Temperatures Selected Seasonally by Four Fishes from Western Lake Erie

When four species of fish were taken from western Lake Erie in each of four seasons and held usually for less than 7 days at ambient lake temperatures, the temperatures they selected during 2–3 days in a horizontal temperature gradient differed seasonally. The differences were largely attributable to the conditions at which the fish had been acclimatized in the lake, and were modified by acclimation during 2–3 days in the gradient.The selected temperatures provided insights into the temperatures that might be selected by these species each season if the lake basin or other waters with similar seasonal ambient temperatures were subjected to thermal discharges. Temperatures selected were above ambient lake temperatures except for emerald shiners (Notropis atherinoides) in summer and fall. In general, white bass (Morone chrysops) and smallmouth bass (Micropterus dolomieui) selected a high range in temperatures throughout the year (18–30 C and 18–31 C, respectively), yellow perch (Perca flavescens) an intermediate range (10–29 C) and emerald shiners the lowest range (6–23 C). Three of the species were distributed within a relatively precise temperature range in the summer and within a larger range during other seasons; emerald shiners selected a narrow range during all seasons. A fairly stable temperature preference was usually reached within several hours in summer, but the temperatures selected by three species generally increased with time in the gradient during the other seasons; emerald shiners selected constant temperatures in all seasons. Temperatures selected by young and adults differed mainly in yellow perch and emerald shiners in summer and winter, when the lake temperatures fluctuated least.