Forecasting contributions of lake whitefish year-classes to a Lake Superior commercial fishery from estimates of yearling abundance

We developed a simple linear regression model to forecast year-class contributions of lake whitefish Coregonus clupeaformis to the commercial harvest in the Apostle Islands region of Lake Superior. We indexed year-class strength from catches of yearling fish in bottom trawl samples. Recruitment of each year-class was measured by its relative abundance in the fishery at age 6. The relation between recruitment to the commercial fishery and year-class strength indices was positive and significant (r ² = 0.67, P < 0.01). The model produced reliable estimates of recruitment to the fishery within the range of the regression. Projected recruitment of the 1983–1987 year-classes to the fishery in 1989-1993 should be sufficient to sustain current levels of harvest through 1993.