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

Climate change affects inland recreational fisheries by influencing lake thermal structure, water clarity, habitat, and other factors that influence economically valuable sport fishes. The Safe Operating Space (SOS) for a given fishery is the range of biophysical and social conditions that allows for self-sustaining populations of target species. Walleye, a socially and economically important sportfish across much of North America, is undergoing declines due to recruitment failures in many lakes throughout their range. Studies of the SOS for Walleye suggest that many factors are involved, including warming and changes in thermal structure, loss of habitat, increasing clarity (perhaps due to drought), and biotic interactions with other fish species. We propose research to identify mechanisms behind recruitment failures that will help inform rehabilitation of Walleye recruitment and populations. In a whole-lake experiment we will remove centrarchid fish species. In parallel, we will conduct a structured comparison of lakes with contrasting habitat and centrarchid densities to evaluate the effects of water clarity, growing degree days, and predation mortality on young-of-year growth and survivorship of Walleye. Results of these studies, in combination with simulation modeling and additional analyses of long-term data from lakes in Northern Wisconsin, will sharpen our understanding of the SOS for Walleye and inform a new vision for recreational fisheries management in a changing climate. Members of the research team work closely with fisheries managers, which will foster a regular exchange of information. Results will also be communicated to managers through regular management workshops, as well as technical papers in the scientific literature.