland, Kaslo and -1-Nelson hatcheries. Collections from the Royal Ontario Museum of Zoology and various other sources were also examined. Anal ray counts and other measurements have been made on over 4000 specimens from some 54 l o c a l i t i e s . -3-ACKNOWLEDGEMENTS The guidance and enthusiasm of Dr. P. A. Larkin, and his unstinted support during c o l l e c t i o n of material f o r this study, have been genuinely appreciated. The assistance and advice of Dr. W. A. Clemens, who suggested the problem, i s also g r a t e f u l l y acknowledged. Much of the design and construction of apparatus, as well as c o l l e c t i o n of material i n the f i e l d , was c a r r i e d out by Arnold D. Nemetz. I am indebted to other fellow stu-dents f o r assistance and suggestions, p a r t i c u l a r l y to the following: G. C. Anderson, W. H. Cottle, R. G. Ferguson, Craig MacPhee and T. G. Northcote. Work during the summers of 1948 and 1949 was con-ducted under the auspices of the B r i t i s h Columbia Game Com-mission, and specimens from several l o c a l i t i e s were kindly submitted by personnel of that organization. Special thanks are extended to the following: Inspector G. F.. Kearns, Sup-ervisor J. Robinson, Hatchery O f f i c e r A. Higgs and Game War-den R. G. Rutherglen. I am under obligation to W. B. Scott of the Royal Ontario Museum of Zoology, and to Dr. F. E. J. Fry of the University of Toronto. F i n a l l y , I wish to express gratitude to my wife f o r taking second place to this work. -4-LITERATURE ON THE SPECIES The redside shiner has been variously placed i n the genera.Abramis (Cyprinus) t Leuciscus and f i n a l l y Richardsonius. The species was f i r s t named by S i r John Richardson i n 1836. The common name has been given as Columbia r i v e r minnow, Rich-ardson's minnow, red sided bream, shiner, lake shiner and redside shiner. Early nomenclature of the species i s dealt, with by Schultz and DeLac^y (1935). The known range of the genus Richardsonius includes B r i t i s h Columbia south of 56°, Washington, Oregon, and parts of Idaho, Nevada and Utah. Within t h i s area Jordan, Evermann and Clark (1930) recognize four species l a r g e l y on the basis of anal f i n ray counts. They state however that many species i n the group need comparison and v e r i f i c a t i o n , and conclude that "any arrangement of these fishes must be s t i l l wholly p r o v i s i o n a l . " Schultz and DeLac^y (1935) recognize two subspecies of R, ja l t e a t u s , R. b. balteatus (Richardson) i n the Eraser r i v e r , Columbia r i v e r and Streams of Washington and Oregon, and R. b. hydrophlox (Cope) p r i n c i p a l l y confined to the Columbia system above Snake r i v e r f a l l s i n Idaho and the Salt lake drainage i n Utah. Here separation i s apparent-l y a geographic one, again based on variable anal f i n ray counts. M i l l e r and M i l l e r (1948) state that the species i s abundant i n the Colorado r i v e r basin of northeast Nevada and has been recently introduced i n the upper Colorado r i v e r . On the basis of anal f i n ray counts, t h e i r c o l l e c t i o n s f i t the description of R. b. hydrophlox with some intergrades with R. b. balteatus. A group occurs i n the warm springs of southern Oregon characterized by low anal ray counts; i t i s recognized as R. thermophilus Evermann and Cockerell by Jordan, Evermann and Clark (1930). In 1894.Dr. C. H. Eigenmann published ray counts of R. balteatus taken from d i f f e r e n t l o c a l i t i e s on the Praser and Columbia systems. While there was considerable v a r i a t i o n within single populations, there was also great v a r i a t i o n i n mean ray counts of d i f f e r e n t populations. He compared anal ray counts i n the 21 genera of A t l a n t i c Slope Cyprinids with the 17 genera: from the P a c i f i c Slope, the former having from 6 to 14 anal rays (a range of 9), but the l a t t e r varying from 7 to 22, (a range of 15), He concluded from comparison of c o l l e c t i o n s from the Praser system that the number of rays i n the species, and also the range of var i a t i o n , decreases with increasing a l t i t u d e . He also stated without elaboration that the tendency of frequency curves of anal ray counts to be skewed to the l e f t indicates that the number of rays i s i n the process of.increasing. In the same year Gilbert and Evermann (1894) denied Eigenmann's generalizations concerning lower ray counts and less range at higher al t i t u d e s , publishing counts f o r 30 c o l l e c t i o n s with corresponding a l t i t u d e s as evidence. In 1895 Eigenmann r e i t e r a t e d his claims f o r the effect of a l t i t u d e on ray count and presented more data, but denied that he intended i t as a generalization f o r other species. -6-In 1897 Evermann published a table of ray counts and alt i t u d e s f o r seven more l o c a l i t i e s , not conforming to Eigenmann's observations. He states "At one time Dr. Eigenmann thought that a c e r t a i n d e f i n i t e r e l a t i o n existed between the number of anal rays i n this species and the a l t -itude In the.light-of f u l l e r data Dr. Eigenmann now agrees with us that t h i s generalization i s not borne out by the f a c t s . " Further contributions to the subject consisted of additional records of ray counts from o t h e r . l o c a l i t i e s , (Evermann and Mee>e 1898, Snyder 1907, M i l l e r and M i l l e r 1948) and d i s t r i b u t i o n a l records which are l i s t e d i n Schultz and DeLacjefy (1935) (to which should be added recent works mentioned below). Scales of Richardsonius are dealt with by Cockerell (1911a, 1911b), Cockerell and A l l i s o n (1909) and Evermann and Cockerell (1909). Occurrences i n B r i t i s h Columbia are given by Clemens and Munro (1934), Stanwell-Fletcher (1943), and Carl and Clemens (1948). Measurements of specimens are given by Dymond (1936) and Schultz. and Schaeffer (1936). Food i s l i s t e d by Munro and Clemens (1937), Clemens, Rawson and McHugh (1939), Ferguson (MS) and Anderson (MS). In summary, l i t e r a t u r e on the species comprises descriptions and changes i n nomenclature, claims and. denials concerning the effect of a l t i t u d e on anal ray count, and l i m i t e d information on the ecology of the species. Few. data are available i n the l i t e r a t u r e on spawning habits, growth rates or other phases of the l i f e h i s t o r y . -7-LIPE HISTORY RANGE AND HABITAT The present study does not extend the range of the redside shiner reported i n the l i t e r a t u r e . I t includes 54 l o c a l i t i e s i n B r i t i s h Columbia, d i s t r i b u t e d as follows: Skeena r i v e r drainage - 1 Praser r i v e r drainage Driftwood v a l l e y - 1 Caribou area - 5 Thompson r i v e r drainage -12 Lower Praser v a l l e y - 2 Columbia r i v e r drainage Okanagan drainage - 8 Arrow-Kootenay drainage - 21 Kootenai r i v e r drainage - 4 L o c a l i t i e s where c o l l e c t i o n s were made together with pertinent information are given i n Appendix I. The species i s not l i s t e d by Clemens, Boughton and Rattenbury (1945) i n T e s l i n lake at the northern boundary of B r i t i s h Columbia. Cowan (1939) does not l i s t i t from the Peace r i v e r drainage, nor has i t been reported authentically on Vancouver i s l a n d . Shiners occur i n a wide range of habitats. Some frequent small warm^e^ltrophic lakes such as Rosebud, with abundant aquatic vegetation and r e l a t i v e l y high concentration of dissolved s o l i d s . Others are found i n large cold Pig.2. Diverse habitats occupied by shiners Top - E r i e Pothole Bottom - Kaslo "bay, Kootenay lake -8-oligotrophlc lakes such as Arrow, Kootenay and Okanagan, with barren shores and l i t t l e dissolved material. An extreme i n 7 low temperature tolerated by shiners was encountered i n E r i e Pothole, a c i r c u l a r pool some 200 metres i n diameter and 7 metres deep, surrounded by a f l o a t i n g marginal mat. Through-out the summer a steep temperature gradient persisted; on 28 August 1949 the surface temperature was 21°C. and the bottom was 7°C. The species also inhabits running water. Shiners were present among log tangles i n the Inonoaklin r i v e r , where they occurred together with Kamloops trout i n a surface cur-rent of one foot per second. Specimens were taken i n swift current about p i l i n g s of a bridge across the Shuswap r i v e r at Grinrod; others were found i n Bonanza creek, a shallow stream with gravel bottom and reedy borders. Appendix I includes temperatures and some notes on limnological conditions. Pig. 2 i l l u s t r a t e s the d i v e r s i t y of habitats occupied by shiners. The redside shiner i s adaptable to a considerable range of physical and chemical conditions, and i s one of the most successful of fresh-water f i s h e s i n B r i t i s h Columbia. I t cohabits this area with r e l a t i v e l y few other fresh-water species, (63 i n B r i t i s h Columbia as against about 200 i n Ontario,) and appears to f i l l an important niche or series of niches i n a number of habitats. I t has probably invaded the northern part of i t s range from the south through the Columbia and Praser r i v e r systems following the re t r e a t of the l a s t g l a c i a t i o n , (Carl and Clemens 1948). Its absence from many lakes i n B r i t i s h Columbia i s probably due not to i t s i n a b i l i t y to maintain Its p o s i t i o n there, but to i t s f a i l u r e so far to gain entrance due to geographical b a r r i e r s . This contention i s borne out by the explosive success of shiners introduced recently into such new l o c a l i t i e s as the Pinantan - Paul lake chain near Kamloops and many lakes i n the Kootenay d i s t r i c t . In recent years introduction has commonly occurred through release of shiners used by anglers fo r l i v e b a i t . SPAWNING No information on the spawning habits of the red-side shiner i s available from the l i t e r a t u r e . Throughout the summer of 1949 a l l e f f o r t s to observe spawning f a i l e d ; no eggs were found despite detailed examination of the bottom and vegetation i n the v i c i n i t y of young f r y . Information on spawning places and dates has been i n f e r r e d from other data. A few eggs were stripped from shiners and hatched successfully under a r t i f i c i a l conditions. Of about 1000 females tested, only 14 yielded eggs which subsequently dev-eloped. Ripe females d i f f e r e d i n size, and were taken i n a variety of habitats at varying depths and times of day. Dissection revealed quantities of unripe eggs remaining i n females which had been stripped of r i p e eggs. Unripe eggs were present at a l l times i n most individuals large enough to be mature. In Rosebud lake, females with r i p e eggs occurred sporadically i n c o l l e c t i o n s from 3 June to 22 July. The maj-o r i t y of males provided free-flowing milt over the same -10-period; dissection and flooding of testes yielded active sperms both before and aft e r these dates. Individuals may possibly spawn several times i n a season, the production of eggs and sperms being a more or less continuous process. The small number of females with ripe eggs compared with the number with near-ripe eggs sug-gests that time between complete ripening of eggs and their deposition i s r e l a t i v e l y short. Pig. 3 shows the size range of f r y c o l l e c t e d at d i f f e r e n t dates i n Rosebud lake. Average hatching size i s estimated from hatchery-reared specimens to be 5.0 mm. Growth rate of reared f r y between hatching and absorption of yolk sac i s plotted on the same f i g u r e . (Growth of hat-chery specimens f a l l s o f f beyond t h i s point probably due to improper feeding.) Starting from the size of the largest f r y i n the e a r l i e s t sample, the slope of t h i s l i n e i s used to obtain the approximate date on which these f i s h were 5.0 mm. long, i . e . just hatched. The period from f e r t i l i z a t i o n to hatching, estimated from experimental data as 8 days, i s subtracted i n order to give the date of f i r s t spawning. No f r y l e s s than 7.2 mm. long were taken i n any lake. Between hatching and reaching t h i s length, f r y are probably l i v i n g on yolk reserves and are r e l a t i v e l y i n a c t i v e . e r y (Hatchteg specimens i f undisturbed remain quiescent on the bottom during the f i r s t 5 to 12 days afte r hatching, but subsequently swim f r e e l y near the surface.) Rosebud lake samples on 3 July and 8 August probably represent only those individuals old enough to be a c t i v e l y feeding; smaller f i s h J I I I —I I I I I I MAY J U N E J U L Y A U G . S E P T . Fig. 5. Estimate of spawning period from length frequency-distributions of fry, Rosebud lake, 19^9* -11-were present i n the lake but were not taken i n the net. By 28 August the l a s t f r y of the 1949 year class had grown beyond minimum catcheable size, so that the smallest f i s h i n t h i s l a s t sample are the l a s t hatched during the year. The l a s t date of spawning can be estimated by running a l i n e with appropriate slope back from the smallest f r y on 28 August to give the date at hatching, and then subtracting the prehatching period. I t has been assumed that size l i m i t s i n the samples were representative of those i n the lake, that early growth rate of 21°Chatchery specimens equaled that of wild f r y , that their prehatching periods were equivalent, that incuba-t i o n periods and growth rates were equal throughout the sum-mer, and that growth between hatching and 15.0 mm. was l i n e a r . Probably these assumptions are only approximately true, but the resultant error i s considered to be small, as dates for rip e egg c o l l e c t i o n s (shown i n the figure) f i t the estimated spawning period. Spawning i n Rosebud lake i n 1949 probably extend-ed from the end of May to the f i r s t week of August. Fry co l l e c t i o n s from Kaslo on Kootenay lake suggest that spawn-ing at that l o c a l i t y was more r e s t r i c t e d , occurring from the t h i r d week of June to the l a s t week of July. This was r e f l e c t e d i n a smaller size range i n each year class. Scanty data f o r other lakes suggest that usually length of spawning season i s intermediate between that of Rosebud and Kootenay lakes. Protraction of the spawning -12-period i s apparently the r e s u l t of two fact o r s ; d i f f e r e n t individuals spawn at d i f f e r e n t times, and each i n d i v i d u a l may spawn more than once during a single season. As no eggs were found i n the wild, l i t t l e can be said as to spawning l o c a l i t i e s except that they are probably near shore i n protected sit u a t i o n s . In Rosebud lake small f r y were taken at many d i f f e r e n t points about the shores, usually i n sheltered situations among matted vegetation. Eggs may have been deposited i n the thick bottom layer of loose organic debris, or perhaps i n abundant Chara beds i n deeper water adjacent to shore. Small f r y were observed among f l o a t i n g logs and about boat houses over deep water i n Kaslo bay on Kootenay lake, but these may have moved out from the surrounding shore. Large numbers of f r y were taken i n the west arm of Kootenay lake along a sand beach with l i t t l e or no submerged vegetation. The va r i e t y of habitats occupied by the shiner as well as the v a r i e t y of l o c a l i t i e s i n which young f r y were taken suggest that spawning require-ments are not r i g i d . EMBRYOLOGY An attempt was made to r a i s e shiners under con-t r o l l e d temperature conditions during the summer of 1949 at the Kaslo hatchery. While a few eggs were hatched and the f r y were kept a l i v e f o r periods up to 57 days, none developed anal f i n rays before death. Consequently the experiments did not contribute s u b s t a n t i a l l y to study of str u c t u r a l v a r i a t i o n , but did provide information on early -13-development. Eggs were kept i n baths at 9°, 12°, 15°, 18° and 21°C, supplied with a steady flow of oxygenated water. The apparatus i s described i n Appendix I I I . In the f i e l d , eggs were squeezed from r i p e females by s l i g h t pressure on the abdomen, and co l l e c t e d In the dry inverted top of a screw top jar . M i l t from one or more males was obtained i n the same manner, and mixed with the eggs. Eggs, milt and a small amount of water were swirled about and then l e f t quiescent f o r a few minutes. The l i d with adhering eggs was submerged gently i n a p a i l of water and screwed onto an inverted jar underwater so as to exclude a i r bubbles. The Jar, kept i n an inverted position, could then be transported safely. The l i d with adhering eggs was removed at the hatchery and placed d i r e c t l y into the temper-ature bath. Any eggs which had come loose and were free i n the jar were poured out into the bath. In some cases l i v e parents were brought to the hatchery i n cans and stripped d i r e c t l y into the baths. Eggs passed f r e e l y from ripe females with the application of s l i g h t pressure. They were a clear golden yellow, spherical and about 1.6 mm. i n diameter. The max-imum number of ripe eggs obtained from one female was about 250. The chorionic membrane enlarged, when placed i n water, u n t i l i t stood well away from the yolk, becoming increasingly f i r m and e l a s t i c . F e r t i l i z e d eggs adhered even to smooth surfaces. M i l t , which streamed f r e e l y from r i p e males when -14-only very s l i g h t pressure was applied, was white and opaque. When activated by water, sperms were discernable at a mag- . n i f i c a t i o n of 720 diameters as minute c i r c u l a r bodies, exhibiting a c t i v i t y comparable to intense Brownian movement. A c t i v i t y l a s t e d about one minute. Figure 4 shows a series of stages i n the develop-ment of the egg. Time of development i s not indicated as the series i s a composite of sketches made from eggs at diff e r e n t temperatures on d i f f e r e n t occasions. Figure 4 A shows an early stage i n cleavage of the germinal disc. In F i g . 4B the blastoderm s i t s as a cloudy cap on top of the clear yellow yolk. In F i g . 4C the blast-oderm i s beginning to spread around the yolk, and i n F i g . 4D envelopment has proceeded so that the yolk i s protruding beneath as a plug. F i g . 4E shows the neural folds forming on top of the embryo, while F i g . 4F and 4G are l a t e r a l and ventral views of a l a t e r stage with optic v e s i c l e s forming. Complete development and hatching occurred at temperatures from 12° to 21°C. In the 9° bath i n i t i a l cleavage occurred, but, at 100 hours a f t e r f e r t i l i z a t i o n , the germinal disc appeared as a group of i r r e g u l a r c e l l s scattered on the surface of the yolk (Fig. 4H). No further development occurred at this temperature. At l a t e r stages of development the t a i l bud i n c r -eases i n length u n t i l the embryo i s curled around i n a s p i r a l within the chorion. The heart beat and blood c i r c u l a t i o n become e a s i l y v i s i b l e , and periods of spasmodic m o t i l i t y occur. Fig. 5« Shiner larvae showing raedian f i n fold and development of f i n rays. X 7s approx. -15-The mean number of days between f e r t i l i * a t i o n and hatching at d i f f e r e n t temperatures are summarized below. The wide difference i n number of individuals hatching i n dif f e r e n t baths i s probably not d i r e c t l y attributable to affect of temperature on v i a b i l i t y , as the parents, the i n i t i a l number and the treatment of the eggs varied. Water temperature - Centigrade 9° 12° 15° 18° 21° Hatching time, days - 15 11 8 7 Number hatched 0 9 200 4 7 METAMORPHOSIS In the present study metamorphosis of the embryo was studied with special reference to the development of the anal f i n . Nomenclature of the stages i s that suggested by Hubbs (1943). Nomenclature of the f i n elements i s that of Eaton (1945). Details of development of the redside shiner from f e r t i l i z a t i o n to juvenile stage appear to follow i n general the course outlined f o r Cyprinids by Balinsky (1948). When hatched, the l a r v a bears a r e l a t i v e l y small yolk sac. Within a short time the head, which i s at f i r s t bent down towards the yolk sac, straightens, and the yolk i s ra p i d l y absorbed. As yolk i s assimilated the l a r v a becomes more active, leaving the bottom to swim f r e e l y f o r increas-ing periods and s t a r t i n g to feed. The smallest free swim-ming larvae (Pig. 5, top) have a median f i n running from the centre of the b e l l y around the t a i l and forward dors a l l y to a point some distance ahead of the d e f i n i t i v e p o s i t i o n of the -16-dorsal f i n . This f i n i s interrupted only at the anus. In e i t no d e f i n i t i v e f i n rays ( l e p i d o t r i c h i a ) are present, but a continual series of c l o s e l y set d e l i c a t e horny rays, (actinotrichia) are v i s i b l e . The pectorals are present as t h i n leaves, but at this stage there i s no trace of the p e l v i c s or median f i n s . The rudiment of the a i r bladder i s obvious. As the l a r v a grows, the f i n f o l d becomes higher i n the region of the dorsal, and l a t e r the anal f i n (Pig. 5, -centre). Concentration of tissue occurs i n a s t r i p marking the base of the f i n , and d e f i n i t i v e f i n rays become v i s i b l e commencing at the anterior end of each f i n . The dorsal rays are f u l l y formed before the anal. As the anal f i n develops a s t r i p of denser tissu e at the f i n base forms into a series of discrete masses. The^se appear from anterior to posterior, somewhat e a r l i e r than the f i n rays, so that i t i s possible i n a l a r v a at t h i s stage to distinguish a greater number of discrete basal elements than discrete l e p i d o t r i c h i a . At this stage the p e l v i c f i n rudiments begin to appear as s l i g h t protuberances on either side of the median f i n anter-i o r to the anus.-As formation of the dorsal f i n rays i s completed and that of the anal f i n rays progresses, the f i n f o l d diminshes i n width ahead of the dorsal, between dorsal and caudal, and between anal and caudal (Pig. 5, bottom). The pelvic rudiments grow r a p i d l y and appear as l i t t l e paddles without v i s i b l e rays, the ventral f i n f o l d p e r s i s t i n g ahead of the anus. -17-Later the embryonic f i n f o l d disappears. Rays appear l a s t of a l l In the pelvic fins,marking the d i v i s i o n between larvae and juvenile stages; beyond t h i s point the i n d i v i d u a l i s essentially adult i n appearance. GROWTH Growth of f r y during the f i r s t year has been dealt with i n the discussion of spawning periods. The best method of ageing subsequent year groups was by their length frequency d i s t r i b u t i o n s . Figure 6 shows lengths of f i s h sampled at various times during the summer of 1949 at Kaslo bay on Kootenay lake. The f i r s t c o l l e c t i o n , taken on May 29 i s shown at both ends of the series to indicate the r e l a t i v e l y s l i g h t growth occurring during the winter months. Collections from two other parts of the Kootenay lake system are shown i n the same fi g u r e . The c o l l e c t i o n from Taghum, on the lower Kootenay r i v e r about four miles below Nelson, apparently indicates more rapid growth than at Kaslo, while f i s h from Lardeau at the north end of Kootenay lake show a s l i g h t l y slower growth. Temperature observations, plankton hauls, bottom dredgings and water analysis were made during the general survey of Kootenay lake i n 1949 by the B r i t i s h Columbia Game Commission. These indicate that the north end of the lake i s colder and r e l a t i v e l y poorer In plankton and bottom organisms than the south end and west arm. The lower Kootenay r i v e r i s supplied by warm water r i c h i n plankton, drawn o f f the surface of Kootenay lake along the 3 0 2 0 iO \o 5 - 2 , 9 M A Y 10 J U N E L B K A S L 0 Q U E E N ' S B A Y 1 6 J U L Y T A G H U M L I 5 J U L Y L A R D E A U o 72.1 J U L Y u . . i . l . K A S L O 40 3 0 b_ 4° 0 20 o Z 20 \o -I2> A U G K A S L O K A S L O . - 2 9 M A Y K A S L O 2 0 4 0 6 0 S T A N D A R D L E N G T H 8 0 M M , Fig. 6. Length frequency distributions- of shiner collections;: from Kootenay lake, 19^ -9 • -18-shallow west arm. Apparently ecological conditions at Lardeau, Kaslo and Taghum are r e f l e c t e d by growth rates of shiners i n these l o c a l i t i e s . Kootenay lake shiners appeared to show the slowest growth of any populations examined. The opposite extreme was represented by f i s h from Pinantan lake. This body of water i s highly eutrophic (Rawson 1934), with large areas of weedy shallows. Shiners are extremely abundant and many are of large s i z e . According to the available length f r e q -uency data shiners i n Pinantan lake reach an average length at the end of t h e i r second year approximately equal to the average reached by Kootenay lake shiners at the end of three years. Growth rates of the two populations are summarized below; growth i n other l o c a l i t i e s studied was apparently intermediate between these two. Estimated Mean Standard Length on Sept. 1. Year 0 Year I Year III Kootenay lake, Kaslo 17 mm. 34 mm. 55 mm. Pinantan lake 27 mm. 55 mm. 75 mm. In the younger age groups of several populations males had a greater mean size than females. Range of var-i a t i o n was great, and i t was not possible to attribute s t a t i s t i c a l significance to the difference. However, males possibly have a higher metabolic rate than females, growing fas t e r and dying sooner. Ageing of the largest individuals by length frequency d i s t r i b u t i o n i s not possible because of the small -19-number of specimens. Scale reading i s an unsatisfactory method of age determination as few c i r c u l i are formed each year and annuli are usually i n d i s t i n c t . Nevertheless, ageing by scales could probably be c a r r i e d out i n most pop-ulations by careful study of nuclear formations of f i s h spawned at the start and f i n i s h of the season. This would allow d i s t i n c t i o n between, fo r example, small two year olds and large one year olds. Age determination of the largest i n d i v i d u a l taken was attempted by scale examination. This f i s h , taken by g i l l net from Rosebud lake, had a standard length of 123 mm. and a t o t a l length of 151 mm. I t was i n i t s s i x t h or poss-i b l y i t s seventh year. The oldest class which forms an appreciable per-centage of most populations i s made up of f i s h i n t h e i r fourth year, the majority of which are females. SEX RATIO There i s some i n d i c a t i o n that the sex r a t i o i s unbalanced i n some populations. Of 21 samples from d i f f e r e n t l o c a l i t i e s , 12 showed sex r a t i o s not s i g n i f i c a n t l y d i f f e r e n t from 50:50 at the 5% p r o b a b i l i t y l e v e l . Seven l o c a l i t i e s had s i g n i f i c a n t l y more females than males (p < 0.01 f o r 4 samples, 0.02 - 0.01 f o r 2 samples and 0.05 - 0.02 f o r 1 sample). Two l o c a l i t i e s . h a d s i g n i f i c a n t l y more males than females (p < 0.01 for 1 sample, 0.02 - 0.05 f o r the other). There are several possible explanations f o r the r a t i o s found i n these samples. In many populations the - 2 0 -largest f i s h were almost exclusively females. (These i n d i v -iduals were probably older, rather than f a s t e r growing, as suggested i n the previous section.) The same condition i s reported by Cooper (1935) for the golden shiner Notemigonus  crysoleuca3. In thi s species females show greater v i a b i l i t y , r e s u l t i n g i n a drop i n the percentage of males i n older year classes. Such a factor would tend to ra i s e the percentage of females i n a sample containing a l l year classes. To correct f o r t h i s d i f f e r e n t i a l mortality i t i s possible i n some cases to separate the sample by length frequency d i s t r i b u t i o n into d i f f e r e n t year groups, and to consider the sex r a t i o i n each year group separately. While thi s reduces the sample siz e and hence raises the p r o b a b i l i t y of a given r a t i o being due to "chance", there s t i l l remain some samples with s i g n i f i c a n t l y more females even among one year olds. The preponderance of males i n some samples cannot of course be at t r i b u t e d to higher male mortality. There i s also the d i s t i n c t p o s s i b i l i t y of non-random sampling due to segregation or di f f e r e n t behaviour of the sexes. Such a phenomenon r e s u l t i n g i n biased sampling i s reported by Heuts (1947) for Gasterosteus aculeatus. There i s also the p o s s i b i l i t y that d i f f e r e n t growth rates of the two sexes coupled with selection of one size class i n sampling might res u l t i n heterogenous sampling. Neverthe-les s , the redside shiner appears to be p l a s t i c i n many environmentally controlled features, and there i s strong suggestion i n the l i t e r a t u r e (; Efcerhardt, 1943 ) that -21-unequal sex r a t i o s may be produced environmentally i n some fis h e s . Consequently, while the evidence presented here i s by no means conclusive, the p o s s i b i l i t y of environmental control of sex r a t i o i n R. balteatus should not be neglected. The species might serve as suitable experimental material for investigating the subject. MOVEMENTS Size Differences Shiners of d i f f e r e n t sizes tend to occupy d i f f e r e n t depth zones. Frequently f r y were observed close to shore i n a few inches of water while adults were present only farther offshore. To demonstrate t h i s phenomenon quantitatively a series of c o l l e c t i o n s was made on Rosebud lake on 28 August 1949. A round shallow dip net of wire screening, three feet across and suspended by four wires from the end of a f i v e foot bamboo handle, was used to sample shiners at varying depths. The unbaited dip net was lowered onto the bottom, l e f t there for exactly sixty seconds and then drawn rapidl y straight up out of the water. This procedure was repeated u n t i l an adequate sample had been obtained. Sampling was conducted i n the same manner i n each depth zone. Table I summarizes the size d i s t r i b u t i o n %f f i s h caught. A l l f i s h taken i n one foot of water were f r y below 25 mm. i n length. Very few f r y were taken i n two feet of water. No f r y were taken i n the two deeper zones, while the largest percentage of large f i s h was taken from the deepest zone. -22-TABLE I Standard Length of Shiners i n Different Depth Zones, Rosebud lake, 28 August 1949 DEPTH FEET DISTANCE FROM SHORE FEET NO. IN SAMPLE PERCENT 10-24mm OF 25-SAMPLE •39mm 40 IN SIZE -59mm 60 RANGE -80mm 1 6 16 100 0 0 0 2 12 63 6 29 62 3 4 20 58 0 36 55 9 9 30 79 0 3 83 14 The above experiment was conducted i n an area characterized by a dense growth of Chara and other aquatic vegetation. The tendency of young shiners to congregate inshore was also observed on barren beaches. Schools of small one year old shiners mixed with young suckers and squaw-f i s h , were several times observed l y i n g i n long narrow bands within ten inches of shore i n Kaslo bay. This may have res-u l t e d from temperature preference of the f r y . On 6 July 1949 the temperature of the water where such a band of young f i s h was present was 23.5°C.,. compared with 21.5°C. a few feet o f f shore. Presence of food might also account f o r such d i s t r i b u t i o n ; f r y taken along a beach i n the west arm of Kootenay lake were distended with copeCpods. Night A c t i v i t y . Shiners are apparently active at night i n some l o c a l i t i e s . Night seining at Kaslo and Kuskanook on Kootenay lake yielded shiners along exposed sandy beaches, In Rosebud lake on 22 July 1949, a trap suspended one foot beneath the -23-surface i n the centre of the lake caught a large number of shiners between 11 P.M. and 8:30 A.M. The same trap caught no f i s h between 8:30 A.M. and noon, nor were shiners observed i n the centre of the lake during daylight hours. A r t i f i c i a l l i g h t at midnight revealed shiners moving about o f f shore, but these may have been attracted or stimulated by the l i g h t s . Summer Range. During the summer of 1949, a few shiners at Kaslo bay were marked by c l i p p i n g the l e f t pectoral f i n . Numbers involved were too small to be used f o r s a t i s f a c t o r y population estimates. Up u n t i l June 25, 92 f i s h had been marked; no marking was done for the following 13 days. On July 8, a sample of 18 f i s h taken at the same boat house where the others had been released contained two marked in d i v i d u a l s . This indicates that at l e a s t some of the f i s h were i n the same v i c i n i t y where they had been taken., 13 days previously. From a t o t a l of about 200 f i s h marked at this l o cation, 10 were recovered. About 40 f i s h were marked by c l i p p i n g other f i n s at locations a few hundred yards from the f i r s t , but none of these was recovered. These and other similar observations suggest that shiners may sometimes frequent the same l o c a l i t y f o r considerable periods of time, returning repeatedly to the same boathouse s l i p or group of f l o a t i n g logs. Winter Habits. Scattered observations were made on winter habits of the species. In Cultus lake, shiners were r e a d i l y seined -24-i n shallow water on 25 September 1948. On 11 November 1948 no shiners were seen i n t h e i r former habitats, but a school was found i n the shelter of a sunken barge over deeper water. Fisheries Supervisor J. Robinson reports that shiners cannot be caught near shore on Kootenay lake during winter. In Kaslo bay, few shiners were v i s i b l e about the boathouses and log booms on 7 May 1949. Shiners became increasingly numer-ous during the following month, perhaps moving i n from deeper water. Shiners were r e a d i l y obtainable from E r i e pothole throughout the summer of 1949, but Game Warden T. Rutherglen reports that the only specimens obtainable i n la t e November 1949 were a few f r y dug out of the mud near shore. On 22 November 1948 f i v e shiners from Cultus lake were placed i n an a r t i f i c i a l pool at the north end of the University of B r i t i s h Columbia l i b r a r y grounds. During the winter the pool froze over completely. On 28 February 1949 a sample was taken of the bottom i n two feet of water. This contained one shiner, a l i v e and apparently buried i n decaying leaves. The foregoing observations suggest that during winter shiners may move into deeper water or i n some l o c a l i t -ies may bury themselves i n the bottom and l i e dormant. FOOD RELATIONSHIPS Relation to Game Species The r e l a t i o n which shiners bear to game f i s h i s of considerable importance i n B r i t i s h Columbia. Shiners have -25-been introduced recently and have m u l t i p l i e d enormously i n several lakes which formerly contained only game species. This s i t u a t i o n i s usually viewed with alarm by sportsmen, on-the assumption that shiners w i l l seriously compete with trout for food, or that shiners w i l l consume young trout. On the other hand i n some lakes such as Snowshoe, shiners have been purposely introduced as food f o r game f i s h . The species sometimes reaches phenomenal le v e l s of abundance. Whatever rol e they may play, shiners must exert an important pressure on the economy of many lakes. The present study concerns, only d i r e c t predation and the p o s s i b i l i t y of competition f o r food. Studies on competition are confined to q u a l i t a t i v e determination of food present i n samples of shiners and game species taken together. The game f i s h considered are the Yellowstone cut-throat Trout Salmo c l a r k i i l e w i s i (Girard), the Kamloops trout Salmo g a i r d n e r i i kamloops Jordan, the mountain Kamloops trout? S. g. whitehousei Dymond and the speckled char Salveyllinus f o n t i n a l i s ( M i t c h i l l ) . Predation by Shiners Consumption of trout f r y by adult shiners was investigated experimentally. In 1948 three t r i a l s using young Kamloops trout f r y from Summerland hatchery gave negative r e s u l t s . Shiners, chub and sculpins were placed f o r several days i n a hatchery trough with trout f r y ; only sculpins (Cottus asper) were found to eat f r y . Similar -26-r e s u l t s were obtained when an assortment of f i s h including shiners were confined with trout f r y i n an enclosure on A l l i s o n lake; only the sculpins ate f r y . On 1 Sept. 1948, a seine was set i n an arc out from the shore of Taylor lake, and approximately 1000 Kamloops trout f r y were released i n -side the arc. After 10 minutes the seine was drawn i n cap-turing a number of shiners. No f r y were found i n their stomachs. In the summer of 1949, shiners from Rosebud lake were kept i n a trough at Kaslo hatchery f o r several weeks. Kamloops trout f r y were then introduced. Dead or injured f r y were eaten by the shiners, but healthy f r y remained a l i v e for two days i n the trough. Shiners would approach f r y swimming near the surface, but would not pursue i f the f r y attempted to evade them. Shiners with a t o t a l length of 80 to 100 mm. ate injured f r y with t o t a l length of approxim-ately 25 mm. On 27 July 1946 Dr. D. C. 0. MacKay co l l e c t e d shiners from Pinantan lake following planting of Kamloops trout f r y . The stomachs of eight of these preserved specimens were examined by the writer i n 1950; two contained trout f r y and three others contained u n i d e n t i f i e d f i s h remains. Apparently shiners are capable of eating trout f r y and i n some instances they may do so under natural conditions. Although conditioning of the hatchery shiners may have biased r e s u l t s of the Kaslo experiments, i t i s suggested that shiners may be discouraged from attacking f r y i f the f r y make a det--27-ermined e f f o r t to escape. Trout f r y poured from a hatchery can Into shallow water were several times observed to l i e i n a c t i v e on the bottom f o r some minutes afte r release. This observation coupled with feeding experiments and the presence of f r e s h l y released f r y i n shiner's stomachs suggests that trout f r y may be p a r t i c u l a r l y susceptible to predation when they are f i r s t introduced into new surroundings. Predation on Shiners Various observations indicate that shiners are eaten by Kamloops trout, cut-throat trout and speckled char. At Nelson hatchery on 20 Aug. ^  1949^ a number of Rosebud lake shiners, from 20 to 40 mm. long, were introduced i n a c i r c u l a r rearing pond containing yearling Kamloops trout about 100 mm. long. Trout were seen to eat the shiners, usually swallowing them whole. Dead trout f r y were also eaten by the yearlings. Shiners occurred i n the stomachs of trout from various lakes. Stomachs of the larger Kootenay lake Kamloops trout taken i n 1949 contained mainly f i s h , usually kokanee Oncorhynchus nerka kennerlyi (Suckley) but occasionally shiners. Kamloops trout i n Pinantan lake are said to feed l a r g e l y on shiners; thermal s t r a t i f i c a t i o n and severe oxygen stagnation i n the hypolimnion (Rawson 1934) may force the two species into close contact. Shiners have recently entered Paul lake but have so f a r been reported by l o c a l residents as occurring i n only a few trout stomachs. Ander-son (MS) suggests shiners must reach a c e r t a i n c r i t i c a l l e v e l of abundance before serving as trout food. -28-In Rosebud lake speckled char were observed chas-ing shiners. Two char, 10 and 12 inches long, swam back and f o r t h i n a dense school of shiners, darting at a shiner every few seconds. The shiners were apparently unconcerned, swimming within a foot of the char. No shiners were eaten during the period of observation, but injured shiners thrown on the water were immediately seized by the char. In Cottonwood lake the shiner population apparently contains a disproportionate number of old f i s h . Of 37 spec-imens taken on f i v e d i f f e r e n t occasions, 30 were over 80 mm. standard length and probably three or more years old. The dense population of small mountain Kamloops trout present may prey upon shiners up to a certa i n c r i t i c a l s i z e , prod-ucing t h i s uneven age d i s t r i b u t i o n . While no shiners were found i n trout stomachs from the lake, only a small percen-tage of the shiner population, as sampled by dip netting, was small enough to be eaten by the trout. Shiners too large to be eaten apparently l i v e successfully alongside trout of almost the same s i z e ; the two species were frequently•taken i n the same dip net. Competition Table II shows the food items i n stomachs of f i s h taken from Rosebud and Cottonwood lakes by g i l l net and dip net. In Rosebud lake a l l three species of game f i s h ate shiners, and the large shiners also contained small shiners. In both lakes, a l l food items eaten by game species were also taken by shiners. This i s also true of co l l e c t i o n s of shiners -29-not included i n Table II,taken along with speckled char f i n g e r l i n g s and cut-throat (or possibly Kamloops) f r y i n a cold stream entering Rosebud lake. S i m i l a r l y c o l l e c t i o n s of Kamloops trout together with shiners from South Champion lajce and also from the Inonoaklin r i v e r a l l contained t e r r e s t r i a l insects plus a few les s e r items. TABLE II Food of Shiners and Game Species Taken Together, 1949 (Rosebud lake - 20, 21 June, 22, 23 July, 7 Aug. Cottonwood lake - 11 July, 16 Aug.) NO. OF STOMACHS CONTAINING FOOD ITEM ROSEBUD LAKE Cut-throat trout SAMPLE SIZE Algae i . C CO O jG W) Ph CO !>> & U rH £, Q «H C Larval Diptera Terr'l insects Mollusca Shiners o CO •H S 9 1 1 7 2 1 Kamloops trout 1 1 1 Speckled char 25 15 . 3 1 14 2 Redside shiner 14 6 3 2 1 3 3 1 COTTONWOOD LAKE Mtn. Kamloops trout 12 2 1 7 1 Redside shiner 9 1 2 7 2 2 Ecological Relations In summary, shiners and game species apparently often have a d e f i n i t e e f f e c t on each other. It has been shown that under c e r t a i n conditions shiners eat trout, trout eat shiners, shiners eat shiners and trout eat trout. In -30-addltion shiners and young or adult Salmonids have been found to contain similar food when taken together. Shiners may therefore be injurious to.game f i s h production by consuming young and by competing f o r food of both young and old, or they may be beneficial by serving as prey for large Salmonids,converting d i f f u s e nutrients i n t o r e a d i l y available food. They probably f i l l a l l of these roles i n various habitats, environmental conditions govern-ing the precise r e l a t i o n s h i p . Dymond (1930) has suggested that the c r i t i c a l f a c -tor a f f e c t i n g production of trout i n some B r i t i s h Columbia lakes i s the food available for the young during t h e i r f i r s t year; once trout are large enough to consume f i s h they are i n command of an ample food supply. This s i t u a t i o n may produce r e l a t i v e l y small numbers of r e l a t i v e l y large f i s h . From the present study i t i s suggested that shiners may i n some cases i n t e n s i f y the condition outlined by Dymond, o f f e r r i n g competition to young trout and serving as food for old trout. The amount of contact between species of f i s h probably varies i n d i f f e r e n t seasons. Physiological studies on the physical and chemical tolerances of each species involved might fu r n i s h evidence as to the degree of overlap of the zones occupied by each. -31-STRUCTURAL VARIATION LITERATURE ON VARIATION IN PISH Body proportions and the number of f i n rays,verte-brae and scales are known to vary from population to popula-t i o n i n many species of f i s h . In order to make taxonomic use of these characters i t i s necessary to be able to separate genotypic from phenotyplc v a r i a t i o n . I t i s therefore d e s i r -able to know which factors control phenotyplc v a r i a t i o n , and what are the mechanisms and extent of t h e i r operation. The l i t e r a t u r e contains many d i f f e r e n t l y contrad-i c t o r y r e s u l t s of investigations on the e f f e c t of p a r t i c u l a r environmental factors on p a r t i c u l a r meristic characters of f i s h . Concerning the effect of temperature on f i n rays, Schmidt (1917) concluded from experimental studies on Lebistes r e t i c u l a t u s that higher temperatures during develop-ment of the young produced higher numbers of f i n rays. S i m i l a r l y Jensen (1939) finds i n the p l a i c e and the dab that the number of anal rays i s d i r e c t l y proportional to water temperature when the larvae are small, 1°C. corresponding to 0.4 anal rays. Schultz (1927) finds a d i r e c t c o r r e l a t i o n between the highly variable anal ray count of the golden shiner Notemigonus crysoleucas and mean temperature during the spawning season. In contrast.to the foregoing, Hubbs (1922a) has demonstrated that the number of dorsal and anal rays of both Notropis atherinprdes and Lepomls Incisor i s greater when the -32-developmental period i s colder. Northcote (MS) shows that the average number of dorsal rays i n the p r i c k l y sculpin Cottus asper Increases from south to north between C a l i f o r n i a and B r i t i s h Columbia, presumably inversely to developmental temperature. The effects of temperature on vertebral count has been studied by several investigators. The works of H ubbs (1921, 1922a, 1922b) on Leptococcus armatus, Notropis a t h e r i - noldesj Lepomis i n c i s o r , Notropis hudsonius and Notropis  blennius, of Schmidt (1930) on the A t l a n t i c cod, of Suhd .T-(1943) on the Norwegian herring and of Hart and McHugh (1944) on the capelin, to mention only a few, a l l indicates that lower temperatures tend to produce higher vertebral counts. However, Schmidt (1921) shows data f o r Salmo t r u t t a which suggest that the curve of environmental temperature against vertebral count i s a c t u a l l y V-shaped, with high counts at low and high temperatures and low counts at intermediate temperatures. Mottley (1937) also makes thi s suggestion. Gabriel (1944) challenges the v a l i d i t y of Schmidt's conclusions and presents data on c a r e f u l l y controlled exper-iments with Fundulus heteroclitU3. These show that high temperature produces fewer vertebrae, but lowering of devel-opmental temperature below a c e r t a i n point does not r e s u l t i n further increase of vertebrae. He concludes that d i f f e r -ences i n vertebral count at d i f f e r e n t temperatures are due to differences i n temperature r e l a t i o n s of processes control-l i n g growth and processes c o n t r o l l i n g d i f f e r e n t i a t i o n . -33-H i s t o - d i f f e r e n t i a t i o n i s more accelerated by high temperature than somittf separation and growth; consequently at high temperature vertebral d i f f e r e n t i a t i o n takes place when the embryo i s smaller and fewer vertebrae are formed. However, there are also g e n e t i c a l l y controlled differences i n develop-mental rate and i n the degree of temperature control. Verte-bral count i s therefore probably the resultant of both environmental and hereditary effects i n the species studied. There i s some doubt as to the effect of temperature on vertebral count of the golden shiner Motemigonus crysoleucas a cyprinid similar i n many respects to R. balteatus. S chultz (1927) concluded that anal ray count was re l a t e d to tempera-ture during development, and yet he states that there i s no s i g n i f i c a n t c o r r e l a t i o n between number of anal rays and number of caudal vertebrae. Gosline (1948) gives figures suggesting that there i s a tendency f o r the t o t a l vertebral count of the species to increase towards the north-east of i t s range (Texas to Maine). Hart (MS) on the other hand shows a r i s e i n t o t a l vertebral count from north to south (between Ontario, Ohio and F l o r i d a ) . Other environmental factors may af f e c t vertebral count. Heuts (1947) l i s t s s i x species of f i s h i n which increased s a l i n i t y produces higher vertebral counts. Scale count may likewise be controlled by environment; Hubbs (1922a) claims high temperatures produce high scale counts i n Notropis atherinoides and Lepomis i n c i s o r , while Mottley (1934) suggests high temperature produces low scale counts -34-i n Salmo g a i r d n e r i i . Hubbs (1941) shows that young suckers infected with parasites show a delay i n time of scale forma-t i o n and a concurrent r i s e i n number of scales produced. Part of the c o n f l i c t i n the foregoing examples may be due to f a i l u r e to separate genetical from environmental va r i a t i o n ; differences occurring over the geographic range of a species might show spurious c o r r e l a t i o n with a tempera-ture gradient but a c t u a l l y be due to a genetic c l i n e . How-ever, most of the examples chosen above deal either with ex-perimental observations or with differences between d i f f e r e n t year classes. Consequently i t seems clear that i n some cases environment does modify the structure of f i s h e s . W. R. Martin (1949) has proposed a mechanism for of environmental control of body form. Log-log plots Abody parts against standard length of f i s h are characterized by a ser-ies of "stanzas" each with a d i f f e r e n t r e l a t i v e growth constant. Transition from one stanza to the next i s usually abrupt. The successive growth constants displayed are a l i k e f o r a l l individuals of a species, but the body size at the point of i n f l e c t i o n from one stanza to another i s subject to environmental cont r o l . Thus one i n d i v i d u a l may enter a per-iod of decelerated growth of a given part at a smaller size than another, and w i l l therefore have a r e l a t i v e l y smaller part during the remainder of i t s progress through the stanza. Martin showed experimentally that trout raised at higher temperatures showed f a s t e r growth rates, had larger body size at i n f l e c t i o n from f a s t to slower growth of head -35-and f i n size, and consequently had r e l a t i v e l y larger heads and f i n s i n l a t e r l i f e . The di r e c t i o n of i n f l e c t i o n from one stanza to the next determines whether larger body size at i n f l e c t i o n r e s u l t s i n r e l a t i v e l y larger or smaller parts. ANAL RAY COUNTS Counting Methods Anal f i n ray counts were made with the aid of a binocular microscope. The l a s t double ray of the f i n has been counted as one, and the two (or r a r e l y three) rudiment-ary rays ahead of the f i r s t long ray have been omitted. There are very few cases i n which the ray count i s i n doubt, although r a r e l y the l a s t ray i s single or an intermediate ray i s s p l i t almost to i t s base. In general the number of divisions at the bases of the l e p i d o t r i c h i a have been taken as i n d i c a t i v e of the ray count. Omission of the anterior rudimentary rays (the procedure usually followed i n the l i t e r a t u r e ) i s not thought to have introduced an important error. The time required to count rays would be considerably increased by dissection to locate the occasional t h i r d rud-imentary ray, which i s r e l a t i v e l y small. In f i s h i n t h e i r second or higher year the l a s t rudimentary ray i s almost invariably less than half the length of the f i r s t f u l l ray, (see Pig. 1). The f i r s t ray counted i s unbranched; the remainder are s p l i t d i s t a l l y one or more times. Range of Variation Appendix II contains anal ray counts f o r 54 l o c -Fig„ 7o Anal ray counts of shiners from three localities,, -36-a l i t i e s i n British Columbia. Means varied from 12.00' to 17.44 with a range from 10 to 21. No obvious relation was apparent between ray count and altitude,latitude or drain-age system. Populations separated by less than a mile di f f e r -ed markedly, while populations some 600 miles distant were similar. Counts from three selected l o c a l i t i e s are shown i n Pig. 7. These represent the lowest and highest means obtained and one intermediate population. The range of the collections with highest and lowest means overlap by only one specimen. A r t i f i c i a l Introductions \ Ray counts were made on shiner stocks recently introduced from other known l o c a l i t i e s , and on samples from the parent populations. The species was introduced into Snowshoe lake from the Inonoaklin river by A, P. Coates in 1936, 1937 and 1938. Ray counts of samples taken from the two lo c a l i t i e s i n 1949 did not dif f e r significantly. (p>0.05). According to local residents, shiners were f i r s t introduced into the Paul lake watershed i n Hyas lake; they spread Into Pinantan lake sometime after 1930, and from here entered Paul lake in about 1945. The mean ray count of a sample from Pinantan was significantly lower than one from Hyas (p 0.02 - 0.05.) Ray counts of f i s h from the east end of Paul lake near the creek from Pinantan lake did not differ significantly from Pinantan counts, but counts of f i s h from the west end of Paul (3 miles distant) were significantly lower (p< 0.01) than those from the east end, and those from Pinantan. -37-An attempt at a r t i f i c i a l introduction by the writer was unsuccessful. Shiners from Cultus lake were i n t -roduced i n November 1948 i n t o three a r t i f i c i a l ponds on the University of B r i t i s h Columbia grounds. These apparently did not reproduce and were not seen after February 1949. Intra-population Variation The d i s t r i b u t i o n s for Pinantan and Nicola lake populations, (Fig. 7), display a s t r i k i n g phenomenon observed i n several populations. In the former the males have a s i g n i f i c a n t l y higher anal ray count than the females (p <0.0l) while i n the l a t t e r the reverse i s true, the females having a s i g n i f i c a n t l y higher ;niean (^ ><0.01). Females had s i g n i f i c -y antly more anal rays at Queen*s Bay, Kootenai lake (p 0.G2 -0.05), while males had s i g n i f i c a n t l y more rays i n Snowshoe lake (p 0.01 - 0.02) and i n the west end of Paul lake (p 0.02 - 0.05). The remaining 14 c o l l e c t i o n s i n which the. phenomenon was investigated d i d not show differences which were s t a t i s t i c a l l y s i g n i f i c a n t . A possible explanation of sex differences i n ray count i s discussed l a t e r . Variation, i n ray count was found also within single year classes. For example, Pinantan lake f r y taken on 18 August 1948 showed a s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n (p 0.01 - 0.02) between standard length and anal ray count. While i n t h i s and most other samples the larger f r y had high-er ray count, the reverse trend (not s t a t i s t i c a l l y demonstr-able) was found i n some sample^ Mean anal ray count also may vary from year to -38-year i n one l o c a l i t y . Mean count of shiners of a l l sizes c o l l e c t e d from Pinantan lake i n 1946 was s i g n i f i c a n t l y lower (p<,0.01) than the mean of individ u a l s taken there i n 1948. The higher mean of the 1948 sample appeared to be due l a r g e l y to one year old f i s h , which showed a higher mean than older f i s h , (on the basis of size frequency d i s t r i b u t i o n ) . Despite annual v a r i a t i o n found i n some populations, ray counts of shiners taken by the writer at Sicamous on Shuswap lake i n 1949 d i d not d i f f e r s i g n i f i c a n t l y from counts reported for the same l o c a l i t y by Dr. Eigenmann i n 1894. Summary of Adult Variation In summary, s i g n i f i c a n t differences i n anal ray counts have been found between f i s h i n d i f f e r e n t bodies of water, between recently introduced populations and the i r parent stock, between f i s h i n d i f f e r e n t parts of the same lake, and between c o l l e c t i o n s made i n d i f f e r e n t years from the same l o c a l i t y . Sometimes males have s i g n i f i c a n t l y fewer rays than females, sometimes s i g n i f i c a n t l y more. With-i n a year class, the larger f i s h sometimes have s i g n i f i c a n t l y more rays, and possib.l.x they sometimes have fewer. These are strong indications that anal ray count i s not- at l e a s t p a r t i a l l y subject to environmental control. -39-VARIATION IN ANAL PIN BASE Morphology of the Pin Base Schmidt (1917) and Hubbs (1922a) claim a d i r e c t r e l a t i o n s h i p between vertebral count and anal ray count i n cert a i n species of f i s h . However, i n families such as Cyprinldae the anal f i n Is short r e l a t i v e to the caudal reg-ion, and no s t r i c t s e r i a l arrangement common to f i n ray and vertebral elements i s apparent. Goodrich (1930) states that i t i s debatable whether the r a d i a l s of median f i n s are derivatives of the a x i a l skeleton or are s p e c i a l structures developed to support the f i n j at any rate i t i s impossible i n many adult Teleosts to associate each anal f i n segment with a corresponding body somite, either by the musculature or innervation. The supporting elements of the anal f i n of R. bal- teatus were examined on specimens cleared ¥/ith KOH and u l t r a -v i o l e t radiation, and stained with a l i z a r i n according to the methods outlined i n H o l l i s t e r (1934), and also on X-ray photographs of specimens. The anal f i n ray elements (Pig. 8) appear i n general to correspond to the figures and descript-ions of Goodrich (1930). A series of long, l a t e r a l l y f l a t -tened plates, the proximal r a d i a l elements, project inward toward the haemal spines of the vertebrae. At the outer end each proximal element a r t i c u l a t e s with a small c y l i n d r i c a l and s l i g h t l y tapering median r a d i a l element. This projects down and backwards, and bears on i t s posterior face a t h i r d s t i l l smaller d i s t a l r a d i a l element. The l e p i d o C t r i c h i a Pig.8. P r i n t of X-ray photograph Pig.9. V a r i a t i o n i n anal f i n s of shiners Top - 1.3 anal rays, Argenta slough. Bottom - 20 anal rays, S.Champion lake. -40- S arise as two s t r i p s , ...straddling the junction of the proximal and median elements and u n i t i n g some distance below to form a single c y l i n d r i c a l anal ray. D i s t a l to the junction of i t s two elements each ray i s divided by a series of j o i n t s , and each of the f u l l y developed rays, with the exception of the most anterior one, bifurcates one or more times antero-p o s t e r i q r a l l y . Anterior to the f i r s t long anal ray there i s , i n adult i n d i v i d u a l s , an unbranched ray about one t h i r d the length of the longest, and i n addition one, or r a r e l y two, much smaller rudimentary rays. The l a s t two rays of the f i n are united at the base. The number of proximal r a d i a l elements does not correspond to the number of somites they occupy nor, there-fore, to the number of haemal spines i n the region occupied by the anal f i n . There i s a crowding of proximal elements es p e c i a l l y toward the posterior end of the serie s . Also, the number of f i n rays does not necessarily correspond to the number of proximal r a d i a l elements supporting them nor to any simple f r a c t i o n thereof; there i s a variable degree of fusion of proximal elements, e s p e c i a l l y at either end of the seri e s . A t y p i c a l series r e s u l t i n g from t h i s crowding and fusion, taken from one of the cleared specimens, i s : 18 distinguishable l e p i d o t r i c h i a supported by 16 distinguishable proximal r a d i a l s , opposite 9 haemal spines on the vertebral column. The number of r a d i a l s may be as true an index of the number of segments i n the f i n base as the rays, but count-ing f i n rays rather than r a d i a l s has the considerable advan-Fig. 1 0 . Relation of anal ray count to mean postanal length (converted to preanal length of 50 mm. )„ 409 f i s h . -41-tage of much greater speed. Pin Base Proportion Ford (1933) and others f i n d that vertebrae of the eaudal region tend to be the most variable i n number. ) Though no homology between anal rays and caudal vertebrae was v i s i b l e i n R. balteatus, the p o s s i b i l i t y was examined that differences i n anal ray count might be due to differences i n length of the caudal region. Post^anal length (as defined i n Appendix IV) i s pl o t t e d against anal ray count i n Pig. 10. In order to compare f i s h of d i f f e r e n t sizes i t was necessary to correct f o r the d i f f e r e n t i a l growth of the two portions of the body.. Each postanal length was therefore converted to the corres-ponding measurement at an a r b i t r a r i l y chosen - standard—length of 30 mm., assuming that the slope of the l i n e of best f i t f o r the log-log plot of postanal against -s+^ae^ard length of a l l f i s h , described the slope of growth of each i n d i v i d u a l Ofertin 1949). While postanal lengths of individuals with the lowest ray counts appear to be somewhat les s than f o r those with intermediate and high ray counts, the difference i s not s u f f i c i e n t to account f o r the whole range of v a r i a t i o n of anal rays. The proportion of the postanal region occupied by the anal f i n base i s next considered, and i s plotted against anal ray count i n Pig. 11. Clearly, f i n s with more Pig. 11. Relation of anal ray count to mean length of f i n base. 115 f i s h . -42-rays generally occupy a greater proportion of the caudal region. This i s also apparent i n Pig. 9, which shows f i s h with ray counts of 13. and 20 respectively; the anal f i n of the l a t t e r can be seen to extend much farther p o s t e r i o r l y . Postanal length (expressed as a f r a c t i o n of the standard length) was greater for males than females a t ^ a l l anal ray counts. However, considering only f i s h of a given ray count, there i s no s i g n i f i c a n t difference between sexes i n the proportion of the postanal distance occupied by the f i n base. Probably sex differences i n postanal length are due to an i n f l e c t i o n i n r e l a t i v e growth of the posterior part of the body which occurs aft e r r a t i o of f i n base to postanal length, and also anal ray count, has been f i x e d . Log-log plots of postanal r e l a t i v e growth of 200 E r i e pothole adults suggest that t h i s i n f l e c t i o n occurs at onset of sexual mat-u r i t y i n the second or t h i r d year of l i f e . Further, post-anal length of males i s greater even i n those populations having s i g n i f i c a n t l y lower male ray counts^ suggesting again that sex difference i n postanal length i s not d i r e c t l y dep-endent on the same fact o r which controls anal ray counts. -43-PIN RAY FORMATION AND ECOLOGICAL FACTORS Body Size at Ray Formation Collections were made of f r y i n which the anal rays were just forming. F i g . 12 shows the number of f i n rays v i s i b l e i n f r y from d i f f e r e n t samples. In each c o l l e c -t i o n there was apparently a s p e c i f i c size at which anal rays started to appear, but this size d i f f e r e d on d i f f e r e n t dates i n Rosebud lake, and also between d i f f e r e n t l o c a l i t i e s . It seems u n l i k e l y that there are g e n e t i c a l l y d i f f e r e n t strains of early and l a t e spawners, as no such condition was apparent from the spawning data already discussed. Apparently size at appearance of anal rays i s subject to environmental control. The factor or factors responsible evidently a f f e c t a l l i n d i v -iduals about equally, and vary from time to time at a given l o c a l i t y . Data are i n s u f f i c i e n t to decide whether size at ray formation i s related to mean ray count attained, though there i s some i n d i c a t i o n that f i s h forming rays at larger s i z e form fewer rays. Nevertheless, environment apparently influences at l e a s t the f i n a l stage of formation of the anal f i n , as i t a f f e c t s the time of appearance of d e f i n i t i v e f i n rays. Correlation with Temperature Temperature observations at time of f r y c o l l e c t i o n s might be expected to f u r n i s h d i r e c t evidence on the r e l a t i o n of temperature to ray formation. However, sharp temperature <io _ l < z < 0 Id CO | . o O i ' o 5 J U L Y o xo X X ox • o 8 A U G . X OX OlXO • X M0( XX • 6<»t»xx x x • • »x — r 8 • RAYS STILL FORMING ° PROBABLY COMPLETE * COMPLETE T 10 12 T S T A N D A R D L E N G T H — i — 14 M M Fig. 12. Variation in size at formation of anal rays, Rosebud lake fry, 1949. -44-gradients frequently exist i;3f the environment of shiner f r y , and diurnal changes may be great. Temperatures at Kaslo bay on 9 July 1949 were as follows: Surface temperature, centre of bay - 17.9°C. Shade side of boat house - 19.0 Sun side of boat house - 21.5 Ten inches from beach, two inches deep - 23.5 Rosebud lake temperatures were 4C° warmer on the inshore than the offshore side of a l o g close to shore. Gradients of 6 C° within.three feet i n E r i e pothole have been mentioned. Many other"examples were noted where sharp temperature d i f -ferences were set up by current, wind action or sunlight. The mean temperature to which a group of f r y were subjected could be derived only from an extensive set of observations throughout the whole diurnal- cycle i n each l o c -a l i t y studied. Such observations were not made, but the range of temperatures i n which f r y were moving was recorded f o r most c o l l e c t i o n s . Table III shows co l l e c t i o n s i n which anal rays were s t i l l forming. A posit i v e c o r r e l a t i o n appears to exist between observed temperature and mean adult anal ray count. . , -45-TABLE I I I Temperatures at Which Developing Pry Taken, 1949 MEAN ADULT ANAL RAY COUNT TEMPERATURE ° C Erie pothole, 28 Aug.,1230 hrs. 12.08 15° - 21° L i t t l e Shuswap lake, 4 Sept.,1030 14.90 18° - 19° Eri e lake, 16 Aug., 0900 16.01 17° - 23° Rosebud lake, 5 July, 1300 16.09 20° - 24° Rosebud lake, 8 Aug., 1200 16.09 23° Middle Champion lake,12 July,1400 17.04 25° Geographic Variation While l o c a l differences have been shown to af f e c t water temperature profoundly, a c o r r e l a t i o n between tempera-ture and mean ray count, i f i t exists, should be apparent i f a s u f f i c i e n t number of l o c a l i t i e s from a number of geographic areas are considered. Table IV shows mean ray counts of 51 l o c a l i t i e s i n the United States from which ray counts have been recorded. These are grouped according to the average summer a i r temperature between June and August" as given i n the Atlas of American Agriculture (Baker 1936). Number of l o c a l i t i e s i s indicated i n brackets below each mean. Means of i n d i v i d u a l l o c a l i t i e s were each given equal weight. No comparable temperature data i n s u f f i c i e n t d e t a i l were a v a i l -able for B r i t i s h Columbia. -46-TABLE IV Mean Anal Ray Counts Within Temperature Isotherms AVERAGE SUMMER TEMP., JUNE-AUGUST (20 yr. average, mean of d a i l y extremes) 55-60 P 60-65 P 65-70 P 70-75 P R. b. balteatus 13.10 (5) 14.30 (23) 16.27 (3) 16.80 (8) R. b. hydrophlox 11.42 (6) 13.40 (3) R. thermophilus 12.07 (3) Combined mean 13.10 (5) 13.55 (32) 14.83 (6) 16.80 (8) A general r e l a t i o n s h i p appears to exist between summer a i r temperature and mean ray count. In addition the lower means f o r R. b. hydrophlox within the same isotherms as R. b. balteatus suggests that t h e i r taxonomic separation may be j u s t i f i e d on genetic grounds. The former group occurs at the southern extremity of the range of the genus; other-wise d i s t r i b u t i o n of means forms no regular geographic arrangement except when considered r e l a t i v e to the ir r e g u l a r pattern of summer isotherms. R. thermophilus inhabits warm springs of high a l k a l i content, and may well be a phenotypic variant. Eigenmann (1894) claimed a negative c o r r e l a t i o n between al t i t u d e and anal ray count, as discussed previously. Probably such a general r e l a t i o n does exist, but i s l a r g e l y masked i n the parts of the Columbia system from which his -47-opponents drew the i r examples. Sections of the Columbia and Snake r i v e r s f a l l i n g within the hottest summer isotherms, (in the v i c i n i t y of Walla Walla, Wash., and again i n the v i c i n i t y of Nampa, Ida.) are at a higher elevation than cooler coastal areas. Hence ray count, which follows temp-erature, does not i n these areas follow a l t i t u d e . The hypotheses of temperature controlled anal ray count f i t s i n general the B r i t i s h Columbia c o l l e c t i o n s . Highest ray count was found i n Champion lakes, - small, shallow, rapi d l y warming bodies of water. Lowest ray count was found i n E r i e pothole, with the coldest shallow water encountered. There i s no evidence f o r c o r r e l a t i o n of ray count with dissolved s o l i d s . Analysis for p r i n c i p a l dissolved solids were made on several lakes containing shiners by R. J. Waldie of the P a c i f i c B i o l o g i c a l Station. While calculations from the f i e l d data have not yet been made, there are i n d i c -ations that Rosebud lake and E r i e pothole are both r e l a t i v e l y r i c h i n dissolved solids while varying greatly i n ray count; Kootenay lake, with ray count similar to Rosebud, i s r e l a t -i v e l y poor i n dissolved material. 5 10 ( C U R V E S 2 , 4 - , 6 ] 5 0 P R E A N A L L E N G T H ; M M . Figo lpo Relative growth of body parts of shiners, plotted on log-log coordinateso (Axes for each curve are indicated in the margins)„ -48-VARIATION IN OTHER STRUCTURES Relative Growth of Parts Figure 13 shows growth of various parts r e l a t i v e to preanal length, plotted on log-log axis. Methods of measurement are l i s t e d i n Appendix IV. Preanal rather than standard length was used as abscissa because postanal growth has an i n f l e c t i o n at a preanal length of about 11.0 mm. as shown i n F i g . 13. As might be predicted from Martin's hypo-thesis, (1949), v a r i a t i o n i s found between di f f e r e n t popula-tions i n the proportion of postanal length, probably r e s u l t -ing from difference of body length at i n f l e c t i o n as already di-scussed. Consequently preanal length was thought to be a better standard of reference f o r describing growth of parts. Growth of a part at the same rate as growth of the whole i s termed isometry. Parts growing f a s t e r than the whole are said to show tachyauxesis; parts growing slower than the whole are said to show bradyauxesis (Martin 1949). In a log-log plot of length of part against body length, the former condition r e s u l t s i n a slope of less than 45°, while the l a t t e r produces an angle of more than 45° with the abscissa. Eye, head, anal height and postanal length a l l show i n f l e c t i o n from tachyauxesis to bradyauxesis at a preanal length of about 11.0 mm. I n f l e c t i o n i s sharpest i n eye and head growth. Postanal growth shows i n addition an e a r l i e r i n f l e c t i o n from bradyauxesis to tachyauxesis at about 7.0 mm. -49-A sharp i n f l e c t i o n i s seen i n development of the p e l v i c s . These appear at a preanal length of about 7.0 mm., grow r a p i d l y u n t i l about 9.0 mm., and then i n f l e c t from ex-treme tachyauxesis to moderate tachyauxesis. At a l a t e r stage both pectorals and p e l v i c s show heterosexual growth, females apparently i n f l e c t i n g to approximately isometric growth (isauxesis) of these parts at a smaller size and hence having shorter pectorals and p e l v i c s . It i s possible to det-ermine the sex of older f i s h by t h i s c h a r a c t e r i s t i c . In old males the pectorals overlap the o r i g i n of the pe l v i c s , and the pelvics extend posterior to the anus; i n females the ' pectorals do not reach the pe l v i c s , and the p e l v i c s do not reach the posterior border of the anus. Adult Variation i n Proportions Considerable v a r i a t i o n i s founds between individuals and between populations, i n those structures showing i n f l e c -t i o n i n growth. Examples are shown i n Pig. 13 for.eye, head and postanal growth. These differences are probably caused by difference i n average size at i n f l e c t i o n , perhaps due to temperature, diet or genetic e f f e c t s . Differences were part-i c u l a r l y marked i n eye diameter, a measurement showing sharp i n f l e c t i o n i n growth. Eye diameters from 3.5 mm. to 4.9 mm., and head lengths from 10.1 mm. to 14.0 mm. occurred i n i n d i v -iduals of 30.0 mm. preanal length. I n s u f f i c i e n t measurements we're taken for detailed c o r r e l a t i o n of body proportions %© anal ray count. Eye diameter appears to show rough p o s i t i v e c o r r e l a t i o n with ray - 5 0 -count. Champion lake shiners with high ray count have stat-i s t i c a l l y greater eye diameters than E r i e pothole and Paul lake f i s h with low ray counts (p.< 0.01); other populations studied were intermediate i n mean eye diameter and ray count. Correlation of ray count with other proportions studied i s apparently not close. This i s not surprising i n that considerable time elapses between f i x i n g of the anal ray count (sometime before reaching a preanal length of 6.5 mm.) and i n f l e c t i o n of most body proportions at about 11.0 mm. The l a t t e r occurs when the f i s h are swimming act-i v e l y and feeding; the former may occur before absorption of the yolk sac when the f i s h are l y i n g i n a c t i v e . Vertebrae X-ray photographs were taken of 109 shiners with anal ray counts from 11 to 20. Use of a small dental X-ray unit was kindly provided by Dr. Otto Bluh of the Physics Department, University of B r i t i s h Columbia. Pish were l a i d on holders containing 5" 7" medical X-ray f i l m and exposed two seconds to "hard" rays at a distance of two feet. Figure 8 shows an X-ray picture of a shiner with 37 vertebrae. Counts started at the f i r s t vertebra bearing a neural spine and included the hippural p l a t e . Table V gives the r e l a t i o n of vertebral to anal ray counts. Scatter i s considerable, but there i s a tendency f o r higher ray count to be associated with higher vertebral count. The mean vertebral count for f i s h with from 11 to 15 rays i s s i g n i f i c a n t l y lower than the mean for f i s h with 16 -51-to 20 rays (p < 0.01). TABLE V Vertebral and Anal Ray Counts. NO. OP VERTEBRAE 11 12 13 NO. 14 OP 15 ANAL 16 RAYS 17 18 19 20 MEAN 36 2 1 3 2 2 1 13.36 37 4 7 12 9 10 8 7 5 7 1 15.00 38 1 3 2 3 3 6 4 2 2 1 15.48 39 1 No s i g n i f i c a n t difference was found between the vertebral counts of the sexes. Si m i l a r l y , the numbers of vertebrae posterior to the f i r s t proximal r a d i a l of the anal f i n were similar i n the sexes, (range 18 to 21, mean 19.81 ± 0.06). This i s further i n d i c a t i o n that the longer postanal length of males discussed previously i s due to an adjustment occurring after segmentation i s complete. In many species of f i s h vertebral count has been shown to be negatively correlated with temperature. I f high-er temperatures produce more anal rays, i t might be supposed that high ray count would be associated with fewer vertebrae. b Apparently the reverse i s true f o r R. Balteatus. A similar condition may exist f o r Notemigonus crysoleucas as reported by Hart (MS). -52-Scales Counts of l a t e r a l l i n e scales were made on 115 f i s h from Snowshoe lake and Inonoaklin r i v e r . These showed a v a r i a t i o n from 54 to 67, with a mean of 60.98 ± 0.25. As i n the case of vertebral count, scale count appeared to show a loose p o s i t i v e c o r r e l a t i o n to anal ray count within the two populations studied. Mean ray count of Snowshoe f i s h with 54 to 61 scales was s i g n i f i c a n t l y lower (p 0.02 - 0.05) than those with 62 to 67. Such a r e l a t i o n i s i n keeping with Hubbs1 (1922) findings that high temperature produced both high ray count and high scale count i n the minnow Notropis atherinoides. From data In Carl and Clemens (1948), the range of v a r i a t i o n of scales count i s probably greater i n R. balteatus than i n a l l other B. C./3'yprinids, but less than i n some of the Salmonids. CONCLUSIONS: A POSSIBLE MECHANISM FOR ANAL RAY COUNT VARIATION Evidence f o r Environmental Control Two types of v a r i a t i o n i n body form have been con-sidered; v a r i a t i o n i n proportions involving continuous var-iables which are measured, and v a r i a t i o n i n number of met-americ parts involving discontinuous variables which are counted. The former included lengths of f i n s and r e l a t i v e size of d i f f e r e n t sections of the body; the l a t t e r included f i n rays, vertebrae and scales. Variation may be either genotypic or phenotypic. -53-It i s necessary to separate the two before investigating which factors are operative i n the l a t t e r . Only the prob-lem of anal ray count v a r i a t i o n has been examined i n d e t a i l . Considerable evidence has been presented that anal ray count i s subject to environmental control. Populations i n c l o s e l y adjoining bodies of water may d i f f e r widely i n mean ray count. No pattern i s apparent i n the d i s t r i b u t i o n of ray counts within drainage baisins or' other geographic features such as might be expected i f genetic clines were involved. Ray counts of recently introduced populations d i f f e r from those of t h e i r parental stock. Counts d i f f e r from year to year i n one l o c a l i t y , and d i f f e r between large and small individuals of the same year class. Mean ray count also varies between d i f f e r e n t parts of the same lake. On the other hand comparison of ray counts of R. b. hydrophlox with those of R. b. balteatus i n comparable temperature zones suggests that a genetic c l i n e may occur at the southern end of the range. Evidence i s purely nega-ti v e i n the case of the Inonoaklin - Snowshoe lake trans-plant which produced no v a r i a t i o n i n mean ray count. Genetic differences i n sex evidently can affect ray count, but the fact that males are sometimes higher and sometimes lower than females suggests that there i s no simple sex-linked control of ray number. It therefore seems apparent that among the popula-tions studied environment plays a large part i n determining anal ray count. That temperature i s an important factor i s -54-suggested by several l i n e s of evidence. Temperature d i f f e r -ences offer a ready explanation f o r the v a r i a t i o n between times and l o c a l i t i e s already mentioned. Temperature obser-vations at time of formation of anal rays roughly f i t the observed ray counts, and mean ray counts grouped according to temperature zones are re l a t e d to average a i r temperature during the developmental period. Possible Causes of Intra-population Variation Considerable v a r i a t i o n has been noted i n several body proportions. Sharp i n f l e c t i o n s i n r e l a t i v e growth of these parts has been demonstrated. Probably the mechanism outlined by Martin (1949) i s operative; environment controls body size at i n f l e c t i o n to a new growth stanza and therefore governs r e l a t i v e size of parts during that stanza. S i g n i f i c a n t differences i n anal ray count have been found between the sexes. As either males or females may have the higher counts i n d i f f e r e n t populations, simple sex-linked control of ray count seems improbable. Possibly one sex develops fa s t e r and reaches the stage at which the number of rays i s determined at an e a r l i e r date than the other. (That males grow fa s t e r than females has been sug-gested. ) I f a l l f r y i n a year class developed at the same temperature, no difference between sexes would be apparent. This i s the case i n most populations studied. I f , however, f r y developed during a period of st e a d i l y r i s i n g water temp-eratures, the sex which developed fa s t e r would on the average -55-l a y down rays at lower temperatures and show a lower mean ray count. I f water temperatures were f a l l i n g during develop-ment, f a s t growers would then tend to have more rays. Lower ray count of lar g e r individuals i n a year class may also be the r e s u l t of r i s i n g water temperatures, and higher ray count of larger f r y the re s u l t of f a l l i n g temper-atures. I t seems u n l i k e l y that a l l intrapopulation v a r i a -t i o n i s purely environmental. Though a l l individuals may form v i s i b l e rays at the same siz e under given conditions, they do not a l l form exactly the same number of rays. Data presented f o r v a r i a t i o n of R. b. balteatus and R. b. hydro- phlox i n comparable temperature zones suggests that the mean value about which environmental control operates i s genetic-a l l y determined. S i m i l a r l y some degree of genetic v a r i a b i l -i t y i s probably present within populations. Hypothesis It has been shown that anal f i n s with r e l a t i v e l y large number of rays occupy a r e l a t i v e l y large proportion of the postanal region. Variation has been observed i n the size at which p a r t i t i o n i n g of the postanal tissue into segments becomes v i s i b l e . There i s some evidence to suggest that size at which f i n rays become v i s i b l e i s governed by temper-atures, and that f i s h which form rays at a larger size are those which form fewer rays. The highest ray count observed was 21, and the highest number of vertebrae posterior to the -56-o r i g i n of the anal f i n was also 21. ,A hypothetical mechanism f o r the determination of anal ray count i s offerred. Two assumptions are required. 1-. The number of segments into which the f i n base div-ides Is governed by the number of body somites l y i n g adjacent to i t at the time of f i n segmentation. 2. Environment af f e c t s the r e l a t i v e lengths of the caudal region and the presumptive anal f i n base at the time of segmentation. According to thi s hypothesis the s t r i p of tissue which w i l l become anal f i n i n i t i a l l y occupies the whole ven-t r a l length of the caudal region. I f the s t r i p i s broken into i t s d e f i n i t i v e elements now, the maximum number of f i n rays w i l l l a t e r develop; no amount of environmental manipul-ation can produce more f i n ray segments than there are body segments l y i n g adjacent to them. Though In t h i s case the segmentation of the f i n base i s h i s t o l o g i c a l l y determined while the base i s as long as the postanal length, the defin-i t i v e rays do not form u n t i l l a t e r ; by this time the caudal region has grown more r a p i d l y than the f i n base, and the base occupies l e s s than the whole of the caudal. The consequent s l i d i n g of t a i l somites past f i n segments produces the stag-gered effect seen i n the adult. When f i n rays and associated r a d i a l elements develop, the proportion of f i n base to caudal region i s "frozen" and remains r e l a t i v e l y constant through-out l i f e . I f , however, environmental factors delay the time -57-at which h i s t o l o g i c a l d i f f e r e n t i a t i o n of the f i n base into segments occurs, then the base w i l l have come to occupy less than the whole caudal region. Fewer body somites w i l l l i e adjacent to the base, and fewer segments w i l l be l a i d down when d i f f e r e n t i a t i o n occurs. Development of the rays and ra d i a l s w i l l also occur l a t e r than i n the f i r s t instance, so that, the f i n base, consisting of fewer segments, w i l l occupy a smaller proportion of the postanal distance when "frozen". Environmental control of the proportion of f i n base to caudal length at time of segmentation, (the second assumption) might operate i n several ways. 1. The temperature c o e f f i c i e n t f o r growth of the two parts might vary with segmentation of the f i n base occur-r i n g at a given s i z e . I f Q, 10 (temperature c o e f f i c i e n t ) f o r the f i n base were higher than for the whole t a i l region, then at higher temperatures the base would be better able to keep pace with the t a i l and would occupy more somites at time of segmentation. 2. Another mechanism would involve f i n base and t a i l each growing at a constant rate, with the t a i l growing fa s t e r . I f temperature determined the size at which segmen-tatio n of the base occurred, i t would a f f e c t the number of somites adjacent to the base at that time. 3. Other mechanisms might be postulated involving piracy of the preanal or other region on the f i n base, so that the more delayed the segmentation was 'the less base -58-material would be available. At present the exact nature of the mechanism involved i s almost e n t i r e l y conjectural. ><• General Application of the Hypothesis Determination of the number of f i n rays i n f i s h by a mechanism similar to the one suggested might account f o r many of the apparent contradictions i n t h e . l i t e r a t u r e . I t has been pointed out that low temperature apparently produces increased f i n ray counts i n some species but decreased counts i n others. Let us suppose that the number of segments into which a presumptive f i n base divides i s influenced by the number of body somites adjacent to i t at the time of d i f f e r -entiation. I f the base i s growing fa s t e r than the adjacent somites, any fac t o r (such as low temperature) delaying seg-mentation of the f i n base w i l l produce more f i n segments. If on the other hand the base i s growing slower, a factor delaying segmentation w i l l produce fewer f i n segments. Sim-i l a r l y , i f the mechanism involves d i f f e r e n t temperature coef-f i c i e n t s for growth of f i n base and body proper, then high temperature w i l l produce more rays i f f i n base Q 10 i s the higher, fewer rays i f body Q 10 i s the higher. If i n some species the f i n base takes i t s segmenta-tion pattern from the adjacent somites at an early stage, before any d i f f e r e n t i a l growth has occurred, then the number of f i n rays w i l l be governed to some extent by factors a f f e c t -ing the number of body somites, (e.g. temperature a f f e c t i n g the number of vertebrae). -59-Evolution of f i s h with short median f i n s from ancestors having long many-rayed f i n s could be postulated by the simple process of delay i n time of ray d i f f e r e n t i a t i o n . A mutation or series of mutations i n h i b i t i n g ray d i f f e r e n t i a -t i o n might confer selective advantage by producing f i s h with improved speed or maneuverability. This mechanism suggested i s as yet hypothetical, but the available data appear to f i t the hypothesis. Cont-r o l l e d experiments and h i s t o l o g i c a l sectioning are required, but d i f f i c u l t i e s encountered i n a r t i f i c i a l rearing must be f i r s t overcome. Due to i t s spectacular v a r i a b i l i t y i n anal f i n ray count, R. balteatus i s suggested as admirable material f o r further study. -59a-SUMMARY 1. Shiners occur i n a wide v a r i e t y of habitats including small warm lakes, large cold lakes, cold springs and running water. 2. The spawning period varies from 7 to 10 weeks, s t a r t -ing i n the l a s t week of May i n some l o c a l i t i e s and the second week of June i n others. •3. Different individuals spawn at di f f e r e n t times, and one i n d i v i d u a l may spawn more than once i n a season. . 4. Eggs can be hatched experimentally at temperatures from 12°C. to 21°C., with corresponding mean hatching times varying from 15 to 7 days. At 9°G. eggs show i n i t i a l cleavage and then die. 5. Pry l i e quiescent f o r about a week following hatching, then swim a c t i v e l y i n the shallow water after the yolk sac i s absorbed. 6. Growth rates, 'of d i f f e r e n t populations vary consider-ably. Most populations contain few individuals older than year II or I I I . The largest f i s h taken was i n year V or VI. 7. Females l i v e longer than males. Older year groups are almost exclusively females. 8. Different sizes of f i s h frequent d i f f e r e n t depth zones, the smaller f i s h occupying shallower water. 9. Shiners and game species probably aff e c t each other considerably. Under ce r t a i n circumstances shiners eat trout -59b-f r y , trout eat shiners, and shiners eat the same food as trout. 10. Great differences exist between mean anal ray counts of d i f f e r e n t populations. 11. Variation i n ray count i s due at least p a r t i a l l y to environmental conditions during development. 12. Temperature i s probably an important environmental f a c t o r c o n t r o l l i n g ray count. 13. There i s v a r i a t i o n i n proportion of body parts between d i f f e r e n t populations. Early i n f l e c t i o n s occur i n the r e l a t i v e growth rates of these parts. Environmental factors probably cause v a r i a t i o n i n proportions by varying body size at i n f l e c t i o n . 14. Differences exist between body proportions of the sexes. 15. Differences exist between anal ray counts of the sexes i n some populations. Males sometimes have more rays, sometimes fewer. Environmental control i s suggested. 16. Anal f i n rays do not appear u n t i l r e l a t i v e l y l a t e i n development. Environment affects size at which rays appear. 17. It i s suggested that the number of segments i n the f i n i s governed by the number of body somites l y i n g adjacent to i t at the time of segmentation, and that envir-onmental factors may control the proportion of the caudal region occupied by the f i n base at this time. 18. This mechanism might account f o r many of the con--59c-t r a d i c t o r y reports i n the l i t e r a t u r e on the affect of envir-onment on number of f i n rays i n di f f e r e n t species. > -60-LITERATURE CITED Anderson, G. C. M.S. a Study of the production of Kamloops trout (Salmo g a i r d n e r i i kamloops Jordan) i n Paul IgJs©, B r i t i s h Columbia. Unpub. M.A. thesis, Univ. of B.C., 1949 , " Baker, 0. E, 1936. Atlas of American agriculture. y.S. Govt. P r i n t . Off., Washington.' Balinsky, B. I. 1948. On the development of s p e c i f i c char-acters i n c y p r i n i d f i s h e s . Proc. Zool. Soc. London. 118 (2): 335 - 344. Car l , G. C. and W. A. Clemens. 1948. 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Doc. 1055 (App. to Rept. U. S. Fish. Comm^ ., 1928) : 1-670. Martin, W. R. 1949. '^ he mechanics of environmental control of body form i n f i s h e s . Univ. Toronto Studies, B i o l . , No. 58. Pub. Ont. Fish. Res. Lab., No. 70: 1 -. 81. M i l l e r , R. R. and Ralph G. M i l l e r . 1948. The contribution of the Columbia r i v e r system to the f i s h fauna -of Nevada. Copeia (1948) (3): 174-187. Mottley, C.. McC. 1934. The ef f e c t of temperature during development on the number of scales i n the Kamloops trout Salmo kamloops. Cont. Can. B i o l . Fish. 8 (20): 255-263. . Mottley, C. McC. 1937. The number of vertebrae i n trout (Salmo). Jour. B i o l . Bd. Can., 3 (2): 169-176. -65-Munro, J. A. and W. A. Clemens. 1937. The American merganser i n B r i t i s h Columbia and i t s relation:, to the f i s h population. B i o l . Bd. Can. B u l l . No. 55: 1-49. Northcote, T. G, MS. Some aspects of the comparative mor-phology and ecology of Cottus asper Richardson and Cottus rotheus (Rosa Smith). Unpub. g. A. thesis, Univ. of B. C , 1950. Rawson, D. S. 1934. Productivity studies i n lakes of the Kamloops region, B r i t i s h Columbia. B i o l . Bd. Can. B u l l . No. 42:*----31.. ...... Richardson, John. 1836. Fauna Boreali - Americana (Pt. 3 -The f i s h ) . Richard Bentley, London: 1-327. (Ref. from Carl and Clemens 1948). Schmidt, J. 1917. Racial investigations. I. Zoarces viviparus L. and l o c a l races of the same. C. R. Trav. Lab. Carlsberg. 13 (3): 279-396. Schmidt, J. 1921. Racial investigations. VII. Annual fluctuations of r a c i a l characters i n Zoarces ' viviparus L. C. R. Trav. Lab. Carlsberg. 14 (15) : 1 - 24. Schmidt, J. 1930. Racial investigations. X. The A t l a n t i c cod (Gadus c a l l i a r i o s L. ) and l o c a l races of the same. C. R. Trav. Lab. Carlsberg. 18 (6): 1-72. Schultz, L. P. 1927. Temperature-controlled v a r i a t i o n i n the golden shiner, Notemigonus crysoleucas. Pap. Mich. Acad. S c i . , Arts, Let. 7: 417-432. -66-Schultz, L. P. and A. G. DeLacy, 1935. Pishes of the Amer-ican Northwest. Mid-Pac. Mag., Oct.-Dec. 1935: 365-380. Jan. -Feb.: 63-76. Apr.-June: 127-142. July-Sept.: 211-226. Oct.-Dec.1936: 275-290,.' Schultz, L. P.. and M. B. Schaeffer. 1936. Descriptions of new intergenetic hybrids between c e r t a i n Cyprinid fishes of Northwestern United States. Proc. B i o l . Soc. Wash. 49: 1-10. Snyder, J. 0. 1907. Relationships of the f i s h fauna of the lakes of Southeastern Oregon. B u l l . U. S. Bur. Fis h . 1907. 27 : 69-102. Stanwell-Pletcher, John F. and Theodora C. 1943. Some acc-ounts of the f l o r a and fauna of the Driftwood Valley region of north central B r i t i s h Columbia. Occ. Pap. B. C. Prov. Mus., No. 4: 1-97. Sund, Oscar. 1943. Variation i n number of vertebrae i n the Norwegian winter herring. Ann. B i o l . (Copenhagan) 1: 56-57. -67-APPENDIX I -Data on Shiner Collections The geographical indices are similar to those used i n the Geographical Gazeteer of B r i t i s h Columbia, Department of Lands. Latitude and longitude r e f e r to the south-east • corner of the quadril a t e r a l i n which the l o c a l i t y l i e s ; compass references -give the appropriate quarter of this area. D i s t r i c t s referred to are Land D i s t r i c t s , (for administrative purposes only). Dates following r e f e r only to time of c o l l e c t i o n of specimens dealt with i n Appendix I I . Tempera-ture readings are i n Centigrade degrees; A refers to a i r temperature, S to surface temperature. Numbers preceding each dash re f e r to depths i n metres. B indicates bottom. Thus 2 - 18.5 indicates that the temperature was 18.5°C. at 2 metres depth. Permanent c o l l e c t i o n numbers of specimens from the Royal Ontario Museum of zoology are indicated by the l e t t e r s R.O.M.Z-. -68-ALLISON L. 49° 120° N.W. Expansion of A l l i s o n cr., near head, Kamloops d i s t . 29 Aug., 6 Sept. 1948. Temp. 5 Sept. 1949, 1030 hrs. : A-18, S-16, 1-15, 7-15, 9-12, 11-9, 12.5-8, 38B-4.5. ARGENTA SLOUGH. 50° 116° S. W. Off Duncan r., on road to Howser, Kootenay d i s t . 4 June 1949. Collector I. Barrett. ARROW. LAKES. Kootenay d i s t r i c t . Deer Park. 49° 118° S.E. E. side Lower Arrow 1. 7 June 1949. Fosthall Ck. 50° 117° S.W. W. side Upper Arrow 1. 29 July 1949. Nakusp 50° 117° S.W. E. side Upper Arrow 1.. 18 July 1949. BABINE L. 54° 126° N. W. Cassiar d i s t . 1947. Collector A l . Johnson. BAPTISTE L. 50° 116° N. E. Trib. to Macaulay cr., near Edgewater, Kootenay d i s t . 15 June 1949. Area 34 acres, deepest 10 m., shallow shores. Collector H. Tyler. BLUE L. (TURKEY L.) 49° 120° N. W. Expansion of A l l i s o n cr., Kamloops d i s t . 1948. CARDEJV. L. (SHUMWAY L.) 50° 120° N.E. Expansion of Campbell cr., Kamloops d i s t . 4 Sept. 1949. CHAMPION LAKES. 49° 117° S.W. Three small lakes at head of -head of Landis cr., t r i b . to Champion cr., Kootenay d i s t . 12 July 1949. Temp. South 1. 1230 hrs: S-21, Middle 1. 1400 hrs.: S-25.2. -69-CHILLIWACK SLOUGH. 49° 121° S. W. New Westminster d i s t . 2 Oct. 1932. Collector W. E. Ricker. R.O.M.Z. #8581. CHIMNEY L. 51° 121° N. W. Head of Chimney cr., L i l l b o e t d i s t . 8 Sept. 1949. Deepest 25 m. Collector Sam M i t c h e l l . COLUMBIA R., CASTLEGAR. 49° 117° S. W. Near mouth of Kootenay r. 6 July 1949. Backwater near sawmill one mile below Castlegar. Temp. 1030 hrs: S-13.5 - 15.5. COTTONWOOD L. 49° 117° S. E. head of Cottonwood cr., S. E. of Nelson, Kootenay d i s t . 11, 14 July; 12, 16, 27 Aug. 1949. Temp, at outlet 20 June 49, 1430 hrs: 15.5. 29 June 49, 1630 hrs: 11.0. 5 July 49, 1000 hrs: 15.0. 11 July 49, 1500 hrs: 18.8. . 27 Aug. 49, 1800 hrs: S-17, 14B - 11. Av. depth 13 - 14 m. CULTUS L. 49° 121° S.W. Head of Sweltzer r . , t r i b . to Chilliwack r., New Westminster d i s t . 25 Sept. 1948 near outlet; 11 Nov. 1948 one mile W. on S. shore. DOUGLAS L. 50° 120° S. E. Expansion of Nicola r., ca. 10 miles E. of Nicola 1., Kamloops d i s t . 7 Sept. 1949. DUCK L. (ELLISON L.) 49° 119° N. E. 8 miles N. E. of Kelowna, Osoyoos d i s t . 6 Sept. 1949. DUTCH L. 51° 120° N. E.. One mile N. E. of junction of North Thompson and Clearwater r i v e r s , Kamloops d i s t . 27 Aug. 1946. Collector D. C. G. MacKay. ERIE L. (BEAVER L.) 49° 117° S. E. Three miles W. of Salmo, Kootenay d i s t . 16 Aug. 1949. Temp. 28 June 49, 1815 hrs: S-17. 16 Aug. 49, 0800 hrs:S - 17. 1030 Hrs: S - 23. Lake Shallow, weed beds i n centre. -70-ERIE POTHOLE. 49° 117° S. E. . 1 .3/8 miles W. of Erie 1., drains W. into Archibald Ck., 28 June, .5 July, 16, 28. Aug.. 1949. Temp. 28 June 49, 1750 hrs: S - 17.2. 16 Aug. 49, 1200 hrs:. S - 20.4. 28 Aug. 49, 1645 Hrs: A - 32, S- 31, 1 - 15, 2 - 14, 3 - 13, 4 - 9, 5 - 9, 6 - 8, 7B - 7. Av„ depth 6 - 7 m. Water stained. GARNET VALLEY L. 49° 119° N. W. Expansion of Eneas ck., Osoyoos d i s t . 6 July 1928. R.O.M.Z. #6203. HYAS L. 50° 120° N. E. Drains into Pinantan 1., Paul ,ck. chain, Kamloops d i s t . 30 July 1948. Collector G. C. Anderson. , . INONOAKLIN R. 49° 118° N. E. Plows S. E. into.Lower Arrow 1. at Edgewood, Kootenay d i s t . 2 Sept. 1949. Murton's sawmill. KOOTENAY L. Kootenay d i s t . Campbell ck. 49° 116° N. W. Enters E. side Kootenay 1. 2 miles N. of Kaslo. 29 May 1949. . Kaslo 490 116° N. W. W. side Kootenay 1. 45,miles by road N. of Nelson. 10 June 1928. R. 0. M. Z. #6541. 29 May, 21 July, 14 Aug. 1949. Kuskanook 49° 116° S.W. E. side Kootenay 1. near S. end. 21 July 1949. Lardeau 50° 116° S.W. N. end Kootenay 1. 15 July 1949. Nelson 49° 117° S.E. S. shore, West arm Kootenay 1. 26 June 1949. Boathouses. -71-Queen's Bay 49° 116° N.W. W. shore Kootenay 1. immediately N. of entrance to West arm. 10 June 1949. KOOTENAY ,R. 49° 117? S.W. Drains West arm of Kootenay 1. into Columbia r . at Castelgar, Kootenay d i s t . Taghum 4 3/4 miles W. of Nelson, highway crossing of Kootenay r . 6 July 1949. S. shore. Three-mile.Pool Cut off from Kootenay r. by railway embankment. .S. shore, 3 miles W. of Nelson. 24 June 1949. Temp. 1700 hrs: S - 17.5. LAIRD L. 49° • 120° N.W. Expansion of A l l i s o n cr., Kamloops d i s t . 4 Sept. 1948. LITTLE SHUSWAP L. 50° 119° N.W. W. of W. end of Shuswap 1., Kamloops d i s t . 4 Sept. 1949. Temp. ,. E. end 1025 hrs; S - 19. MC BAINS L. (ROSEN L.). 49° 115° S.E. 2^ miles N.E. of Jaffray, Kootenay d i s t . 1949. NADSILNICH L. (WEST L.) 5.3° 122° N.W. Head of Beaverly cr., Nechako r . , Cariboo d i s t . 1949. NICOLA L. 50° 120° S.W.. Expansion of Nicola r.,, Kam-loops d i s t . 7 Sept. 1949. OKANAGAN L. Osoyoos d i s t . North End 5 July 1928. R.O.M.Z. #6206. Okanagan Landing 50° 119° , S.E. E. side Okanagan 1. 5 miles S.W. of Vernon. 6 Sept. 1949. PADDY RYAN LAKES. 50° 116°. N.E. .4 miles S.W. of Invermere, Kootenay d i s t . 15 June 1949. Five shallow lakes, sources of water for town of Invermere. Each lake 3 -72-acres. Collector H. Tyler. PAUL L. 50° 120° N.E. Expansion of Paul cr., Kamloops dist. W. end 3 Aug. 1949; E. end 4 Aug. 1949. Collector G. C. Anderson. PINANTAN L. 50° 120° N. E. Expansion of Paul cr. near head, Kamloops dist. 27 July 1946 Collector D. C. G. MacKay; 18 Aug. 1948. PUNTCHESAKUT L. 52° 122° N.W. Expansion of Puntchesakut ck., Cariboo dist. 12 July 1949. Collector B i l l H i l -len. ROSEBUD L. 49° .117° S.. E. Head of Rosebud ck., Salmo r., Kootenay dist. 21 June, .28 Aug. 1949. Temp. 17 May 49, 1535 hrs: S - 16. 3 June 49, 1350 hrs: S - 19 (shade), 22 (sun). 20 June 49, 1800 hrs: S - 19 (east shore), 5 - 2 1 (W. shore), 19 - 12.3 - 10.8 (ascending inlet ck.). 21 June 49, 0700 hrs: 17, 0915 hrs: 5 - 18.5, 1330 hrs: S - 1915) 28 June 49, 2010 hrs; S - 17. 29 June 49, 0815 hrs: S - 17. 5 July 49, 1215 hrs: S - 20, 24 - 28 (in protected pockets inshore). 23 July 49, 0800 hrs: S -- 19, 1400 hrs: S - 23. 28 Aug. 49, 1215 hrs: A - 34 (in sun), S - 21, 1 - 19, 2 - 18.5, 4-18, 6 - 18, 7 - 17, 8 - 14, 9 - 13, 10 - 11, 11- 9.5, 12 - 8.5, 13.5 - 8, 15 B - 7. SKAHA L. (DOG L.) 49° 119° S.W. Expansion of Okanagan r., 4 miles S. of Okanagan 1., Similkameen dist. 2 Aug.1948. SHUSWAP L. 50° 119° N.E. Head of S. Thompson r., Kam-loops dist. 3 Sept. 1949. Sicamous, entrance of Mara 1. -73-SHUSWAP R., GRINROD. 50° 119° N.E. Similes N. of anderby, Kamloops dist, 3 Sept. 1949, SLOCAN L. 49° 117° N.E. Head of Sloean r., Kootenay dist. 10 Aug. 1949. Silverton. SNOWSHOE L. 49° 118° N.E. In Sees. 34 and 35, T p.69, between Inonoaklin arid Whatshan cks., Kootenay dist. 2 Sept. 1949. Temp. 1905 hrs: A - 23, S - 20, 1 - 18, 5 - 18, 6;- 15, 7 - 11.5, 7 - 11.5, 8 - 9.5, 10 - 8.5, 12 - 8. SPRING L. AND TIMOTHY L. 51° 121° N.E., expansion of 111 mile ck., Lillooet dist. Autumn, 1949. STEVENS L. (ROCK L., LAZY L.) 49° 115° N.W. N.E. of Wasa, between Lewis and Wdlf cks., Kootenay dist. 25 July 1949. Collector J. J. Osman. TAYLOR L. 49° 120° N.W. Head of Gulliford ck., Kamloops and Yale "dists., Merrit - Princeton road, 1948. TETANA L. 55° 126° N.E. Head of Driftwood r., Cassiar dist. Collector J. P. Stanwell-Pletcher. R.O.M.Z. #12,217. WILLIAMS L. 52° 122° S.E. Head of Williamslake ck., Praser r., Cariboo dist. 2 Aug. 1944. Collector G. C. Toner. R.O.M.Z. #14371. - 7 4 -APPENDIX II Anal Ray Counts of Shiners from L o c a l i t i e s i n B r i t i s h Columbia. The symbol T indicates t o t a l counts which include males, females and f i s h whose sex was not determined. Counts include only adults, or co l l e c t i o n s of f r y i n which a l l the anal rays had formed. • . Anterior rudimentary rays not counted; l a s t s p l i t ray counted as one. NO. OP ANAL RAYS LOCALITY 10 11 12 13 14 15 16 IV 18 19 20 21 NO. MEAN ALLISON L. T 3 7 4 6 2 22 1 6 . 8 6 ARGENTA SLOUGH? 3 4 13 7 1 4 1 33 1 3 . 4 5 <r 1 1 6 4 1 13 1 3 . 2 3 T 4 5 19 11 2 4 1 4 6 1 3 . 3 9 ARROW LAKES Deer Park T 2 12 22 22 15 73 1 5 . 4 9 Posthall Ck.s 1 5 7 17 12 a. 1 4 3 1 4 . 8 8 <J 1 '8 11 33 13 5 1 1 73 1 5 . 0 0 T 2 13 18 50 25 5 2 1 116 1 4 . 9 6 Nakusp 1 5 6 7 2 21 1 5 . 1 9 1 2 6 2 1 12 1 5 . 0 0 T 2 7 12 9 3 33 . 1 5 . 1 2 BABINE L. T 2 1 2 5 1 5 . 0 0 BAPTISTE L. T 1 6 1 3 18 8 2 1 49 1 3 . 7 3 BLUE L. T 4 6 4 1 15 1 6 . 1 3 CARDEW L. ? 4 8 4 4 2 22 1 5 . 6 4 1 — 7 8 5 5 2 28 1 5 . 3 6 T 1 - - 11 16 9 9 4 50 1 5 . 4 8 CHAMPION LAKES Middle' Lake 1 4 12 14 14 3 3 51 1 7 . 1 2 c? 1 1 7 6 5 2 22 1 6 . 8 6 T • 2 5 19 20 19 5 3 73 1 7 . 0 4 South Lake 3 7 5 6 1 22 1 7 . 7 7 1 2 3 2 3 1 12 1 7 . 5 8 T 8 33 56 50 25 8 1 181 1 7 . 4 4 -75-CHILLIWACK SLOUGH CHIMNEY L. COLUMBIA R. Castlegar COTTONWOOD L. CULTUS L. 25 Sept. 1948 11 Nov. 1948 Combined DOUGLAS L. DUCK L. DUTCH L. ERIE L. ERIE POTHOLE GARNET VALLEY L. HYAS L. INONOAKLIN R; KOOTENAY L. Campbell Ck. Kaslo, 1928 Kaslo, 1949 KUSKANOOK 10 11 12 13 14 15 16 17 18 19 20 21 NO. MEAN T 2 2 4 17.00 T 1 2 3 5 3 14 14.50 T 2 4 2 1 9 15.22 T 4 11 11 4 4 1 1 36 17.00 2 22 26 16 3 69 14.94 5 36 39 9 6 95 14.73 % 2 5 12 3 4 26 15.08 2 1 11 7 5 - 1 25 14.80 T 29 147184 68 20 1 449 14.79 T 9 18 13 11 1 52 16.56 T 2 5 7 10 6 1 31 15.52 T 1 4 3 1 9 14.44 T 1 1 1 2 3 8 16.62 % 2 38 103 25 4 1 173 11.97 S 43 96 36 5 180 12.02 T 2 80 237 82 12 - 1 414 12.06 T 1 17 21 11 2 1 53 13.98 T 3 8 8 19 14.26 % 2 10 9 8 29 12.79 1 5 10 5 21 12.90 T 3 16 19 13 51 12.82 T 2 7 10 10 5 - 1 35 16.37 T 2 12 19 17 6 1 1 58 16.35 3 5 9 9 2 1 29 16.17 <? 2 9 7 12 1 31 16.03 T 12 32 59 41 8 3 155 16.06 T 1 1 13 11 6 1 1 34 15.79 -76-10 11 12 13 14 15 16 17 18 19 20 21 NO. MEAN Lardeau T 1 11 22 4 1 39 15.82 Nelson T- 1 4 23 19 10 9 66 15.91 Queen's Bay 9- 2 5 19 16 3 1 46 16.34 3 1 6 13 21 12 5 58 15.90 T 1 8 19 41 31 10 1 111 16.14 KOOTENAY R. Taghum $ 1 2 5 6 1 1 16 16.44 6 3 6 2 1 18 16.39 T 1 8 13 13 3 3 41 16.44 Three-Mile Pool T 3 15 16 12 2 1 49 16.96 LAIRD L. % 6 24 22 49 10 6 1 118 16.47 4 10 28 20 10 5 1 1 79 16.58 T 10 34 50 69 20 11 2 1 197 16.51 LITTLE SHUSWAP L. T 4 20 20 15 - 1 1 61 14.90 McBAINS L. $ 1 14 20 17 2 2 56 14.20 <^ 1 2 14 5 4 26 14.35 T 2 18 36 22 6 2 86 14.21 NADSILNICH L. T 3 2 7 5 17 16.82 NICOLA L. 3- 2 2 6 10 4 3 2 29 18.00 2 4 21 9 2 38 17.13 T 4 6 27 19 6 3 2 67 17.51 OKANAGAN L. N. End 1928 T 8 10 11 5 3 37 15.59 Okanagan Lndg, 1 5 13 11 3 1 34 15.38 <? 4 9 2 4 1 20 15.45 T 3 12 24 13 7 3 62 15.29 PADDY RYAN LAKES T 5 20 15 7 47 13.51 PAUL L. -E. End 3 10 3 1 17 14.12 c? 4 12 5 1 22 14.14 T 17 52 20 3 92 14.10 -77-10 11 12 13 14 15 16 17 18 19 20 21 NO. MEAN W. End 5. 1 1 12 14 2 30 13.50 <? 10 14 6 — 1 31 13.96 T 2 4 56 60 19 ' - 2 143 13. 68 PINANTAN L. 1946 * 2 5 7 2 16 13.56 1 _ 7 9 1 18 13.50 T 1 2 12 16 3 34 13.53 1948 5 45 48 16 1 115 13.68 3 13 38 19 9 1 83 14.25 T 10 99161 83 13 2 368 13.99 PUNTCHESA-KGT L. T 3 16 35 12 3 69 13.94 ROSEBUD L. 1 13 25 24 25 8 3 99 15.96 cT 9 25 27 17 7 5 90 16.03 T 1 22 50 51 42 15 8 189 15.99 SKAHA L. T 3 12 12 2 1 30 13.53 SHUSWAP L. T * 3 24 28 23 7 2 1 88 15.19 SHUSWAP R., Grinrod T ;" 7 16 11 1 1 36 15.25 SLOCAN L. T 2 11 14 3 2 32 15.75 SNOWSHOE L. 1 5 29 26 24 3 88 12.86 1 — 14 25 13 5 2 6 0 13.20 T 5 16 122 162 96 17 3 421 12.93 SPRING L. AND TIMOTHY L. T 2 5 18 17 5 5 52 16.63 STEVENS L. 1 3 2 1 7 14.43 3 2 2 7 13.86 T 4 5 4 1 14 14.14 TAYLOR U. . T 5 14 15 3 1 38 13. 50 TETANA L. T 1 2 - 1 4 15.25 WILLIAMS L. T 5 14 19 7 6 1 52 15.96 -78-AFPENDIX I I I D e s c r i p t i o n of Constant Temperature Apparatus. P i g . 14. Constant temperature apparatus, Kaslo hatchery. Apparatus f o r r e a r i n g eggs at constant tempera-tur e was constructed at the Kaslo hatchery during the summer of 1949. Although shiner f r y d i e d a f t e r absorption of the yolk sac, the apparatus was used successfully i n the r e a r i n g of Kamloops t r o u t at temperatures from 9°C. to 21°C. (The l a t t e r temperature i s apparently the h i g h e s t recorded i n the l i t e r a t u r e f o r s u c c e s s f u l h atching of t r o u t . ) Specimens so reared were preserved and have not yet been examined. The apparatus operated s a t i s f a c t o r i l y and prov-i d e d baths of oxygenated water at 9°, 12°, 15°, 18° and 21°C. at ± 0.4°. P i g . 14 shows a general view. Water was f e d i n t o a 10 f o o t l e n g t h of eaves troughing suspended above the baths; excess s p i l l e d over a w a l l at one end, so that a constant l e v e l was maintained i n the -79-trough. Channels of cork, glass and rubber tubing led water across from the trough into each of five galvanized pails. A thermo regulator with pilot lamp was suspended i n each p a i l , and the desired temperature was maintained either by an immersion heater or by an electric hot-plate beneath the p a i l . Tubes from the bottom of each p a i l led to a number of baths. An electric aerator suspended above the pails was provided with tubes entering each p a i l ; these served also as agitators which prevented unequal heating within the pails. Plow to each bath, of about 80 c.c. per minute, was controlled by a screw-type stop-cock. Baths consisted of 3|"x 6"xl2" baking dishes. Overflows were provided by glass tubing with fine metal screen covers. Baths were suspended within 24" hatchery troughs, into which the overflow from the baths passed. A l l metal parts were covered with aluminum paint. Eggs were placed on a wire basket standing one inch above the floor of the bath. Shiner fry were fed plankton tows. Trout fry were fed skimmed milk and ground l i v e r . Floors of baths were cleaned daily with a rubber syringe. -80-APPENDIX IV . Definition of Measurements Made on Shiners Measurements on adult shiners were made with a vernier calip(r\§ reading to 0 . 1 mm., or on a steel rule marked in 0.5 mm. Measurements on fry were made with a binocular microscope containing a calibrated Whipple counting grid. ANAL PIN BASE - Distance from origin to insertion of anal f i n . ANAL HEIGHT - Distance from origin of anal f i n to tip of longest ray. EYE DIAMETER - Antero-posterior diameter of eyeball. HEAD LENGTH - Distance from tip of snout to posterior margin of operculum. PECTORAL AND PELVIC LENGTHS - Distance from insertion of f i n to tip of longest ray. PREANAL LENGTH - Distance from tip of snout to origin of anal f i n . POSTANAL LENGTH - Distance from origin of anal f i n to posterior margin of fleshy part of peduncle. STANDARD LENGTH - Distance from tip of snout to posterior margin of fleshy part of peduncle. TOTAL LENGTH - Distance from tip of snout to tip of longest caudal ray when t a i l compressed. 

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