Date of Award
5-2026
Document Type
Thesis
Department
Biology
First Advisor
Andrew Hafs
Abstract
Over the past several decades, cold- and cool-water fish populations across the Upper Midwest, including Minnesota and Wisconsin, have shown troubling signs of decline. Among the most affected is the walleye/Ogaa (Sander vitreus), a species deeply embedded in the ecological balance, cultural identity, and economic vitality of the region, and central to the lifeways, treaty-reserved rights, and resource stewardship of Tribal Nations, including Ojibwe communities across the Upper Midwest. Despite ongoing stocking efforts and harvest regulations, many lake systems have experienced persistent declines in natural recruitment, prompting resource agencies to investigate the underlying causes. One such system is the Minocqua Chain of Lakes in northern Wisconsin. Historically regarded as a productive walleye fishery, the chain has witnessed a sharp and sustained drop in age-0 walleye abundance, suggesting the presence of ecological bottlenecks during early life stages. Recruitment failures in this region raise essential questions about the timing and drivers of mortality - whether these occur during egg incubation, larval emergence, or early juvenile development. First, this study draws on the existing literature to identify when recruitment bottlenecks are most likely to occur and to evaluate the biological and environmental conditions that may be contributing to the decline. Second, by employing assisted reproduction techniques, this research aims to improve understanding of egg survival, larval growth, exposure to predation, and key abiotic stressors. Findings will inform science-based management decisions for agencies such as the Wisconsin Department of Natural Resources and the Great Lakes Indian Fish and Wildlife Commission and contribute to the growing body of research on walleye recruitment challenges across North America.
Recommended Citation
Keiser, Douglass, "Enhancing Walleye (Ogaa) Recruitment: Evaluating Assisted Reproduction as a Mitigation Strategy" (2026). Biology Graduate Theses. 18.
https://pines.bemidjistate.edu/thesis-biol/18
Included in
Aquaculture and Fisheries Commons, Biology Commons, Environmental Health Commons, Environmental Health and Protection Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Laboratory and Basic Science Research Commons, Natural Resources and Conservation Commons, Population Biology Commons, Terrestrial and Aquatic Ecology Commons
