Environment Canada Environnement Canada Fisheries Service des pêches and Marine Service et des sciences de la mer
The 1972 Sports Fisheries of Great Bear and Great Slave Lakes, Northwest Territories
by M.R. Falk, D.V. Gillman, L.W. Dahlke
Technical Report Series No. CEN/T-73-8
Resource Management Branch Central Region
DEPARTMENT OF THE ENVIRONMENT
FISHERIES AND MARINE SERVICE
Fisheries Operations Directorate Central Region
TECHNICAL REPORT SERIES No. CEN/T-73-8
THE 1972 SPORTS FISHERIES OF GREAT BEAR AND GREAT SLAVE LAKES, NORTHWEST TERRITORIES
by
Senior Biologist: M.R. FALK Technical Staff: D.V. GILLMAN L.W. DAHLKE Lake Management Section Resource Management Branch
1973
i
ABSTRACT
Creel census and biological sampling programs were carried out on the lake trout (Salvelinus namaycush) and other species of Great Bear and Great Slave Lakes, Northwest Territories. 4,386 anglers were interviewed from 6 sports fishing lodges. Information on the number and species composition of the catch retained and released was obtained. An estimated 46,897 and 25,286 kg of lake trout were harvested on Great Bear and Great Slave Lakes, respectively. 3,212 lake trout were sampled for length, weight, sex and maturity. Otoliths were removed and aged at later dates.
Ages ranged from 5 to 42 years, lengths from 360 to 1,020 mm, and weight from 450 to 14,400 g. On Great Bear Lake trout first exhibited sexual maturity at age 13 (519 mm; 1,538 g) and were all sexually mature at age 22. Trout from Great Slave Lake, however, first attained sexual maturity at age 8 (490 mm; 1,253 g) and were fully mature at age 19. Sex ratio on each lake varied little from a 1:1 relationship. Growth rates differed among individual lodge samples and between Great Bear and Great Slave Lakes. All growth rates were similar until approximately 400 mm and age 6. After this age Great Slave trout exhibited larger gains in weight for a corresponding increase in length. Great Slave trout averaged 1;500 g heavier and 10 mm longer than Great Bear trout for corresponding ages beyond 6 years of age. Growth rates of trout were found to be much slower than those found in southern lakes. Comparisons were also made to other lake trout populations to determine the possible effect of the present exploitation rate.
The present harvest of lake trout as trophies, fillet and angler lunches is substantial. Trout used for filleting comprised over 65 percent of the total catch. The data collected and local information sources indicate that the overall size and availability of trophy lake trout is declining due to the nature and magnitude of the present fishing harvest. In addition, all mature fish are susceptible to sports angling on the lake and the harvest is indiscriminate as to size and age. This raises a threat to the entire population because of the poor reproductive capacity and late maturation age of the stocks. The economic and conservation demands of the resource base to provide a sustained yield of lake trout can be best met by the continuance of the fishery on a trophy basis only. To ensure this, recommendations to convert the harvest primarily to trophy fish are made. Regulation changes are recommended to lower the catch and possession limits and to reduce mortality among released fish by implementing barbless hooks. Recommendations are also made to expand the creel census and sampling programs to portions of the fishery not covered and to investigate the effect of hooking mortality.
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ACKNOWLEDGEMENTS
The Department is grateful to the lodge operators of the Northwest Territories who provided necessary information and cooperated in data collection for this study. Our appreciation is given for the work conducted during 1972 by the following students; L. French, M. Klassen, M. Busch, K. Callele, L. Cardinal, B. Thompson and K. Howard. C. Read and J. Favell assisted in age determinations and data analysis.
Fisheries Service staff, based in Yellowknife, deserve special thanks for their involvement with the field program. iii
TABLE OF CONTENTS
Page
Abstract...... i
Acknowledgements ...... ii
List of Figures ...... v
List of Tables ...... viii
List of Appendices...... x
Introduction ...... 1
Description of the Areas ...... 2
Description of the Fisheries ...... 8
Materials and Methods ...... 13
General ...... 13
Creel Census ...... 14
Individual Lodge Harvest ...... 15
Utilization of Harvest...... 16
Total Lake Harvests...... 17
Fillet Study ...... 17
Results...... 19
A. Great Bear Lake...... 19
Great Bear Lodge: Neiland Bay and Bear Island Outpost Camps...... 19 Great Bear Lake Lodge...... 29 Cameron Bay Lodge ...... 33 Great Bear Trophy Lodge ...... 37 Arctic Circle Lodge ...... 40
Total Harvest from Great Bear Lake...... 44
Comparison of Great Bear Lake Lodges ...... 45
iv
Page
B. Great Slave Lake ...... 47
Great Slave Lake Lodge ...... 47 Frontier Fishing Lodge ...... 57 Arctic Star Lodge...... 62 Indian Mountain Lodge ...... 64 Trophy Lodge ...... 64
Total Harvest from Great Slave Lake, 1972 ...... 67
Comparison of Great Slave Lake Lodges...... 70
C. Fillet Study ...... 70
D. Comparison of Great Bear and Great Slave Lakes...... 71
Discussion ...... 81
Summarv ...... 89
Recommendations...... 91
Literature Cited ...... 93
Appendix...... 95 v
LIST OF FIGURES
Page
1. Map of Great Slave Lake illustrating the sports fishing lodges...... 3
2. Map of Great Bear Lake illustrating the sports fishing lodges...... 6
3. Location of Great Bear Lodge, Neiland Bay Outpost Camp, showing the approximate area fished for lake trout, 1972...... 20
4. Length-weight relationships of lake trout from three lodges on Great Bear Lake, 1972 ...... 23
5. Comparison of length versus age of trout from three Great Bear Lake lodges, 1972 ...... 25
6. Comparison of weight versus age of lake trout from three Great Bear Lake lodges, 1972 ...... 26
7. Comparison of the age frequency distributions of lake trout from three Great Bear Lake lodges, 1972 ...... 27
8. Comparison of the length frequency distributions of lake trout from three Great Bear Lake lodges, 1972 ...... 28
9. Map illustrating the location of Great Bear Lake Lodge and the approximate area fished for lake trout, 1972...... 30
10. Location of Cameron Bay Lodge and the area fished for lake trout, 1972...... 34
11 Location of Katseyedie River Outpost Camp and the approximate area fished for lake trout, 1972...... 35
12. Location of Great Bear Trophy Lodge and the approximate area fished for lake trout, 1972...... 38
13. Location of Arctic Circle Lodge and the approximate area fished for lake trout, 1972...... 41
14. Location of Arctic Circle Lodge outposts and the, approximate area fished for lake trout,1972...... 42
vi
Page
15. Location of Great Slave Lake Lodge and the approximate area fished for lake trout, 1972...... 48
16. Comparison of the length-weight relationship of lake trout collected from two Great Slave Lodges, 1972...... 51
17. Comparison of length versus age of lake trout collected from two Great Slave Lake lodges, 1972 ...... 53
18. Comparison of weight versus age of lake trout collected from two Great Slave Lake lodges, 1972 ...... 54
19. Comparison of age frequency distributions of lake trout from two Great Slave Lake lodges, 1972 ...... 55
20. Comparison of length frequency distributions of lake trout collected from two Great Slave Lake lodges, 1972...... 56
21. Location of Frontier Fishing Lodge and the approximate area fished for lake trout, 1972...... 58
22. Location of Arctic Star Lodge and the approximate area fished for lake trout, 1972...... 63
23. Location of Indian Mountain Lodge and the approximate area fished for lake trout, 1972...... 65
24. Location of Trophy Lodge and the approximate area fished for lake trout, 1972...... 66
25. Number of anglers versus the weights of fillets taken at 10, 20 and 30 pounds (4.5, 9.1 and 13.6 kg) of fillets per angler ...... 71
26. Number of anglers versus the round weights of fish killed at 10, 20 and 30 pounds (4.5, 9.1 and 13.6 kg.) of fillets per angler ...... 72
27. Length-weight relationships of lake trout from Great Bear and Great Slave Lake compared to southern lakes ...... 74
28. Length versus age comparison of lake trout from Great Bear and Great Slave Lakes with southern Lakes ...... 76 vii
Page
29 Weight versus age comparison of lake trout from Great Bear and Great Slave Lakes with southern lakes ...... 77
30. Length frequency distribution comparison of lake trout from Great Bear and Great Slave Lakes with Lac la Ronge, Saskatchewan ...... 78 31. Age frequency distributions of trout from Great Bear and Great Slave Lakes...... 79
viii
LIST OF TABLES
Page
1. Sampled and estimated harvest of lake trout from Great Bear Lodge, 1972 ...... 21
2, Age, number, mean length, mean weight, sex and maturity of lake trout from Great Bear Lodge, 1972 ...... 22
3. Maturation rates and expected lengths and weights for lake trout from Great Bear Lodge, 1972...... 24
4. Sampled and estimated harvest of lake trout from Great Bear Lake Lodge, 1972 ...... 31
5. Mean length, mean weight, age, sex and maturity of lake trout from Great Bear Lake Lodge, 1972 ...... 32
6. Maturation rates and expected lengths and weights for lake trout from Great Bear Lake Lodge, 1972...... 33
7 Sampled and estimated harvest of lake trout from Cameron Bay Lodge, 1972...... 36
8. Mean length, mean weight, age, sex and maturity of lake trout from Cameron Bay Lodge, 1972...... 39
9. Maturation rates and expected lengths and weights of lake trout from Cameron Bay Lodge, 1972,...... 40
10. Harvest of lake trout and grayling taken at Great Bear Trophy Lodge, 1972 ...... 40
11. Weekly harvest of lake trout taken by Arctic Circle Lodge, 1972...... 43
12. Number and weight of trophy lake trout from Arctic Circle Lodge, 1972...... 44
13. Total harvest of lake trout from Arctic Circle Lodge, 1972...... 44
14. Total sampled and estimated harvest of lake trout from Great Bear Lake, 1972 ...... 45
ix
Page 15. Sampled and estimated harvest of lake trout from Great Slave Lake Lodge, 1972...... 49
16. Mean length, mean weight, age, sex and maturity of lake trout from Great Slave Lake Lodge, 1972...... 50
17. Maturation rates and expected mean lengths and weights of lake trout from Great Slave Lake, 1972...... 52
18. Sampled and estimated harvest of lake trout from Frontier Fishing Lodge, 1972...... 59
19. Mean lengths and mean weights, age, sex and maturity of lake trout from Frontier Fishing Lodge, 1972 ...... 60
20. Maturation rates and expected lengths and weights of lake trout from Frontier Fishing Lodge, 1972...... 61
21. Estimated total harvest of lake trout from Arctic Star Lodge, 1972 ...... 62
22. Estimated harvest of lake trout from Indian Mountain Lodge, 1972 ...... 64
23. Estimated harvest of lake trout conducted by Trophy Lodge on Great Slave Lake, 1972...... 67
24. Total sampled and estimated harvest of lake trout from lodges on Great Slave Lake, 1972 ...... 68
25. A demonstration of lake trout fillet weight converted to round weight ...... 73
x
LIST OF APPENDICES
Page
1. Example of creel data calculations ...... 95
2. Letter sent to Northwest Territories lodge operators requesting information...... 96
3. Results from a fillet study carried out at three Great Bear Lake lodges during 1972...... 97
4. Revenue and employment in Great Slave Lake (Area 6) sports and commercial fisheries...... 98
5. Creel data from Great Slave Lake, 1972 ...... 99
6. Creel data from Great Bear Lake, 1972 ...... 100
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INTRODUCTION
The lake trout is a highly regarded game fish throughout North America, and provides the major attraction to anglers visiting the lakes of the Northwest Territories. Great Bear and Great Slave Lakes, centrally located in the District of Mackenzie, provide the core of a highly advertised lake trout sports fishery. Fishing lodges located on both lakes operate during the summer months offering angling for lake trout, grayling, Thymallus arcticus, and northern pike, Esox. lucius. This fishery is economically viable and valuable to the N.W.T. as a tourist attraction. It is recognized that angling pressure will undoubtedly increase on the lakes as economic and industrial expansion continues and as more southerly fisheries continue to decline. At present, the fishery is isolated in that access to the areas fished is limited to air travel. However, access roads will likely be constructed in the near future and the protection offered by this natural remoteness will be lost. The susceptibility of lake trout populations to overfishing is well known and the ability of the stocks in Great Bear and Great Slave Lakes to withstand heavy angling pressure is in question at present.
From June to September, 1972, a creel census and biological sampling program was carried out at lodges on Great Bear and Great Slave Lakes. Information on length, weight, sex, maturity and of lake trout was collected and analysed to determine the present status of the lake trout populations. Records were kept of the numbers of fish taken by anglers and estimates were made of the total harvest of lake trout on Great Bear and Great Slate Lakes. The application of the data collected to provide a basis for the future regulation and development of the fishery is the main intent of this study.
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DESCRIPTION OF THE AREAS
GREAT SLAVE LAKE
Great Slave Lake is situated between north latitudes 61° and 63° north and west longitudes 109° to 117° east (Fig. 1). It is the fifth largest in North America with Superior, Huron, Michigan and Great Bear being larger in that order. The lake has a total surface area of 11,070 square miles, of which 10,430 and 640 sq mi are water and islands, respectively (Kennedy 1954). Great Slave Lake stretches 275 miles from Reliance in the east arm to the outlet of the Mackenzie River and 100 miles from the Slave River to Fort Rae. The lake has a large, open, central area with two arms extending to the north and east.
The Canadian Shield divides Great Slave Lake on the line from the Slave River to Hardisty Island. Rocks to the north and east of this line are crystalline with occasional intrusions of sedimentary and volcanic formations. Granites and gneisses of the Shield resist weathering and as a result the area is rugged with innumerable reefs, islands and narrow bays. Cliffs are common, rising abruptly above the water level to heights of 600 feet. Silt or sand beaches are rare in this area. Lakes of all sizes are common among the numerous rough hills surrounding the east arm. Lockhart, Yellowknife, Snare and several smaller rivers are found along the north and east slopes but provide little drainage. Surface vegetation in the area consists of scattered areas of spruce intermingled with lesser growths of white birch, lichens and mosses.
The waters of the Precambrian region of the lake are cold, clear and deep. Average surface temperatures of the east arm seldom exceed 11C and decrease to a winter mean of 2C. The water of the eastern section is clear and in some areas the bottom may be seen to a depth of 20 feet or more. (Depths of 2,015 feet have been recorded in the east arm and areas over 1,000 feet are common.) West of the Simpson Islands water depth decreases and the water becomes less clear. The central area of the lake has a mean depth of 135 feet and half is less than 80 feet. Rawson (1947) has given a detailed description of the physical characteristics of Great Slave Lake.
The area to the south and west of the Precambrian divide is known as the Mackenzie lowlands. This is the northern fringe of the Great Plains and encompasses a major portion of the central lake area, extending from the Slave River delta along the south shore and west to Hardisty Island. The area is typically low and the contours are regular with the exception of a few gentle hills and rock outcrops. Shallow lakes, marshes and muskeg areas are common. Glacial
4
till, limestones and other soft rocks have allowed the formation of soils throughout the area. As a result, the surface vegetation is abundant compared with the Shield. Spruce is the dominant growth with mixtures of poplar, jackpine, balsam and birch. Groundcover species are abundant and vary according to the soil type present. Muskeg is common throughout the poorer drained areas. The Slave is the largest river flowing into Great Slave Lake. The Hay, Buffalo, Taltson and several other, smaller rivers enter along the south shore. A large amount of silt carried into the lake by these rivers increases the turbidity of the water in the southwest portion. The general shallowness of the lake, combined with the warming effect of the rivers, contributes to the surface waters being on an average 1 to 3°C warmer than the remainder of the lake. The outlet of the Mackenzie River in this area presents a situation in which the flow of water within the lake is confined to the southwest portion. Little exchange of water between the eastern and western portions of the lake is thought to occur because of this continued flow pattern between the Slave and the Mackenzie River. Drainage from the plains is typified by slow, siltaceous streams originating from rich soil and vegetation areas: As a result, high levels of nutrient material are discharged into this portion of the lake. The Precambrian drainage on the other hand typified by clear, cold, fast flowing streams originating from poorer soil and vegetative areas, contributes little nutrient material.
Climatic factors also have a profound effect on the region. Long, cold winters and short, warm summers coupled with low annual precipitation constitute a typical north continental climate. Air temperatures vary from an annual mean of 23F to winter low means of -15F during January. Summers, with 15 to 20 hours of sunlight per day are warm with mean temperatures for the months of June, July and August between 50 and 60F. Annual precipitation is low, averaging 8 to 13 inches. Snowfall contributes 40 percent of the total, with averages in the 35 to 40 inch range. Ice cover remains from early December to early or mid-June on the main portion of the lake. Breakup in the eastern sections averages two to three weeks later. Ice reaches average thicknesses of 3 to 5 feet with records of 8 feet in some areas.
Rawson (1945) has investigated the chemical nature of the lake. Oxygen measurements throughout the lake indicate a high oxygen-content with near saturation levels at all times of the year. Average surface pH readings were 7.7 to 8.3 and averaged 0.3 lower at depths greater than 300 feet. Water in the main lake averaged 150 ppm total dissolved solids. The eastern areas held less with averages of 111 ppm in Christie Bay and 22 ppm in McLeod Bay. 5
GREAT BEAR LAKE
Great Bear Lake exhibits many characteristics which are similar to those of Great Slave Lake due to the environmental and geological history of both areas. However, substantial differences do occur due to local drainage and geographic location. Great Bear Lake lies between latitudes 64° 40’ and 67° north and longitudes 118° and 125° west (Fig. 2). It lies 60 miles east of the Mackenzie River with the Arctic Circle intersecting its northernmost arm. Slightly larger than Great Slave Lake, Great Bear is the fourth largest lake in North America. Its total area is 12,029 square miles of which 11,800 are water (Kennedy 1952). A geological division similar to. that found on Great Slave is present on Great Bear. The lake consists of five arms radiating from a large central area. The eastern arm of the lake, composed of McTavish Arm, lies within the Precambrian Shield while the remainder of the arms, Smith, McVicar, Dease and Keith lie in the Mackenzie Lowlands. An outcrop of the Precambrian Shield occurring in Dease Arm rises several hundred feet out of the water and forms the Narakay Islands. The eastern Precambrian Shield composed of hard igneous rocks produces a shoreline which is steep and irregular with narrow bays, inlets and numerous reefs. Cliffs and rugged hills up to 500 feet in height are common. As in the east arm of Great Slave Lake, erosion and weathering are slow processes, allowing little soil formation. As a result, ground vegetation is restricted with stunted black spruce, few birch and numerous lichens, herbs and-mosses
The western lowlands are of an opposite nature with the exception of the hills between McVicar and Keith Arms. Between Smith Arm and Deerpass Bay the relief is low; shorelines are regular, and generally composed of gravel. The component rocks of the area are soft sandstones, shales, limestones and glacial till. This has allowed substantial soil formation and resulted in heavy growths of spruce and numerous shrubs and bushes. The northern shores have a tendency to display a tundra type vegetation with scattered patches of stunted, spindly spruce and open mossy areas.
The drainage basin of the lake is very small with the majority of the rivers being short and often intermittent. Rivers are randomly distributed and are clear, cold and swiftly flowing. No major river systems other than the Camsell enter the lake and the only outlet is the Great Bear River, located at the western tip of Keith Arm: The lake's waters are extremely transparent with visibility often extending to depths of 40 feet or more in all parts of the lake. McTavish Arm is the deepest part of the lake with soundings of 1,400 feet. No extensive shallow areas are found on the lake.
7
The lake may be described as one unit with regard to temperature, dissolved oxygen content and chemical properties. Due to its cold nature water at depths of over 100 feet seldom varies from the maximum density temperature of 4C (39F) (Johnson 1966). Surface temperatures vary several degrees on the main lake and may go as high as 9C (50F) in the more protected shallow bays. A gradual warming is observed from breakup to mid-summer. Freeze-up begins in late October and is usually complete by early December. Breakup is not complete until late June or the first week of July and is sometimes not complete until the third week of July.
Miller (1947) found that the oxygen levels in the lake were in the order of 85 to 91 percent saturation throughout the lake. Hydrogen ion concentrations were uniform within the range of 7.2 to 7.4. Bottom fauna and plankton investigations have been described by Miller (1947). Great Bear Lake has a north continental climate with mean temperatures only a few degrees lower than those of Great Slave Lake. Its more northerly position subsequently causes earlier winters and later springs. Annual precipitation levels of 11 inches (Johnson 1966) are slightly less than those found in the Great Slave Lake area.
Great Slave and Great Bear Lakes exhibit extremes in oligotrophic conditions. Although the western portion of Great Slave is an area of moderate exception, the remainder, along with Great Bear, possesses the typical characteristics of clear, cold water, extreme depths and uniform oxygen concentrations. Great Bear is the climatically more extreme of the two, and is less productive than Great Slave. Life forms tend to concentrate themselves in the shallow shore areas where conditions are more conducive to growth. Great Slave is similar in this regard in its eastern portion. However, in the western portion the shallowness and the moderating effect of nutrient-rich drainage from the south produces marked differences. The influence of these changes is felt in an increase of productivity over the southwest basin and produces a richer environment for the fish population. 8
DESCRIPTION OF THE FISHERIES
Development of the fish resources of Great Bear and Great Slave Lakes has taken place during the past decade. The resource was recognized during the early 1940's and studies were undertaken by Rawson (1947), Miller (1947) and Kennedy (1953) to determine their value and possible utilization. A unique situation was found in that the fish populations were unexploited prior to their studies. Following studies on physical characteristics, limnology and fauna of Great Slave Lake, recommendations for the establishment of a commercial fishery were put forth. The fishery was established in 1945 and has been operating to this date. Lake whitefish (Coregonus clupeaformis) and lake trout have been the principal catch. Similar studies were undertaken on Great Bear Lake (Miller and Kennedy 1948). It was recommended that the lake, because of its oligotrophic nature and limited productivity, could not support a commercial fishery. To this date no fishery has been established for commercial purposes. Subsequent reports regarding certain aspects of both lakes and their fish resources have been published by Kennedy (1953) and Johnson (1966). Information regarding the composition of the fish populations of Great Slave is available (Rawson 1951). Twenty-one species had been captured and recorded at that time and descriptions are offered. Additional information for individual species are found in McPhail and Lindsey (1970).
During the years following development of the commercial fishery on Great Slave Lake interest was expressed in the sports fishing capabilities of the area. With the recognition of this resource, private entrepreneurs established sports fishing lodges on the lake as early as 1953. Lake trout and arctic grayling provided the bulk of angler attention with limited catches of yellow walleye (Stizostedion vitreum vitreum) and northern pike. Areas that produced these species were chosen for lodge sites. The east arm of Great Slave Lake proved suitable and Great Bear in its entirety has been utilized. Only a few lodge operations were developed during the 1950's but in recent years the number has climbed. To date ten major operations have been established on these lakes. The possibility of these operations having a substantial and adverse effect on the fish resources has been recognized and efforts to assess and direct the sports fishery are currently being made.
At the present time there are six lodge operations on Great Slave Lake. Brabant Island Camp is located on Brabant Island at the outlet of the Mackenzie River. This is primarily a grayling and northern pike fishery (Fig. 1). Information concerning the present fishery at Brabant Island is available (Gillman and Dahlke MS 1973). 9
The remaining five lodges: Frontier, Great Slave, Trophy, Indian Mountain and Arctic Star are located in the east arm of Great Slave Lake and are principally lake trout fisheries. Six lodges operate on Great Bear Lake and all are lake trout and grayling orientated. A small lodge, Sah-Tew, operates at Fort Franklin while the remainder, Great Bear, Great Bear Lake, Cameron Bay, Arctic Circle and Trophy lodges are scattered at different locations around the lake (Fig. 2).
The lodges are fairly uniform in their techniques of operation. During winter months guests are contracted for dates during the summer season. Deposits are paid and reservations made for one week periods at most lodges. Longer or shorter periods are frequent where transportation is readily available. The remaining payment is collected in one lump sum and covers all facets of the guests' stay. Charges include air fare, meals, accommodations and guide services while at the lodge. Lodges are for the most part quite modern, having running water, plumbing, separate sleeping facilities and excellent cuisine. Small stores of fishing equipment arid necessities are usually present. Facilities for the preservation and handling of fish retained are provided. Guides are local or brought in from southern centres. Kitchen and general help is usually hired from outside areas.
Fishing usually begins when the ice breaks up in the area adjacent to the lodge and continues until late August or September, weather permitting. Sixteen foot aluminum boats with 15 to 25 horsepower outboards are a common combination. Guests supply the majority of their fishing gear which ranges from heavy trolling rods and steel line to light spinning gear and monofilament line. Guides choose the areas to be fished, which are usually reefs and shorelines in early and late summer, while deeper regions are chosen during midsummer: Guides usually assist the angler in landing and/or-releasing fish. Guests fish one or two per boat and spend from four to eight hours fishing per day. Air trips at extra cost are available from some lodges to fish for Arctic char (Salvelinus alpinus) in rivers along the Arctic coast, or for other fish species in inland lakes. Lodges with numerous clients have established outpost camps at other locations on the lakes to provide better or easier fishing. Although trophy fish are the main interest of the majority of the fishermen, recreation and seclusion are also felt to be of high value. In addition to trophy fish, fillets are also taken out by the majority of the anglers.
The lake trout of Great Slave and Great Bear are known for their trophy size, availability and excellent sport. Lake trout on proper tackle provide the angler with a hard and often enduring fight. The trout are prized as trophies and provide the angler with an attractive trophy mount. Trout exhibit a variable body shape., from the lakes. 10
Often the larger trout are extremely deep and thick in the body and lose the streamlined contours normally associated with salmonoids, For this reason trout may often exhibit a great range in weight for the same length at older ages. This is not attributed to sexual or structural dimorphism as both sexes are externally similar. On both lakes instances of "big head trout" have been recorded. These are trout with large heads and small thin bodies. No explanation of the cause is available at present. External coloration is also variable between different sections of the lakes. Colors from dark brown to deep black occur, but the majority of trout from both sexes taken are deep green to black on the upper back, light green with mottled light patches on the sides and white to light pink on the belly. The single fins display light patching and paired fins are white or pale yellow to a deep orange in color. The flesh of lake trout from Great Slave and Great Bear Lakes is excellent and anglers on both lakes enjoy the shore lunches of lake trout prepared over open fires by the guides. The flesh of smaller trout is preferred as the larger, older trout tend to be fattier and the flesh slightly oily. Smoking of lake trout fillets is also popular at several of the lodges. The flesh of trout from Great Bear and Great Slave Lakes varies with respect to color and ranges from pale white to a deep reddish-orange. Rawson (1951) on Lac la Ronge and Miller and Kennedy (1948) on Great Bear noted the variety of flesh colors and interpreted them as representative of the reserve of proteins and fats in the flesh. Records of flesh coloration were kept and among mature fish it was found that non-spawning fish exhibited deep coloration while spawning fish were white or pale yellow in color.
Miller and Kennedy (1948) noted a uniform distribution of lake trout throughout Great Bear Lake from test nets set during their study. Trout appeared in the greatest densities in areas adjacent to shallows and were most commonly found in depths of 40 feet or less. Observations made during 1972 of the areas and depths fished on Great Bear yielded the same information and it was noted that no marked change occurred in the depth range at which trout were caught throughout the entire summer. Great Slave trout exhibited a series of movements throughout the summer. In June and early July the trout are taken quite close to the surface. During July and August the trout moved to deeper areas and remained at these depths until late August or September. In the majority of literature available similar seasonal shifts are recorded in lake trout populations. Fry (1939) noted that lake trout of Algonquin Park lakes exhibited this movement into deeper waters in late June. Rawson (1960) noted that trout of Lac la Ronge, Saskatchewan moved out of shallow areas when the temperature rose above 8 – 10C. Martin (1952) noted that trout in Red Rock and Louisa Lakes in Algonquin Park also moved to deeper water in conjunction with surface temperatures of 14 - 15C. 11
The lack of movement exhibited by Great Bear trout may be explained by the limited temperature fluctuation within the lake. This factor, plus the confinement of major food species to littoral areas on Great Bear, accounts for this unique pattern. From the information available, lake trout respond to temperature fluctuations within lakes by movement to deeper or shallower water. With the exception of Great Bear, the seasonal movement appears to be similar in all lake trout systems encountered.
Lake trout demonstrate varied lateral movement within lakes. Miller and Kennedy (1948) found that the infection of trout with Triaenophorus crassus was confined to well-defined areas and suspected from this that little movement occurred among trout in Great Bear Lake. Cable (1956), from the results of a tagging study conducted on trout from Lake Michigan, stated that trout exhibited little movement from original tagging sites . Rawson (1951) postulated that there was a general migration of trout from the eastern section of Great Slave to the west during their life. However, Keleher (1963), in a tagging study conducted on lake trout of Great Slave, showed that this did not occur. Rawson (1960) noted that the trout of Lac la Ronge exhibited extensive movements and intermingled throughout the lake. From these observations it is apparent that variability exists in the movements of different lake trout populations. However, with the exception of the Great Slave Lodge area, the lake trout of Great Bear and Great Slave appear localized and exhibit generally limited movement.
The availability of trout to the angler in Great Bear and Great Slave is excellent. Although the lake trout sports fishery is confined to the East Arm of Great Slave, catches of trout are taken in the majority of inshore areas throughout the entire season. Keleher and Meeker (1960) conducted a survey determining the relative distribution of trout available to anglers and reported few areas where good catches could not be taken. At present the entire McLeod Bay and areas east of a line from Utsingi Point to Redcliff Island are restricted to the use of sport fishery operators. Availability of trout fluctuates both on a seasonal and size basis, with lodges recording catches of heavier, larger fish in the early parts of the season. During August the general size of fish declines while the numbers taken often increases. This occurrence is similar to a pattern noted by Fry (1939) in lake trout catches in Algonquin Park lakes. Rawson (1960) also reported heavier catches of trout during June in Lac la Ronge, but noted that angler success remained stable throughout the entire season. Different angling methods could be responsible for the shift in catch on Great Slave. Deep and shallow trolling, according to the season, is the most common method used. Shallow trolling appears more successful as the catch 12
taken during the early summer, when this method is utilized, is greater. Cordone and Frantz (1966) report that of four methods used by anglers in Lake Tahoe, deep water trolling was the most successful. In this regard lake trout availability in Great Slave depends on what segment of the trout are feeding and at what depth they are occurring. From 1972 observations, lake trout in Great Slave are most vulnerable during June, early July and September when they are close to the surface. Great Bear Lake trout do not appear to demonstrate shifts in availability during the fishing season as harvest methods and the overall size and number of the catch changes little throughout the summer. 13
METHODS AND MATERIALS
GENERAL
Personnel were stationed in selected lodges on Great Bear and Great Slave Lakes from the beginning of their 1972 fishing season to near the end. Each observer was supplied with a tent and proper facilities to maintain himself in the field. A sixteen foot aluminum-boat with a 20 HP outboard motor was supplied to each for transportation. Tent and dock sites were chosen at some distance from the lodge to allow the worker to be as independent as possible. Biological sampling equipment appropriate for the program was supplied. The worker then fitted himself into the daily operation of the lodge. This, in most cases, involved angling and record work until late afternoon. At this time the majority of fishermen began returning to the lodge. Fishermen or guides were then questioned on the number and species of fish caught and/or released and the area and hours fished for the day. When possible, trophy fish numbers and weights 'were noted. Workers usually filleted or helped the guides fillet fish when sampling was complete.
Fish were weighed (scale accuracy plus or minus 10 g), measured for length (tip of snout to distal end of shortest caudal fin ray in mm), sex and maturity recorded and scales or otoliths taken. Otoliths were obtained from the majority of lake trout by removing the top or splitting the skull and locating the saggital otolith with tweezers. Scales were removed from the left side of the fish slightly above the lateral line and below the dorsal fin. Scales or otoliths were stored dry in envelopes marked with the sample information. Stomach contents were also taken and preserved in 10 percent formalin for laboratory analysis if field identification was not possible. Maturity was determined by the condition of the gonads. A scale of five divisions was used with numbers from one to ten representing the maturity state. Numbers. below five represented females and numbers six and above represented males. In each case the lowest number (1 or 6) represented an immature or juvenile fish. The remaining numbers were used to identify the various states of maturity encountered. Lake trout are thought to spawn only every second or third year (Miller 1947; Rawson 1950; and Kennedy 1954). During the interval following a spawning year gonads resemble those of a juvenile fish: Efforts were made to identify these fish from the remainder by designating these as maturing fish; those thought to be mature but not spawning in this year. The third division was labelled mature indicating a positive identification of an adult but allowing doubt as to 14
spawning condition. The fourth and fifth divisions, ripe and spent respectively, were used where spawning condition was plainly visible (milt or eggs issuing from the cloaca). Observations of ectoparisitim, endoparisitism, deformities and flesh color were noted.
Materials collected in the field for laboratory processing were handled in the following manner. Scales were mounted dry between two glass slides and enlarged (X2.5) by a microprojector for accurate reading. Areas of compacted circuli or annuli were counted and ages applied from the total count. Little difficulty was encountered in aging scale samples from species other than lake trout. Otoliths were used for determining ages for lake trout due to the small scale size and large ages encountered. The surface of an otolith was ground on a fine carborundum stone (to remove the opaque exterior layer). The otolith was then immersed in a benzyl-benzoate-methyl salicylate solution (3:1) on a depression slide and read under a dissecting microscope. The solution cleared the otolith and allowed better resolution and identification of annuli. Each ring corresponds to a completed year of life. Using this criteria a fish entering its 10th year would have 9 rings. Difficulty was encountered in some samples due to the great ages involved. Conferral among readers, however, usually resulted in close agreement.
Data collected from sampled fish was coded, key-punched, verified and analysed by use of a computer (IBM 360 model 65, University of Manitoba). Information was transferred from computer printout to report forms with the exception of the estimates of annual mortality and harvest. These calculations were done from information collected from the 1972 sample records. Mortality (natural + fishing) was calculated using the method outlined by Robson and Chapman (1961).
CREEL CENSUS
The objective of the creel census of 1972 was to determine the present harvest being taken by sports fishing operations on Great Bear and Great Slave Lakes. Six lodge operations were censused during the 1972 summer season. To obtain total figures for both lakes in terms of numbers and weight of fish taken, several parameters were necessary. The method of obtaining the totals is demonstrated in the following sections and an example based on the data gathered is shown in Appendix 1. Sampling periods for the majority of lodges constituted 80 percent or better of the lodge's fishing season. During the actual sampling of creel as many as possible, if not all, anglers were interviewed. The number of 15
fishermen, whether questioned or not, was recorded. Corrections were then applied to include all fishermen.
Numbers of Anglers: Each lodge is capable of supporting guests to the number of beds available for them. In most cases lodges are booked to capacity but last minute cancellations may result in the number of anglers being below capacity. Personnel noted the number of anglers present at the lodge by the day and by the week. The total number of anglers recorded during the sampling season was divided by the interview period (days) to obtain average number of fishermen present per day. Any portion of the lodge's total fishing season not censused by our survey was assumed to have the average number of anglers present. Calculations were based on this figure to take into account the number and pounds of fish caught during periods in which no survey was done.
Numbers of Fish Caught: The average number of fish caught per day was calculated by totalling the numbers of fish caught over the total sampling season and dividing by the total number of days in the sampling season. This yields an average number of fish caught per sampling day. Division of the average number of fish per day by the average number of anglers per day equals the average number of fish per day per angler.
Average Weight of Fish: The retained catch is the amount of fish brought back to the lodge by anglers. This figure was determined by totalling the number of fish brought in during the sampling season. Portions or all of the catch were sampled by fisheries personnel for length, weight, sex and maturity. Important to the creel is the average weight of fish sampled. This was obtained by dividing the total weight of fish sampled by the total number sampled. Fish to be sampled were selected at random from the total catch brought into the lodge. However, trophy fish (9.1 kg or 20 lb) were seldom included in the sampled weights. Thus, the average weight of lake trout is biased toward smaller fish.
INDIVIDUAL LODGE HARVEST
Estimations of total number and weight of trout taken by each lodge are necessary because of two factors not accounted for by our sampling technique. Firstly, all fishermen could not be sampled each day by our workers. Secondly, sampling periods included only approximately 80 to 90 percent of the total fishing season. The 16
total number of anglers was obtained by calculating the average number of fishermen fishing per day at each lodge. The average catch numbers and weights of sampled fish were applied to the remaining catch. This provided the daily estimated catch of fish in total numbers, total weights and average weight of fish taken per lodge. This total catch per day was expanded to include the total days of fishing taking place at each lodge.
Catch On-Line: The total numbers of fish caught by fishermen includes the number of fish released. Totals for all fishermen in kilograms was obtained by calculating the average number caught on line per day per angler and multiplying by the average weight of fish sampled. This yielded the estimated total weight of fish caught by lodge.
Retained Catch: Retained catch is the number of fish brought back to the lodge by anglers. Average weight of the sampled fish was applied to the number not sampled and the total weight of retained catch was obtained. This figure represents the total weight of fish utilized by a lodge and its guests.
UTILIZATION OF HARVEST
Lake trout retained by fishermen on Great Bear and Great Slave Lakes .are utilized in three ways; trophies, fillets and shore lunches. Lake trout ranging from 6.8 to 29.5 kg (15 to 65 lb) are taken as trophies from the majority of lodges. Weights and lengths of these fish were obtained only in a few instances by our personnel. Observations taken during the summer enabled us to assign reasonably accurate estimates of the average weight of trophy fish taken from each lodge. Most anglers are successful in obtaining one or two trophy fish. Assigning the average trophy weight to each guest yields a total poundage figure of lake trout removed as trophies from each lodge.
In addition to trophy fish, lodges attract guests by advertising large catches and easy fishing. Portions of the catch not taken as trophies are usually filleted, frozen and shipped out with the guest. Weights taken vary with the lodge and range between 4.5 to 13.6 kg (10 to 30 lb) of fillets per person. These figures do riot represent round weights and corrections are applied based on a filleting survey described later.
Shore lunches are the remaining use applied to lake trout taken on Great Bear and Great Slave Lakes. Fishermen take on the average one fish ranging between 1.4 to 2.7 kg (3 to 6 lb) for shore lunches each day. Guides fillet and prepare the fish at shore areas close to the fishing area. Average weights taken for shore lunches are calculated on the 17
number of fishermen present ,at each lodge and multiplying this figure by the average round weight used per shore lunch per fisherman. Total weights calculated for shore lunches for each lodge by this method represent round weight.
TOTAL LAKE HARVEST
In lodges sampled by our personnel accurate estimates are given in terms of total weight taken. For remaining lodges on the two lakes the following method was used to obtain total numbers and poundage of fish taken. Estimates for the number of fish taken and of weight of trout taken per guest were compiled from the lodges sampled. These figures were applied to the number of guests known to have stayed at each lodge not surveyed in 1972. Since operational methods are uniform among the lodges totals given for the entire lakes may be assumed to be relatively accurate since lake trout are well distributed throughout the lakes.
Included in the results are estimations of the areas fished and the total harvest expressed as yield in terms of kilograms/hectare. Lodges have well defined areas in which the bulk of their fishing occurs. Few lodges have large areas due to the range (approximately 20 miles) of open boats on the lakes. Observations of these areas taken by our personnel during the 1972 season were used to compute the total area fished by each lodge. The total catch retained, in pounds, was divided by the total area in hectares to determine average weight taken per hectare. Maps of the areas designated were sent to lodge owners and managers for their approval or disapproval of our description of the areas fished (Appendix 2). Since information was not gathered from some lodges some yields were not expressed in this way.
FILLET SURVEY
During 1972 it was noted that many of the guides, while filleting their catch, were leaving much of the flesh on the carcass. The reasons were that they were a) in a hurry, b) they were not instructed properly or c) that the bags in which they were to be packaged were too small to hold the entire fillet. As a result .a survey was undertaken to determine the relative percentages of fish flesh utilized as fillets and that discarded. The survey was conducted at the three lodges censused on Great Bear Lake: Cameron Bay Lodge, Great Bear Lake Lodge, and Great Bear Lodge-Neiland Bay Outpost. The fillets and discarded carcasses of lake trout were randomly obtained 18
from the guides of each lodge. The carcass of a lake trout consists of the head, including the opercula, fins, backbone, ribs, and viscera. The fillets consist of the fleshy muscular covering on the ribs and backbone, either with or without the skin. The object of the survey was withheld from the guides in order to avoid biased results. 19
RESULTS
A. GREAT BEAR LAKE
GREAT BEAR LODGE: NEILAND BAY AND BEAR ISLAND OUTPOSTS
General: Great Bear Lodge, located on the southwestern portion of McTavish Arm at Sawmill Bay was established in the mid 1960's. During the Second World War this camp was used as a stopover for trans continental flights. Still using this camp as the main base because of runway facilities, the lodge operation was moved across the Leith Peninsula to the northeastern portion of McVicar Arm (Fig. 3). Here outpost camps were established on an island in Neiland Bay and on Bear Island, approximately 20 miles south. Guests land at Sawmill Bay and by means of a float plane are distributed to either of the two camps. Grayling fishing at Blackwater Lake and the mouth of the Great Bear River is available on a fly-in basis from the outposts. The lodge is one of the smallest camps on the lake and caters to husband and wife teams more so than other lodges. The 1972 season lasted from July 8 to August 25. Lake trout fishing is confined to the immediate vicinity of the Neiland Bay Outpost covering an area of approximately 4,448 acres (Fig. 3) .
Creel Census: Creel census and sampling programs were conducted at the Neiland Bay Outpost camp from July 13 to August 24. The survey determined that 435 fishermen (13.6 per day) caught 2,004 lake trout and 215 grayling during the 32 day sampling period (Table 1). This figure represents 85 percent of the guest capacity at Neiland Bay. The outpost camp at Bear Island is capable of handling an estimated additional 12 guests but monitoring was not done at this location. The Neiland Bay Outpost anglers retained 367 lake trout and 92 grayling during the sampling period of which 262 trout and 85 grayling were sampled. The average weight of lake trout sampled was 4.74 kg and of grayling 1.01 kg. Figures obtained from the sampling period are exclusively from Neiland Bay and estimations of the total harvest conducted by the lodge are from both Neiland Bay and Bear Island.
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Table 1. Sampled and estimated harvest of lake trout from Great Bear Lodge, 1972. ______
No. caught Total wt. Total wt. Shore Yield on line on line retained lunches (kg/ (kg) (kg) (kg) hectare) ______Samples 2,004 541.6 ------
Estimated 4,670 21,523.7 3,943.1 1,449.2 2.23 ______No. sampled = 367; Average wt. = 4.7 kg. ______
During 1972, the average number of anglers present at Bear Island outpost was not fully recorded. Assuming 12 guests at a minimum and 80 percent capacity the catch figures from Neiland Bay were applied to Bear Island and total weight of lake trout killed by Great Bear Lodge was estimated. At an estimated 26 guests per week total weight killed was 3943.1 kg plus shore lunches as 14492.2 kg. Trophies are included in this weight. Fillet removal was low at Neiland Bay averaging 4.5 kg of fish per man. The management at Great Bear Lodge encourage their guests to return as many fish as possible to the lake and to remove only trophy fish. Guests, during 1972, retained less than 20 percent of the fish caught on line and of this percentage over half were used as trophy fish.;
Of the 252 lake trout sampled during the 32 day survey age determination and data analysis was conducted on 216 fish. Lake trout sampled from Great Bear Lodge had a mean length of 732 mm, a mean weight of 4,667 kg and a mean age of 23.95 years. Table 2 summarizes the data collected on lake trout from Great Bear Lodge.
Length-weight Relationship: Figure 4 illustrates the length-weight relationship of 216 lake trout from Great Bear Lodge in relation to the other Great Bear lodges sampled. The logarithmic equation expressing the regression is: ln (W) = -3.67 + 2.55 (ln L)
where; W = weight in grams
L = length in millimeters
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Age and Growth: Figures 5 and 6 illustrate growth in length and weight respectively for lake trout from Great Bear Lodge in relation to two other lodges studied. The large number of small fish returned by this operation limited the size of fish sampled to those over 10 years of age.
Age, and Length Frequency Distributions: The age frequency distribution of lake trout taken by Great Bear Lodge is given in Figure 7. Ages 10 to 37 are represented with the majority of the catch occurring from ages 19 to 26. Lake trout become susceptible to the gear at ages 10 to 12 but the high release rate of these smaller fish tends to shift the sample distribution to older and larger fish. If it was possible to sample released fish a high percentage of fish aged 15 or less would probably result. Few trophy fish were sampled from Great Bear Lodge. This fact acts to reduce the average weight and age.
The length frequency distribution of lake trout collected from Great Bear Lodge in 1972 is illustrated in Figure 8. Fish ranged in length from 400 to 1,000 mm with the majority within the 500 to 700 mm length interval.
Mortalitv Rate: The irregular distribution among age groups in the sample from Great Bear Lodge (Table 2) made an accurate mortality figure difficult. However, based upon ages 30 to 37 an annual mortality rate of 18.5 percent was calculated.
Sex Ratio and Maturity: -Of 216 aged lake trout taken in 1972, 118 were female and 98 were male (1.2:1). Maturity was determined for the sample arid estimated maturation rates and the corresponding mean lengths and weights are presented in Table 3.
Table 3. Maturation rates and expected lengths and weights for lake trout from Great Bear Lodge, 1972.
______Percent Age Mean Length Mean Weight mature (yrs) (mm) (g)
______50 13 553 2,100 75 15 616 3,060 100 18 670 3,050
______
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GREAT BEAR LAKE LODGE
General: Great Bear Lake Lodge is located on the east side of Dease Arm, 15 miles above the Arctic Circle (Fig. 2). The lodge has been in operation here for only the past four years. Prior to this time the lodge was located in the southern portion of Conjuror Bay in McTavish Arm. Having a 58 bed capacity it is the largest lodge on the lake. Guests are flown in to a private airstrip located a short distance from the lodge. They are then taken to the lodge which is situated on an island by boat (Fig. 9). Lodge guests usually stay a period of one week and are then flown back to Winnipeg, the point of origin. The season, depending on spring ice conditions, generally runs from the first week of July to the end of August. Due to bad ice conditions in the 1972 season the operation started on July 8 and lasted to September 2. While at the lodge each guest, for a nominal fee, is able to go to Tree River on the Arctic coast for a day of Arctic char fishing. Flying up to the outpost by means of a beechcraft on floats the guests angle from shore due to the rough river conditions. The rest of their stay is taken up at the lodge fishing for lake trout, generally from 9:00 a.m. to 5:00 p.m. with many trying their luck in the evening. Many also attempt angling for grayling at several prime areas in the immediate vicinity of the lodge. Fishing is confined to the Dease Arm, with an area of 45,536 acres being fished (Fig. 9).
Creel Census: During 1972, the creel census and biological sampling program extended from July 11 to August 24 (45 days). During this period 1,927 fishermen were interviewed for an average of 42.8 per day. This represented 73.8 percent of the total number of guests, assuming that the lodge was operating at full capacity. Their catch consisted of 6,877 lake trout. During the entire season, it was estimated that a total of 11,389 lake trout were taken on line. This amounted to a total weight of 40,847.8 kg, assuming an average of 3.6 kg per fish. Of this total it was estimated that 64.6 percent (9,377 lake trout or 26,387.7 kg) were retained either to be taken home as trophies, fillets or used for shore lunches.
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Table 4. Sampled and estimated harvest of lake trout from Great Bear Lake Lodge, 1972. ______
No. caught Total wt. Total wt. Yield on line on line retained (kg/ (kg) (kg) hectare) ______Sampled 6,877 2,012.1 -- --
Estimated 11,389 40,847.8 26,387.7* 1.43 ______No. sampled = 115; Average wt. = 3.6 kg. ______* includes shore lunches, trophies and fillets. ______
Data were not obtained on the actual number of trophy lake trout taken or the number of guests which took their quota of 30 pounds of fillets. It can be safely assumed, however, that, the majority of guests took both. A trophy by most guests is considered to be anything over 9.1 to 11.4 kg. Data collected during the 1972 creel census is summarized in Table 5.
Length-Weight Relationship : The relationship of weight to length for Great Bear Lake Lodge trout is shown in Figure 4, and the liner equation given by the following equation:
In W = -3.10 + 2.35 (ln L)
Age and Growth: Growth rates of the sampled lake trout were taken from the data in Table 5. Figures 5 and 6 illustrate growth in length and weight for 561 lake trout sampled.
Age and Length Frequency Distributions: Figure 8 shows the age frequency distribution of the sampled fish. One lake trout aged as 42, was not included in the plot. The length frequency analysis of the 561 lake trout sampled is indicated in Figure 8. The majority of the angled lake trout were found to lie between 600 and 800 mm.
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Mortality Rate: Using the age frequency distribution (Fig. 7) the mortality rate was found to be 28.7 percent per year using fish between year classes 28 and 37.
Sex Ratio and Maturity: Using the 561 sampled fish, it was found that 254 were male and 307 were female, giving a ratio of 1:1.2 males to females. Overall, 95 percent were mature and the remaining were juvenile. Table 6 breaks this down by age and gives the corresponding mean lengths and weights.
Table 6. Maturation rates and expected lengths and weights for lake trout from Great Bear Lake Lodge, 1972. ______
Percent Age Mean Mean Mature (yrs) Length Weight (mm) (g) ______50 13 539 1659 75 16 583 2172 100 22 645 3153 ______
CAMERON BAY LODGE
General: Cameron Bay Lodge is located in the central portion of McTavish Arm, a short distance east of Port Radium (Fig. 2). The operation was initiated in the mid-sixties at the old town of Cameron Bay. Like the other lodges on the lake the season generally runs from about the first week of July to the end of August. In 1972 the season extended from July 8 to August 18.
The Lodge has a capacity of 40 guests and can be considered medium in size. Lacking runway facilities, guests are flown in from Edmonton to the Sawmill Bay airstrip, approximately 40 miles south of the lodge. Guests are then picked up by float plane and flown to the lodge (Fig. 10). In addition to the main camp an out post on the north shore of Smith Arm at the Katseyedie River (Fig. 11) is also operated by the lodge. Daily flights are made to this camp for better angling success. Special flights for Arctic char are also available to the Coppermine River located on the Arctic coast. Both trips are usually one day in duration. Guests usually stay at the lodge for one week with the majority of the time
36
spent angling for trophy lake trout. In addition, some time is spent angling for grayling.
Creel Census: During the period from July 16 to August 18 a creel and biological survey was undertaken at Cameron Bay Lodge. During the 33 day creel census 635 anglers (19.2 per day) were interviewed (Table 7). This represented 48 percent of the total number of fishermen. Out of the 2,544 lake trout (7,122.98 kg) caught 220 were sampled. Assuming that the lodge operated at 90 percent capacity it was estimated that 6,623 lake trout averaging 2.8 kg for a total of 19,193.4 kg were caught. Of this total it was estimated that 51.5 percent was retained as fillets or trophies. This represents 3,411 lake trout or 9,884.7 kg: No data were collected on the number of trophies caught or kept. Each guest was allowed 11 - 14 kg of skinned fillets; two fillets equal approximately 40 percent of the total round weight. In addition, 2 guests would consume 1.8 to 2.7 kg of lake trout each day for their shore lunch (6 days a week). Data collected during the 1972 creel census are summarized in Table 8.
Table 7. Sampled and estimated harvest of lake trout from Cameron Bay Lodge, 1972. ______No. caught Total wt. Total wt. Yield on line on line retained (kg/ (kg) (kg) hectare) ______Sampled 2,544 619.3 -- -- Estimated 6,623 19,193.4 9,884.7* 1.20 ______No. sampled = 220; Average wt. = 2.8 kg. ______* includes shore lunches, trophies and fillets. ______
Length-Weight Relationship: The length-weight plot from 130 lake trout .is illustrated in Figure 4. The logarithmic equation for the regression of weight on length is stated as:
In W = -5.14 + 3.06 (ln L)
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Age and Growth: Figures 5 and 6 illustrate the mean values of length and weight by age for lake trout sampled at Cameron Bay Lodge.
Age and Length Frequency Distribution: As shown in Figure 8 anglers harvest a restricted population with the majority ranging from 500 to 700 mm. The age frequency plot (Figure 7) shows peaks at age 15 and age 20. The smaller, younger fish were released and therefore not sampled. Table 8 breaks down these plots indicating the percentage of the catch in each age class.
Mortality Rate: A mortality rate of 29.8 percent was calculated using fish from age 22 - 30 (Fig. 7).
Sex Ratio and Maturity: From the data (Table 8) the sex ratio was calculated to be 1:1.2 in favor of females. It was found that 85 percent of the total sample was mature and 15 percent juvenile. Table 9 shows the rate of maturity and corresponding mean ages and weights.
GREAT BEAR TROPHY LODGE
General: Trophy Lodge, situated on the western end of Smith Arm in Ford Bay (Fig. 2) was established in the 1960's. The lodge has a capacity of 40 guests with a usual stay of one week. Operations normally run from the first week of July to the end of August but the 1972 season ran from July 8 to August 26. Most of the anglers' efforts are directed toward lake trout, with some grayling and northern pike fishing. Angling is restricted to the Smith Arm (87,020 acres) with trips of up to 35 miles not uncommon (Fig. 12). The lodge also conducts an additional lake trout fishery on a fly in basis to Lake-de-Bois.
Creel Census: A creel census was not undertaken by Fisheries Service at Trophy Lodge during 1972. Information as to the composition and number of the catch was volunteered and can be seen in Table 10. The lodge was thought to have operated at near capacity.
The lodge retained 6682 kg of lake trout in the form of shore lunches and fillets (round weight). Included in this. number are 52 trophy lake trout which weighed 731.8 kg. In addition-to this 39 grayling weighing 55.4 kg and averaging 1.4 kg were taken as trophies:
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Table 9. Maturation rates and expected lengths and weights of lake trout from Cameron Bay Lodge, 1972. ______
Percent Age Mean Mean mature (yrs) length weight (mm) (g) ______
50 14 518 1520 100 15 582 2205 ______
Table 10. Harvest of lake trout and grayling taken at Great Bear Trophy Lodge, 1972. ______Weight retained Weight as fillets No. of retained & shore Total Species Trophies as trophies lunches weight (kg) (kg) (kg) ______Grayling 39 55.4 - 55.4 Lake Trout 52 731.8 5950.1 6682 ______
ARCTIC CIRCLE LODGE
General: Arctic Circle Lodge, situated on the north shore of McTavish Arm, lies approximately 20 miles north of Port Radium (Fig. 2). After being non-operational for two years it came under new management in 1972. The lodge has a capacity of 34 and an average of 22 guests per week were present during the 1972 season. The season normally runs from the first week of June to the end of August, but operations in 1972 began on June 22 and ended August 26. Guests usually stay for one week, angling for lake trout and grayling in the northern half of McTavish Arm, (21,000 acres) (Fig. 13). Guests are also given the opportunity to fly to the Coppermine River on the Arctic coast for Arctic char and for trophy lake trout at the lodge outpost camp situated approximately 60 miles east, near the Dease Arm (Fig. 14).
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Creel Census: No creel census or biological sampling was conducted by Fisheries Service during 1972. A summary of the lodge catch for the season was voluntarily submitted. Table 11 shows the weekly catches as well as estimates for the last week during which 15 guests were present. Each guest was allowed one trophy fish and 10 pounds of fillets. In most cases, both the trophy and the fillets were taken. The number and weight of trophy lake trout taken during 1972 is given in Table 12. Using the average weights retained at lodges where a creel census was done, estimates of the total catch were calculated and are shown in Table 13.
During the 1972 season 112 lodge guests caught a total of 5,386 lake trout, averaging 2.5 kg for a total of 13,667.7 kg (Table 13). Of this total 2,975.1 kg or 21.8 percent were retained as trophies, filleted fish and shore lunches. This represents a yield of 0.35 kg of lake trout per hectare. Seventy-five lake trout over 9.0 kg were taken as trophies during the season.
Table 11. Weekly harvest of lake trout taken by Arctic Circle Lodge, 1972. ______
From 22/7/72 29/7/72 5/8/72 12/8/72 19/8/72 To 28/7/72 4/8/72 11/8/72 18/8/72 25/8/72 Total ______
Total fish caught 1078 1103 1049 1430 721 5336
Total wt. (kg) 3006.8 2988.7 2674.1 3168.9 1829.6 1366.7
No, of guests 23 22 29 23 15 112 ______
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Table 12. Number and weight of trophy lake trout from Arctic Circle Lodge, 1972. ______
Weight (kg) Number 9.0 - 10.9 44 11.0 - 13.2 14 13.3 - 17.7 14 17.8 - 22.2 3 22.3 or greater 0 ______
Table 13. Total harvest of lake trout from Arctic Circle Lodge, 1972. ______
No. caught Wt. caught Average Weight Shore Yield in on line on line weight retained lunches (kg/hectare) (kg) (kg) (kg) (kg) ______5,386 13667.7 2.5 2975.1 1525.4 0.35 ______
TOTAL HARVEST FROM GREAT BEAR LAKE, 1972.
The sampled and estimated harvests of lake trout from the lodges on Great Bear Lake for the 1972 season is given in Table 14. Figures for Trophy Lodge were included in the total estimated weight retained only.
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Table 14. Total sampled and estimated harvest of lake trout from Great Bear Lake, 1972,
______No. caught Total wt. Total wt. Yield On line on line retained (kg (kg) (kg) hectare) ______Sampled 11,425 3,172.9 -- --
Estimated 22,682 81,564.9 46, 897.4* 1.29 ______No, sampled = 1,148; Average wt. = 3.7 kg ______* includes weights submitted by Trophy Lodge. ______
It was estimated that the lodges on Great Bear Lake, other than Trophy Lodge accommodated a total of 974 guests during the 1972 season. These guests caught an estimated 22,682 lake trout weighing 81564.9 kg. Of this figure 46897.4 kg were retained as trophies, filleted fish or eaten as shore lunches. In addition, Trophy Lodge retained 6682 kg giving an overall harvest of 46897.4 kg. Using these results and omitting those for Trophy Lodge the yield was found to be 1.29 kg per hectare. All estimates were kept to a minimum.
COMPARISON OF GREAT BEAR LAKE LODGES
Through examination of the information collected from individual lodges on Great Bear Lake it became evident that the lake trout population differs with respect to location. The length-weight relationships illustrated in Figure 4 are initially similar but diverge after trout attain a length of 850 mm and a weight of 6700 g. Cameron Bay trout show a more rapid increase in weight at this length. Trout from Great Bear Lake Lodge appear to grow more rapidly than those from the other two lodges. This is illustrated with respect to both length and weight at a given age in Figures 5 and 6. The age frequency distributions of trout from the three lodges is given in Figure 7. Modal ages for trout were 20 years from the Great Bear and Cameron Bay Lodges and 25 years from the Great Bear Lake Lodge. Ages for trout ranged from 10 to
46
37 for Great Bear and Great Bear Lake Lodges but only age 10 to 30 for Cameron Bay Lodge. There appeared to be a general absence of trout greater than age 25 (Trophy size) from Cameron Bay Lodge when compared to the other two lodges. Trout younger than age 10 were either not vulnerable to the fishing gear or were returned to the lake by anglers. The greatest percentage of lake trout from the three lodges fell between 100 and 700 mm (Fig. 8). Trout from Great Bear Lodge exhibited a gradual decline from this length group with no fish greater than 1000 mm. In contrast trout from Cameron Bay and Great Bear Lake Lodge exhibited a more rapid decline. There was an absence of trout greater than 900 mm from Cameron Bay Lodge while from Great Bear Lake Lodge few trout were taken in the 900 to 1100 mm range. Estimated annual mortality rates for trout were 18.5 percent at Great Bear Lodge, 28.7 percent at Great Bear Lake Lodge and 29.8 percent at Cameron Bay Lodge. The ratio of females to males (1.2:1) differed little among the lodges. However, the rate of sexual maturation differed considerably. Maturity is not fully realized until age 15, 18 and 22 for trout from Cameron Bay, Great Bear and Great Bear Lake Lodge, respectively.
It was expected from the previous description of Great Bear Lake that ,since the physical characteristics of the lake were similar throughout the same would hold for the lake trout population. However, it is apparent that this is not the case. Since no outstanding physical differences exist among the lodge fishing areas the past and present operation of the lodges must be given consideration. Of the three lodges, Neiland Bay Outpost Camp and Great Bear Lake Lodge have been located at their present site for less than five years. Prior to this time they were located in McTavish Arm near the Cameron Bay Lodge. From this fact .it is apparent that McTavish Arm has witnessed heavier sports fishing pressure in the past than other areas of the lake. If this fishing pressure has had an effect on the lake trout population one would expect differences would be evident in the age and length frequency distributions, growth rates, fish availability and yield as shown previously. Major differences in growth must occur prior to the age or length of vulnerability to sports fishing since increments in length and weight remain relatively constant after this point. Differences in food sources at younger ages and the amount of littoral feeding area could account for more or less rapid growth rates among trout in isolated areas of the lake. The possibility also exists that throughout the years, distinct areas have produced specific populations possessing characteristic growth rates, sex ratios and maturation rates. The fact that the lake trout population sampled from Cameron Bay and Great Bear Lake Lodges exhibit similarity while that from Great Bear Lodge does not reject this assumption. 47
Through examination of the age and length frequency distributions there is evidence that concentrated angling has occurred in the McTavish Arm area. This is substantiated by the general absence of trout over 800 mm from the Cameron Bay Lodge. Lodges operating for shorter time periods exhibit catches of larger and older trout. It is expected that through continued harvesting of lake trout from these areas at the present rate a reduction in large fish will result. This is expected to occur since the rate of exploitation appears to be outstripping the rate of replacement.
B. GREAT SLAVE LAKE
GREAT SLAVE LAKE LODGE
General: Great Slave Lake Lodge is located at Taltheilei Narrows in the East Arm of Great Slave Lake (Fig. 1) midway on the channel between McLeod Bay and the Hearne Channel: The lodge (Fig. 15) enjoys scenic surroundings from steep cliffs on the Pethei Peninsula and has been operating at this location since the early 1950's, and the season usually runs from early June to late August. During 1972 the lodge operated from June 15 to August 20. The capacity of the lodge is 40 and it operated at near capacity for the entire 1972 season. Guests are flown directly to the lodge by charter flight from Winnipeg for an average .stay of one week.
Lake trout fishing is usually confined to the narrows between Utsingi Point to the south and Kluzai Island to the north. As is illustrated in Figure 15 fishing is concentrated immediately about the lodge. An estimated 3,110 acres were fished for lake trout in 1972. Grayling, northern pike, and additional lake trout fishing may involve travel to smaller inland lakes.
Creel Census: A creel census and biological sampling program was carried out at Great Slave Lake Lodge from June 18 to August 8. An average of 27:5 fishermen per day caught 1,504 fish during the 51-day survey. This figure represents approximately 80 percent of the guests present at the lodge during each sampling day. A total of 1,199 fish were sampled, consisting of 1,155 lake trout, 33 walleye, 9 grayling and 3 northern pike. The average weight of lake trout sampled was 5.88 kg and the total weight of 1,134 lake trout was 6666.99 kg (Table 15).
As explained previously, estimations were made to cover the remaining 14 days of the fishing season not included in our survey.
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Yield per acre of fishing is given for both sampled and estimated portions of the catch. The sampling period was 51 days and the estimated season was 65 days. During this time an estimated 372 anglers were present.
The total weight of lake trout killed by Great Slave Lake Lodge guests in 1972 was 11,906.15 kg. This includes the catch retained and that utilized for shore lunches. Not all trophy fish are included in this estimate as information is usually not available on these fish:
Table 15. Sampled and estimated harvest of lake trout from Great Slave Lake-Lodge, 1972. ______
No, caught Total wt. Total wt. Shore Yield on line on line retained lunches (kg/ (kg) (kg) hectare) ______
Sampled 1,504 6,666.99 ------
Estimated 2,636 15,652.1 9,663.39 2,242.76 12.59 ______No. sampled = 1,155; Average wt. = 5.8 kg. ______
One trophy lake trout, averaging 9 or more kilograms, and 13 kg of fillets were removed by the majority of guests. As fillets represent 40 percent of the round weight, 372 guests would remove 11041.28 kg of lake trout (round weight) or approximately 80 percent of the fish killed.
Aging and data analysis was carried out on 918 lake trout. The data are summarized in Table 16. Mean length of the sample was 687 mm, mean weight was 5,826 g, and mean age was 17.7 years.
Length-Weight Relationship: Figure 16 illustrates the length-weight relationship of 918 lake trout from Great Slave Lake Lodge. Relatively few fish were caught below 400 mm in length and 1,000 grams in weight due to the selectivity of angling. The logarithmic equation stating the linear regression is:
In W = -2.52 + 2.2 (ln L)
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Age and Growth: Length and weight values for each age are illustrated in Figures 17 and 18. Weights and lengths are averaged from the 918 lake trout taken from Great Slave Lake Lodge.
Age and Length Frequency Distributions: The age frequency distribution of lake trout from Great Slave Lodge is shown in Figure 19. Lake trout became susceptible to fishing methods utilized at Great Slave Lodge in their 10th to 12th year. Numbers taken in each age class from age 13 to age 21 remain relatively constant and from this point decline slowly. The mean age of the sample was 17.7 years. At present 33 years is the largest age recorded from our samples. Many trophy fish, larger and presumably older, were taken but no ages were obtained. Figure 20 illustrates the length frequency distribution of 918 lake trout sampled from Great Slave Lake Lodge, 1972. The majority of fish sampled were within 500 to 900 mm in length.
Mortality Rate: The mortality rate of lake trout from Great Slave Lake Lodge was calculated to be 31.8 percent. Fish from 21 to 33 years of age were used in the calculations.
Sex Ratio and Maturity: Of the 916 lake trout sampled, 475 were female and 441 were male (1.1:1). Maturation rates are illustrated in Table 17. Trout were not 100 percent mature until their 24th year. However, values over 90 percent were in effect from the 18th year on. It is therefore assumed that the majority of fish mature between their 12th and 18th years.
Table 17. Maturation rates and expected mean lengths and weights of lake trout from Great Slave Lake, 1972. ______
Percent Age Mean Mean mature (yrs) length Weight (mm) (g) ______
25 9 461 2,301 50 10 518 3,054 75 16 629 4,820 100 24 811 8,534
______
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FRONTIER LODGE
General: Frontier Lodge is located in the south east portion of the east arm of Great Slave Lake (Fig. 1). The lodge is situated on the north shore of a small bay located at the mouth of the Stark River. It has been in operation since the early 1960's and usually operates from June 15 to September 15. The lodge has a capacity of 24 and guests are flown in by charter from Yellowknife. The length of stay is quite variable, but, averages 3 to 7 days per guest. Lake trout, grayling and pike provide angling within the area. Stark Lake and Stark River are utilized as fishing grounds in addition to the main lake areas (Fig. 21). Numerical success is excellent for the majority of the anglers, who fish one per boat. The majority of guides employed by the lodge are from Snowdrift village, located immediately across the bay. The fishing season at the lodge began in earnest on June 21, 1972, due to the late spring. Guests were still booked as late as September 21:
Creel Census: A creel census and sampling program was conducted at Frontier Lodge from June 23 to August 23. During this period 48 fishing days were monitored by Fisheries Service personnel. An average of 12.5 fishermen were interviewed per day, representing approximately 75 percent of the normal number of guests present. An estimated 191 guests were present during the 1972 season. A total of 874 lake trout, 53 arctic grayling and 12 northern pike were sampled during the survey. 609 fishermen caught 3,329 lake trout on line for an average of 67.27 trout per day. Average weights were: lake trout - 2.51 kg; grayling = 0.68 kg; and northern pike = 2.39 kg. Total weight of lake trout sampled was 2,195.54 kg, grayling 37.73 kg and northern pike 28.69 kg. The flow of guests into the lodge is irregular and often full capacity is not met. For the purposes of estimating the total catch taken by Frontier Lodge in 1972, a 75 percent occupancy was assumed or an average of 16 guests per day for the total 85-day season. Table 18 illustrates the sampled and estimated catches of lake trout from Frontier Fishing Lodge in 1972. Yields in fish weight per hectare are calculated using the areas designated in Figure 21. Areas fished in Stark Lake are not recorded in the area estimation.
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Table 18. Sampled and estimated harvest of lake trout from Frontier Fishing Lodge, 1972. ______
No, caught Total wt. Total wt. Shore Yield Yield on line on line retained lunches (kg/ (kg/ (kg) (kg) (kg) hectare) ______
Sampled 3,229 2,195.54 - - - Estimated 7,171 17,905.76 4,665.3 2,469.76 1.53
______No. sampled = 874; Average wt. = 2.51 kg. ______
In our survey, no accurate figures were obtained for the amount of fish removed as fillets and trophies. Retained weight in the above table is the estimated weight taken as shore lunches, plus the actual weight of fish sampled by our personnel. The figure is minimal considering that an estimation is made that each guest takes 11 kg of filleted or smoked fish, plus a trophy. .However, since trophy fish are at a minimum in this area, and the majority of fish were removed as fillets the estimation is believed to be accurate. Grayling fishing is excellent in the Stark River and these, together with other species, are used for both trophy and eating purposes.
Of the 874 lake trout sampled at Frontier Lodge, 841 were aged and the sample information analysed. Table 19 summarizes this information collected from Frontier Lodge. The mean length of lake trout was 561 mm, the mean weight was 245 g and the mean age was 14.5 years
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Length-Weight Relationship: The length-weight relationship calculated for 841 lake trout is illustrated in Figure 16, The regression is stated by the logarithmic equation:
In W = -5.94 + 3.38 (ln L)
Age and Growth Rate: Figures 17 and 18 illustrate the annual mean values for both length and weight of lake trout from Frontier Lodge on Great Slave Lake. The plots illustrate annual gains in both length and weight as age increases.
Age and Length Frequency Distributions: Figure 19 shows the length-frequency distribution of lake trout from ages 4 to 32. Trout aged 10, 11 and 12 accounted for approximately 35 percent of the total catch. Relatively few trout are represented in the distribution from the trophy size ages of 25 years and older.
Figure 20 demonstrates the length frequency distribution of lake trout from Frontier Lodge. Trout between 300 and 1000 mm in length were recorded with trout between 50 and 600 mm comprising approximately 45 percent of the total.
Mortality Rates: Annual mortality rate was calculated to be 21.5 percent, based on fish aged 16 to 32.
Sex Ratio and Maturity: Of 841 lake trout sampled from Frontier Lodge, 497 were male and 344 female (1.4;1). Maturity was determined and 87 percent of the fish sampled were adult. Rates of maturation are shown in Table 20,
Table 20, Maturation rates and expected lengths and weights of lake trout from Frontier Fishing Lodge, 1972, ______
Percent Age Mean Mean mature (yrs) length weight (mm) (g) ______
50 8 458 1144 75 11 506 1594 100 18 602 3087 ______62
ARCTIC STAR LODGE
Arctic Star Lodge is located at the mouth of the Barnston River on the north west shore of McLeod Bay in the east arm of Great Slave Lake (Fig. 1). The lodge has been in operation at present site since its opening in the late 1960's. The season usually runs from July to the end of August, and the lodge has a guest capacity of 32. Guests are flown by float plane from Yellowknife for an average stay of 1 week.
Trout; grayling and pike are taken by anglers, with, lake trout providing the major attraction. Principle lake trout fishing areas are illustrated in Figure 22. Fish retained are used for fillets or trophies. Minimal survey work was conducted on the lodge's operation in 1972, however an estimate of total harvest was made by taking the estimated number of guests present in 1972 (75 percent capacity) and applying the average weights removed per fisherman in lodges where intensive creel censusing was carried out. Table 21 illustrates estimations made in this manner for a 14 day survey at Arctic Star Lodge. Estimations for the remaining lodges on Great Slave Lake, Indian Mountain and Trophy Lodges have been made in a similar manner.
Table 21. Estimated total harvest of lake trout from Arctic Star Lodge, 1972.
______Average Estimated weight Total Total Guest no, guests lake weight weight Shore capacity in 1972 trout on line retained lunches (kg) (kg) (kg) (kg)
______32 80 4.02 5309.53 2240.49 544.80 ______
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INDIAN MOUNTAIN LODGE
Indian Mountain Lodge is located at Thompson's Landing on the north west shore of McLeod Bay (Fig. 1). Due to its location between Arctic Star and Great Slave Lake Lodge, Indian Mountain has a rather restricted fishing area (Fig. 23). Guest capacity of the lodge is 10 and during 1972 operations were carried out on an irregular basis. Guests are flown to the Lodge by float plane from Yellowknife and their length of stay is variable: Estimations of the lake trout harvest are based on average number and weight removed by fishermen at other lodges.
Table 22. Estimated harvest of lake trout from Indian Mountain Lodge, 1972. ______Total Weight Total Weight Shore No. guests on line retained lunches (kg) (kg) (kg) ______20 1834.16 408.60 163.4 ______
TROPHY LODGE
Trophy Lodge is located near the townsite of Reliance in McLeod Bay of Great Slave Lake (Fig. 1). The lodge has a capacity of 30 and has been in operation at the present site since late 1960's. Lake trout, grayling and northern pike are taken by the fishermen. No survey was conducted at the Lodge in 1972, but available information indicated that the catch of lake trout by the lodge is substantial. The majority of the fishing occurs in the vicinity of the lodge (Fig. 24) with occasional side trips for grayling being made to small rivers along the north shore of McLeod Bay. The lodge usually operates at near capacity from late June to September. Estimates for the harvest taken by the Lodge in 1972 are shown in Table 23.
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Table 23. Estimated harvest of lake trout conducted by Trophy Lodge on Great Slave Lake, 1972.
______
Average Average Total Total No. no.fish weight weight weight Shore Guests per guest per fish caught retained lunches (kg) (kg) (kg) (kg) ______
120 21 4.0 10,024.3 1906.8 980.6 ______
The figures above are estimations based on 120 guests each taking an average of 4.5 kg of fillets and 1 trophy fish (6.8 kg). At this rate Trophy Lodge would have taken 2,887.4 kg of lake trout during 1972.
TOTAL HARVEST FROM GREAT SLAVE LAKE, 1972
The total harvest figures for lake trout, grayling and northern pike are illustrated in Table 24. The table includes both sampled and estimated figures from lodges not sampled: During 1972 an estimated 783 anglers were present at sports fishing lodges on Great Slave Lake. An estimated 50725.9 kg of lake trout, 624.3 kg of grayling and 663.7 kg of northern pike were caught on line. Of these totals 18,884.6 kg of lake trout were retained and used for fillets or trophy purposes. Approximately 62 percent of this figure represents round weight removed as fillets or approximately 6.8 kg of filleted lake trout per fisherman. This figure is minimal for two reasons. First, the assumption is made that every guest present on the lake removed a 9 kg lake trout as atrophy. Trophy success was observed not to be this high per angler on Great Slave Lake. Second, each guest removes on an average 6.8 kg of fillets. This demonstrates that fillet removal may account for as much as 80 percent of the total amount taken. In addition to the 18,884.6 kg retained an estimate of 6401.4 kg of lake trout were used for shore lunches bringing the total weight utilized to 25,285 kg. Based on calculations that the total area fished by the Great Slave Lodges is 8089.5 hectares, a yield of 3.17 kg of lake trout per hectare was calculated;
COMPARISON OF GREAT SLAVE LAKE LODGES
Distinct differences were evident between the lake trout populations sampled from Great Slave Lake and Frontier Lodges. The ength-weight relationships (Fig. 16) show that trout are lighter for a given length at Frontier Lodge
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up to 850 mm. After this point trout from Great Slave Lake Lodge are heavier at each interval. Growth of trout expressed in both length and weight is more rapid for trout from Great Slave Lake Lodge (Figs. 17 and 18). Length up to age 7 appears to be equal for both lodges but quickly diverges past this age. Weight however, appears to be significantly different from a very early age. Age frequency distributions (Fig. 19) show that the majority of the catch from Frontier Lodge was comprised of 10 to 16 year old fish while that from Great Slave Lake Lodge fell within the 12 to 21 year range. Both are reasonably indicative of the catch as over 65 percent of the total catch was retained by both lodges. The distribution of catch at Great Slave reflects the greater success in obtaining fish of trophy size. Few fish are available at Frontier Lodge in the trophy ages of 25 years and older whereas Great Slave Lodge has larger fish exhibiting ages of 30 and over. The distribution in both cases would be lengthened into the older age classes if the trophy fish taken had been aged. Despite similar length ranges for lake trout from both lodges modal lengths for Great Slave Lake and Frontier Lodges fell within the 600 to 700 and 500 to 600 mm intervals, respectively. Trout from Great Slave Lake Lodge were well represented between 500 and 900 mm while there was an abundance of trout between 500 and 600 mm from Frontier Lodge. Sex ratios were similar with ratios of 1.1:1 and 1.4:1 in favour of males for Great Slave and Frontier Lodges. Maturation rates differed with trout becoming fully mature at age 18 from Frontier Lodge and at age 24 from Great Slave Lake Lodge. Annual mortality of trout from Great Slave and Frontier Lodges was 31.8 and 21.5 percent, respectively. The greater mortality for the Great Slave Lodge trout is attributed to the more rapid decline in abundance of trout greater than age 21.
Of the lodges sampled on Great Slave Lake sufficient samples were obtained only from Frontier and Great Slave Lake Lodge. In terms of fishing success, the Great Slave Lake Lodge angler enjoy larger, heavier trout with substantial numbers of trophies being taken. Despite large catches at Frontier Lodge, fish were smaller and fewer trophy trout were taken. This was illustrated in the previous comparisons of growth rates and age and length frequency distributions. Kennedy (1953) found that trout in the east arm of Great Slave Lake exhibit similar growth rates. Data collected in 1972 point to separate and distinct growth rates which are likely due to sub-populations of lake trout inhabiting the areas sampled. There also exists the possibility that these differences may be the result of fishing pressure being exerted on the lake trout population and their subsequent response. This subject is discussed later in the report. 70
FILLET STUDY
Fillets and wasted carcasses of 22 lake trout were weighed at three lodges on Great Bear Lake: Cameron Bay Lodge, Great Bear Lake Lodge and Neiland Bay outpost camp. The results are summarized in Appendix 3. At Great Bear Lake Lodge the fillets were not skinned, whereas at Cameron Bay Lodge and Neiland Bay they were. Guides at Great Bear Lake Lodge and Cameron Bay Lodge filleted the fish caught by their assigned guests. At Great Bear Lodge one man was hired specifically to fillet fish caught by the lodge guests. Results obtained at the three lodges are roughly identical with the maximum amount of flesh which can be retained in a lake trout lying between 50 - 55 percent in most instances. Some fish, being more slender, may yield substantially less. In some cases it was noted that fillets were cut short so that they would readily fit into the plastic bags in which they were wrapped. The average amount of flesh retained as fillets at each lodge was: Cameron Bay Lodge - 39.8 percent; Great Bear Lake Lodge - 40.1 percent; Great Bear Lodge - 40.1 percent. This represents an overall average of 40.0 percent of the fish being utilized, with up to 60 percent being discarded.
Figures 25 and 26 were produced from Table 25 to show the amount of whole fish required, given various weights of fillets to supply anglers take home quotas. Three different retained weights are given to indicate the weights one would encounter if the quotas were dropped. In each case fillets were taken to constitute 40 percent of the whole fish. As shown in Table 25, if the weight retained per person were to drop from 13.6 kg to 4.5 kg an estimated 13620 kg of lake trout would be available for future use. If the estimated 2,009 anglers who were on both Great Bear and Great Slave Lakes during the 1972 season were limited to 4.5 kg (10 lb) of fillets each, the harvest of lake trout would be reduced by 45583.9 kg (round weight).
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Table 25. A demonstration of lake trout fillet weight converted to round weight.
______Kilograms retained per person 4.5 kg 9.1 kg 13.6 kg Number of fillet whole fillet whole fillet whole Anglers weight weight weight weight weight weight ______
50 227 568 454 1136 681 1703 100 454 1135 908 2272 1362 3405 150 681 1708 1362 3405 2043 5108 200 908 2270 1816 4540 2724 6810 250 1135 2838 2270 5675 3405 8513 300 1362 3405 2724 6810 4086 10220 350 1589 3973 3178 7945 4767 11895 400 1816 4540 3632 9080 5448 13620 450 2043 5108 4086 10215 6129 15323 500 2270 5675 4540 11350 6810 17025 550 2497 6243 4994 12485 7491 18728 600 2724 6810 5448 13620 8172 20430 ______
COMPARISON OF GREAT SLAVE AND GREAT BEAR LAKES
Length-Weight Relationship: The length-weight relationships for lake trout from Great Slave and Great Bear Lakes are given in Figure 27. Relationships for southern lake trout populations are also shown for comparison purposes. After attaining a length of 400 mm the relationships for trout from Great Bear and Great Slave Lakes diverge and are considerably different. Trout from Great Slave Lake are 1.5 times as heavy as those from Great Bear Lake at any given length. Miller and Kennedy (1948) found that about 44 percent of trout from Great Bear Lake had eaten fish as compared to 62 percent or more on Great Slave Lake (Rawson 1951). The remainder of the diet consisted primarily of aquatic invertebrates. Martin (1969) has shown that non-fish eating trout grow slower than those having only a fish diet. This combined with lower water temperatures, longer ice cover and limited food supply accounts for lighter weight in Great Bear. Lakes Green and Tahoe where abundant food and warmer temperatures prevail show a marked increase in weight relative to length between 600 and 700 mm in length.
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Age and Growth: Growth in length and weight for lake trout from Great Slave and Great Bear Lakes are compared to those in southern lakes in Figures 28 and 29. Trout from Great Slave and Great Bear Lakes show only slight differences in length at a given age with Great Bear Lake exhibiting a slower growth rate. However, there is a substantial difference between these rates and those reported from southern lakes after age 5. By age 10 southern trout are in excess of 100 mm longer and at age 17 in excess of 250 mm. Growth in weight differs greatly between Great Slave and Great Bear Lakes with trout being approximately one-third lighter from the latter. Both the rate of growth and weight at a given age are greater for trout from southern lakes. Hansone and Cordone (1967) in a comparison of lake trout from Lake Tahoe with Wollaston, Cree and other lakes found that lake trout in southern regions grow almost twice as fast as the trout from Great Bear Lake. Martin (1961) substantiated this and noted an increase in growth rate from south to north.
Length and Age Frequency Distributions: Length frequency data available from Lac la Ronge (Rawson 1961) are compared to Great Slave and Great Bear Lakes in Figure 30. Differences among the three lakes are not great, although trout from Great Slave Lake show a peak at 550 mm. Trout from Lac la Ronge were caught in gill nets. The age frequency distributions of lake trout from Great Slave and Great Bear Lakes are illustrated in Figure 31. The greatest percentage of trout from Great Slave Lake fell between ages 11 and 21 while those from Great Bear Lake were between ages 19 and 25. No trout were found to be older than age 30 from Great Slave Lake while the oldest from Great Bear Lake trout was 42. The distribution was skewed towards older fish for Great Bear Lake and towards younger fish for Great Slave Lake.
Sex and Maturity: Maturation rates of lake trout populations are variable and appear to fluctuate according to the density of the population occurring at ages above the maturation date. In populations where there are many older fish the population appears to limit itself by the suppression of maturation for a longer period of time. Fry (1938) noted this density factor for the lake trout of Algonquin Park and demonstrated that as heavier fishing occurred the length of the trout at maturation decreased.
Trout have been shown to become fully mature at age 11 (617 mm) from Lake Tahoe and age 10 (571 mm) from Lake Opeongo. A majority of the literature agrees that lake trout first exhibit maturation at about 350 to 400 mm. Ages at this length correspond to the growth rate applicable from the system and varies from 6 to 13 years of age. The increase in age appears to correspond to an increase in latitude as the more northerly lakes demonstrate the
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oldest maturation ages. Maturation is not complete on Great Slave or Great Bear until 20 years of age but in more southern systems, maturity is complete by ages 10 to 12. Maturation estimates on Great Slave and Great Bear Lake may be slightly extended by the small differentiation between non-spawning adults and immature fish. Lake trout on Great Slave and Great Bear Lake appear to spawn every second or third year, causing 50 percent or more of the adult population to appear as "infertile" in one year. Miller and Kennedy (1948) on Great Bear and Kennedy (1954) on Great Slave, reported this phenomenon and indicated it to be common among other species, in particular the whitefish of Great Bear. The presence of infertile fish among mature trout was noted by Rawson (1961), who found approximately 10 percent of Lac la Ronge trout infertile and Martin (1966) who found 16.6 percent of trout infertile in Lake Opeongo during 1937-38. This rate also appears to increase as more northerly latitudes are approached; Infertility is not a permanent condition and trout in this condition are expected to spawn in following years.
Maturation rates do not appear to be solely influenced by the population density as diet may also affect the maturation age as pointed out by Martin (1966). He found that slow-growing, plankton-feeding trout matured earlier than fast-growing trout in fish-feeding populations. Martin (1969) documented the change in diet of trout from plankton to fish with a resulting increase in weight, age of maturity, and a decrease in numbers of infertile fish. On Great Bear Lake a large percentage of the trout's diet is composed of terrestrial and aquatic insects. This is also true on Great Slave Lake but f o a lesser degree, and to what extent this affects the growth rate and maturation dates on both lakes is not evident in the data collected at present. It appears that lake trout populations on Great Bear and Great Slave Lake exhibit a high density of older fish and that maturity dates and size at maturity reflect this. It is thought that as the density is changed by the removal of older fish, the maturation age and size will decrease. Indications of this are present in the maturation dates and sizes at two lodges, Frontier on Great Slave and Cameron Bay on Great Bear. With the decrease in age of maturing fish, it would be expected that greater recruitment to the population would result. However, the success or failure of the trout to reproduce at lower ages is unknown at present, although the suggestion has been made that younger year classes are incapable of maintaining the population's reproductive requirements, thus leading to a collapse of the fishery. 81
DISCUSSION
The maintenance of the lake trout fishery on Great Bear and Great Slave Lakes is dependent upon the recognition of the unique and vigorous environment in which they exist. The limitations placed on the populations by biotic and abiotic factors must be considered to determine the effect of present harvest levels and to direct future management efforts. Relevant problems are often present in other, more fully investigated, systems and the comparison of findings provides guidance for use in the problems of managing these fish stocks.
Several factors are peculiar to the creel census and biological programs conducted on Great Bear and Great Slave in 1972. The sample of lake trout was restricted to those fish available from anglers and their gear and creel selectivity affected the distribution of the catch. Smaller fish are less vulnerable to the gear employed, and when caught are most often returned to the, water. Large, trophy size fish for mounting purposes were not made available for sampling or age determination. The result is a distribution of sampled fish exhibiting large numerical strength in the median ages and few fish in the young (10 or less) and old (35 plus) age groups. The low numbers of older fish is expected but the loss of those normally available affects the mortality rates, length and age frequency distributions of the sample. Mortality rates from the 1972 sample reflect a sharper rate of decline than would be the case if all trophy fish were included. The inclusion of older fish would therefore yield a lower annual mortality rate. Although lake trout exhibit a slight increase in length at older ages, the loss of the trophy size fish causes the length frequency distribution to be shortened. The length-weight relationships of lake trout from the lakes shows few fish to be below 400 mm in length and 700 grams in weight: However, from comparisons with other populations of lake trout, it is apparent that little difference exists in their relationship below these sizes.
Maturity determination in lake trout in populations that exhibit biannual or triannual breeding cycles is difficult because immature gonads often resemble "dormant" or developing gonads of adult fish. Individual judgements often show a wide range of results, particularly in male fish, as the testes do riot exhibit a large size or colour range that can be used as an indicator. Females, however, often retain eggs within the gonad from previous spawnings and these eggs are larger than developing eggs. This provides an accurate method for determining which adult females have spawned previously. 82
In lake trout populations, the rates of growth are comparable only to the extent of accuracy in the aging of the fish. In all of the studies of lake trout used in the text, ages were determined by the reading of scales, whereas otoliths were used from trout on Great Slave and Great Bear. Cable (1956) demonstrated the validity of scale readings of trout to determine age, however, the study was confined to young fish and as trout attain older ages greater difficulty is encountered in obtaining accuracy. The otolith method is not perfect at present but based on the comparison of scale readings obtained by Miller and Kennedy (1948) on Great Bear. with our findings in 1972, a large degree of compatibility is found and confidence is expressed in ages obtained for large lake trout.
The comparison of lake trout populations is also dependent upon the climatic factors affecting them. The characteristics of lakes supporting lake trout populations are generally similar: deep, cold, clear, water and high oxygen levels. However, the lakes in southern latitudes of the lake trouts' range exhibit far greater productivity than do those lakes in northern areas. As more northerly latitudes are encountered the age at maturation of trout increases, the frequency of spawning decreases and the rate of growth declines. Great Bear and Great Slave Lakes demonstrate these changes when compared to such lakes as Tahoe in California and Green Lake in Wisconsin. Fry (1959) noted the same variance in response to the climatic conditions encountered at the lake location.
In evaluating the lake trout fishery on Great Bear and Great Slave Lakes, knowledge of the conditions present in sub-Arctic lakes is necessary to realize the limiting factors placed on fish populations by this specialized climate. Sub-Arctic lakes exhibit extremes in oligotrophic conditions; cold, clear, water, high oxygen content and low nutrient values. These values combined have a marked effect on fish populations within the system. The higher an individual animal occurs within the food chain the more time necessary to achieve full growth. This dilemma is faced by all species within these lakes and lake trout in particular due to their position at the highest trophic level. The ultimate yield in lakes that demonstrate retarded growth rates is the production of a population that is comprised of very old, mature fish. Sub- Arctic conditions create populations of lake trout ,in which larger, more successful fish comprise the majority of the distribution (Nikolski 1965). The effect of this overbalance of older fish creates a competition factor which affects the maturation and spawning frequency of the population. Fish populations, when faced by a limited food supply and high density, adapt by maintaining only enough adult fish to utilize the food supply present. As natural mortality is low, reproduction is the only method of curtailment available to the trout within these systems. 83
A second factor, also dependent on food supply, is the reserve of fats and proteins that is necessary for gonadal development within fish. Limited food supply hinders the development of these reserves in low-productivity areas. Both of these factors may produce the situation found in Great Slave and Great Bear Lakes, where lake trout are unable to conduct an annual breeding cycle.
Most lakes comparable in size to Great Bear and Great Slave exhibit equal distribution and uniform characteristics of the trout therein. However, due to the large areas of Great Bear and Great Slave and the sedentary habits of the trout within it is believed that distinct sub-populations of trout exist within different areas of the lakes. On this basis unique management methods need to be employed for the individual lakes and in addition, as distinct areas support sub-populations complete with individual characteristics, then individual applications for each area must be considered in terms of harvest potential.
The realization of the danger of over-exploitation raises the important question of determining the present harvest on the lakes, and its likely effect on the fish populations. On an individual angler basis, the harvest is substantial, averaging 80 lbs (36.3 kg) of fish removed per fisherman. This represents three principal methods of removal: trophies, fillets and shore lunches. In the majority of the operations fillet removal accounted for 65 to 80 percent of the round weights taken. Trophy fish arise from the older age classes, usually those over 25 years of age. These fish are retained whole and mounted for display purposes by the majority of the anglers.
Fish used for fillets range from the age classes immediately below the trophy range to below the maturation age of the population. Maturation occurs on the average between the 12th and 18th year for lake trout on Great Bear and Great Slave Lakes. At 10 to 14 they become susceptible to sports fishing gear and remain so throughout their life. The great danger to this old slow-growing population lies with all the adult mature fish being susceptible to the fishing gear. If overfishing occurs and this segment of the population is removed, virtually no reproduction can occur. This, combined with the fact that fish not yet mature are also harvested greatly reduces the ability of the population to recover. In the majority of lodge catches 80 percent or better are adult mature fish that are of non-trophy size.
This removal of non-trophy fish guarantees that only a very limited replacement is available for trophy fish on the lake within a short time. With the loss of trophy-sized fish more and younger fish will be taken each year until the point can 84
be reached where no reproducing adults remain. At present the sports fishing on Great Bear and Great Slave Lakes is advertised as a trophy fishery in regard to lake trout. However, the information gathered during 1972 points out that the fishery actually harvests on a "meat" or fillet basis with trophies representing only a small portion of the take. The question therefore arises in regard to the time span required for the fishing of intermediate-aged trout to affect the total and trophy output of a lodge. The existence of sub-populations, of lake trout within distinct areas may further affect the fishing encountered.
If trout were uniform throughout the lakes, fishing success in different areas should be similar, but substantial differences exist in the catches obtained by the individual lodges. Within these differences lies the answer to the question on the time span that is necessary to deplete the lake trout population within localized areas. Lodges, in particular those on Great Bear Lake, that have been in operation for some time (5 to 10 years) and fishing distinct areas are experiencing difficulty in obtaining trophy fish. These lodges, in response to this problem, have either moved location or opened one or more outpost camps in virgin areas of the lake to secure larger fish. These facts point out that intensive sports fishing within localized areas can significantly affect the trout population within a 10-year period. The original sports fishing operation on Great Bear Lake was centred on the McTavish Arm. Since the early 1960's, of 4 lodges that operated solely within that area, one has moved location entirely; one has moved operations to two major outposts; one has presently closed, and the one remaining operates an outpost camp on the opposite side of the lake. The remaining lodge, Cameron Bay, demonstrates the smallest, youngest and fewest trophies of any lodge on the lake. The area utilized by Cameron Bay Lodge, to produce the fish they do obtain, is similar in size to that utilized by Great Bear Lake Lodge. However, comparisons between the lodges demonstrates the differences in their fish catches. Great Bear Lake Lodge catches older, larger fish and provides many trophies, while Cameron Bay provides, on the average, younger, smaller fish and fewer trophy fish. The net result shows that intensive angling within a localized area has significantly affected the size and number of trout taken.
At present on Great Bear Lake, the majority of lodges enjoy successful fishing, mostly due to their relative newness in the areas they are utilizing. Harvest rates differ between the lodges and the more conservative approach used by some lodges will undoubtedly lengthen the life span of the trophy trout fishing within their own areas. However, present harvest rates in some areas could result in a similar situation to the McTavish Arm developing within a limited period of time. 85
This situation does not exist on Great Slave as the lodge operations and catch appear to be significantly affected by the separate physical circumstances encountered in the lodges censused in 1972. Also, this lake is perhaps more productive than Great Bear Lake. However, the catch at Frontier is significantly smaller in size and larger in numbers taken per fisherman than at the Great Slave Lake lodge location. Individual fishing methods and harvest levels may also have influenced the population structure and growth rates within each area. The limnology of the lodge areas on Great Slave varies little. Trout within the Great Slave Lake Lodge area show faster growth rates and attain older ages than trout at Frontier. However, in a physical aspect differences are present within each of the lodge areas. The fishing area for Frontier Lodge includes the Stark River mouth and portions of Stark Lake. The probable influx of smaller, younger fish may affect the population structure of lake trout in this area. However, size difference in the catches from Stark Lake and Great Slave are minimal. In regard to fishing pressure, no previous information is available on the original population present within the Snowdrift area. However, if the size distribution of lake trout was consistent with the remainder of Great Slave before the inception of the lodge, then the overall size has fallen in response to fishing. Ricker (1958) states that this type decrease in average fish size and .a shift to younger aged fish is indicative of an over harvest. In addition, in most fish populations, when the competitive factor of older, larger fish is removed, the remaining fish usually demonstrate increased growth rates due to the greater availability of food. This does not appear to be happening for trout from the Frontier Lodge area. Without previous information this opinion may not reflect the actual occurrence. In support of the loss of older trophy fish from the area, local information points out that many larger and heavier fish were taken in the area during its opening years and the additional pressure exerted by the closed Snowdrift Lodge may have had its effect.
Great Slave Lake Lodge, located at Taltheilei Narrows, exhibits a physical factor which may influence growth rates and trout distribution within the area. The passage between McLeod Bay and the Hearne Channel is narrowest at the lodge location. Strong currents are present within the area and winter ice cover is absent over portions of the channel within the lodge’s fishing area. This open water may allow greater productivity in the area and stimulate faster growth rates among the trout. The location could be attractive to forage fish thus providing a good food source for trout. 86
It has been established that lake trout exhibit little movement within lakes, often spending their entire life in a small area (Cable 1965; Keleher 1963). Taltheilei Narrows appears to demonstrate the converse of this, due to the limited area fished. Great Slave Lake Lodge retained almost 80 percent of the trout caught and removed an average of 8 kg per hectare of trout during 1972. The lodge has been in operation since 1954 and at this harvest rate in a confined area, all local trout would have been caught in a short period. From this it is thought that lake trout move through the narrows from McLeod Bay, allowing Great Slave Lodge to have a continual replacement of adult fish. In this regard the area is unique and an explanation, probably on the basis of a spawning or feeding movement will be sought in future programs.
The lodges sampled on Great Slave Lake during 1972 are not comparable due to the unique situations found at each lodge. The lodges situated in McLeod Bay, being of fixed fishing areas and normal ice cover, could be expected to be similar. At present the survey of the fishery being conducted on Great Slave indicates a decline in the overall size and availability of trophy trout.
The tangible evidence presented is obtained by sampling of catches and by observing the methods of fishing and areas fished to determine harvest level and physical effect on the resource. However, the conclusions regarding internal occurrences such as mortality may be affected by our inability to observe the actual population. From the sample obtained in 1972, mortality rates, based on several year classes in most lodges, were calculated using the method outlined by Robson and Chapman (1961) modified from Ricker (1958). An unbiased estimate may be obtained using this method if it is assumed that year class strength and survival rate are constant and that all fish beyond a minimum age are equally vulnerable to the gear employed. From the 1972 study these factors apparently hold true for the lake trout of Great Bear and Great Slave. However, little information other than Kennedy's (1954) regarding mortality rate of lake trout on the two lakes is available at present. It has been stated previously that natural mortality is low among sub-Arctic fish populations, and at present among the trout population of the lakes the bulk of mortality occurs due to angling removal. The actual removal rate of trout can be obtained by censusing the angler catch on the lake. However, large numbers of trout are released back into the lakes, often suffering extensive damage from hook removal and handling methods. Klein (1962) and Hunsaker and Marnell (1970) reported mortality rates of 5 to 20 percent occurring among rainbow (Salmo gairdneri) and cutthroat (Salmo clarki) trout hooked on artificial flies and lures. Mason and Hunt (1963) reported that of rainbow trout caught by single-baited hooks 42 percent died. From this information it is apparent that substantial fish loss may occur among released fish. Often the released weight of trout on Great Bear and Great Slave Lakes is nearly equal to the 87
retained catch, thus subsequent mortality rates of 10 to 20 percent among released fish would represent an additional 20 percent gain in round weight of fish killed on the two lakes. It is obvious from the above that the loss rate in released fish may actually multiply the harvest considerably and this factor must be considered in estimating what harvest levels constitute a sustainable yield.
The evaluation of the lake trout fishery on Great Slave and Great Bear must consider each of the following points:
(1) The effect of the environment upon trout populations in regard to growth, reproduction and life spans within individual lakes and respective areas of each lake.
(2) The type and level of harvest that will allow the population to sustain itself and continue to provide a harvest similar to that being experienced, and the value and direction of the harvest in terms of economic or recreational gain.
The effect of the environment is clear in limiting the population physically. Normal recovery mechanisms to over-exploitation such as increased spawning frequency, faster growth rates, and larger recruitment values do not appear to be in effect in sub-Arctic conditions. This indicates that trout populations existing in these conditions operate at optimal success rate at all times. Over-exploitation via a sports fishery is therefore extremely dangerous because all fish are equally vulnerable to most types of gear being utilized. The effect is to remove the capital stock of the population and, as the capital stock is also the reproducing segment of the population, replacement is affected. The smaller-sized component of the catch taken by angling includes immature fish, which further endangers the reproductive capacity of the stock. Even limited utilization once the capital or adult stock is lost appears to prevent the recovery of the population. Therefore, the necessity of maintaining sufficient adult stock to provide replacement fish is recognized and, due to the equal susceptibility of different sized fish, must be dealt with by limiting the size or state of trout being removed.
Resolutions dealing with the problem of what and how much fish should be harvested must satisfy the requirements of both fishermen and the fish stocks themselves. On the basis of harvest there are two avenues of approach:
(1) To maintain the fishery on the basis of trophy fish. 88
(2) To disregard the trophy attraction and seek a total recreational fishery, allowing many people to catch many fish.
These aims have to be considered via the different aspects of their effect on the population and, secondly, the economic value derived from each. In the first instance the fishing methods presently in effect would have to be modified to sustain an annual yield of true trophy fish. This involves protecting the young and medium-aged segments of the population from harvest. In terms of the effect on the population by allowing the fishery to exist on a total numbers basis, the susceptibility of the population to overfishing is recognized and eventually the lake trout will decline due to their poor growth and reproductive rates.
The trophy fishery is profitable both for operators and the occupants of N.W.T. The value of the fishery is demonstrated by the comparison of commercial fishing operations and sports fishing operations in Area 6 of Great Slave Lake (Appendix 4). Although the flow of capital out of the territories is high (59 percent) (Economic Report N.W.T.) a large portion of revenue is retained by residents of the north in the form of employee salaries, and local transport and supply costs. If the fishery were conducted on the basis of providing recreation, with many people utilizing the resource the total value to the north would multiply considerably, but the life span of the fishery would be limited. If provisions are made for a trophy lake trout fishery to sustain itself indefinitely within the territories, a long-term economic value will be in effect for the residents of the north. As the number of sportsmen utilizing the resource continues to increase at the present rate, the value felt will increase accordingly. Therefore, both economic and conservation demands can best be met by regulating the harvest of lake trout by the sports fishing industry on Great Slave and Great Bear Lakes to provide and to protect a sustained yield of trophy fish. 89
SUMMARY
1. A creel census and biological survey of sports fisheries was carried out on Great Bear and Great Slave Lakes during 1972.
2. The harvest of lake trout by anglers on Great Bear and Great Slave Lakes is composed of trophy fish, fillets and shore lunches.
3. The total retained harvest of lake trout on Great Bear Lake was 103,293.3 lb (46,895.6 kg) and on Great Slave Lake 55,696 lb (25,486 kg).
4. A total of 1,757 lake trout were sampled and aged on Great Slave Lake and 907 on Great Bear Lake during 1972.
5. Lake trout reach 100 percent maturity between the ages of 18 and 19 on Great Slave Lake and between the ages of 21 and 22 on Great Bear Lake.
6. The sex ratio of the lake trout on Great Slave Lake was found to be 1.2:1 in favour of males and on Great Bear Lake was found to be 1:2:1 in favour of females.
7. Mortality rates of the lake trout were 18 and 27 percent per annum on Great Bear and Great Slave Lakes, respectively.
8. The majority of the lake trout caught on Great Slave Lake were between 500 and 600 mm and on Great Bear Lake between 600 and 700 mm.
9. On Great Bear Lake 41 percent of a lake trout was utilized as fillets and 59 percent was discarded.
10. The mean age of the lake trout sampled on Great Bear Lake was 22.8 years with a mean length of 700 mm and a mean weight of 4,409 g.
11. The mean age of the lake trout sampled on Great. Slave Lake was 16.1 years with a mean length of 624 mm and a mean weight of 4,143 g.
12. The comparison of the lake trout of Great Bear and Great Slave Lakes with each other, and with more southerly systems demonstrated that as more northerly latitudes are approached the growth rate declines, the age of maturation lengthens and the frequency of spawning decreases.
90
13. Substantial differences are found among the lake trout present within separate lodge areas on each lake. It is suspected that distinct sub-populations exist within the lakes due to the sedentary habits of the trout. It is also probable that a portion of the difference in age distribution, mean ages, lengths and weights is attributable to duration and magnitude of fishing pressure.
14. 65 percent or more of the harvest of lake trout on Great Slave and Great Bear Lakes is confined to fillet removal and concentrates on the age classes below trophy size fish of 15 lb (6:7 kg) or more.
15. The availability and size of trophy fish within the lakes has decreased within a 10 year period as demonstrated by the McTavish Arm area of Great Bear Lake.
16. The economic and conservation demands on the sports fishery on Great Bear and Great Slave Lakes can be best met by restricting the fishery to a trophy only basis and minimizing the loss of fish in the younger age groups.
17. Recommendations to provide a sustained yield of trophy fish and the expansion of the 1972 field program are given.
91
RECOMMENDATIONS
A rationale must be established from the effort being conducted on Great Bear and Great Slave Lakes to provide direction for the future development of sports fishing within the Northwest Territories. The factors governing the success or failure of fish populations within these lakes apply generally to the scope of those sub-Arctic lakes which have already been developed or which are receiving consideration. The size of the two large lakes tends to be deceiving in that the view taken is one of inexhaustible supply. The productive areas (adjacent to reefs arid shallows) is only one-tenth of their total size. In this regard smaller shallower lakes will tend to have an advantage in productive capacity. Thus, the future development (or regulation) of fish stocks within the Territories should be controlled along the lines of the recommendations given in connection with the Great Bear and Great Slave Lakes fisheries.
The important fact in determining the exploitation rate of a fishery should be that the rate of recovery in sub-Arctic fish populations is extremely slow. Once lost, twenty to thirty years may be necessary for the stock to return to the original state. For this reason, decisions regarding the allowable rate of exploitation should function at minimal values to provide adequate protection. At present, there is no sports lake trout fishery in North America comparable to Great Slave and Great Bear Lakes in regard to availability and overall size of trophy fish. On this basis all efforts should be made to conserve the fishing. In addition, as the harvest is sports-oriented in regard to lake trout, a suitable number of trout must be kept within the lakes to provide a catch for the anglers. This number cannot be the minimum value necessary for the survival of the trout as at this value the availability of trout to angling likely would be negligible. The primary objective here is to attempt to guarantee sustained production of trophy fish by minimizing the harvest of younger and smaller fish. This includes the recognition of the effects of hook release mortality on the population. Possible recommendations for the management of the lake trout fishery on Great Bear and Great Slave Lakes to maintain a trophy fishery are:
1. The lake trout fishery be recognized as strictly a trophy fishery.
2. The introduction of a permanent tag to be attached to the trophy choice immediately upon landing. 92
3. The introduction of barbless hooks to be used solely for lake trout angling on Great Bear and Great Slave Lakes.
4. The establishment of fillets, smoked or canned fish constituting whole fish (2 fillets to equal 1 fish). A. recommendation be considered that all lake trout removed from the vicinity of Great Bear and Great Slave Lakes be in round or whole form.
5. Fishermen wishing to utilize the one trout in possession as shore lunches should be restricted to lake trout of 4 or less pounds.
Recommendations for the changing and future direction of the Fisheries Service programs in the Great Bear and Great Slave area are as follows.
1 The 1972 field program be continued and enlarged to include all lodges presently on the lakes.
2. A program be established to determine the effect of barbed and barbless hooks on the mortality rate among released lake trout.
3. A survey utilizing tagging methods be conducted to collect additional information on the movements and life history of lake trout within Great Bear and Great Slave Lakes.
4. A study be conducted to estimate the fecundity as well as spawning locations and cycles of lake trout within Great Bear and Great Slave Lakes.
5. A direct effort be made to educate anglers and lodge operators utilizing Great Bear and Great Slave Lakes on the inherent conservation problems.
The ultimate aim of these recommendations is to provide a method of preserving the unique fisheries of Great Bear and Great Slave Lakes for future utilization. As good sports fishing becomes rarer and numbers of fishermen increase, Great Bear and Great Slave Lakes' appeal of unmarred wilderness and trophy fishing will become increasingly valuable, both aesthetically and economically. 93
LITERATURE CITED
Cable, L.E. 1956. Validity of age determination from scales and growth of marked Lake Michigan lake trout. U.S. Dept. Int. Fish and Wildlife Serv. Fish. Bull. No. 107:1-59.
Cordone, A.J. and T.C. Frantz. 1966. The lake Tahoe sports fishery. Calif. Fish Game. 52(4):240-279.
Hunsaker, D. and C.F. Mornell. 1970. Hooking mortality of Yellowstone cutthroat trout. Prog. Fish. Cult. 32: 231-235.
Johnson, L. 1966. Great Bear Lake. Can. Geog. J. 11 p.
Keleher, J.J. 1963. The movement of tagged Great Slave Lake fishes. J. Fish. Res. Bd. Canada 20(2):319-326.
Keleher, J.J. and B.E. Meeker. 1962. Results of a preliminary survey of Great Slave sport fishery. Fish. Res. Bd. Canada. Manuscript Report Series No. 725:63 p.
Kennedy, W.A. 1949. Some observations on the Coregonine fish of Great Bear Lake, N.W.T. Bull. Fish. Res. Bd. Canada 82:10 p.
______1954. Growth maturity and mortality in the relatively unexploited Lake Trout, Cristovomer namaycush, of Great Slave Lake. J. Fish. Res. Bd. Canada 11:827-852.
Klein, W.D. 1961. Mortality of trout caught on artificial lures and released by fishermen. Trans. Amer. Fish. Soc. 90:87- 95
Martin, N.V. 1951. A .study of the lake trout in two Algonquin Park, Ontario, lakes. Trans. Amer. Fish. Soc. 81:111-137.
______1966. The significance of food habits in the biology, exploitation and management of Algonquin Park, Ontario, lake trout. Trans. Amer. Fish. Soc. 95:415-422.
______1969. Long term effects of diet on the biology of lake trout and the fishery in Lake Opeongo, Ontario: J. Fish. Res., Bd. Canada. 27:125-146.
Mason, S.W. and R.L. Hunt. 1967. Mortality rates of deeply hooked rainbow trout. Prog. Fish-Cult. 29:87-91. 94
McPhail, J.D. and C.C. Lindsey. 1970. Freshwater Fishes of Northwestern Canada and Alaska. Bull. Fish. Res. Bd. Canada. 173:381 p.
Nikolski, G.V. 1965. Theory of Fish, Population Dynamics, Nauka, Moscow, Oliver and Boyd Ltd., England. 1969.
Paterson, R.J. 1968; The lake trout, Salvelinus namaycush, of Swan Lake, Alberta. Alberta Fish and Wildlife Division, Fisheries Section, Res. Report No; 2.
Rawson, D.S. 1961. The lake trout of Lac la Ronge, Saskatchewan. J. Fish. Res. Bd. Canada 18(3):423-462.
______1950. The physical limnology of Great Slave Lake. J. Fish. Res. Bd. Canada. 8(1):1-66.
______1951. Studies of the fish of Great Slave Lake. J. Fish. Res. Bd. Canada. 8(4):207-240.
______1953. The bottom fauna of Great Slave Lake. J. Fish. Res. Bd. Canada. 10:486-520.
______1959. Limnology and fisheries of Cree and Wallaston Lakes in Northern Saskatchewan. Bull. Sask. Dept. Nat. Res. Report No, 4.
Ricker, W.E. 1958. Handbook of Computations for Biological. Statistics of Fish Population. Bull. Fish. Res. Bd. Canada. 119:300 p.
Robson, D.S, and D.G. Chapman. 1961. Catch curves and mortality rates. Trans. Amer. Fish. Soc. 90(2):181-189.
Royce, W.F. 1951. Breeding habits of lake trout in New York. Fish. Bull. Fish. Wildlife Serv. 52(59):57-76.
Van Oosten, J. 1934. The values of questionnaires in commercial fisheries regulation and surveys. Trans. Amer. Fish. Soc. 64:107-111.
95
APPENDIX I
Creel Data Calculations from Great Bear Lake Lodge
Length of season July 8 - Sept. 2 55 days Length of creel census July 11 - Aug. 24 45 days
Number of fishermen interviewed 1,927 (in 45 days) Average/day 42.8 Actual number of beds 58 Percent interviewed 42.8 58 73.8
Total lake trout caught 6,877 Total lake trout retained 4,442 Percent retained 64.6 Average catch/day 152.8 Average catch/man/day 3.6 Average number retained/man/day 2.3
Total lake trout sampled 578 Percent of total caught 8.4 Percent of total retained 13.0 Weight of lake trout sampled 2,087.3 kg (43,597.5 lb) Average weight/trout 3.6 kg ( 7.9 lb)
Therefore: Total weight of lake trout caught on line 24,757.2 kg (54,531.3 lb)
Total weight of lake trout retained 15,991.2 kg (35,222.9 lb)
Assuming that the lodge operated at 100 percent capacity: Lake trout 73.8% of total (in 45 days) 6,877 100 % of total (in 45 days) 9,318.4
Lake trout Caught in 45 days 9,318.4 Caught in 55 days 11,389
Average weight/lake trout 3.6 kg (7.9 lb) Total weight of lake trout caught 41,000.4 kg (89,973.1 lb) Retained 64.6 percent 26,086.3 kg (58,122.6 lb)
or:
Area fished (in acres) 45,536 Harvest/acre 0.57 kg (1.25 lb)
98
APPENDIX IV
Revenue and Employment in Great Slave Lake - Area 6
COMMERCIAL VS SPORT FISHERY1 Commercial Fishery Sports Fishery No. employed 21 77 No. of N.W.T. employees 21 61 Gross Revenue $49,096 $443,000 Wages to N.W.T. employees 57,000
1 Note a) Commercial fishery statistics are for the period January 1 to October 31, 1972. b) Of the 21 employees in the commercial fishing, 3 men were owners of boats and winter outfits, 18 men were employed at the going wage of $350.00 monthly plus board for a period of approximately 5 months.
Wages - 18 x 350 x 5 = $31,500 Balance to outfit owners $17,596 gross earnings Estimated expenses for food, fuel etc. is 40% Estimated net earnings to outfit owners: $10,558 10,558 / 3 - $3,519.
c) Sport fishery statistics are from three major fishing lodges located in the East Arm and are for the summer 1972. In total, there are five sport fishing lodges and one sport fishing outfitter operating in the East Arm. A total of 649 guests stayed at the three major lodges in 1972.
GREAT SLAVE LAKE - COMMERCIAL FISHING
Total lake
Summer 1972 Winter 1971/72
24 large boats 18 outfits - 26 bombardiers 40 skiffs and canoes 5 skidoos 62 men
Area 6 - East Arm
3 large boats 3 outfits 12 men