Spatial distributions of Lake Erie walleye

Abstract

The spatial distributions of Lake Erie walleye stocks are examined from tagging data from 1990-2001. Releases and recoveries from four western basin tagging sites ? Monroe, Chicken and Hen Islands, Sandusky Bay, and Sandusky River ? and from one eastern basin site, Van Buren Bay, are analyzed. Walleye tagged at the Monroe, Chicken and Hen Islands, and Van Buren Bay are considered individual stocks and walleye tagged at the Sandusky Bay and Sandusky River sites are considered one stock. Spatial distributions are quantified by construction of a spatially-explicit population model that follows groups of releases from the first May after spring tagging through October of the second year after release and estimation of model parameters in a maximum-likelihood framework. Two different estimation frameworks are implemented that handle tag-loss rates and tag-reporting rates uniquely, so the effects of these ?nuisance parameters? can be analyzed. The results confirm previous tagging studies that show movement of western basin walleye