Walleye in Mille Lacs Lake display strong loyalty to specific spawning sites, according to new research released on May 22 by the Great Lakes Indian Fish and Wildlife Commission, Mille Lacs Band of Ojibwe, and the University of Illinois Urbana-Champaign. The study tracked 70 walleye during their spring spawning periods from 2019 to 2021 and identified six primary “hotspots” for spawning activity.
The researchers found that about 96% of walleye returned to the same areas each year. “Approximately 96% of the fish in this study spawned at the same site in 2019 and in 2020. These fish use the same areas to spawn year after year, which means that their reproductive success is tied to a specific place,” said Kayla Lenz, lead author and doctoral student at the Department of Natural Resources and Environmental Sciences at Illinois. The identified hotspots were located in rocky areas exposed to wind and wave action near undeveloped shorelines.
Walleye populations in Mille Lacs have declined over recent decades due largely to poor recruitment linked with environmental changes, habitat degradation, overfishing, and shifting ecosystem dynamics. Kelly Applegate, Commissioner of Natural Resources for the Mille Lacs Band of Ojibwe, said, “As the very first protectors of water and fish, we care deeply about the habitats which give life to the Ogaawag that sustain us. By learning more about important Ogaawag spawning sites, we can obtain valuable knowledge, allowing us to further build on our centuries-old reputation for successfully and sustainably managing our fisheries resources.”
Lenz said development or alterations such as breakwalls or marinas could disrupt these critical habitats: “Development of these areas may have temporary or permanent negative effects on walleye reproduction and recruitment.” She also noted that management practices mitigating erosion, pollution or climate change could benefit not only walleye but other species within Mille Lacs Lake.
The study suggests landowners can help protect walleye by limiting wake boat use during spawning season; delaying dock installation until after spawning; planting riparian buffer zones; and reducing chemical use near shorelines. More information is available in “Identifying Spawning Sites and Fidelity of Ogaa (Walleye Sander vitreus): Implications for Fishery Stewardship,” published online in Frontiers in Fish Science.
The University of Illinois College of Agricultural, Consumer and Environmental Sciences supports research through its Illinois Agricultural Experiment Station on campus while promoting social well-being through extension programs focused on nutrition, wellness and community development; it allocates $3.8 million annually for scholarships; maintains a high freshman retention rate; provides over 400 study abroad opportunities; advances knowledge globally across agriculture-related fields—all according to its official website.
