.+ Environment Canada Environnement Canada • Fisheries Service des peches and Marine Service et des sciences de la mer ... The Limnology and Fish Biology of TenMile Lake, Labrador , " • by . R. F. Pa rsons Technical Report Series No, NEW/T-75-3 Resource Development Branch Newfoundland Region • , DEPARTMENT OF THE ENVIRONMENT FISHERIES AND MARINE SERVICE NEWFOUNDLAND REGION TECHNICAL REPORT SERIES NO. NEW/T-75-3 THE LIMNOLOGY AND FISH BIOLOGY OF TEN MILE LAKE, LABRADOR by R.F. PARSONS RESOURCE DEVELOPMENT BRANCH ST. JOHN'S, NEWFOUNDLAND A limnological investigation and fish inventory was conducted on Ten Mile Lake, Labrador, during the summer of 1974. Chemical and physical parameters were measured for the lake. The pH levels ranged between 6.0 and 6.6, while specific conductance values varied between 12.0 and 21.0 microhoms @ 25 C. The water area of the lake is 26.39 km2 with a mean depth of 2.90 m. Thermal stratification was noted in two areas of the lake. Seven fish species were sampled from the lake. These include Coregonus clupeaformis (lake whitefish), Prosopium cylindraceum (round whitefish), Salvelinus fontinalus (brook trout), Salvelinus namycush (lake trout), Esox lucius (northern pike), Catostomus commersoni (white sucker), and Lota lota (burbot). White sucker was the most abundant species, contributing 25.0% by number and 24.3% by weight of the total sample. TABLE OF CONTENTS Page LIST OF FIGURES.................................................... ii LIST OF TABLES ••••• . .. ..... .. .. .... .. .. .... iv LIST OF APPENDICES.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •• vi INTRODUCTION •••••••••••• .. ..... ... ..... .. .. .. .. 1 DESCRIPTION OF THE STUDY AREA.... • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •• 2 }1A.TERIALS AND METHODS.. • . • . .. • • . • . • . • . • • • • • . .. • • . • • . • • . • • 5· RESULTS AND DISCUS SION. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 9 s~y ••••..•.. II ••••••••••••••••••••••••••••• , • • • • • • • • • • • • • • • • • • •• 65 ACKNO~EDGMENTS •••• , •••••••••••••• It • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •• 70 REFERENCES • ... .. , ............................... , .............. 71 APPENDIX ••• ... ...... .. ...... .. ... .... ........ ..... 74 i LIST OF FIGURES Figure Page 1. Ten Mile Lake in relation to Smallwood Reservoir, Labrador ......... 41. • • • • • • • • • • • • • • • • • • • • • • •• • • • • • • • • • • •• • • • 3 2. Bathymetric map of Ten Mile Lake ••..........••.••••.•.•.•. 6 3. Locations of gillnets and trap nets, and of the sampling stations for plankton and water quality •...•.•.•.••.•••••• 7 4. Temperature profile showing thermocline in two areas of Ten Mi Ie Lake............................................. 11 5. Dissolved oxygen profile showing chemocline in two areas of Ten Mile Lake........................................... 12 6. Fish-length to scale-length relationship for lake white­ fish from Ten Mile Lake ................................... 20 7. Comparison of growth rates for lake whitefish from Ten Mile Lake and Jacopie Lake, Labrador .•..•••••••••.•••••••• 23 8. Fork-length distribution of lake whitefish •••••••••••••••• 24 9. Age-composition of lake whitefish from Ten Mile Lake •••••• 24 10. Fish-length to scale-length relationship for round white­ fish from Ten Mile Lake................................... 28 11. Comparison of growth rates for round whitefish from Ten Mile Lake, Labrador, and the Ungava area •••.•..••.•••.•.•• 29 12. Fork length distribution of round whitefish from Ten Mile Lake. 31 13. Age composition of round whitefish from Ten Mile Lake ••••• 31 14. Fish-length to scale-length relationship for northern pike from Ten Mile Lake................................... 36 15. Comparison of growth rates of northern pike from Ten Mile Lake and Jacopie Lake, Labrador........................... 38 16. Length distribution of northern pike from Ten Mile Lake •••••••••••••••••••••••••••••••••••••••••••••••••••••• l1li ••• 40 17. Age composition of northern pike from Ten Mile Lake ••••••• 40 18. Comparison of the growth rates of lake trout from Labrador and other northern Canadian lakes......................... 45 ii Figure 19. Length distribution of lake trout from Ten Mile Lake •••••••• 46 20 . Age composition of lake trout from Ten Mile Lake •••••••••••• 46 21. Comparison of growth rates of brook trout from Avalon Peninsula of fiel,ffoltndland, and t~vo areas of La brador ••.•.••• 52 22. Length distribution of brook trout from Ten Mile Lake ••••••• 53 23. Age composition of brook trout from Ten Mile Lake ••••••••..• 53 24. Fish-length to scale-length relationship for white suckers from Ten Mi Ie Lake.......................................... 58 25. Comparison of growth rates for white suckers from Ten Mile Lake and the Mac Kenzie River a rea. • • • • • • • • • • • • • • • • • • • • • • • •• 59 26. Length distribution of white suckers from Ten Mile Lake •••••• 60 27. Age composition of white suckers from Ten Mile Lake ••••••••• 60 iii LIST OF TABLES Table 1. Morphometry of Ten Mile Lake, Labrador .........•......•.•.•. 9 2. Water quality analysis from two selected stations and one deep hole on Ten Mile Lake. (Samples collected during June and July, 1974) ........................................................................ 14 3. Check-list of plankton species identified in Ten Mile Lake, 1974 ...................... 1,.".,1 •••••••••• II •••• II ••• '" ••••••••• II i6 4. Mean scale length and calculated fork length at annulus formation of lake whitefish from Ten Mile Lake •••.••.••••••• 21 5. Stomach contents of lake whitefish from Ten Mile Lake •.••••• 25 6. Mean scale length and calculated fork length at annulus formation of Ten Mile Lake round whitefish •••.•••••••••••••• 30 7. Comparison of weights for round whitefish from the different lakes ........................ 01 ....... 0 •••••••••••••••• 32 8. Stomach content analysis of round whitefish from Ten Mile Lake.. .. .. .. .. • .. • . .. .. • . .. • .. • . .. • .. .. • . • • • .. • • • • • • . • • • • .. .. • . • • • • •• 33 9. Mean scale length and calculated fork length at annulus formation of northern pike from Ten Mile Lake ••..•••••.•..•• 37 10. Stomach content analysis of northern pike from Ten Mile Lake .................... f • • .. .. • .. • • • • • • • • • .. • • • • • • • • • • • .. • • • • .. • • •• 41 11. Mean scale length and calculated fork length at annulus formation of lake trout from Ten Mile Lake .•.......•.••.•.•. 44 12. Stomach content analysis for lake trout from Ten Mile Lake ........... II ..................................................................... 48 13. Mean scale length and calculated fork length at annulus formation of brook trout from Ten Mile Lake •...••...••••.... 51 14. Stomach content analysis for brook trout from Ten Mile Lake ................................................................. o!I • .. • • •• 54 15. Mean scale length and calculated fork length at annulus formation of white suckers from Ten Mile Lake •...•..••••••.• 56 16. Stomach content analysis for white suckers from Ten Mile Lake ......................................................................... 61 iv Tab1e~' Page 17. Percent number and weight of each species taken from Ten Mile Lake, Labrador, 1974............................ 64 v LIST OF APPENDICES 1. Conversion of conductivity values to T.D.S •••.•.••••••••.. 74 2. Temperature readings for Ten Mile Lake (June-July, 1974) 75 vi INTRODUCTION A limno1ogica1 and fish inventory study of Ten Mile Lake was con­ duct d during t he summer of 197 4 . This study is part of a detailed, long-term program initiated by the Resource Deve l opment Branch i n 197 3, designed to evaluate the fiah and wa t er resources of i nland La brador. Th e objectives of this study were three-fold. It marked the first t ime that any Unatural" waters of Labrador were i nvestigated in terms of physical, chemica l and bi otic parameters. This study would also be the basis for compar ison of s t udies done on the already flooded Smallwood Reservoir. Since there we r e no baseline studie s done on the lakes which now constitute the reservoir , we can only extrapolate f r om the data now available from Ten Mi le Lake, being in the vicinity and not affected by flooding. The data obtained will also be useful for comparison with the waters and f ish resources on insular Newfoundland. -2­ DES CRIPTION OF THE STUDY AREA THE LAKE Ten Mile Lake (Fig. 1) is situated approximately 32.9 km northwest of the town of Churchill Falls at a latitude of 53°43' North and a longitude of 65°05' west. The lake has an elevation of approximately 457 m above sea level. The drainage area for the lake is approximately 2 46.3 km . most of which is small bogs; marshes and streams. The major inlet to the lake is Brook 61, (Fig. 2) flowing from the southwest. The major outlet is a large brook in the extreme western end of the lake. Ten Mile Lake is a typical glacial lake , very irregular in shape and including 268 islands. Geographic Situation: Ten Mile Lake is one of the thousands of lakes on the Labrador Plateau. The Plateau forms the eastern section of the Canadian Shield which extends across much of the northern portion of the continent. The bedrock, which is widely visible in this area, is of archaen granites and gneisses, dating back to the Cambrian era, Climate: The average annual precipitation for the Churchill Falls area is 760 rom (30"),