Effects of exploitation and emigration on apparent survival of Walleye in Lake Sharpe, South Dakota.

This article focuses on a five-year mark–recapture study conducted from 2017 to 2022 to estimate apparent survival, angler exploitation, and downstream emigration of Walleye (Sander vitreus) in Lake Sharpe, South Dakota, to inform fishery management. The study found that apparent survival was primarily influenced by Walleye length and a 381-mm minimum harvest length restriction, with lower survival during months when this restriction was suspended. Annual exploitation rates were generally low (8–25%), and emigration probabilities (11–28%) increased with proximity to Big Bend Dam and higher reservoir discharge, though neither exploitation nor emigration fully explained the magnitude of mortality observed. The findings highlight the importance of harvest regulations on angler behavior and suggest that natural mortality and emigration contribute substantially to Walleye population dynamics, indicating a need for further research on immigration, natural mortality, and angler harvest motivations to better guide management strategies.