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

In several recent years, Wyoming Game and Fish Department spring gillnet surveys in Pathfinder Reservoir suggest near 100% mortality of salmonids stocked the previous fall. Similar surveys in Alcova Reservoir suggest reliable and stable recruitment of stocked salmonids following their first winter, although it varies by species. Wyoming Game and Fish Department biologists suspect Walleye predation on newly-stocked salmonids is the primary driver of stocking failures; however, verifying this hypothesis and quantifying the seasonal magnitude of Walleye consumption of newly-stocked salmonids is required to develop and evaluate alternative management actions. This research is a collaboration of researchers across multiple agencies and includes the Wyoming Game and Fish Department, Casper Regional Fisheries Management Crew, Aquatic Assessment Crew, and the University of Wyoming. Results from this project will provide the Wyoming Game and Fish Department with an improved understanding of the timing and magnitude of Walleye consumption of newly-stocked salmonids in the Upper North Platte Reservoirs. This information will inform harvest regulations for Walleye, newly-stocked salmonids, and other fish species, and could guide development of a future salmonid stocking evaluation to identify best practices to maximize survival post-stocking (e.g., composition, fish size, density, location, and timing).