The influence of abiotic factors on gillnet catch rates of yellow perch in southern Lake Michigan, 1989-2006

P>The difference in yellow perch, Perca flavescens (Mitchill), catch rates were evaluated for gillnets set on the bottom at 10- and 15-m depths in southern Lake Michigan during June, July and August from 1989 to 2006. More yellow perch were captured in gillnets set at 10 m than at 15 m. Differences in water temperature were significant in explaining variation in catch rates, but differences in Secchi depth and wave height were not significant. These results suggest that yellow perch may associate with habitat based on water temperature during the summer and move in response to thermal changes. In addition, this portion of the lake lacks noticeable heterogeneous structural habitat features that normally influence yellow perch behaviour. Fisheries managers should consider sampling based on temperature in addition to depth or other habitat features when designing sampling protocols.