Resolving Some of the Complexity of a Mixed-Origin Walleye Population in the East Basin of Lake Erie Using a Mark–Recapture Study

Abstract

At least two genetically distinct populations of walleye Sander vitreus reproduce in Lake Erie: one west-basin-origin population and one east-basin-origin population. Each year, some west-basin-origin walleyes migrate to the east basin and create a mixed-origin walleye population. Uncertainties associated with this migratory behavior make it difficult to describe the dynamics of the east-basin-origin population. We used mark–recapture analysis to estimate the dynamics of the east-basin-origin walleye population and to measure the contribution of west-basin-origin walleyes to the total walleye harvest in the east basin. Compared with the west-basin-origin walleyes, the east-basin-origin walleyes experienced lower fishing pressure, lower natural mortality, and a higher survival rate. On average, the west-basin-origin walleye migrants comprised about 90% of the annual harvest in the east basin. The number of the west-basin-origin walleyes migrating to the east basin was linearly related to their abundance. Walleyes showed a strong fidelity to their spawning sites. This study provided an approach to the assessment of population dynamics and the management of walleye fisheries in the east basin of Lake Erie.

Received June 7, 2010; accepted December 30, 2010

ACKNOWLEDGMENTS

We acknowledge contributions of the field staff of the NYSDEC's Lake Erie Unit, especially Brian Beckwith, Douglas Zeller, and Richard Zimar. We also thank Andy Cook and Stan Powell of the Ontario Ministry of Natural Resources for their assistance on creel survey data. The comments from Kevin Kayle, the associate editor, and three anonymous reviewers significantly improved the manuscript. The lead author acknowledges the encouragement of Cheryl Lewis and Brian Shuter in the early stage of the project. Analytical work for this project was financially supported by the Ontario's Fish and Wildlife Special Purpose Account and Ontario Funding for Canada–Ontario Agreement (7–00) Respecting the Great Lakes Basin Ecosystem to Y.Z.

Notes

^aThe confidence intervals for S, F,α _i , and β _i are maximum likelihood estimates derived from program MARK; those for z and m were derived by the delta method.