Factors in the Declining Contributions of Walleye (Stizostedion vitreum vitreum) to the Fishery of Lake Nipissing, Ontario, 1960–76

Abstract

Analysis of the 1960–76 creel survey data for Lake Nipissing and relevant data collected by the Lake Nipissing Fisheries Assessment Unit from 1969 to 1976 showed a generally declining walleye (Stizostedion vitreum vitreum) contribution to the Lake Nipissing fishery. Variable year-class strengths alone did not adequately account for the changes. Overexploitation of the resource was strongly suggested by decreased catches per unit of effort, recruitment of younger walleye (many of which probably never spawned) into the fishery at least after 1968, and increased growth rate. The population is probably affected as well by climatic factors, interactions with white suckers (Catostomus commersoni), northern pike (Esox lucius), and yellow perch (Perca flavescens), and by technology and watershed influences. Key words: walleye, Lake Nipissing Ontario, Lake Nipissing fishery, Percidae, Stizostedion