FIRST-YEAR GROWTH, RECRUITMENT, AND MATURITY OF WALLEYES IN WESTERN LAKE-ERIE

In some lakes, first-year growth of walleyes Stizostedion vitreum has been identified as an important factor governing recruitment of juveni les to the adult population. We developed a regression model for walle ye recruitment in western Lake Erie by considering factors such as fir st-year growth, size of the spawning stock, the rate at which the lake warmed during the spring, and abundance of gizzard shad Dorosoma cepe dianum. Gizzard shad abundance during the fall prior to spring walleye spawning explained over 40% of the variation in walleye recruitment. Gizzard shad are relatively high in lipids and are preferred prey for walleyes in Lake Erie. Therefore, the high degree of correlation betwe en shad abundance and subsequent walleye recruitment supported the con tention that mature females needed adequate lipid reserves during the winter to spawn the following spring. According to the regression anal ysis, spring warming rate and size of the parental stock also influenc ed walleye recruitment. Our regression model explained 92% of the vari ation in recruitment of age-2 fish into the Lake Erie walleye populati on from 1981 to 1993. The regression model is potentially valuable as a management tool because it could be used to forecast walleye recruit ment to the fishery 2 years in advance. First-year growth was poorly c orrelated with recruitment, which may reflect the unusually low incide nce of walleye cannibalism in western Lake Erie. In contrast, first-ye ar growth was strongly linked to age at maturity.