Fisheries Investigation in the 1837 Ceded Territory: Estimates of Population Sizeand Exploitation of Northern Pike and Walleye in Knife, Platte, and Sullivan Lakes. Completion Report

摘要

Walleye and northern pike population size and angler exploitation were estimatedfor three central Minnesota lakes. Knife Lake northern pike population structure was dominated by low densities of fish over 17 inches. Platte and Sullivan Lakes had higher densities of northern pike dominated by fish less than 24 inches. Walleye population structures also differed between Knife and Sullivan Lakes. A strong natural year class was observed in Knife Lake and few small fish were observed in Sullivan Lake. Differences in population estimates suggested that multiple gear types should be used when conducting spring population estimates. Exploitation rates varied considerably by fish species and size. Walleye exploitation estimates for larger size classes were estimated at 38% in Sullivan Lake and 50% in Knife Lake. Northern pike exploitation ranged from 16% to 43%. These exploitation rates need to be viewed cautiously given low numbers of tag returns observed in the creel.