Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Ecology of the yellowstone cutthroat trout (Salmo clarkii lewisi Girard) in Kiakho Lake, British Columbia Stenton, Charles Ernest 1960

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1960_A6_7 S85 E2.pdf [ 4.22MB ]
Metadata
JSON: 831-1.0106396.json
JSON-LD: 831-1.0106396-ld.json
RDF/XML (Pretty): 831-1.0106396-rdf.xml
RDF/JSON: 831-1.0106396-rdf.json
Turtle: 831-1.0106396-turtle.txt
N-Triples: 831-1.0106396-rdf-ntriples.txt
Original Record: 831-1.0106396-source.json
Full Text
831-1.0106396-fulltext.txt
Citation
831-1.0106396.ris

Full Text

ECOLOGY OF THE YELLOWSTONE CUTTHROAT TROUT (SALMQ CIARKII LEWISI GIRARD) IN KIAKHO LAKE, BRITISH COLUMBIA by CHARLES ERNEST STENTON B. A. Un i v e r s i t y of B r i t i s h Columbia, 1957 A THESIS SUBMITTED IN PARTIAL. FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department of ZOOLOGY We accept t h i s t h e s i s as conforniing to the required standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , I960 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study. I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department o r by h i s r e p r e s e n t a t i v e s . I t i s understood t h a t copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be allowed without my w r i t t e n p e r m i s s i o n . Department of Zoology The U n i v e r s i t y of B r i t i s h Columbia, Vancouver 8, Canada. Date 1 3 A P r i l 1 9 6 0 i i ABSTRACT A knowledge of the b a s i c biology of any f i s h i s a primary require-ment f o r the p r a c t i c a l management of that stock of f i s h . This i n v e s t i -gation was d i r e c t e d at a pure c u l t u r e population of Yellowstone cutthroat t r o u t , t o describe the b a s i c biology and provide a b a s i s f o r management and f u r t h e r research. KLakho Lake has a. surface area of 67.42 acres, a maximum depth of 32 f e e t and a mean depth of 16.5 f e e t . Due t o the rocky substrate, lack of l i t t o r a l development and low t o t a l dissolved s o l i d s , the production of plankton and bottom fauna was small and c h a r a c t e r i s t i c of o l i g o t r o p h i c conditions. The food o f cutthroat tro u t i n Kiakho Lake i n May was comprised of 83.9 percent by volume and 81.3 percent by occurrence of chironomid pupae. In June the food was 46.7 percent by volume and 45*8 and 35«5 percent by occurrence of chironomid larvae and Gammarus r e s p e c t i v e l y . In J u l y the Gammarus were 57.8 percent by volume and 60.3 percent by occurrence. In Lumberton Reservoir and Monroe Lake the Gammarus com-p r i s e d 51»0 and 55.6 percent by volume and 34.4 and 78.2 percent by occurrence r e s p e c t i v e l y of the food. In Garcia Lake, Chaoborus was 32.9 percent by volume and 36.0 percent by occurrence and the redside shiner, Richardsonius balteatus, was 27.8 percent by volume and 31.8 percent by occurrence. The f i s h appeared t o be second i n preference to Chaoborus. i i i The body-scale r e l a t i o n s h i p i s described by a s t r a i g h t l i n e having a slope of 1. A graph of instantaneous growth rate p l o t t e d against length, revealed t h a t f a s t e r growing f i s h have a f a s t e r decrease i n growth r a t e . Due to the absence of c e r t a i n c h a r a c t e r i s t i c s e.g. a con-c a v i t y i n the upper l i m i t of the graph, the growth of Kiakho Lake cut-throat appeared t o support the view that f a s t e r growing f i s h are selected by the f i s h e r y , and that i t can be demonstrated i n t h i s type of graph. The data, f i t t e d to a Parker and L a r k i n (1959) growth equation gave a z value of 0.71. The absence of "Lee's Phenomenon" gave support t o the premise that the phenomenon can r e s u l t from s e l e c t i o n by a f i s h e r y , and i n v a l i -dated the other ideas concerning the causes as f a r as t h i s population was concerned. The spawning run i n Kiakho Lake was estimated at 3,000 f i s h . A tagging program revealed that the f i s h spent on the average of 13 days to spawn, and that there was approximately a 54 percent m o r t a l i t y . The male f i s h appeared on the spawning grounds f i r s t . The female f i s h showed a decrease i n s i z e , l a t e r i n the run, which was not shown by the males. The eggs hatched sometime i n mid June and the young f i s h apparently spend one year i n the o u t l e t stream. The female f i s h mature between the ages of 2—4 and the males between 1—3. The mean number of eggs per female, plus or minus two standard deviations was 944* 393.29. A multiple regression a n a l y s i s revealed that body length a f f e c t e d the number of eggs produced, 2.5 times as much as egg diameter. Recommendations were made, due t o the probable e f f e c t s of i v competition, that cutthroat t r o u t be kept i n pure culture populations. I t was f u r t h e r suggested that cutthroat trout numbers be maintained i n view of the severe reduction and almost e x t i n c t i o n of the species i n other areas. TABLE OF CONTENTS Page TITLE PAGE i ABSTRACT i i TABLE OF CONTENTS . , . v LIST OF FIGURES . . v i i i LIST OF TABLES . . . . . . x ACKNOWLEDGEMENTS . . . xi INTRODUCTION 1 LAKES 4 A. Physical and Chemical Limnology of Kiakho Lake . . . 4 1. Location, Size and Drainage . . . . . . . . . 4 2. Temperature 7 3. Oxygen Content 9 B. Biological Limnology of Kiakho Lake 12 1. Flora . 12 2. Bottom Fauna 12 3. Plankton 17 C. Trophic Development of Kiakho Lake . 22 D. Description of Other Lakes Sampled 23 1. Monroe Lake 23 2. Lumberton Reservoir . . . . . . . . . . . . . 23 v i Page 3 . Garcia Lake 24 FISH 25 A. Food Habits 25 B. Foods Taken 26 1. Kiakho Lake 26 2 . Monroe, Lumberton and Garcia Lakes . . . . . . 3 0 C. Changes i n Stomach Contents Volume . . . . . . . . 32 D. Age and Growth 3 4 1. Size at Scale Formation 35 2 . Body-Scale Relationship 3 5 3 . Growth Rate 3 7 4 * Lee's Phenomenon 44 E. Spawning Run 48 1. Time and Place 48 2 . Movement and M o r t a l i t y 49 3 . Size Composition and Sex Ratio 55 F. Upstream Migration of F i n g e r l i n g s . . . . . . . . . 57 G. Maturity and Fecundity 61 1. Age of Maturity 61 2 . Fecundity 62 3 . Factors A f f e c t i n g Egg Number 63 H. D i s t r i b u t i o n of F i s h Within the Lake 64 DISCUSSION 66 v i i Page SUMMARY 70 LITERATURE CITED 74 v i i i LIST OF FIGURES Page Figure 1 . Depth contour map of Kiakho Lake, showing the p o s i t i o n of the l i m n o l o g i c a l s t a t i o n s . . . . . . 5 Figure 2. Temperature s e r i e s f o r the summer months at four stations 8 Figure 3» Oxygen s e r i e s f o r the summer months at four s t a t i o n s . 10 Figure 4. Graphical analysis by percent volume and percent occurrence i n t o t a l number of dredgings, of the bottom fauna of Kiakho Lake. . . . 13 Figure 5« Graphical a n a l y s i s of the stomach contents of cutthroat trout for May, June, and J u l y i n Kiakho Lake and f o r Monroe, Lumberton and Garcia Lakes 29 Figure 6. Change i n average stomach volume and number of empty stomachs over the summer period, i n Kiakho Lake • 33 Figure 7. Body-Scale r e l a t i o n s h i p 36 Figure 8. Instantaneous growth rate ( l o g | Q fork length at age n + 1 minus l o g ) 0 fork length at age n) i n r e l a t i o n t o fork length at the beginning of the year f o r cutthroat t r o u t i n Kiakho Lake. . . . . . . 38 Figure 9» Lo§io instantaneous growth rate i n r e l a t i o n to l o g 1 0 fork length of cutthroat t r o u t i n Kiakho Lake 39 Figure 10. L o g ) 0 instantaneous growth rate p l o t t e d against l o g i o of fork lengths f o r rainbow trout i n Pinantan Lake (MacLeod, 1958) 42 Figure 11. Walford p l o t of fork length a t time T + 1 against fork length at time T and a Parker and .Larkin transformed Walford p l o t with exponent 0.7, f o r four year o l d cutthroat trout from Kiakho Lake. . . . 43 ix Page Figure 12. Relation of average fork length of age classes t o age 45 Figure 13. Diagram o f trap f a c i l i t i e s 50 Figure 14. D a i l y numbers of f i n c l i p p e d marked f i s h and d i s c tagged f i s h moved through the t r a p . . . . 53 Figure 15. Length frequency of male and female f i s h moving downstream i n the spawning run 56 Figure 16. D a i l y numbers of year old f i n g e r l i n g s moving upstream into Kiakho Lake 58 Figure 17. Length frequency of year old f i n g e r l i n g f i s h moving upstream i n t o Kiakho Lake 59 X LIST OF TABLES Page Table 1 . Morphometry of Kiakho Lake 6 Table 2 . Numerical Analysis of the Bottom Fauna of Kiakho Lake 15 Table 3. Numerical Analysis of Paul Lake Dredging data (from Rawson, 1934) 16 Table 4 . Species Goimpositibn of the Plankton o f Kiakho Lake, and Their R e l a t i v e Abundance 18 Table 5 . Volumes of Plankton at Two Stations Over the Summer 19 Table 6 . Approximate Trophic D i s t r i b u t i o n of Dominant Limnetic Algae i n Lakes of Western Canada (from Rawson, 1956) 21 Table 7 . Stomach Contents Analysis from Kiakho, Garcia, Lumberton and Monroe Lakes . . . . 27 Table 8 . Average Lengths a t D i f f e r e n t Ages i n Various Age Classes . . . . . . . . . . . . . 44 " Table 9 . Numbers of Eggs Taken i n 1958 at Kiakho Lake . 4 8 Table 10. Date and Numbers of Petersen Disc Tagged F i s h Put Upstream on Completion of Spawning . . . . . . . . 51 Table 11. Results of F i n C l i p Marking Program . . . . . . . . . 52 Table 12 . Mean Catch Per Net Set, of F i s h at Various Depths i n the North and South Basins of Kiakho Lake 65 x i ACKNOWLEDGEMENTS This study was f i n a n c i a l l y supported by the B r i t i s h Columbia F i s h and Game Branch and the I n s t i t u t e o f F i s h e r i e s , U n i v e r s i t y of B r i t i s h Columbia. The author would l i k e t o g r a t e f u l l y acknowledge J . Boone, M. Y. A l i , R. E. Johannes and J . Varty f o r t h e i r valuable assistance i n the f i e l d work. S p e c i a l thanks to T. Miura far assistance i n data a n a l y s i s , F. P. Maher f o r suggesting Kiakho Lake as a study area and l.Li, Withler f o r c o n t r i b u t i n g data from Garcia Lake. The author wishes t o express h i s gratitude t o Dr. P. A. Larkin f o r suggesting the problem and h i s valuable c r i t i c i s m . INTRODUCTION In the management of any f i s h e r y , i t i s e s s e n t i a l t o have an understanding of the b i o l o g y of the f i s h or f i s h e s concerned* During the summer of 1958, a study of the l i f e h i s t o r y and ecology of the Yellowstone cutthroat t r o u t (Salmo c l a r k i i l e w i s i Girard) was i n i t i a t e d . The study was d i r e c t e d at d e s c r i p t i o n of a l l phases of the l i f e h i s t o r y , with p a r t i c u l a r reference t o food h a b i t s . Many of the lakes i n B r i t i s h Columbia have natural or a c c i d e n t l y planted stocks of "coarse f i s h " , pre-dominantly the redside shiner (Richardsonius b a l t e a t u s ) , the squawfish (Ptychocheilus oregonense) and various species of suckers and minnows. Larki n and Smith (1954) described the e f f e c t of redside shiners on the rainbow t r o u t (Salmo ga i r d n e r i ) population i n Paul Lake, B r i t i s h Columbia. Their work i n d i c a t e d that the t r o u t were adversely a f f e c t e d by the shiners, because rainbow t r o u t w i l l not feed on shiners u n t i l they (the tr o u t ) a t t a i n a length of 10 to 12 inches. At the same time, young t r o u t s u f f e r from competition with shiners and have a reduced growth r a t e . The present study was i n i t i a t e d to determine whether the cutthroat t r o u t , being more piscivorous would make b e t t e r use of coarse f i s h stocks and s u f f e r l e s s from competition. Within the province o f B r i t i s h Columbia, there e x i s t two subspecies of cutthroat t r o u t , the Coastal cutthroat t r o u t (Salmo c l a r k i i c l a r k i i Richardson) and the Yellowstone cutthroat t r o u t (Salmo c l a r k i i l e w i s i G i r a r d ) . Qadri (1959) gave a b r i e f review of the d i s t r i b u t i o n of these 2 subspecies within the province. The Coastal cutthroat trout is found in most of the coastal lakes and streams and on the majority of the coastal islands. Fish culture activities have resulted in the Coastal cutthroat being planted east of the coast mountains, in Garcia Lake (1954) near Merritt and in the Shuswap and Similkameen Rivers. The Yellowstone cutthroat is found in the southeastern part of the province. It occurs in the Flathead River, the upper Columbia and Kootenay Rivers, as far west as the Arrow Lakes and north to the Revelstoke area. Fish culture activities have distributed the Yellowstone cutthroat across much of the southern part of the province. There have been no major studies of the biology of the cutthroat trout in British Columbia. As a result the majority of this study was concerned with the pure culture of Yellowstone cutthroat trout in Kiakho Lake. This information should provide a basis for comparison with later work on mixed populations of cutthroat trout and other species. Kiakho Lake near Craribrook, British Columbia, was chosen as a pure culture stock of Yellowstone cutthroat trout. This lake was suitable for several reasons; it is easily accessible, it has had no fishery on it for more than fifteen years, there is a large spawning run in the outlet stream and trap facilities were already installed. Kiakho Lake has been an egg taking station for more than twenty years and has supplied several million eggs for stocking in other lakes. British Columbia Fish and Game Branch records show Kiakho Lake was stocked thirteen times between 1938 and 1952. The stocking was done mostly with eggs, but some cutthroat fry were also used. To supplement the food habit data, samples of cutthroat were taken 3 from other lakes, some of which had other species of f i s h i n them. These lakes were Monroe Lake and Iumberton Reservoir near Graribrook and Garcia Lake near M e r r i t t . A l l the data c o l l e c t e d i s f i l e d a t the I n s t i t u t e of F i s h e r i e s , U n i v e r s i t y o f B r i t i s h Columbia. LAKES: A. PHYSICAL AND CHEMICAL LIMNOLOGY OF. KIAKHO LAKE 1. Location, Size and Drainage Kiakho Lake is situated in southeastern British Columbia, approxi-mately 6 miles due west of Cranbrook, (115° 57' west, 49° 3 0 ' north). The lake lies in a small valley at an altitude of 3,600 feet (1,098 m.) and the geology of the drainage area consists of argillites and quartzites (Chapman and Turner, 1956). The lake basin has been formed by a rock slide obstructing the valley and is of type 20a as described by Hutchinson (1957). The average annual precipitation is 40—50 inches per year with 50—70 percent of this in the form of snow (Chapman and Turner, 1956). The total drainage area coming into the lake covers approximately 3 square miles. The lake is frozen about 5 months of the year, from late November to late April. The ice left the lake in 1958 on April 28. Kiakho Lake has an area of 67.42 acres (27.30 ha.), is 1.1 miles long and averages 550 feet wide. The maximum depth i s 32 feet (9.8 m.) and the mean depth is 16.5 feet (5.0 m.). The lake consists of two basins, the large south basin and the small north basin (Fig. 1). These basins are joined by a narrows in the lake, which is 200 feet wide and 5 feet deep. Table 1 summarizes the morphometry of the lake. The lake is bordered on the east and west by precipitous rock slides, which drop Figure 1. Depth contour map of Kiakho Lake, showing the p o s i t i o n of the l i m n o l o g i c a l s t a t i o n s . 6 TABLE 1. MORPHOMETRY OF KIAKHO IAKE Surface Maximum Mean Volume Secchi Shore- Shore- Volume Area Depth Depth Disc line line Develop-Factor Devel- ment opment 67.42 32.0 16.5 1,112.8 17.0 .0043 2.11 1.55 acres f t . f t . acre-ft. f t . 27.30 9.8 5.0 5.2 ha. m. m. m. into the lake. The sides of the lake basin, down to a depth of approxi-mately 12 feet consist of steep slopes of broken rock, ranging in size from fine gravel to pieces 10 feet across. The remainder of the lake bottom consists of organic ooze mixed with very fine sand. The total dis-solved solids content is 100 parts per million. There are two inlets, one at the north end and one about half way along the east side of the south basin. Both inlets are small and each had a flow of approximately 0.25 cubic feet per second in 1958. The inlet at the north end arises from another small lake, but is probably not indi-cative of the water movement between the lakes. The area between the lakes is swampy and considerable undetected ground water movement could be involved. The inlet on the east side arises from a spring approximately 150 yards up the hillside above the lake. The outlet at the south end of the lake is small with a flow of approximately 3—4 cubic feet per second during the spring, and nearly dry by midsummer. The lake fluctuation controls the size of the outlet stream 7 flow. The fluctuation was about 8 inches in 1958 as measured from the high water mark cn the lake shore. A small spring enters the stream about 25 yards below the lake, and this holds the stream flow at about 0.25 c.f .s. The fi r s t 75 yards of the stream consists of rapids over large boulders and gravel bars. The remaining part of the stream that was surveyed, approxi-mately 2,000 yards, consisted of a slow flowing meandering stream with a mud bottom. Approximately 200 yards below the lake a small pool was formed by a beaver dam. In this 200 yards, 2 small springs entered the stream and brought the flow up to approximately 0.50 c.f.s. For 25 yards below the beaver dam the stream flowed through many diverse channels. These channels met and formed a single channel. In the remaining surveyed por-tion of the stream, the bottom was composed of mud. inter spaced with 4 small patches of gravel. The gravel patches were approximately 40 feet in length. 2. Temperature A l l temperatures were taken with a standard maximum-minimum thermo-meter. Figure 2 shows the temperature curves for the four stations over the summer period. Stations 1, 2, and 3 were in the south basin, are com-parable in depth and show great similarity in the shape of the curves. Station 4 was in the north basin which is only half as deep as the other stations and relatively isolated, as a result, showed much different curves. In late May and early June the epilimnion extended down to 6 feet, as shown at a l l four stations. By mid August the epilimnion descended down to 18 feet at stations 1, 2 and 3* Station 4 was isothermal by mid August and was virtually a l l epilimnion. 8 46 ' 5 0 ' 54 ' 58 ' 62 66 ' 7 0 46 ' 5 0 ' 54 ' 58 62 66 7 0 TEMPERATURE (°F.) O—O MAY 29; •—• JUNE 3; «—< JUNE 26; •—• JULY 26; a—a AUGUST 16. Figure 2. Temperature s e r i e s f o r the summer months at four s t a t i o n s . 9 The thermocline e x i s t e d throughout the summer at stati o n s 1, 2 , and 3 . In l a t e May the thermocline extended from 6 to 20 f e e t , and by mid August i t had been displaced down t o 18 t o 25 f e e t , which i s the bottom at stations 1 and 3» By l a t e J u l y and e a r l y August the thermocline was probably e f f e c t i v e i n sea l i n g o f f the area below 20 f e e t from any wind induced c i r c u l a t i o n . 3 . Oxygen Content Water samples were taken with a Kemmerer b o t t l e and oxygen deter-minations were done by the Winkler method. Figure 3 shows the oxygen saturation curves, corrected f o r a l t i t u d e and temperature f o r the four stat i o n s over the summer period. The curves f o r May and e a r l y June show that a clinograde d i s t r i b u t i o n , as described by Hutchinson (1957) was formed: i . e . t o t a l saturation a t the surface with a reduction of oxygen with depth. In l a t e June at stati o n s 1 and 2 a p o s i t i v e heterograde d i s t r i b u t i o n formed, with supersaturations up t o 120—125 percent, occur-r i n g at the 15 f o o t l e v e l . In l a t e J u l y the curves were again clinograde, with a weak p o s i t i v e heterograde d i s t r i b u t i o n formed at s t a t i o n 3 . This change from heterograde to clinograde d i s t r i b u t i o n was probably the r e s u l t of severe wind a c t i o n . P o s i t i v e heterograde d i s t r i b u t i o n s formed again i n mid August at st a t i o n s 1 and 2 , and t h i s time a t the 20 foot l e v e l . By mid J u l y there was severe stagnation i n the area below 25 f e e t . S t a t i o n 4 had two periods during the summer i n which there was uniform saturation from the surface to the bottom. These two periods corresponded with the formation of the heterograde d i s t r i b u t i o n s a t s t a t i o n 1 and 2 . Ricker (1934) pointed out that supersaturations at depths such as those shown 10 O 20 40 60 80 IOO I20 O 20 40 60 80 IOO 120 OXYGEN —PERCENT SATURATION O-OMAY 29; •—'JUNE 3;<—' JUNE. 26; ' -~-JULY 26, A—a A UGUST 16. Figure 3. Oxygen serie s f o r the summer months at four s t a t i o n s . 11 in Figure 3, are not absolute supersaturations but apparent supersatura-tions. Water under the increased hydrostatic pressure, results in increasing the saturation value of that water. In order to have this higher oxygen value at this depth, there must be a source. The small creek, entering the lake from the east side, flowed down a steep rocky hillside for approximately 150 yards. The stream water is probably saturated with oxygen by the time i t reaches the lake. The temperature of this stream in mid August was 52°F. This water would probably sink on reaching the lake. As i t sinks i t would mix with lake water and become warmer, eventually stopping at some intermediate level. The increase in the temperature of this water would result in a supersatura-tion of oxygen. Since, however the hydrostatic pressure at that depth increases the saturation level of the water, the supersaturation is only apparent and not absolute. At a l l stations, by late July and early August there was a small supersaturation in the surface waters. This is probably the result of cooling of the surface waters at night, which allows more oxygen to be dissolved, then a warming of the water in the morning, with no loss of oxygen. This would only be a temporary situation and the f i r s t wind action would release the excess oxygen. 12 B. BIOLOGICAL LIMNOLOGY OF KIAKHO LAKE 1. Flora There are two common species of plants on the lake bottom—the rooted aquatic, Potamogeton praelongus and the alga Cladophora sp. The distribution of these plants was limited, the Cladophora was found in depths from 12—18 feet in the north basin and 10—25 feet in the northwest corner of the south basin. The Potamogeton was found in depths from 5—12 feet in the north basin and 5—12 feet at the south end of the lake. 2. Bottom Fauna The bottom samples were taken with a 6 inch Ekman dredge and the material was separated through a screen having 24 meshes to the inch. The species were separated and their volume measured in graduated centri-fuge tubes, to the nearest one hundredth of a cubic centimeter. The total number of samples taken was 110. Figure 4 shows graphically the results of the bottom fauna analysis, of the lake taken as a whole, for the arbitrarily chosen depth zones of 10, 20 and 30 feet, and for the two basins. The graph for the 0—20 foot depth zone of the south basin was included for comparison with the north basin which i s 18 feet deep. The chironomid larvae were scarce in the 0—10 foot zone, were common in the 10—20 foot zone and very abundant in the 20—30 foot depth zone. Gammarus showed the opposite distribution, abundant in shallow waters and rare in the deep waters. Leeches occurred in greatest 13 SOUTH BASIN 0 - 2 0 F T . PERCENT V O L U M E CHIRONOMID LARVA Q\] HYALELLA GAMMARUS | § § § BIVALVE MOLLUSCA OTHERS MOLLUSCA jjjjljl HIRUDINEA ^ | OLIGOCHAETA [ = z | TRICHOPTERA LARVA jiggi] CHAOBORUS Figure 4 . Graphical a n a l y s i s by percent volume and percent occurrence i n t o t a l number of dredgings, of the bottom fauna of Kiakho Lake. 14 numbers i n the 10—20 foot zone and were small i n numbers i n the shallow and deep waters. Figure 4 a l s o shows a comparison of fauna of the north and south basins. The north basin fauna was predominantly Gammarus and leeches, while the south basin fauna was predominantly chironomid 1 larvae. A comparison of the 0—20 foot depth zone of the south basin and the whole north basin, showed that the north basin produced a greater amount of bottom fauna. Table 2 shows the numerical a n a l y s i s of the bottom fauna. The fauna of the 0-10 foot zone was made up predominantly of Chironomidae, H y a l e l l a , Gammarus and Mollusca. These organisms accounted f o r 90.3 per-cent of the t o t a l fauna. The 10—20 foot zone had the same organisms present and the same forms i n predominance. The t o t a l number of organisms per square meter had shown a considerable decrease. This would appear to be the s u b l i t t o r a l minimum often found i n eutrophic lakes (Rawson, 1930). The 20—32 foot depth zone can be considered as the profundal zone, due t o the sudden and c h a r a c t e r i s t i c faunal change. The dominant forms found here were chironomid larvae (83.6$) and Chaoborus (10.3$) with the other organisms being v i r t u a l l y absent. Table 3 i s the numerical a n a l y s i s of the bottom fauna of Paul Lake taken from Rawson (1934). Comparing Kiakho Lake bottom fauna with that of Paul Lake shows that the abundant organisms are the same and are of the same general magnitude. The comparison of two d i f f e r e n t size lakes must proceed cautiously, since many f a c t o r s a f f e c t small lakes, which do not a f f e c t large lakes. However, the f a c t that there i s great s i m i l a r i t y i n the type and amount of bottom fauna, would i n d i c a t e that the t r o p h i c nature of the lakes might be s i m i l a r , although probably r e s u l t i n g from 15 TABLE 2. NUMERICAL ANALYSIS OF THE BOTTOM FAUNA OF KIAKHO IAKE Average Number Percent of Total per Square Meter Organisms • . . . 1 . • 1 0-101 10-20' 20-30' 0-10' 10-20' 20-30' (0-3m) (3-6m) 6-9. 8m  Chironomidae 305 606 2,206 16.2 49.3 83.6 Hyalella 464 142 13 24.7 11.5 0.5 Gammarus 559 120 34 29.7 9.8 1.3 Mollusca 370 194 56 19.7 15.8 2.1 Hirundinea 22 22 13 1.2 1.8 0.5 Oligochaeta 112 99 39 6.0 8.0 1.5 Chaoborus 9 11 271 0.5 0.9 10.3 Trichoptera Larva 17 13 3 0.9 1.1 0.1 Nematoda 3 0 1 0.2 0 0.04 Zygoptera Larva 3 9 0 0.2 0.7 0 Ephemeroptera L. 13 9 3 0.7 0.7 0.1 Hydracarina 2 5 1 0.1 0.4 0.04 Megaloptera L. 2 0 0 0.1 0 0 Total 1,881 1,230 2,640 100 100 100 TABLE 3. NUMERICAL ANALYSIS OF PAUL LAKE DREDGING DATA (FROM RAWSON, 1934) Organisms Average No. per sq. m. in Depth Zones #0-20 meters # whole lake 0-5m. 5-10 10-20 20-30 30-40 40-50 50-55 wo. per. Sq. m. % of Total No.per Sq. m. % of Total Chironomidae 100 69 945 360 940 560 410 679 28.5 672 49.5 Ampnipoda -Hyalella 2149 $34 40 + - - - 752 31.7 198 14.6 Gammarus 66 51 510 39 — 40 58 372 15.6 166 12.2 Mollusca -Physa 32 180 2 - - - - 28 1.2 7 0.5 Lymnaea 7 42 13 - - • - - 15 0.6 4 0.3 Planorbis 5 - - - - - - 1 0.0 - — Sphaeriidae 40 4 482 990 195 105 17 340 14.7 247 18.1 Odonata -Zygoptera 19 67 - - - - - 12 0.5 3 0.2 Anisoptera 19 - - - - - - 6 0.2 2 0.1 Trichoptera 20 44 2 - - - - 12 0.5 3 0.2 Ephemeroptera 4 - - - - - - 1 0.0 - -Hirundinea 54 49 80 - • - - - 75 3.2 19 1.4 Planaria 19 59 45 3 108 10 10 42 1.8 30 2.2 Oligochaeta 29 - 7 5 - 24 10 13 0.5 10 0.7 Miscellaneous 28 • + . - - - - 8 .... 0.3 2 0.1 A l l Organisms 2,591 1,399 2,126 1,397 1,243 739 505 2,356 100 1,363 100 17 two d i f f e r e n t causes. Kiakho Lake, being small and shallow, i t was an t i c i p a t e d that there would be a high production of bottom fauna. The data had shown that the quantity o f bottom fauna i s small, and that there i s a higher production i n the north basin than i n the south b a s i n . To explain the paucity of bottom organisms, one must look at the structure and p h y s i c a l nature of the lake b a s i n . The north b a s i n i s shallow and the greater part of the bottom i s a gentle slope covered with mud, and overgrown with Potamogeton. This basin i s v i r t u a l l y isothermal a l l summer and there i s no stagnation. With the r i c h zone of rooted aquatic plants and the higher production of bottom organisms, t h i s was the only part of the lake which showed signs of l i t t o r a l development. In contrast t o the north basin, the south basin, has very steep sides and a rocky substrate. There i s very l i t t l e area of shallow mud covered bottom where rooted aquatic plants could grow. The south basin had only the deep water area i n which bottom organisms were produced, r e s u l t i n g i n the appearance of being the profundal zone of a much l a r g e r l a k e . The low production of bottom fauna i n the south basin i s probably a t t r i b u t a b l e t o the Lack of any l i t t o r a l development. The south basin, i n respect to bottom fauna production showed an extreme degree of o l i g o -trophy, while the north b a s i n bordered on mesotrophy. 3. Plankton Plankton samples were taken i n t o t a l v e r t i c a l hauls, with a No. 20 s i l k Wisconsin type plankton net. Table 4 shows the composition and r e l a t i v e abundance of various organisms. In June the plankton was 18 TABLE 4. SPECIES COMPOSITION OF THE PLANKTON OF KIAKHO LAKE, AND THEIR RELATIVE ABUNDANCE June 6 August 16 Diatoms—Asterionella  Navicula  Fragilaria  Synedra Blue-Green ALgae— Anabaena Protozoa— Dinobryon Desmids—Staurastrum *•*• Rotifera-Anuraea Triarthra  Conochilas  Asplanchna ' 4 *•-•• 4 Diatoms—Asterionella  Navicula  Fragilaria Blue-Green Algae— Anabaena  Aphanocapsa  Gloeotrichia Green Algae— Pleurococcus  Tetraspora  Anki strode smis Protozoa— Ceratium + + Copepoda— Cyclops Diaptomus Nauplii Cladocera— Daphnia Rotifera— . Asplanchna  Conochilus  Triarthra  Notholca Copepoda— Cyclops  Diaptomus + Cladocera-Daphnia Very abundant, ++ Common, **• Present in small numbers. 19 dominated by diatoms, rotifers and copepod nauplii. In August the dia-toms, desmids, blue-green algae, rotifers, copepods, and cladocerans were abundant. There was a progression from the diatoms and rotifers in the early summer to a rotifer, copepod, cladoceran dominance by late summer. Table 5 shows the settled volume of plankton from stations 2 and 4 . The plankton of the south basin (station 2) reached a peak in volume in late June and then dropped to a constant level in July and August. The plankton of the north basin (station 4) had a smaller settled TABLE 5 . VOLUME OF PLANKTON AT TWO STATIONS, OVER THE SUMMER Station 2 Station 4 Date - ~ Vol. in c.c.'s Vol. in c.c.'s June 6 0 . 6 5 0 . 5 5 June 26 1.40 0 . 7 0 July 26 1.20 0 . 5 5 Aug. 16 1.25 1.90 volume than the south basin, but showed a sudden increase in volume in August. The smaller settled volume found in the north basin is probably due to the depth of water sampled. In the north basin only 18 feet of water was sampled, where as in the south basin, 32 feet of water was 20 sampled. A comparison of the mean s e t t l e d volume of plankton on the t o t a l d i s s o l v e d s o l i d s from Kiakho Lake, with that found by Northcote and Lar k i n (1956) f o r 100 B r i t i s h Columbia lakes, showed a very poor product-io n of plankton. The values of 1.13 c c , i n June and 0.93 c c . i n August f o r Kiakho Lake, f e l l below the c a l c u l a t e d average of 2.25 c.c. f o r lakes with 100 p.p.m. t o t a l dissolved s o l i d s as described by Northcote and L a r k i n (1956). An examination of the species composition of the plankton can give an i n d i c a t i o n of the t r o p h i c status of a l a k e . Rawson (1956) has reviewed and summarized the subject of a l g a l i n d i c a t o r s of t r o p h i c lake types. Rawson points out that o l i g o t r o p h i c lakes have been characterized by a poor quantity of plankton, many species present i n the plankton, and a r a r i t y of water-blooms. Table 6 i s a l i s t of the approximate tr o p h i c d i s t r i b u t i o n of algae i n lakes of Western Canada, according t o Rawson (1956). Kiakho Lake would be considered o l i g o t r o p h i c due to poor product-io n of plankton, the presence of many species i n the plankton, and the r a r i t y of water-blooms. A f u r t h e r a n a l y s i s of the plankton revealed that A s t e r i o n e l l a , F r a g i l a r i a , and Staurastrum were abundant and Dinobryon was present. A l l these forms are l i s t e d by Rawson as o l i g o -t rophic i n d i c a t o r s . The blue-green and green algae were represented i n the plankton, with Anabaena the most abundant. Ceratium was present, but not abundant. The blue-green algae Anabaena and the protozoan Ceratium are l i s t e d as mesotrophic i n d i c a t o r s . However, since the o l i -gotrophic i n d i c a t o r s were more abundant, the plankton would i n d i c a t e 21 TABLE 6. APPROXIMATE TROPHIC DISTRIBUTION OF DOMINANT LIMNETIC ALGAE IN LAKES OF WESTERN CANADA (FROM RAWSON,1956) Oligotrophic A s t e r i o n e l l a formosa  Melosira i s l a n d i c a  T a b e l l a r i a f enestrata  T a b e l l a r i a f l o c e u l o s a  Dinobryon divergens  F r a g i l a r i a capucina  Stephanodiscus niagarae Staurastrum spp. Melosira granulata Mesotrophic F r a g i l a r i a crotonensis  Ceratium h i r u n d i n e l l a  Pediastrum boryanum  Pediastrum duplex  Coelosphaerium naegelianum  Anabaena spp. Aphanizomenon flos-aquae  Mi c r o c y s t i s aeruginosa  Mi c r o c y s t i s flos-aquae 22 that Kiakho Lake was oligotrophies. Rawson (1956) remarks that the use of a l g a l i n d i c a t o r s of lake types i s s t i l l i n i t s infancy and that more in v e s t i g a t i o n s are necessary t o substantiate t h e i r use. I t i s unfor-tunate that no such work has been done i n B r i t i s h Columbia, where there e x i s t s a great d i v e r s i t y of l i m n o l o g i c a l conditions, as pointed out by Northcote and L a r k i n (1956). C. TROPHIC DEVELOPMENT OF KIAKHO LAKE Rawson (1939) i n d i c a t e s that there are probably three major f a c t o r s a f f e c t i n g the p r o d u c t i v i t y of l a k e s . These are morphometric, edaphic and c l i m a t i c f a c t o r s . Thienemann (1927) and more r e c e n t l y Rawson (1952) support the view that mean depth i s a s i g n i f i c a n t index of t r o p h i c development of lakes. Thienemann (1927) established the c r i -t e r i o n that lakes with a mean depth greater than 10 meters were o l i g o -t r o p h i a and those with a mean depth l e s s than 10 meters were eutrophic. According t o t h i s c r i t e r i o n , Kiakho Lake with a mean depth of 5 meters would be eutrophic. I t has been shown that the low production of bottom fauna and plankton, the lack of L i t t o r a l development, and the presence of i n d i c a t o r organisms i n the plankton i n d i c a t e that Kiakho Lake i s o l i -gotrophia. I t i s apparent that the o l i g o t r o p h i c state i s a r e s u l t of the l i m i t a t i o n by some f a c t o r or f a c t o r s other than morphometry. The t o t a l d i s s o l v e d s o l i d s content of Kiakho Lake i s low compared with the average of 285 p.p.m. f o r the area as c a l c u l a t e d by Northcote and L a r k i n (1956). This low t o t a l d i s s o l v e d s o l i d s content i s probably 23 due t o the very small drainage area, the high p r e c i p i t a t i o n and the general g e o l o g i c a l composition of the area. I t has been in d i c a t e d pre-v i o u s l y , that the steep sloped sides of the lake basin with the rocky substrate was not s u i t a b l e f o r the production of plant and animal l i f e . This has r e s u l t e d i n l i t t l e or no l i t t o r a l development. I t now appears that the f a c t o r s l i m i t i n g production i n Kiakho Lake are, low t o t a l d i s s o l v e d s o l i d s and an unsuitable substrate. Both of these f a c t o r s would come under the c l a s s i f i c a t i o n of edaphic f a c t o r s as suggested by Rawson (1939). This i n d i c a t e s that the l i m i t a t i o n by c e r t a i n edaphic f a c t o r s has r e s u l t e d i n an o l i g o t r o p h i c condition being expressed over a eutrophic morphometry. D. DESCRIPTION OF OTHER LAKES SAMPLED 1. Monroe Lake Monroe Lake i s situated approximately 12 miles south of Granbrook, B r i t i s h Columbia. I t has a surface area of 230 acres and a maximum depth of 108 f e e t . The f i s h species present were, cutthroat t r o u t , rainbow t r o u t , and the cutthroat-rainbow hybrid. 2. Lumberton Reservoir Lumberton Reservoir i s an a r t i f i c i a l lake created by a water storage dam, and i s located approximately 14 miles south west of Cranbrook. I t has a surface area of 59.4 acres and a maximum depth of 6 f e e t . Cut-throat trout were the only f i s h present. 24 3» Garcia Lake Garcia Lake i s situated approximately 8 miles south of M e r r i t t , B r i t i s h Columbia. I t has a surface area of 51.4 acres and a maximum depth of 57 f e e t . Cutthroat tro u t (Salmo c l a r k i i c l a r k i i ) and the red-side shiner (Richardsonius balteatus) were the only f i s h present. FISH A. FOOD HABITS Stomach samples of cutthroat trout were collected from Kiakho, Garcia, Monroe and Lumberton Lakes, during the summer of 1958. Kiakho Lake was sampled regularly during May, June and July. The other lakes were sampled in late June and late July. Additional food data on fish from Garcia Lake were taken from the British Columbia Fish and Game Branch fil e s . This material had been collected in June and August of 1957. A l l the sampling of fish was done with monofilament nylon experi-mental g i l l nets with mesh sizes of 1, 1 1/2, 2, 2 l/2, 3, 3 l/2, and 4 inch stretched mesh. The stomachs collected were placed in cloth sacks, labelled and preserved in 5 percent formalin. The analysis of the stomach contents was done by washing them from the stomach, separating the various con-stituents and measuring their volume by water displacement in a graduated centrifuge tube. 26 B. FOODS TAKEN 1. Kiakho Lake Table 7 and Figure 5 summarize the r e s u l t s of the stomach contents from a l l o f the lakes. Figure 5 shows the monthly change i n the d i e t of Kiakho Lake f i s h . The food i n May i n Kiakho Lake was almost e n t i r e l y chironomid pupae, with Chaoborus larvae the next l a r g e s t item. A change occurred i n June to the Gammarus-chironomid larvae d i e t , and by l a t e J u l y the amphipods, Gammarus and H y a l e l l a were the major food items. This change was probably a r e f l e c t i o n of the change i n the i n s e c t larvae and other aquatic invertebrate populations. The chironomid pupae r e s u l t i n g from larvae which had wintered over one or two years, would be very vulnerable during t h e i r emergence. According t o M i l l e r (1941) the pupae emerge soon a f t e r the i c e leaves a l a k e . When the numbers of emerging chironomid pupae dwindled the f i s h began u t i l i z i n g other food sources. The Gammarus population would probably be increasing i n numbers due to the warming of the water. A population of chironomid larvae were s t i l l present and would not emerge u n t i l l a t e summer or the following spring ( M i l l e r , 1941)* This s i t u a t i o n could account f o r the change to a Gammarus-chironomid larvae d i e t . The chironomid larvae show a con-siderable reduction from the d i e t between June and J u l y . This i s pro-bably due to the stagnation o f the 25—32 foot depth area, which Figure 4 shows produces the majority of the chironomid larvae. I t has been shown that there i s a seasonal v a r i a t i o n i n the food habits of Kiakho Lake cutthroat t r o u t . This v a r i a t i o n appears t o be a r e s u l t o f the change i n the a v a i l a b i l i t y of food organisms. TABLE 7. STOMACH CONTENTS ANALYSIS FROM KIAKHO, GARCIA, LUMBERTON AND MONROE LAKES K i a k h o L a k e May June ' Jul y August $ Occ. % ! V o l . $ Occ. $..Vol. $ Occ, . % V o l . % Occ. % V o l . F i s h 1.3 0.14 1.4 0.3 Gammarus 37.5 4.7 46.7 45.8 57.8 60.3 H y a l e l l a 5.4 Tr. 9.3 2.6 26.8 13.5 50.0 11.0 Chironomid Larvae 10.7 0.16 46.7 35.5 11.3 13.3 Chironomid Pupae 8359- 81.3 4.0 1.1 9.9 3.3 Chaoborus 53.6 10.4 16.0 3.8 7.0 1.7 100.0 89.0 Ephemeroptera Larvae 8.0 0.16 16.9 6.4 Zygoptera Larvae 5.4 Tr. Trichoptera Larvae 3.6 0.16 8.0 3.8 Mollusca 3.6 T r . 14.7 0.53 19.7 0.6 T e r r e s t r i a l Insects 8.9 3.1 2.7 Tr. 4.2 Tr. Zygoptera (Adult) 4.0 0.8 Diptera (Adult) 2.7 0.9 1.4 Tr. Hirudinea 4.0 3.7 2.8 0.2 Dyticidae Larvae 1.8 Tr. Notonectidae 4.2 Tr. Daphnia 5.3 0.7 1.4 Tr. Hydrachnids 1.8 Tr. Algae 1.4 0.3 Wood 1.8 Tr. 4.0 0.5 1.4 Tr. Rock 1.8 Tr. 1.4 0.3 T o t a l Sample Size 62 89 163 5 T o t a l Volume 193.1 cc. 70.2 cc. 75.4 cc. 0.9 cc. Average Volume 3. 5 cc. 0.98 cc. 1.1 cc. 0.5 cc. No. Empty 6—9.7$ 14 .—15.7$ 92—56.4$ 3—60.0$ TABLE 7 (Cont). STOMACH CONTENTS ANALYSIS FROM KIAKHO, GARCIA, LUMBERTON AND MONROE LAKES Garcia Lake Lumberton . Monroe Lake % Occ. % V o l . % Occ. % V o l . % Occ. 5 i vol. Neuroptera Larvae 3.7 4.0 F i s h 27.8 31.9 Gammarus 51.0 34.4 55.6 78.2 Chironomid Larvae 55.2 13.5 3.7 Tr. Chironomid Pupae 34.4 7.3 7.4 0.7 Chaoborus 32.9 36.0 Anisoptera Larvae 5.1 8.4 13.5 11.6 1.9 1.7 Zygoptera Larvae 1.3 0.9 2.1 0.9 Trichoptera Larvae 11.5 2.1 27.8 13.6 Plecoptera Larvae 2.1 T r . Mollusca 10.8 6.7 7.4 Tr. Corixidae 28.1 5.1 T e r r e s t r i a l Inse ct s 25.3 13.7 14.6 4.4 Zygoptera (Adult) 1.3 Tr. Diptera (Adult) 1.3 Tr. 3.1 0.7 Dyticidae Larvae 1.0 0.1 Notonectidae 12.6 0.9 10.4 1.3 Daphnia 1.3 0.6 1.0 Tr. 3.7 1.1 Chydorinidae 12.5 5.3 Algae 11.8 6.3 Wood 3.7 0.4 Anisoptera (Adult) 1.3 0.9 Copepoda 1.3 1.6 T o t a l Sample Size 79 102 64 T o t a l Volume 202.3 cc. 57.6 cc. 30.1 c c . No empty 6 10 29 80-6 0 40-: 2 0 u 2 0 4 0 6 0 8 0 IOO O 2D 4 0 6 0 8 0 IOO PERCENT VOLUME G A M M A R U S j , | H Y A L E L L A [ ^ J^JCHIRONOMID LARVA ^ C H I R O N O M I D PUPA C H A O B O R U S ANISOPTERA LARVAJSI E P H E M E R O P T E R A LAR. | | T E R R E S T R I A L INSECTS| = = )TRICHQPTERA LAR. HIRUDINEA j I j j i| FISH M O L L U S C A C O RIXIDAE ||f|||CHYDORINIDAE |'.SSj O T H E R S Figure 5 . Graphical a n a l y s i s of the stomach contents of cutthroat trout f o r May, June, and J u l y i n Kiakho Lake and f o r Monroe, Lamberton and Garcia Lakes. 30 Only two cases of cannibalism were recorded from 319 stomachs analysed. They occurred i n June and J u l y , a f t e r the young f i s h had mi-grated i n t o the lake from the stream. There was no apparent difference i n the food of d i f f e r e n t s i z e d f i s h . The range of s i z e of f i s h sampled was 15—35 cm. fork length. I t was not an t i c i p a t e d there would be a di f f e r e n c e i n food of d i f f e r e n t s i z e d f i s h , since there was a l i m i t e d number and type of food organisms a v a i l a b l e . 2. Monroe, Lumberton and Garcia Lakes The food of the cutthroat trout from Lumberton and Monroe Lakes consisted of Gammarus and immature aquatic i n s e c t s . Gammarus was the la r g e s t single c o n t r i b u t o r t o the food of the f i s h fro£ Lumberton Lake, but was only 34 percent by volume, the remaining 66 percent was mostly iramature aquatic i n s e c t s (see Figure 5)» There appeared t o be no difference i n the food of d i f f e r e n t sized f i s h . The range of s i z e sampled was 11—38 cm. fork length. Monroe Lake f i s h f e d mostly on Gammarus (78 percent by volume), the remaining items were immature aquatic i n s e c t s , with t r i c h o p -t e r a larvae the major element, (see Figure 5). The size of f i s h sampled from Monroe Lake were 19—42 cm. fork length. The f i s h i n Garcia Lake f e d mostly on Chaoborus larvae and f i s h (Redside Shiner), with small amounts of immature aquatic i n s e c t s and t e r r e s t r i a l i n s e c t s being present (see Figure 5). There appeared t o be a d e f i n i t e preference f o r i n s e c t larvae and i n s e c t s over the Redside Shiner, since the combined r e s u l t s f o r the i n s e c t larvae and insect s would be much greater than that of the Redside Shiner. 31 Dimick and Mote (1934) and G r i f f i t h s and Yoeman (1940), working on c o a s t a l cutthroat found the majority of t h e i r food consisted of t e r r e s t -r i a l i n s e c t s and immature aquatic i n s e c t s , of which the majority were d i p -teran larvae and pupae. They found that f i s h were an i n s i g n i f i c a n t element of the d i e t . Echo (1955)J Hazzard and Madsen (1933)J Hildebrand and Towers (1927)j I r v i n g (1954) and Robertson (1947), working on Yellowstone cut-throat t r o u t , a l l found that the food was predominantly immature aquatic i n s e c t s (mostly dipterans), amphipods and t e r r e s t r i a l i n s e c t s . Hildebrand and Towers (1927) and Calhoun (1944b) found cutthroat t r o u t using substan-t i a l amounts of microcrustaceans i n mid and l a t e summer. Calhoun (1944b) working with the cutthroat t r o u t (Salmo-clarkii  henshawi) found the majority of the food was chironomid pupae and l a r v a e . He a l s o noted that the t r o u t f a i l e d to use the minnow Rhinichthys oscula, which was very abundant i n the l a k e . Hazzard and Madsen (1933) reported that from one lake, f i s h contributed 67 percent, by volume t o the d i e t of the cutthroat. Echo (1955) found 40 percent of the cutthroat stomachs contained f i s h . To generalize, the food o f the cutthroat t r o u t i s predominantly immature aquatic i n s e c t s , t e r r e s t r i a l i n s e c t s and amphipods. Gammarus and dipteran larvae and pupae are the greatest contributors t o the food. F i s h occur i n the d i e t , but appear t o be a second choice t o the i n s e c t s . Dimick and Mote (1934) studied rainbow t r o u t along with cutthroat and found t h e i r d i e t s were v i r t u a l l y the same. In comparing the r e s u l t s of t h i s i n v e s t i g a t i o n with those found by L a r k i n and Smith (1954) on rainbow trou t f o r 1946—49, there i s no difference between the d i e t o f rainbow and 32 cutthroat t r o u t as shown by these s t u d i e s . I t now appears that Yellowstone cutthroat t r o u t at l e a s t i n the lakes studied i n B r i t i s h Columbia, i s no more piscivorous than the rainbow t r o u t , but i n f a c t has v i r t u a l l y the same d i e t . For t h i s reason i t would be doubtful that the cutthroat would make better use of coarse f i s h as a food than rainbow t r o u t . Larkin and Smith (1954) described the e f f e c t of redside shiner on rainbow t r o u t , p o i n t i n g out that the shiner was a severe competitor of the t r o u t . Calhoun (1944b) noted that the minnow Rhiniehthys oscula u t i l i z e d the same food as the young cutthroat, but i t s e l f was not part of the cut-throat d i e t . He advised against the use of i t as a forage f i s h , due t o the p o s s i b l e competition with the young t r o u t . The r e s u l t s i n d i c a t e that cutthroat t r o u t would r e a c t t o coarse f i s h populations the same as the rainbow trout as described by L a r k i n and Smith (1954). C. CHANGES IN STOMACH CONTENTS VOLUME Figure 6 shows the change i n average stomach volume and number of empty stomachs over the summer f o r f i s h from Kiakho Lake. There was a sudden drop i n the average volume when the d i e t changed from ehironomid pupae t o Gammarus and chironomid larvae. This decrease may be a r e f l e c t i o n of the a v a i l a b i l i t y i n numbers of the p a r t i c u l a r organisms. Another drop occurs i n the volume on the change t o an almost complete amphipod d i e t . Calhoun (1944b) found a s i m i l a r drop i n average volume when the f i s h changed t h e i r d i e t . The number of empty stomachs increased r a p i d l y bet-ween June and J u l y and then l e v e l l e d o f f i n August. The lower average stomach volume and increased number of empty 33 Figure 6. Change i n average stomach volume and number of empty stomachs over the summer period, i n Kiakho Lake. 34 stomachs may be i n part a r e s u l t of the water temperature and the method of sampling. A l l of the samples were taken with g i l l nets, i n which f i s h w i l l l i v e f o r varying lengths of time a f t e r being caught. The water tem-perature i s at the summer maximum i n J u l y and e a r l y August. With the increased water temperature, the f i s h (being poikilothermic) would have an increased p h y s i o l o g i c a l a c t i v i t y . Maltzan (1935) found that young carp, passed food through the alimentary canal much quicker a t higher water temperatures. This would i n d i c a t e that f i s h caught i n a g i l l net could empty t h e i r d i g e s t i v e t r a c t more q u i c k l y i n midsummer, thus appearing that the feeding a c t i v i t y had been reduced. Other f a c t o r s such as the decrease i n a v a i l a b i l i t y of food, and a decrease i n feeding a c t i v i t y at higher water temperatures may contribute t o the phenomena. A study of short term growth e.g. weekly growth, could conceivably r e v e a l whether f i s h have a reduced feeding a c t i v i t y . With the water temperature high, the physiolo-g i c a l a c t i v i t y would be high, and a reduction i n feeding should be r e f l e c t e d i n a reduction of weight. With the higher p h y s i o l o g i c a l a c t i v i t y and the reduced feeding, a u t i l i z a t i o n of body f a t would be required to maintain the energy supply. D. AGE AND GROWTH Scale samples used f o r age and growth determinations were taken from f i s h caught i n the lake, and from f i n g e r l i n g s taken i n the ou t l e t stream. The scales were sampled from a standard area on the f i s h , from the l e f t side between the i n s e r t i o n of the d o r s a l f i n and the l a t e r a l l i n e . Determinations of age and growth were made from reading scale 35 impressions made on c e l l u l o s e acetate s t r i p s by use of a jeweller's press. 1. Size at Scale Formation The smallest f i s h that had scales was 3.5 cm. fork length and the la r g e s t f i s h without scales was 4.3 cm. f o r k length. Brown and B a i l e y (1952) found young cutthroat trout farm t h e i r s c a l e s a t approximately 4 cm. fork length. The f i r s t annulus was d i f f i c u l t t o determine, and an examination of the y e a r l i n g upstream migrant scales revealed that there were 5—8 c i r c u l i contained within the f i r s t annulus. Brown and B a i l e y (1952) found young f i s h wintering over only p a r t i a l l y scaled or without . scales and as a r e s u l t some f i s h had scales showing none or one annulus, and some f i s h were a year o l d before the scales formed. This was not found i n Kiakho Lake f i s h . 2. Body-Scale Relationship The r e l a t i o n s h i p between fork length and scale diameter was worked out to form a basi s f o r back c a l c u l a t i n g lengths. Figure 7 shows the r e s u l t s of the body-scale r e l a t i o n . The l i n e shows an i n f l e c t i o n at 5 cm. fork length, suggesting the i n i t i a t i o n of isometric growth between scale and body dimensions. Smith (1955) found a s i m i l a r i n f l e c t i o n a t 4.5 cm. f o r k length i n the coas t a l cutthroat t r o u t . The l i n e above 6 cm. fork length i s described by the formula; l o g Y = 1.284 + 1.033 l o g X The slope, 1.033 was t e s t e d by a »t" t e s t t o determine i f i t was s i g n i f i -c antly d i f f e r e n t from a slope of 1. The value f e l l on the l i n e between s i g n i f i c a n t and n o n s i g n i f i c a n t . For convenience of c a l c u l a t i o n the l i n e 36 Figure 7. Body-scale relationship. 37 was assumed t o have a slope of 1. With t h i s slope, back c a l c u l a t i o n s were done by d i r e c t proportion as described by Smith (1955). I r v i n g (1954) described the body-scale r e l a t i o n of cutthroat t r o u t as a parabola. The data presented i n h i s paper could have been adequately described with a s t r a i g h t l i n e . Fleener (1952) a l s o described the body-scale r e l a t i o n of cutthroat t r o u t as a parabola. His data showed an apparent curvature and h i s calculated parabola was almost a s t r a i g h t l i n e . A s t r a i g h t l i n e would appear t o describe h i s data as w e l l as a parabola. Smith (1955) found a s t r a i g h t l i n e r e l a t i o n s h i p f o r c o a s t a l cutthroat t r o u t . 3. Growth Rate The instantaneous growth rate ( l o g ) 0 of length at age n + l minus l o g t o of length at age n) was c a l c u l a t e d f o r a l l year classes and p l o t t e d against length at the beginning of the growing season. Figure 8 shows the r e s u l t i n g graph p l o t t e d on arithmetic axes. To analyse the percent v a r i a -t i o n i n growth r a t e between small and large f i s h , the points were p l o t t e d on a graph with the ordinate (growth rate) i n a logarithmic s c a l e . This transforms d the data i n t o a st r a i g h t l i n e regression which i n d i c a t e d that the percent increase i n a u n i t measurement of length was much greater i n small f i s h than i n large f i s h . To correct f o r body s i z e , both axes of the graph were made logarithmic. Figure 9 shows t h i s graph. This made i t possible t o make d i r e c t comparisons of growth rate between large and small f i s h . Despite the co r r e c t i o n f o r body s i z e , there was s t i l l a greater v a r i a t i o n i n the growth rate of smaller f i s h . I t was evident that the v a r i a t i o n i n growth rate became l e s s as the f i s h increased i n length. The negative slope of the scatte r of points i s an expression of the decrease 38 o ro oo • • • CM "CM • • .o _co CM _o -oo ~T-o oo CM — r ~ 00 O i O l o T CM o fM CM (J--1 6 o n - l + - L - 1 6 o n ) = ^ o o Figure 8. Instantaneous growth rate (logio fork length at age n +• i minus logio fork length at age n) i n relation to fork length at the beginning of the year for cutthroat trout i n Kiakho Lake. H* vO 9 o V Cfl c^O g o o 8-trt-W 3 P ft 3* O H j CO o as 3 O 3* & (D 4 0 -3 0 UJ < OL. I o OL O to o UJ z !* Z CO z - -IO 2 0 -5 -• • • • • • • • • • • " • • • •••••• • • •• . •. : 4 5 6 7 8 9 IO 15 2 0 FORK L E N G T H (CM) AT BEGINNING O F Y E A R — i — 3 0 40 i n growth rate with an increase i n length. The point or body length to which the graph converges, or the si z e at which there i s l e a s t v a r i a t i o n , might be considered the ultimate size a t t a i n a b l e i n the p a r t i c u l a r e c o l o g i c a l s i t u a t i o n and r e l a t i v e population density. This si z e i s not the maximum s i z e of the f i s h sampled, i t i s smaller, and r e s u l t s from the method o f a n a l y s i s ; Since growth i s a measure of g a i n i n s i z e (e.g., length) between two d i f f e r e n t s i z e s , i t i s r e f e r r e d to the smaller si z e or the si z e at the beginning of the r a p i d growth period. An examination of the graph shows that the slope of the upper l i m i t of the s c a t t e r of points i s much steeper than t h a t of the lower l i m i t . This would i n d i c a t e t h a t the r a t e of decrease of growth rate i s f a s t e r i n f a s t growing f i s h than i t i s i n slow growing f i s h . I f the rate of decrease of growth rate were constant f o r both slow and f a s t growing f i s h , then i t would be expected that the slope of the upper l i m i t of points would be p a r a l l e l to the slope o f the lower l i m i t . However, i t appears that the e c o l o g i c a l s i t u a t i o n and r e l a t i v e population density can impose an "ultimate s i z e " on f i s h , which r e s u l t s i n a great reduction i n growth r a t e . I t follows then that f a s t growing f i s h would reach t h i s u l t i -mate s i z e much more q u i c k l y than the slow growing f i s h and subsequently have a f a s t e r decrease i n growth r a t e . The decrease i n growth rate of the f a s t e r growing f i s h i n Kiakho Lake had the general form of a s t r a i g h t l i n e , having a negative slope. MacLeod (1958) represented the growth of rainbow tro u t i n a s i m i l a r fashion, but there was one notable d i f f e r e n c e . The decrease i n growth rate of the f a s t e r growing f i s h was represented i n h i s graph by a concave curve. 41 Figure 10 shows MacLeod's graph. He explained this concavity as a reflection of the selection of the faster growing fish, by the fishery. The results found from the Kiakho Lake fish appear to support MacLeod's premise. There has been no fishery on Kiakho Lake for a long time, and the rate of decrease of growth rate showed no concavity as found by MacLeod. The back calculated length of the four year old fish were fitted with a parabolic growth equation (Parker and Larkin, 1 9 5 9 ) . The exponent z was found to have a value of 0.71 for the cutthroat trout. Parker and Larkin found z equal to 0.60 for the freshwater growth of steelhead trout (Salmo gairdneri). Figure 11 shows a Walford plot of the four year old fish, and the transformed Walford plot with the axes adjusted to the exponential 0.71 according to Parker and Larkin. The transformed plot has adjusted the data so i t is parallel to the 45 degree line, but an inflection i s suggested at approximately 7 cm. fork length. Parker and Larkin (1959) take the view that changes in z, or rate of change of slope of the curve are reflections of physiological changes. Martin (1949) found inflections in relative growth curves and related them to ossification and maturity. The inflection at 7 cm. fork length in cut-throat trout growth would seem too small for maturity and possibly too large for ossification. The 7 cm. fork length corresponds to the size of the fish when they migrate from the stream into the lake. This change in environment may involve a change in some physiological activity. The inflection may be related to a size at which some physiological change occurs. Parker and Larkin (1959) indicated that a study of size specific metabolic rates to measure the exponent x could be a new CD o fx CD vO (S § v_r< ct- ci-03 ET p> • CD Hj O CO 9 3 q p . O a 4 <+ <D C+ O ci-'-tf H H- O a » 09 c+ to g H-CO ^ H CD O 60A -SOA LLl » -< - 4 0 I 3 6 - 3 0 -O cc O to =>-20 O L U z z o o .io-• • •• • • • 1\> 5 I O 2 0 3 0 L O G F O R K L E N G T H (CM) A T B E G I N N I N G O F Y E A R LENGTH AT TIME T LENGTH AT TIME T°'7 Figure 11 . Walford plot of fork length at time T + 1 against fork length at time T and a Parker and Larkin transformed Walford p l o t with exponent 0 . 7 , f o r four year o l d cutthroat t r o u t from Kiakho Lake. 4 4 avenue of research. This i n f l e c t i o n may be r e l a t e d t o some change i n the standard metabolic r a t e . 4 . Lee's Phenomenon When the determination of growth of f i s h has been done by back c a l -culations from scale measurements, there often appears t o be a change i n growth r a t e , e s p e c i a l l y i n the older f i s h . This change i n growth rate was thoroughly studied by Lee (1912) and has subsequently been known as "Lee's Phenomenon". The phenomenon can be described simply as; the o l d e r f i s h appear t o have grown more slowly i n t h e i r younger years than the present young f i s h . The average lengths at various ages were calculated f o r d i f f e r e n t age classes of f i s h from Kiakho Lake. Table 8 and Figure 1 2 show the r e s u l t s . TABLE 8. AVERAGE LENGTHS IN CENTIMETERS, AT DIFFERENT AGES IN VARIOUS AGE CIASSES Age I I I AGE CLASSES I I I IV V VI I 6.8 6 . 9 7 . 4 7 . 2 7.1 6 . 4 I I 1 3 . 7 1 3 . 0 1 1 . 7 1 1 . 6 1 4 . 4 I I I 19 . 0 18 . 1 18.8 1 7 . 5 IV 2 5 . 0 2 4 . 0 23 .6 V 29 .3 2 7 . 7 VI 3 3 . 2 45 36 Ov- 1 1 1 1 1 r I 2 3 4 5 6 AGE Figure 1 2 . Relation of average fork length o f age classes t o age. 46 I t i s obvious from Table 8 and Figure 12 that Lee's Phenomenon d i d not e x i s t i n Kiakho Lake f i s h . The s i x year o l d f i s h showed a s l i g h t i n d i -c a tion of slower growth, but not enough t o be considered i n d i c a t i v e of Lee's Phenomenon. Van Oosten (1929) l i s t e d seven possible explanations purposed by Lee (1912) f o r the phenomenon. They are: 1. The sample of f i s h are not representative of a year group:; tha t i s , the youngest year groups are repre-sented only by t h e i r biggest i n d i v i d u a l s , and as we proceed toward the older groups there appears more and more of those that had been smaller i n d i v i d u a l s i n t h e i r e a r l i e s t years, so that the average s i z e s o f the older groups tend t o show a l e s s increment of growth and a l e v e l l i n g i n values i s a t t a i n e d . This Lee termed the " s e l e c t i v e e f f e c t of s i z e " . 2. The nets are s e l e c t i v e , r e t a i n i n g only the l a r g e s t f i s h of the youngest year group and excluded the l a r g e s t f i s h of the oldest year group. 3. Conditions of growth are improving and the f i s h a c t u a l l y are growing more r a p i d l y at present. 4. Females and males that have d i f f e r e n t growth rates are present i n varying proportions. 5. The scales, e s p e c i a l l y the f l e x i b l e newest part, con-t r a c t when new increments are added. 6 . A part of the scale i s absorbed i n the maturation of sex organs during the spawning period, as, f o r example i n the salmon. 7. Occasionally more than one r i n g forms per year. Lee (I92O) pointed out that scales do not farm u n t i l the f i s h has attained a c e r t a i n s i z e . T h i s, she in d i c a t e d , does introduce some er r o r i n t o the c a l c u l a t i o n s , and suggested that i t should be corrected, by subtracting t h i s length from the length of the f i s h before back c a l c u l a t i o n s are made. H i l e (1936) advanced mare ideas about the cause 47 of Lee's Phenomenon. In summary they are: 1. Selection by gear. This is the same as Lee's (1912)suggestion that only the largest members of the youngest age group are sampled. 2. Selection due to dissimilar distribution. This proposal was based on the idea that fish at different states of maturity or of dif-ferent size had different spatial distributions and were subsequently not equally represented in the sample. 3. Selection due to differential mortality. Hile suggested that faster growing fish matured sooner and died sooner, thus the older fish were the slow growing element of the population. Jones (1958) expanded on Hile's idea of differential mortality and pointed out that a fishery could be a major factor in producing i t . His idea was that faster growing fish became available to the fishery sooner and were selected out of the population. The fact that Lee's Phenomenon did not exist in the growth of Kiakho Lake fish would indicate that ;the reasons given by Lee (1912) and Hile (1936) were not valid for this particular population. Since no fishery existed on Kiakho Lake, Jone's (1958) proposal that a fishery could be a factor in producing the phenomenon cannot be rejected. Larkin and Smith (1954) found the phenomenon in rainbow trout in Paul Lake. This population of fish had been subject to a fishery for a considerable length of time. It would be desirable to study a similar population of cutthroat trout in order to determine i f a fishery could cause Lee's Phenomenon. 48 -E. SPAWNING RUN 1. Time and Place Cutthroat t r o u t , l i k e many salmonids require running water f o r spawning. Smith (1941) has described the spawning behaviour of cutthroat t r o u t . The spawning run of Kiakho Lake cutthroat t r o u t occurred i n the o u t l e t , being the only s u i t a b l e stream i n the system. The run began i n l a t e A p r i l and continued almost the whole month of May. The f i r s t f i s h were observed t o move i n t o the o u t l e t on A p r i l 27. This time corres-ponded with the break up of the i c e cover on the lake, which occurred on A p r i l 28. Calhoun (1944a) and I r v i n g (1954) observed th a t cutthroat spawning runs began wi t h i n a few days of the i c e cover break up. A trap had been i n s t a l l e d about 20 fe e t downstream from the lake, and was used as an egg taking s t a t i o n . The f i r s t eggs were taken on May 1 and Table 9 i s a summary of the eggs taken i n 1958. TABLE 9. NUMBERS. OF EGGS TAKEN IN 1958 AT . KIAKHO LAKE May 1 95,000 May 3 115,000 May 5 143,000 May 10 155,000 May 12 79,000 T o t a l 668,000 49 The male fish were held from the beginning of the run, to insure having enough for later fertilization. "Green" females were released downstream and ripe females were "stripped" and also released downstream. Egg taking was stopped on May 12 when approximately 700,000 eggs had been taken. Spawning took place in approximately the f i r s t mile and one half of the stream. A reconnaisance was made down stream for about two miles, and the last fish were seen about a mile and one half from the lake. The section of the stream which was used for spawning consisted of erratically spaced patches of fine gravel, interspaced with a fine mid bottom. The hatchery workers had put a picket barrier across the stream about 200 yards below the lake, to stop fish from going down into old placer mining pits. Previously, fish had been observed trapped in these pits, where they eventually died (Varty, pers. cam.). The barrier was no longer effective, since the stream had undermined i t . 2. Movement and Mortality A.tagging program was initiated to evaluate the movement of the spawners, the population size and the mortality of the spawners. The tagging began on May 12 with 199 Petersen disc tags being put on and the fish released downstream. An additional 99 disc tags were put on, on May 13. A l l marking from this time on was done by fin clipping. Fish which were put downstream had their right pelvic fin clipped off and fish put upstream had their adipose fin removed. The tagged and marked fish were not representative of sex ratio, since many of them were males which had been held for egg fertilization. 50 The trap (Fig. 13) was changed on May 13, to accommodate both downstream and upstream migrants. Fine wire screen was installed to stop i Figure 13. Diagram of trap facilities. small fish from passing through i t . The fi r s t fish returned on May 13 and continued to do so until May 26, when the run abruptly stopped. This abrupt stop may have resulted from a barrier caused by dropping water level or by a temperature barrier. The total size of the spawning run can only be estimated, since many fish had been released downstream before the study began. Table 10 and 11 show the number of fish tagged and fin clipped and the number which returned. From this i t can be calculated by direct proportion the number of unmarked fish that went downstream by the number which returned. Using this figure pj.us the known number of marked fish, the size of the run was estimated at 3,000 fish. Table 10 and 11 and Figure 14 show that the fish spent from 51 TABLE 10. DATE AND NUMBERS OF PETERSEN DISC TAGGED FISH PUT UPSTREAM ON COMPLETION OF SPAWNING Date With Tags Lost Tags T o t a l May 13 ^ 5 5 14 3 3 15 5 5 16 6 6 17 3 3 18 7 7 19 20 13 • 13 21 22 19 9 28 23 12 11 23 24 21 7 28 25 26 19 8 27 27 28 29 30 1 T o t a l 113 35 148 T o t a l d i s c tags released down stream = 298 52 TABLE 11. RESULTS OF FIN CLIP MARKING PROGRAM Date R.V.C.* A.C* R.V.C. and A.C. May 13 36 27 14 69 4 15 59 91 16 28 84 17 33 81 8 18 19 37 76 9 20 36 92 6 21 22 37 93 26 23 8 193 46 24 16 87 27 25 26 13 91 22 27 15 28 29 30 3 June 1 2 10 3 Total 382 940 144 •—Right Ventral Fin clipped—Fish moved downstream. **A.C.—Adipose Fin Clipped—Fish moved upstream. O 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 13 14 15 16 17 18 19 2 0 21 22 23 2 4 2 5 26 2 7 28 29 3 0 31 I 2 M A Y J U N E Figure 14. D a i l y numbers of f i n clipped marked f i s h and d i s c tagged f i s h moved through the trap. 54 10—13 days downstream before returning. There are two estimates of mortality for the fish during this time. One estimate from the Petersen disc tagged fish and one from the fin clipped fish. There was a 50.40 percent mortality in the disc tagged fish and a 62.31 percent mortality in the fin clipped fish. An examination of the time of release of the fin clipped fish showed i t was later than that of the disc tagged fish. With the sudden stop of upstream migrants on May 26, i t meant that the probability of the return of fish released near the 26th would be lower. To compare the mortalities of the two tagging methods, the fi n clipped fish data must be adjusted for the lower probability of return. To adjust this data, the disc tag data was used as a basis. An accumulated percentage return for each day was calculated. Any fish released 13 days before the last day fi n clipped fish were released, were considered to have a 100 percent chance of returning. The figure of 13 days was chosen,, as i t appeared to be the average maximum time spent by fish in spawning. The probability of return of fish released less than 13 days before the final day was calculated by using the accumulated per-centages for days after release as calculated from the disc tag data. This calculation gave an answer of expected fish available for return and was 318 fish instead of 382 as might have been supposed i f the cor-rection had not been used. Using this corrected value, the mortality of fin clipped fish was 54.8 percent. This value is not significantly different to the disc tagged fish mortality (50.44$) as shown by a chi square test. Mortality as used in this text, is a collective term embodying actual death of fish and fish which were not accounted for and were 55 not n e c e s s a r i l y dead. Of the 298 d i s c tagged f i s h released, 113 with tags and 35 which l o s t tags were returned to the lake. There were 26 tagged f i s h known dead, lea v i n g 124 f i s h unaccounted f o r . Explanations f o r these unaccounted f i s h may be: ( 1 ) they died and were not found and recorded, (2) l o s t tags and were not recorded and, or ( 3 ) went down-stream and moved out of the system. 3. Size Composition and Sex Ratio Figure 15 shows the size composition of sexes i n the run on various dates. The females are d e f i n i t e l y smaller l a t e r i n the run, and the males show a s l i g h t trend t o being smaller l a t e r i n the run. The mean siz e s i n d i c a t e that the males are s l i g h t l y l a r g e r than the females. The number of males show a r a p i d decrease e a r l y i n the run, but the females continue t o go down i n r e l a t i v e l y large numbers. I r v i n g (1954) found that the majority of the males migrated s l i g h t l y e a r l i e r than the females. The sex r a t i o was c a l c u l a t e d from the f i s h sampled by g i l l nets. I t was assumed that there was no s e l e c t i o n f o r e i t h e r sex by the nets, and p o s i t i v e i d e n t i f i c a t i o n of sexes was p o s s i b l e . The sex r a t i o came out as 230 females f o r every 100 males. This would appear that there i s a heavy m o r t a l i t y on males, and i t i s probably during spawning time. CD H 3 CD 3 CD 3* 01 H j CB CD CD CD I P-3 15-IO-5 O 2 0 15 ICH u) 5-O-O 2 0 g 15-_i IO § 5-z o-30H 25 2 0 -15-I O -5-O -*=!—H=l-9 - J = H = H n q n q q n q n r K i n n n -•=1—i n n MAY 23,24 & 26 GROUPED i *~l 1 1 1 1 1 r=—i 1 1 1 r MAY 18,20& 22 GROUPED e F= i • H—i F*—l . r-MAY 14,15,16 & 17 GROUPED • H n — i n n n 11 n n n rvu ki - i 1 1 1 1 r 1 1 r-MAY 12 & 13 GROUPED 18 19 2 0 21 22 23 24 25 26 27 28 29 3 0 31 32 33 34 35 36 FORK L E N G T H I N 0 . 5 C M . INTERVALS SOLID B A R S - M A L E S O P E N B A R S - F E M A L E S O - M E A N FEMALE L E N G T H i - M E A N M A L E L E N G T H c+ 57 F. UPSTREAM MIGRATION OF FINGERLINGS The young of the year fish at Kiakho Lake apparently remain in the outlet stream until the follovdng spring, at which time they migrate up to the lake. The young fish emerge from the gravel sometime in June. No information on the exact date of emergence is available, however, smal1 fish approximately 2.5 cm. fork length were taken in the stream on July 1. The water level of the stream was very low by July, and several barriers had formed. The barriers consisted of places where the stream percolated through the gravel. These barriers apparently force the young of the year fish to remain in the stream until the following spring. Figure 16 shows the numbers of year old fish moving upstream on various dates. The f i r s t fish to move through the trap were on May 22, and the peak of the run occurred on May 27 and 28. The work was stopped on June 7, but the run s t i l l continued, although the numbers of fish were small. The total number of fish passed through the trap was 751. A sample of 70 was taken, thus 681 were released into the lake. Every fish put through the trap was measured and the left pectoral fin clipped off as an identifying mark. The marking was done to evaluate the numbers that would return in subsequent spawning runs. Figure 17 shows the size composition of the young fish migrating upstream. The majority of these fish were one year old but a small sample indicated that some were two years old. The sudden increase in the number of fish taken in the trap on May 27 and 28 indicates that possibly some environmental factor such as 58 59 in T ro i r in ADN3n03ti_l in r in Figure 17. Length frequency of year old f i n g e r l i n g f i s h moving upstream i n t o Kiakho Lake. 60 temperature may be c o n t r o l l i n g the time of migration. The maximum tem-perature of the stream a t the trap on these dates was 62° F. The tem-perature changes with the length of the stream. On May 14 the temperature of the trap was 51° F., at approximately 150 yards below the trap i t was 56° F. and one h a l f mile below the trap i t was 60° F. The f i s h p o s s i b l y f o l l o w some temperature gradient up the stream. Calhoun (1944 a ) , Robertson (1947), Cope (1953) and Laakso and Cope (1956) working with Yellowstone cutthroat t r o u t were concerned with i n l e t spawning runs. In none of the l i t e r a t u r e was there any record of o u t l e t spawning cutthroat. The f r y i n i n l e t streams u s u a l l y move or are c a r r i e d by the current i n t o the lake soon a f t e r emergence from the gravel (IAndsey, Northcote and Hartman, 1959)* The f i s h at Kiakho Lake are forced t o stay i n the o u t l e t stream f o r one year, apparently because of b a r r i e r s caused by low water conditions. This year spent i n the stream i s probably very s i g n i f i c a n t i n determining the number of f i s h which w i l l eventually migrate i n t o the lake. Assuming that the s i z e of the previous year's spawning run was comparable i n s i z e to 1958, and the f a c t that only 751 f i s h returned t o the lake, would indi c a t e that severe m o r t a l i t y must have taken place during the year i n the stream. This i s based on the assumption that the f i s h can only move i n t o the lake i n the spring. There may be a high water flow period i n the f a l l i n which the f i s h could move i n t o the la k e . In years when the water flow stays high, the young of the year f i s h may move i n t o the lake i n l a t e summer. Shapley (pers. com.) reports young of the year f i s h moving i n t o the lake i n l a t e J u l y , 1959. The annual l o c a l weather conditions are probably very s i g n i -f i c a n t i n determining the s u r v i v a l of f i n g e r l i n g s . In wet years the 61 s i z e of the year c l a s s may be large and i n dry years, when the f i s h are apparently forced to stay i n the o u t l e t stream over winter, the numbers may be severely reduced. I t would appear that i f there was severe m o r t a l i t y i n the stream, the lake could be considered a large r e a r i n g pond where members of an already severely regulated population were growing. In t h i s study, no attempt was made t o evaluate the stream l i f e of the cutthroat t r o u t . I t would be des i r a b l e to study t h i s phase of i t s l i f e , as a basis of understanding the dynamics of t h i s p a r t i c u l a r popu-l a t i o n . G. MATURITY AND FECUNDITY Samples of f i s h f o r maturity and fecundity analysis were taken at the t r a p during the spawning run. Green females were preserved whole, and the egg s i z e and number were determined l a t e r . Upstream migrating f i n g e r l i n g s were sampled and the gonads were examined. !• Age of Maturity The age of maturity has not been conclusively established i n Kiakho Lake cutthroat t r o u t . An examination of the gonads and scales of the f i s h taken i n the lake and spawning run would place the males as maturing at ages 2 and 3 and the females at 3 and 4. I r v i n g (1954) found male cutthroat mature a t age 2 and 3 and females at ages 3 and 4» C a r l and Clemens (1948) note that Yellowstone cutthroat t r o u t males mature at 8 inches i n length and females at 10.5 inches i n length. 62 These lengths correspond to ages 2 and 3 f o r males and ages 3 and 4 f o r females i n Kiakho Lake. B i l t o n and Shepard (1955) working on c o a s t a l cutthroat t r o u t found t h a t the spawning run was composed of 4—6 years ol d although some 3 year olds were present. An examination of the gonads of the upstream migrating f i n g e r l i n g s showed that many of them had w e l l developed testes and ovaries. One female, 17 cm. fork length and 2 years o l d had several f u l l y developed eggs i n the oviduct and appeared t o have spawned i n the current year. The males which had w e l l developed testes were as small as 10 cm. fork length and one year o l d . I t i s not known whether the small f i s h had come from the lake or were resident i n the stream. The number of pre-cocious f i s h i s not known and furt h e r c o l l e c t i o n and study i s needed t o determine whether they come from the lake or stream. I t now appears that male cutthroat t r o u t mature from ages 1—3 and females from ages 2—4. I t i s d i f f i c u l t t o determine from scales whether there i s a high proportion of repeat spawners. Shapley (pers. com.) working at Kiakho Lake i n the summer of 1959 reports that there were 139 previously tagged f i s h released downstream between May 1 and 9, 1959. I t would appear that repeat spawning i s common i n cutthroat t r o u t . 2. Fecundity The determination of egg number was done by d i r e c t count. The numbers of eggs from the l e f t and r i g h t ovaries were counted separately. Egg diameter was calculated by taking the mean value of the diameter of 20 preserved eggs. Eggs f o r diameter measurement were sampled from the 63 a n t e r i o r , middle and p o s t e r i o r s e c t i o n of each ovary. The mean number of eggs, plus or minus two standard deviations, per female, was 944 £ 393.29. This gives a range of 500—1,300 eggs and i s comparable t o the range of 745—1,495 found by Welch (1952). I r v i n g (1954) found a range of 1,500—3,000 eggs. Rounsefell (1957) l i s t s the ayerage number o f eggs f o r cutthroat t r o u t as 1,130. A " t " t e s t showed that there was no d i f f e r e n c e i n the number of eggs i n the l e f t and r i g h t ovaries (p = 0.35). The means plus or minus two standard deviations of 32 samples were, l e f t 473 ± 227.26 and r i g h t 471 t 216.48 eggs. The mean egg diameter plus or minus two standard deviations was 3.8 0.23 m i l l i m e t e r s . I r v i n g (1954) found that the mean diameter of r cutthroat t r o u t eggs was 0.188 inches (4.7 mm.). A " t " t e s t showed that there was no s i g n i f i c a n t d i f f e r e n c e i n the s i z e of the eggs i n the p o s t e r i o r and a n t e r i o r sections of the ovaries nor i n the l e f t and r i g h t ovaries. 3. Factors A f f e c t i n g Egg Number A multiple regression a n a l y s i s was set up t o determine the e f f e c t of f o r k length and egg diameter on the number of eggs i n the f i s h . The egg diameter was expressed as the t o t a l diameter of 20 eggs f o r ease of c a l c u l a t i o n . The r e s u l t i n g formula i n standard u n i t s i s : Y = 0.934 x; (-0.384 xp and i n ordinary u n i t s : Y - 200.06 - 103.20 X,- 258.29 X 2 where Y i s the number of eggs, X| i s the fork length and X 2 i s the egg diameter expressed as a t o t a l diameter of 20 eggs. When the p a r t i a l 64 regression c o e f f i c i e n t s are i n standard u n i t s , t h e i r magnitude give the r e l a t i v e importance of X ( and X2 as a f f e c t i n g Y. In t h i s p a r t i c u l a r case the c o e f f i c i e n t s show that fork length i s approximately 2.5 times as important i n determining egg number, as i s egg diameter. The negative slope of egg diameter i n d i c a t e s that the eggs are smaller where there i s a greater number of them. The t o t a l regression (R) (Snedecor, 1948) i s h i g h l y s i g n i f i c a n t at the 1 percent l e v e l , and the p a r t i a l regression c o e f f i c i e n t s are both s i g n i f i c a n t at the 5 percent l e v e l . Cartwright (1959) found an increase i n egg number with an increase i n fork length i n rainbow t r o u t . Rounsefell (1957) found an increase i n egg number with increase i n fork length i n s e v e r a l salmonids. H. DISTRIBUTION OF FISH WITHIN THE LAKE The general d i s t r i b u t i o n of f i s h w i t h i n the lake was taken from the mean numbers of f i s h caught i n g i l l net sets at various depths. The majority of the net sets were made on the bottom, but some were made at various depths i n the deeper water, by f l o a t i n g the net. Table 12 shows the r e s u l t s f o r the north and south basins, f o r f l o a t i n g nets and bottom set nets. I t i s obvious that the f l o a t i n g net sets at 0—8 f e e t , 8—16 f e e t and 15—23 f e e t caught i n s i g n i f i c a n t numbers of f i s h . The bottom sets i n the south basin showed that the greatest mean number of f i s h per net set were taken i n the 15-^ -23 foot depth zone. The f a c t that smaller numbers of f i s h were taken i n the shallower zones was probably due t o the lack of bottom organisms (food) r e s u l t i n g from 65 TABLE 12. MEAN CATCH PER NET SET OF FISH AT VARIOUS DEPTHS IN THE NORTH AND SOUTH BASINS AT KIAKHO LAKE Depth i n F l o a t i n g Sets Bottom Sets Feet South North South North Basin Basin Basin Basin 0 — 8 3 (3)* 13 (1) 59 (1) 8—16 4 (3) - 48 (2) 15—23 8 (2) 25 (4) 23—31 — — 12 (4) •^Figures i n parenthesis are the number of net sets upon which the mean catch was based. the rocky substrate. The stagnation i n the area below 25 feet was probably the reason f o r the low mean catches i n the 23—31 foot zone. There i s a twofold d i f f e r e n c e between the mean catches of the north and south basins. This i s probably due to the greater abundance of bottom organisms (food) and considerable growth of Potamogeton i n the north basin. Table 12 shows that the greatest mean catches of f i s h were taken i n net sets on the bottom. This would indi c a t e that the f i s h tend t o stay r e l a t i v e l y close t o the bottom. The food habits would a l s o bear t h i s out, as the food i s composed almost e n t i r e l y of bottom organisms. DISCUSSION This study has underlined many of the b a s i c s i m i l a r i t i e s which e x i s t between Yellowstone cutthroat and rainbow t r o u t . Throughout the previous sections comparisons have been made between the cutthroat and the rainbow trou t and some are worthy of f u r t h e r mention. These com-parisons have indi c a t e d that a p r a c t i c a l management program f o r cutthroat t r o u t would be i n essence the same program used f o r rainbow t r o u t . The general habitat types i n which cutthroat and rainbow t r o u t are found show great s i m i l a r i t y . The Yellowstone cutthroat trout are, i n general, found i n c l e a r , c o o l and r e l a t i v e l y unproductive lakes of south eastern B r i t i s h Columbia. The rainbow trout are found i n s i m i l a r l y unproductive lakes of the i n t e r i o r plateau of B r i t i s h Columbia as i n d i -cated by Rawson (1954) and Lark i n and Smith (1954). I t was previously shown that the food u t i l i z e d by the two species was v i r t u a l l y the same. Comparisons have i n d i c a t e d that cutthroat t r o u t were not more piscivorous than the rainbow t r o u t , but i n f a c t appeared t o u t i l i z e f i s h f o r food i n about the same proportion as rainbow trou t as described by Rawson (1934), Dimick and Mote (1934), Larkin, Anderson, Clemens, and Mackay (1950) and La r k i n and Smith (1954). I t can be pre-supposed, on the basi s of the findings of L a r k i n and Smith (1954), that cutthroat t r o u t would probably show a reduction of growth rate and a decrease i n numbers when subjected t o competition from other species of f i s h . Calhoun (1944b) pointed out that minnows (Rhinichthys oscula) 67 were competitors with small cutthroat trout and were not u t i l i z e d by large cutthroat t r o u t . In forming a management p o l i c y f o r maintaining cutthroat trout populations, i t would appear necessary to keep the popu-l a t i o n s i n a pure culture state. The comparison of growth between cutthroat and rainbow trou t showed that the growth c h a r a c t e r i s t i c s were very s i m i l a r . The »z" value, f o r cutthroat, from the Parker and L a r k i n (1959) growth equation was almost the same as t h a t for the freshwater growth of steelhead t r o u t . The cut-throat t r o u t population of Kiakho Lake has presented an e x c e l l e n t oppor-t u n i t y t o examine f i s h growth where s e l e c t i o n by a f i s h e r y has had no e f f e c t . A comparison was made with McLeod's (1958) work on the growth of rainbow t r o u t i n which c e r t a i n features were a t t r i b u t e d t o the e f f e c t s of a f i s h e r y . The growth of Kiakho Lake cutthroat t r o u t d i d not show the features found by McLeod and would appear to support the view that the e f f e c t s of the f i s h e r y were responsible f o r the d i f f e r e n c e s . Lee's Phenomenon was absent and as a r e s u l t the ideas set f o r t h by Lee (1912) and H i l e (1936) f o r the causes of the phenomenon, are not v a l i d f o r t h i s population. Since the phenomenon was absent, i t lends support t o the view that s e l e c t i o n of the f a s t e r growing f i s h by the f i s h e r y i s a major f a c t o r causing Lee's Phenomenon. The timing, age composition and sex composition of the spawning run were very s i m i l a r t o those of rainbow trout as described by Mottley (1933, 1938) and Lindsey, Northcote and Hartman (1959). I t was found that the male cutthroat precede the females i n the spawning run. Mottley (1933) found the same s i t u a t i o n i n the rainbow t r o u t . The young of the year cutthroat t r o u t remain i n the o u t l e t stream 68 at Kiakho Lake f o r one year before migrating to the lake. Lindsey et. a l . (1959) remarked that young rainbow trout remain i n the o u t l e t stream before moving up to the lake. The fecundity of the cutthroat t r o u t was found to be approximately 1,000 eggs per female. A multiple regression a n a l y s i s showed that body length was a major f a c t o r a f f e c t i n g the numbers of eggs per female. Rounsefell (1957) and Cartwright (1959) found the rainbow trou t had the same magnitude i n numbers of eggs and Cartwright (1959) i n d i c a t e d that body length a f f e c t e d the numbers of eggs i n rainbow t r o u t . Comparison has shown that the b a s i c biology and ecology of the cutthroat and rainbow t r o u t are very s i m i l a r . I t i s known that the two species w i l l h y b r i d i z e . Casual observations by the author and Larkin (pers. com.) indicate that i n lakes where the two species e x i s t together, the rainbow t r o u t appear to be more successful with the eventual sub-ordination of the cutthroat t r o u t through h y b r i d i z a t i o n and competition. Due to t h i s , i t i s not advisable t o put the two species together i n a lake. Calhoun (1944a) remarked that the cutthroat t r o u t i n C a l i f o r n i a has shown considerable reduction i n numbers and now e x i s t s only i n the \ V alpine lakes and streams. Weisel (1957) states that "Cutthroat t r o u t are on the way out". Weisel remarking on cutthroat trout i n d i c a t e s that due t o h y b r i d i z a t i o n , and generally poor management and poor u t i l i z a t i o n of water resource, the cutthroat stocks i n Montana have been depleted. He goes on to say that i n only the unfrequented p r i m i t i v e areas are the cutthroat found i n any numbers. I f f o r no other reason than aesth e t i c values, the cutthroat trout should be preserved i n B r i t i s h Columbia lakes 69 and not allowed t o become a member of the l i s t of now e x t i n c t animals. There are s t i l l s u b s t a n t i a l stocks of cutthroat t r o u t i n B r i t i s h Columbia and through c a r e f u l management they could remain as they are. To i n v e s t i g a t e and describe the l i f e h i s t o r y and ecology of any species of f i s h , i t i s desi r a b l e t o study a population which i s aff e c t e d by a minimum number of f a c t o r s . The Kiakho Lake cutthroat t r o u t popu-l a t i o n f e l l i n t o such a category. There were no other species of f i s h present to complicate the picture with competition and there was no f i s h e r y operating to add i t s complications. The study of cutthroat tro u t under these conditions has given a b a s i s on which evaluations of competition, s e l e c t i o n by a f i s h e r y , and other aspects of cutthroat biology can be compared. SUMMARY 1. Kiakho Lake, located 6 miles west of Cranbrook B r i t i s h Columbia, at an a l t i t u d e of 3,600 f e e t , has a surface area of 67.42 acres, a maximum depth of 16.5 feet and i s composed of two basins. The lake has r e s u l t e d from a land s l i d e and i s s i t u a t e d i n a ge o l o g i c a l area composed of a r g i l l i t e s and q u a r t z i t e s and has a t o t a l d i s s o l v e d s o l i d s content of 100 parts per m i l l i o n . 2. The temperature c h a r a c t e r i s t i c s of the lake show thermal s t r a t i f i -c a t ion with the lower l i m i t of the thermocline on the bottom. 3. The dissolved oxygen content o f the lake waters showed reduction (stagnation) below 25 feet during the summer, and apparent super-saturations up t o 130 p.p.m. at the 15 and 20 foot l e v e l s . 4. Two species of aquatic plants were present i n the lakej the rooted aquatic Potamogeton praelongus and the alga Cladophora. 5. The bottom fauna was predominated by Gammarus, H y a l e l l a , chironomid larvae and leeches, with molluscs, oligochaeta and in s e c t larvae being represented. The production of bottom fauna was poor and was a t t r i b u t e d to the rocky substrate and lack of l i t t o r a l development. 6. The plankton production was small i n r e l a t i o n t o t o t a l dissolved s o l i d s and was composed of many o l i g o t r o p h i c i n d i c a t o r species. 7. The lake has a eutrophic morphometry but has an o l i g o t r o p h i c pro-d u c t i v i t y , which was a t t r i b u t e d t o the low t o t a l d i s s o l v e d s o l i d s content and a rocky substrate. 71 8. The food u t i l i z e d by the f i s h i n Kiakho Lake was wholly derived from the bottom fauna. Considerable changes i n the major food items were found over the summer period. In May chironomid pupae was the dominant food, i n June the major food was chironomid larvae and Gammarus and i n J u l y , Gammarus was the dominant food. 9. The food of the cutthroat t r o u t i n Monroe and Lumberton Lakes was composed mainly of bottom organisms, with Gammarus being the most important. In Garcia Lake the food was mainly Chaoborus and redside shiner (Richardsonius balteatus) with Chaoborus being the most important. 10. I t was concluded that cutthroat t r o u t would u t i l i z e f i s h f o r food, but showed a preference f o r bottom dwelling organisms. 11. The number of empty stomachs increased and the average stomach volume decreased i n the Kiakho Lake cutthroat, as the summer pro-gressed. I t was proposed that t h i s was r e l a t e d t o a higher physio-l o g i c a l a c t i v i t y r e s u l t i n g i n the di g e s t i o n of the food before the f i s h were r e t r i e v e d , and giving the appearance that feeding a c t i v i t y had been reduced. 12. The body-scale r e l a t i o n s h i p was described by a s t r a i g h t l i n e having a slope of 1. 13. The graph of instantaneous growth rate against length at the beginning of the r a p i d growth period, revealed that the e f f e c t of s e l e c t i o n by a f i s h e r y p o s s i b l y could be demonstrated. A comparison with a s i m i -l a r graph of rainbow t r o u t which had been subjected t o a f i s h e r y , seemed to support the view t h a t the s e l e c t i o n of the f a s t e r growing f i s h was apparent as a concavity i n the upper l i m i t of the graph. 72 14. The growth data was f i t t e d t o a Parker and Lark i n (1959) parabolic growth equation. The exponent z was found to have a value of 0.71 f o r cutthroat t r o u t . 15. Lee's Phenomenon was not present and gave support to the view that s e l e c t i o n by a f i s h e r y could be a major f a c t o r causing Lee's Phenomenon. 16. The spawning run at Kiakho Lake was i n the o u t l e t stream and coin-cided with the breakup of the i c e cover on the lake. 17. A tagging program on the spawning f i s h , revealed that approxi-mately 3,000 f i s h went down stream, that they spent approximately 13 days spawning, and that the m o r t a l i t y was approximately 54 per-cent . 18. The male f i s h appeared on the spawning grounds before the female f i s h . The female f i s h were smaller l a t e r i n the run and the male f i s h remained r e l a t i v e l y constant i n s i z e over the run. 19. The eggs hatch sometime i n mid June, and the young f i s h apparently remain i n the o u t l e t stream u n t i l the following spring, at which time they migrate i n t o the lake. The year spent i n the o u t l e t stream i s probably a very s i g n i f i c a n t f a c t o r i n the dynamics of t h i s population. 20. The female f i s h mature between the ages of 2 and 4 and the male f i s h between 1 and 3. 21. The mean number of eggs per female f i s h , plus or minus two standard deviations was 944 393.29. This gives a range of 500—1,300 eggs. 73 22. A multiple regression a n a l y s i s i n d i c a t e d that body s i z e (length) a f f e c t e d egg number 2.5 times as much as egg diameter. 23. The cutthroat t r o u t i n Kiakho Lake were d i s t r i b u t e d i n close proximity t o the bottom. 24. I t was recommended that due t o the probable e f f e c t s of competition, the cutthroat t r o u t be kept i n pure c u l t u r e populations. A furt h e r recommendation was, the numbers of cutthroat t r o u t be maintained. I t has been found i n other areas, that through poor management, the cutthroat t r o u t i s becoming nonexistant. LITERATURE CITED B i l t o n , T. H. and M. P. Shepard. 1955. The sports f i s h e r y f o r cut-throat t r o u t a t Lakelse, B r i t i s h Columbia. Prog. Rept. P a c i f i c S t a t i o n . F i s h . Res. Bd. Can., 104:38-42. Brown,. C. J . D. and J . E . B a i l e y . 1952. Time and pattern of scale formation i n Yellowstone cutthroat trout : 3 ; S a l m o . c l a r k i i l e w i s i . Trans. Am. Micros. S o c , 71(2):120-124. Calhoun, A. J . 1944(a). Black-Spotted t r o u t i n Blue Lake, C a l i f o r n i a . C a l i f . F i s h and Game, 30(1)22-42. Calhoun, A. J . 1944(b). The food of the Black-Spotted tro u t (Salmo c l a r k i i henshawi) i n two S i e r r a Nevada lak e s . C a l i f . F i s h and . Game, 30(2):80-85. C a r l , G. C. and W. A. Clemens. 1948. The freshwater f i s h e s of B r i t i s h Columbia. B r i t i s h Columbia P r o v i n c i a l Museum> Handbook No. 5. Cartwright, J . W. 1959. Egg s i z e and egg number i n some species of B r i t i s h Columbia freshwater f i s h . M. Sc. Thesis, U n i v e r s i t y of B r i t i s h Columbia. Chapman, J . D. and D. B. Turner. 1956. B r i t i s h Columbia, A t l a s of Resources. B r i t i s h Columbia Natural Resources Conference, 1956. Gope, 0. B. 1953. Length measurements of Yellowstone t r o u t . U. S. F i s h and W i l d l i f e Serv., S p e c i a l S c i . ; R e p t . — F i s h , No. 103. Dimick,. R. E. and D. C. Mote. 1934. A preliminary survey of the food of Oregon t r o u t . Oregon St. Agr. Exp. Sta. B u l l . , 323, 23 pp. Echo, J , B. 1955. Some e c o l o g i c a l r e l a t i o n s h i p s between yellow perch and cutthroat t r o u t i n Thompson Lakes, Montana. Trans. Am. F i s h S o c , 84:239-248. Fleener, G. C. 1952. L i f e h i s t o r y of the cutthroat trout;„ Salmo c l a r k i i Richardson, i n the Logan River, Utah. Trans. Am. F i s h . S o c , 81:235-248. G r i f f i t h s , F. P. and E. D. Yoemans. 1940. A comparative study of Oregon coa s t a l lakes from a f i s h management standpoint. Proc. Six t h P a c i f i c S c i . Cong., 3:323-333. 75 Hazzard, A. S. and M. J. Madsen. 1933. Studies of the food of the cutthroat trout. Trans. Am. Fish; Soc, 63:198-207. , Hildebrand, S. F. and I. L. Towers. 1927. Food of the trout i n Fish Lake, Utah. Ecol. 8(4):389~399. Hile, Ralph. 1936. Age and growth of the cisco Leucichthys artedi (LeSueur) i n the lakes of the northeastern highlandsj Wisconsin. B u l l . U. S. Bur. Fish., 48(19):211-317. Hutchinson, G. E. 1957. A treatise on limnology, volume I, geography, physics and chemistry. John Wiley and Sons, Inc. New York. Irving, R. B. 1954. Ecology of the cutthroat trout i n Henrys Lake, Idaho.. Trans. Am. Fish Soc, 84:275-296. Jones, R. 1958. Lee's phenomenon of "apparent change i n growth-rate" with particular reference to haddock and plaice. Inter. Comm. Northwest Atlantic Fish. Spec* Pub. No. 1. Some problems for biological fishery surveys and techniques for their solution. Laakso, M. and 0., B. Cope. 1956. Age determinations i n Yellowstone cut-throat trout by the scale method. Jour. Wildl. Mgmt., 20(2):138-153. Larkin, P. A., G. G. Anderson, W. A. Clemens, and D. C. G. Mackay. 1950. The production of Kamloops trout:(Salmo gairdneri kamloops, Jordan) i n Paul Lake, B r i t i s h Columbia. University of Br i t i s h Columbia Game Department. Larkin, P. A. and S. B. Smith. 1954.' Some effects of introduction of redside shiner on the Kamloops trout i n Paul Lake, B r i t i s h Columbia. Trans. Am. Fish. Soc, 83:160-175. Lee, R. M. 1912. An investigation into the methods of growth deter-mination i n fishes. , Publ. C i r c Cons. Explor. Mer., No. 63. Lee, Ri M> 1920. A review of the methods of age determination i n fishes by means of scales. Fish Invest. Ser. I I , Vol. 4(2). Min. Agric. and Fish., London. Lindsey, C. C, Ti G. Northcote, and G. F-*. Hartman. 1959.: Homing of rainbow trout to i n l e t and outlet spawning, streams at Loon Lake, B r i t i s h Columbia. J. Fish. Res. Bd. Can., 16(5):695-719. MacLeod, J.. C. 1958. Growth rate of rainbow trout i n Pinantan Lake, Bri t i s h Columbia. B. A, Thesis,-University of Briti s h Columbia. 76 Maltzan, G r a f i n Vori M. 1935• .Zur Ernahrungsbiologie und physiology des Karpfens. Zbol. Zentr. Abt. 3(55):191-218. From; Brown, M. E. 1957. Physiology of f i s h e s , volume I.—metabolism. Academic Press Inc. : New York. Martin, ¥. R. 1949. The'mechanics of environmental c o n t r o l of body form i n f i s h e s . Univ. Toronto Stud., B i o l . Ser. No. 58. Pub; Ontario F i s h Res. Lab. No. 70, pp 1-72. -M i l l e r , Ri.'B. 1941. A" c o n t r i b u t i o n t o the ecology of the chironomidae of C o s t e l l o Lake, Algonquin Park> Ontario. Univ; Toronto Stud. B i o l . ' Ser. No. 49. Pub. Ontario F i s h Res. Lab. IX. Mottley, C. McC. 1933.. The spawning migration of rainbow t r o u t . Trans. Am. F i s h . S o c , 63:80-84. Mottley, C. McC. 1938. Fluctuations i n the i n t e n s i t y of the spawning runs of rainbow t r o u t at Paul Lake. J . F i s h . Res. Bd. Can., 4(2):69-87. Northcote, T. G. and P i A. Lar k i n . 1956. Indices of P r o d u c t i v i t y i n B r i t i s h Columbia Lakes., J., F i s h . Res. Bd. Can., 13(4)*515-540. Parker, R. R. and P. A. L a r k i n . 1959. A concept of growth i n f i s h e s . J . F i s h . Res. Bd. Can., 16(5):721-745. . Qadri> S. U. 1959. Some morphological d i f f e r e n c e s between the subspecies of cutthroat t r o u t ; Salmo c l a r k i i c l a r k i i and Salmo c l a r k i i l e w i s i . J . F i s h ; Res. Bd. Can., 16(6):903-922. Rawson,.. Di.-S. 1930. The bottom fauna of Lake Simcoe and i t s r o l e i n the ecology of the l a k e . Pub. Ontario F i s h . Res. Lab. No. 40. 1934. P r o d u c t i v i t y studies i n lakes of the Kamloops region, : B r i t i s h Columbia.. B u l l . B i o l . Bd. Can., No. XLII. 1939. Some p h y s i c a l and chemical f a c t o r s i n the metabolism of lakes, i n Problems of lake biology. Pub. Am. Adv. S c i ; No.10. 1952. Mean depth and the f i s h production of large l a k e s . E c o l . 33(4):513-521. 1956.' A l g a l i n d i c a t o r s of t r o p h i c lake types. Limnol. and Ocean., 1(1):18-25. Ricker, W. E. 1934. A c r i t i c a l discussion,of various measures of oxygen: saturation i n lakes. E c o l . 15:348-363. Rounsefell, G. A. 1957. Fecundity of North American Salmonidae. U. S. F i s h and W i l d l i f e Serv. F i s h . B u l l . , No. 122, v o l . 57, pp. 45I-468. 77 Robertson, 0. H. 1947. An e c o l o g i c a l study of two high mountain trou t lakes i n the Wind River Range, Wy o ming. E c o l . 28(2):87-112. Shapley, P. 1959. Personal communication. Smith, 0. R. 1941. The spawning habits of cutthroat and eastern brook t r o u t s . J . W i l d l . Mgmt., .5(4):46l-471. Smith, S. B. 1955. The r e l a t i o n between scale diameter and body length of Kamloops trout> Salmo g a i r d n e r i kamloops. J . F i s h . Res. Bd. Can., 12(5):742-753. Snedecar, G. W. 1948. S t a t i s t i c a l methods, applied to experiments i n agr i c u l t u r e and biology. Fourth ed. Iowa State College Press, Ames Iowa. Thienemann, A. 1927. Der Bau des Seebeckens i n seiner Bedeutung f u r den Ablauf des Lebens i n See. Verh. Zool. Bot. Ges., 77. (Translated by T. G. Northcote.) Van Oosten, J . 1929. L i f e h i s t o r y of the lake h e r r i n g (Leucichthys a r t e d i LeSueur) of Lake Huron, as revealed by i t s scales, with a c r i t i q u e of the scale method. B u l l . U; S* Bur. F i s h . , 44:265-448. Varty, J . 1958. Personal communication. Weisel, G. F. 1957. F i s h guide f o r intermountain Montana. Montana State Univ. Press, Missoula Montana. Welch, J . P. 1952. A population study of Yellowstone Black-Spotted t r o u t (Salmo c l a r k i i l e w i s l Girard) Ph.D. d i s s e r t a t i o n , Leland Stanford J r . Univ., pp. 1-180. 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0106396/manifest

Comment

Related Items