Genetic population structure and mixed stock analysis of walleye (Stizostedion vitreum) in the Lake Erie-Lake Huron corridor

I used allozymes and mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs) to determine if spawning populations of walleye (Stizostedion vitreum) from the Lake Erie-Lake Huron corridor were genetically differentiated and to estimate the contributions of spawning populations to a mixed fishery in southern Lake Huron (Purdy Fisheries). Both types of genetic markers detected significant differentiation among walleye populations suggesting that fish from Lake Erie, Lake St. Clair and Lake Huron are not a single, genetically homogeneous population. Furthermore, both markers suggest a relationship between geographic proximity and genetic differentiation. The estimated contributions of walleye from different spawning sites to the catch from Purdy Fisheries varied substantially between years. The greater differentiation detected by the mtDNA analysis throughout the sampled area than allozymes suggested that mtDNA is a more sensitive indicator of population substructuring and a better estimator of the composition of the commercial fishery in walleye from the southern Laurentian Great Lakes.