Relationship between Electrofishing Catch Rates of Age-0 Walleyes and Water Temperature in Minnesota Lakes

Abstract

Abstract We compared catch data for age-0 walleyes Stizostedion vitreum captured by night electrofishing 18 Minnesota lakes sampled over a wide range of water temperatures (4–25°C) throughout the fall 1996. The relationship between electrofishing catch per hour (CPE) of age-0 walleyes and temperature showed a curvilinear pattern, CPE rising and peaking at 18.6°C and declining thereafter, as water temperature cooled throughout the fall. Three different patterns of CPE were observed within subsets of the data, but peak CPE generally occurred at intermediate water temperatures, and declines in CPE generally occurred when water temperature dropped below 10°C. Mean lengths differed significantly between August and September in all but three lakes, but did not differ significantly between September and October, except in two lakes. For managers needing to assess age-0 walleye abundance before stocking advanced fall fingerlings, our data suggest that fall assessments should target water temperatures between 20°C...