AUTHORS: Robert Davis, Center for Limnology, University of Wisconsin; Ellen Albright, Center for Limnology, University of Wisconsin; Katie Hein, Center for Limnology, University of Wisconsin; Michael Verhoeven, Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota- Twin Cities; Zach Feiner, Center for Limnology, University of Wisconsin & Office of Applied Science, Wisconsin Department of Natural Resources
ABSTRACT: Aquatic macrophytes provide important habitat for fish at various life stages and can influence fish population characteristics such as growth and size structure. Even though aquatic plants are generally considered to be important to fish communities, the exact nature of the relationship is not well understood. Moreover, multiple factors (climate, aquatic invasive species, nutrient loads) are causing aquatic plant communities to shift through time. Walleye are a culturally and economically important species to the upper Midwest that are currently experiencing declines in recruitment success due to climate change and other factors. In this study, we seek to elucidate the role that aquatic vegetation plays in determining walleye recruitment success. Point-intercept aquatic plant surveys from Minnesota and Wisconsin were used to quantitatively describe plant communities in lakes spanning 2003 to 2018, and annual fall electrofishing recruitment surveys were used to quantify walleye recruitment during the same time period. Random forest models were used to understand the nature of the relationship of aquatic plant communities to walleye recruitment and any interactions that may exist between aquatic plant communities and other important environmental variables previously found to influence walleye recruitment success (e.g., growing degree days, lake surface area). Overall, we hope to determine pertinent interactions between Walleye recruitment success and aquatic macrophyte communities, which could inform habitat management strategies that may benefit Walleye fisheries throughout the region.
