Acute and Final Temperature Preferenda as Predictors of Lake St. Clair Fish Catchability

Geographic distributions of major fish species resident in Lake St. Clair, field assessments of their seasonal thermal distributions, and laboratory determinations of their median and maximum final temperature preferenda were compared with their catchability at different temperatures. Fish catchability at various temperatures was estimated (regression analysis) during the fall pound net set survey (1977–88) using number of fish caught per 24-h net set as the dependent variable. Swimming activity was expected to be higher at temperatures closest to the species' preferred temperature, thereby increasing catchability. Maximum final temperature preferendum was the best predictor of observed fish temperature preferences. Geographic distributions and median final temperature preferenda were better predictors than summer or fall seasonal thermal distributions. Acute temperature preferenda were also good predictors of fish catchability at different temperatures. Of the 22 species examined, the catchability of Centrarchidae (five of six species), Catostomidae (two of five species), Clupeidae (one species), Ictaluridae (two species), and Percichthyidae (two species) was greater in warmer water, while the catchability of Amiidae (one species), Cyprinidae (one species), Catostomidae (three of five species), Esocidae (one species), Percidae (two species), and Sciaenidae (one species) increased in colder water. Temperature significantly accounted for differences in catchability among most species (14 of 22).