NWT RESEARCH DATABASE

Regions: Gwich'in Settlement Area

Tags: biology, fish, wildlife monitoring, dolly varden char, fish migration

Project Description: The northern subspecies of Dolly Varden char is represented by only five populations in Canada. Of these populations, the Vittrekwa River Dolly Varden has been least studied. In the late 1990s, the presence of this fish was confirmed by the Gwich’in Renewable Resource Board and the Department of Fisheries and Oceans. Data collected through studies conducted by these organizations showed that at least a portion of the fish are anadramous (i.e., travel to the ocean to feed). The low number of Dolly Varden char caught by fishermen in downstream locations of the Vitrrekwa River suggests that the population is small. Given its size, this population is worthy of close investigation, monitoring and management. The study will commence with a determination of a minimum population size of migratory Dolly Varden char. As the study progresses, the number of recaptured tagged fish will be used to improve this estimate (mark-recapture population estimate). Basic biological characteristics (e.g., size and age distributions) of this population will also be noted. Downstream recapture of tagged individuals will provide information about the timing and pattern of migration. Genetic samples from micro-satellite markers, and in combination with other data, will be used to delineate stocks of Dolly Varden. These data will answer questions specifically about the Vittrekwa River population, hopefully leading to better management of the region’s Dolly Varden populations. Dolly Varden char will be studied during their annual migration up the Vittrekwa River to spawn. A weir and fish trap will be constructed on the river in early August, and monitoring will continue until the end of the migratory run. Each day, the fish trap will be checked and any caught char will be counted. Individuals will be photographed, sexed, measured, floy-tagged (small individually-identifiable external tags) and released. The adipose fin will be clipped and kept for genetic analysis and scales will be taken for strontium analysis. If the population is large, some fish will be killed and sampled more completely (i.e., stomach contents, gonads, and otoliths or ear bones will be taken). At the end of the field season, a report of the findings of this research will be distributed to the Tetlit Gwich’in and Nihtat Gwich’in Renewable Resource Councils. This report will also be made available through the Gwich’in Renewable Resource Board website (www.grrb.nt.ca). The study will be conducted from July 1 to November 30, 2006. Sampling locations will be determined in consultation with the Tetlit Gwich'in Renewable Resource Council.