Contributions of Lake Erie and Lake St. Clair Walleye Populations to the Saginaw Bay, Lake Huron, Recreational Fishery: Evidence from Genetic Stock Identification

Abstract

Genetic stock identification analyses were conducted to determine spawning population contributions to the recreational fishery for Walleyes Sander vitreus in Saginaw Bay, Lake Huron. Two spawning population groups were considered: (1) the Tittabawassee River, which has been identified as the largest source of spawning Walleyes for Saginaw Bay; and (2) an aggregate of six spawning populations from Lake Erie and Lake St. Clair that were found to be genetically similar. Overall, the Lake Erie and Lake St. Clair spawning populations were estimated to comprise approximately 26% of the Walleye recreational harvest in Saginaw Bay during 2008–2009. Contribution levels were similar for the 2 years in which genetic samples were collected. Contributions from the Lake Erie and Lake St. Clair spawning populations to the harvest of age-5 and older Walleyes were greater during summer (31.8%; SE = 6.2%) than during late winter and spring (6.0%; SE = 3.7%). Conversely, contributions from the Lake Erie and Lake St. Clair spawning populations to the harvest of age-3 and age-4 fish were fairly similar between seasons (late winter and spring: 31.2%, SE = 6.7%; summer: 41.7%, SE = 5.6%), suggesting that younger Walleyes migrate earlier or reside in Saginaw Bay for extended periods. Our finding that one-quarter of the Saginaw Bay recreational harvest of Walleyes comprises fish from Lake Erie and Lake St. Clair has important management implications, as policies for one lake may have bearing on the other lake—one of the challenges associated with managing migratory fish species. Fisheries management in the Laurentian Great Lakes has a history of being highly coordinated and cooperative among the states and province bordering the individual lakes. Results from this study suggest that cooperation may need to be expanded to account for fish movement between lakes.

Received October 28, 2014; accepted February 11, 2015

ACKNOWLEDGMENTS

This research was partially funded by the Great Lakes Fishery Trust (Project 2009.1080). Additional funding was provided by MDNR and by contributing partners of the Quantitative Fisheries Center at Michigan State University (MSU). We thank A. Cook (Ontario Ministry of Natural Resources), M. Thomas (MDNR), C. Schelb (MDNR), T. Kolb (MDNR), and C. Radek for their assistance in the laboratory or field. We additionally thank two anonymous reviewers for suggesting changes that improved this manuscript. This is publication 2015-09 of the MSU Quantitative Fisheries Center.