Mitochondrial DNA Variation and Mixed-Stock Analysis of Recreational and Commercial Walleye Fisheries in Eastern Lake Erie

Abstract

The relative contributions of five spawning stocks of walleye Stizostedion vitreum to three recreational derbies and a commercial fishery operating in eastern Lake Erie in 1995 and 1996 were estimated by analyzing mitochondrial DNA (mtDNA) variation and by using a maximum likelihood model. Simulations of fishery mixtures (N = 100) were used to assess the performance of the likelihood model for estimating contributions from three baselines composed of the five Lake Erie spawning stocks: Chickenolee Reef and Huron River (western basin), Grand River (eastern basin), Van Buren Bay and Smokes Creek (eastern basin). Differences between the simulated mixtures and the mean of the estimates revealed that the model differentiated among varying simulated contributions from the three baselines. Bias among the estimates was greatest when a single baseline contributed entirely to the simulated mixture. Mixed-stock analysis (MSA) of the eastern basin fisheries suggested that the western basin baseline was a major contributor to both the recreational (0.63 ± 0.10) and the commercial (0.81 ± 0.14) fisheries. The eastern baseline contribution estimates were not significantly different from zero, with the exception of the Grand River baseline contribution to the recreational derbies (0.16 ± 0.08). The results are preliminary to show that mtDNA variation and a maximum likelihood model can be used to estimate the relative contributions of walleye stocks to the mixed fisheries of eastern Lake Erie. Further research using comprehensive baselines, including all potential contributing stocks, is recommended before the MSA information presented is used directly for the management of walleyes in Lake Erie.