Effects of Walleye Predation on the Population Dynamics of Small Littoral-Zone Fishes in a Northern Wisconsin Lake

Abstract

Abstract We used a bioenergetics model to assess the effects of predation by juvenile walleyes Stizostedion vitreum vitreum on the populations of darters (Percidae) and minnows (Cyprinidae) in Sparkling Lake, Wisconsin. In 1982, when young-of-the-year yellow perch Perca flavescens were scarce, darters and minnows were important in walleye diets throughout the summer. Walleye predation accounted for approximately 100% of adult darter mortality and 75% of adult minnow mortality. Walleyes appeared to be important in determining abundance of young-of-the-year darters in October, but had little direct effect on abundance of young-of-the-year minnows. In 1983, when young-of-the-year yellow perch were abundant, darters and minnows were only important in walleye diets in June. Walleye predation accounted for 80% of adult darter mortality but only 35% of adult minnow mortality. The decrease in walleye consumption of adult darters and minnows in 1983 compared with 1982 is consistent with the hypothesis that abundan...