Movement of Walleye in Lewis and Clark Lake Inferred From Acoustic Telemetry

ABSTRACT Walleye Sander vitreus is an economically important sport fish species with highly variable movement patterns, with individuals exhibiting site residency and others moving up to 350 km. Movement patterns of walleye are affected by both river regulation and shifting environmental conditions. We utilized mark‐recapture models to assess walleye movement among four management zones corresponding to roughly quarters of the reservoir on Lewis and Clark Lake, a mainstem Missouri River reservoir. We implanted adult walleye ( n = 134) with acoustic tags and assessed movement patterns during 2021–2024. We assessed the relationship between variation in mean weekly movement and environmental factors (e.g., drought, precipitation, temperature) and flow characteristics (e.g., discharge, reservoir elevation) using multiple linear regression. We estimated exploitation from angler‐reported tag returns and estimated entrainment from detections on receivers placed below Gavins Point Dam. A multistate live‐dead model approach suggested apparent survival (mean 88%) varied among seasons, and transition and resight probabilities varied among zones. Walleye movement was driven primarily by reservoir elevation, season, and temperature. Increased temperature was correlated to increased mean weekly male walleye movement. Seasonal walleye concentrations were evident below Fort Randall Dam in the spring and above Gavins Point Dam in the winter. Annual exploitation estimates ranged from 6% to 19%, and annual entrainment estimates ranged from 0% to 3%. Examination of adult walleye movement patterns enables focused management on identified spawning and overwintering areas. Assessment of sources of loss (e.g., entrainment, exploitation) enables fisheries managers to evaluate the appropriateness of current harvest regulations. Identification of the interplay between river regulation and environmental conditions enables managers to have a baseline to reference as environmental conditions shift toward warmer water temperatures.