Size Structure of a Lake Trout ( Salvelinus namaycush ) Population an Arctic Lake: Influence of Angling and Implications for Fish Community Structure

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: McDonald, Michael E., Hershey, Anne E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1989
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Arctic Lake; Thymallus arcticus; Alaska
• Online Access: http://dx.doi.org/10.1139/f89-266; http://www.nrcresearchpress.com/doi/pdf/10.1139/f89-266

The lake trout (Salvelinus namaycush) population in Toolik Lake in arctic Alaska was assessed by gill net during 1977, prior to exploitation. In 1986 we replicated the gill net study to determine the effects of recent angling pressure on the fish community. Relative composition of the catch varied between samples. Round whitefish (Prosopium cylindraceum), which are not susceptible to angling, made up 42% of the catch in 1986 and 28% in 1977. Significant reductions in the median length and weight of lake trout between the sampling periods were observed. The median size of lake trout in 1986 was below the minimum 1977 reproductive size. Differences in median length and weight of grayling (Thymallus arcticus) and of round whitefish during this period were not significantly different. The condition factor of lake trout was significantly higher in 1986. We suggest that large lake trout in Toolik Lake control salmonid recruitment and determine community structure. With continued fishing pressure further changes in the fish community and lake trophic dynamics may result.