Sauger movement patterns, entrainment, exploitation, and apparent survival in Lewis and Clark Lake inferred from acoustic telemetry

Understanding Sauger Sander canadensis movement can inform focused management on large reservoir systems by providing insight into movement patterns, entrainment, exploitation, and apparent survival. However, fish movement patterns have not been assessed in Lewis and Clark Lake since 2006, and unprecedented floods that changed the reservoir's morphology and aging have occurred since the last assessment. We conducted a contemporary analysis of Sauger movement patterns, exploitation, entrainment, and apparent survival to inform management. We implanted adult fish ( n = 79) with acoustic tags between 2021–2024 and assessed movement patterns during 2021–2024. Receivers ( n = 14) distributed throughout the entire length of Lewis and Clark Lake and the 63‐km river reach below Fort Randall Dam enabled quantification of the amount of movement into each management zone. We related environmental factors and flow characteristics to variation in weekly mean movement distance using multiple linear regression. We derived exploitation estimates from angler‐reported tags. We estimated entrainment from angler‐reported tags and receivers placed below Gavins Point Dam, documenting entrainment through the dam. We used a multistate live‐dead model approach to determine that resight probabilities (mean = 0.71, range = 0.44–1.00) varied among strata, and apparent survival (mean = 0.83, range = 0.80–0.86) did not vary between sexes. Approximately 32% of females and 18% of males tagged in the delta zone never left this zone over the study duration. Mean weekly fish movement was driven primarily by reservoir storage, discharge through Fort Randall Dam, mean temperature, and precipitation. Increased reservoir storage was correlated with decreased mean weekly male movement. Exploitation and entrainment were sources of loss for adult fish in the reservoir, with annual exploitation estimates ranging from 0–15%, and annual entrainment estimates ranging from 0–2.5%. Examination of adult Sauger movement patterns enables fisheries managers to focus management on important spawning areas, whereas quantifying exploitation and entrainment informs the effectiveness of current harvest regulations.