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

Overharvest is a persistent concern for lake sturgeon Acipenser fulvescens stocks that support recreational fisheries. Consequently, selecting harvest regulations for these fisheries is an important process for fishery managers. The Menominee River that borders the states of Wisconsin and Michigan currently supports some of the largest stocks of lake sturgeon associated with Lake Michigan and some of these stocks have supported hook-and-line fisheries for decades, but fishery managers are still uncertain as to how angler harvest and changes in harvest regulations affect the sustainability of these stocks. Our objectives were to: 1) determine if current and historic levels of exploitation significantly affect lake sturgeon recruitment and population demographics in the White Rapids section of the Menominee River and 2) determine the potential effects of length-based harvest regulations on lake sturgeon exploitation and recruitment. Lake sturgeon were captured using pulsed DC boat electrofishing on 9 different dates between 12 April 2012 and 9 May 2012 (Table 1). Both the Wisconsin and Michigan Departments of Natural Resources assisted with this sampling. During April-May 2012 we captured 228 lake sturgeon that ranged in total length from 13.5 to 62 inches. We are currently in the process of estimating the population size of lake sturgeon in the White Rapids section using Program MARK. After estimates of population size and age structure are complete, we will begin age-structured simulation modeling to determine the effects of exploitation and length limits on lake sturgeon in this section of the river. This project is funded by Wisconsin Energies-Wilderness Shores Mitigation and Enhancement Fund. The project is a collaborative effort between the FAC, the Wisconsin Cooperative Fishery Research Unit, and the Wisconsin and Michigan DNR.