ABSTRACTLIMITATIONS OF LARVAL WALLEYE (SANDER VITREUS) PRODUCTION IN MICHIGAN'S INLAND WATERWAYByRyan D. MacWilliamsWalleye (Sander vitreus) are one of the most targeted species by anglers in North America. Consequently, there is a need to understand the factors that influence year-class formation in age-0 walleye. Prey availability during the early life stages of walleye is considered the most important factor influencing the success of recruitment. I conducted a two-year study of larval walleye density, zooplankton prey availability, and fall age-0 walleye relative abundance within Michigan's Inland Waterway to document locations of larval walleye concentrations in the system and to determine if adequate prey are available to age-0 walleye. Larval walleye density in Burt Lake (mean=2.47·1000m-3 SE=0.81) was 87% higher than all other study lakes, and 94% higher than Pickerel Lake, which had the lowest density (mean=0.14·1000m-3 SE=0.14). The density of large-bodied zooplankton taxa (Calanoida, Daphnia) across all lakes was low (2·L-1), well below the 100 Daphnids·L-1 recommended for optimal walleye survival. The relative abundance of naturally produced age-0 walleye fall fingerlings was positively related to the spring density of large-bodied zooplankton taxa and larval walleye when all lakes and years were included in the analysis. While it is likely that multiple factors influenced year-class formation in the system, the results of this study suggest that prey availability during critical early life stages limited larval walleye density and year-class formation in Michigan's Inland Waterway.
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