NWT RESEARCH DATABASE

Regions: Sahtu Settlement Area

Tags: biology, fish, genetics, fisheries assessment, taxonomy, fish migration

Project Description: The objectives of this research are: 1) to gather baseline data on size, age structure, fecundity (egg number per female), growth and mortality for lake trout in the study area; 2) to determine if lake trout are genetically distinct between basins of Great Bear Lake; and, 3) to determine the extent of movements by lake trout in Great Bear Lake by using molecular genetics. Field crews will be transported to field sites via float plane. For stock assessment purposes, experimental gill nets with varying mesh sizes (1.5-inch to 5.5- inches) in combination with commercial size gillnets (5.5 inch) will be used to capture a representative sample of lake trout and by catch species of varying sizes. Live by catch species and trophy size lake trout will be measured for length clipped for aging and released. Captured fish will be sampled for the following biological characteristics: fork length, round weight, gonad weight, sex, and maturity. In addition, tissue samples will be removed and archived for contaminant and or genetic analysis and lake trout will be photographed for measurement of morphological characteristics. Data will be analyzed to determine age and length frequencies, age at maturity, size at maturity, growth, mortality and fecundity. Tissue samples will be analyzed for variation in the DNA to infer movement patterns of lake trout. When fishing, sampling effort (soak time of experimental gill nets) will be recorded in order to estimate relative abundance through the calculation of catch per unit effort (CPUE). The researchers expect to catch 500 lake trout, 200 lake whitefish, 500 cisco species, 20 northern pike, 20 round whitefish, 100 arctic grayling, and 20 longnose sucker. Déline community members will be hired as field assistants for the duration of this study and will be trained in fisheries sampling techniques. Findings from this work will be presented to community members. The study will be conducted at the Russel Bay-Keith Arm and Dease Arm areas of Great Bear Lake, from July 26 to August 10, 2005.