Cooperative Fish and Wildlife Research Units Program: Wisconsin Fishery
Education, Research and Technical Assistance for Managing Our Natural Resources

The overall goal of our project is to provide fisheries managers and stakeholders with critical information regarding potential interactions among lake whitefish, walleyes, and yellow perch in Green Bay so that management decisions can be made with a better understanding of the potential implications for all three fisheries and prey resources. We also hope to engage user groups in the research process, by working with them to collect fish needed for analyses, representing a significant opportunity for face-to-face outreach. Our specific objectives are to determine if: 1) lake whitefish and yellow perch represent important prey for walleyes in Green Bay (≥ 20% of diets by weight); 2) diets of these three species vary spatially and temporally and if diet overlap among species is evident; 3) the extent of walleye predation is sufficiently high to influence recruitment potential of lake whitefish and yellow perch and 4) extent of walleye predation varies among individual stocks of lake whitefish. Our working hypotheses are: 1) lake whitefish and yellow perch will not represent important prey for walleyes, but importance will vary seasonally and by location; 2) diet overlap will be relatively limited among species, with the exception of round goby; 3) despite low occurrence in individual diets, walleye predation will be sufficiently high to affect recruitment potential of yellow perch and lake whitefish, and 4) the extent of walleye predation will vary among lake whitefish stocks and will be highest for tributary spawning stocks spawning in southern Green Bay.