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

Stocking is routinely used to supplement or maintain fisheries when natural recruitment is low or nonexistent. Demand for stocking cool and coldwater fish species that support important fisheries will likely increase as a result of climate change, but fish available for stocking are a limited resource. Consequently, climate change is likely to affect the supply-and-demand tradeoffs associated with stocking fish in the future, where demand for fish is likely to exceed supply. We will examine these tradeoffs using walleye, which represent an ideal species for this assessment because they are a native coolwater species supporting economically- and socially-important fisheries across North America, stocking is already used to support or maintain many walleye fisheries, and walleye populations have already declined due to climate change, resulting in increased demand for stocked fish. Resource agencies routinely evaluate walleye stocking success and we will compile information from these evaluations to determine what factors are associated with stocking success. These factors are likely to include the size and number of walleye that are stocked, lake characteristics such as surface area and productivity, availability of both walleye prey and predators, length of growing season, and winter severity. Once these factors have been identified, we can forecast what stocking success might be for individual lakes in the future, given that climate change is likely to affect many factors that regulate stocking success. These projections will allow fishery biologists to compare the number of walleye needed to provide walleye fisheries in the face of climate change (i.e., demand) against the number of walleye that might be available for stocking (i.e., supply). Our work will allow agencies to adapt stocking strategies to ensure that walleye fishing opportunities remain available and to ensure that agency resources are expended in a manner that is biologically relevant yet cost effective.