Seasonal and Spatial Distribution of Walleye in Big Eau Pleine Reservoir, Wisconsin
Fisheries and Aquatic Sciences Aster Kabat
Lucas Koenig (Not Pictured)
Jake Thompson (Not Pictured)
Masters of Natural Resources
We used acoustic telemetry to assess the spatial distribution of walleye Sander vitreus during their first season at large in Big Eau Pleine Reservoir, Wisconsin. Acoustic transmitters with 10-y battery life were surgically implanted in N=30 walleyes during April 2025. Transmitters were distributed equally between sexes among three release locations (five males and five females at each of three release locations). Walleye movements were passively monitored May-September 2025 using an array of acoustic receivers strategically positioned among three reservoir zones (upper reservoir, mid-reservoir, and lower reservoir). Detection histories of tagged walleye were used to determine monthly residency in each reservoir zone and whether walleye transitioned between zones or left the study area through the dam. Each month, ≥ 60% of tagged fish resided within the mid-reservoir zone, whereas ≤ 20% of fish were located within the upper and lower reservoir zones, respectively. We observed relatively little movement of walleye among reservoir zones. One walleye was detected downstream of the Big Eau Pleine dam. The spatial distribution of fish was generally reflective of where fish were captured and released; however, it may also indicate an affinity for biotic (e.g., prey abundance) or abiotic (e.g., oxythermal habitat) conditions in the mid-reservoir zone. This study represents the initial phase of understanding walleye movement and spatial distribution in this system. Future detection data, including downloads from receivers not included in this initial study, will allow for continued and more in-depth analysis of walleye movement ecology in Big Eau Pleine Reservoir.
Advisors: Daniel Dembkowski, Ph.D. Daniel Isermann, Ph.D.
Subject Area: Fisheries and Water
Type: Poster
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Jim and Katie Krause CNR Student Research Symposium
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