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

Wisconsin Fishery Project

Evaluating Potential Factors Limiting Lake Sturgeon Reproductive Success in the Upper Fox River

January 2022 - December 2023


Participating Agencies

  • Wisconsin Department of Natural Resources

The Lake Winnebago System (LWS) in east-central Wisconsin supports one of the largest lake sturgeon populations in the world and the population supports a socially- and economically-important winter spear fishery that is closely managed by the Wisconsin Department of Natural Resources (WDNR). Lake sturgeon spawn at many sites within the LWS, and many fish make extensive spawning migrations into the Fox and Wolf Rivers and their tributaries. The contribution of different spawning sites to the overall lake sturgeon population is unknown and this information is critical to developing management strategies. Ongoing research is helping to address this need. As part of this ongoing research, sampling has demonstrated that larval lake sturgeon successfully hatch at several known spawning sites in the Wolf, Little Wolf, and Embarrass rivers. However, in two years of sampling, no lake sturgeon larvae were captured at the Princeton spawning site on the upper Fox Rive despite spawning activity being observed in both years. Determining what factors are limiting successful spawning of lake sturgeon in the Fox River could help guide efforts to increase recruitment and may help in determining whether direct habitat improvement may be beneficial or if changes at the watershed level would be required to overcome these limiting factors. We hypothesize that siltation rates and periphyton growth may be two factors that are primarily limiting successful hatching of lake sturgeon in the Fox River. Additionally, potential differences in abundance of egg and larval predators at spawning sites could affect reproductive success.