Predator-induced changes in thermoregulation of bluegill, Lepomis macrochirus, from a thermally altered reservoir

Abstract

In the absence of a predator, small bluegill had a mean upper avoidance temperature of 30.0°C compared with 29.8°C for large bluegill. In the presence of a predator (Micropterus salmoides), bluegill upper avoidance temperatures were significantly higher; however, predator size did not influence this relationship. In the presence of a small and large bass, small bluegill had a mean upper avoidance temperature of 34.0 and 33.9°C, respectively, while large bluegill had a mean upper avoidance temperature of 33.8 and 33.1°C. The preferred temperatures of large bluegill (mean 26.3°C) were statistically higher than that of small bluegill (25.2°C). There was no significant difference in the preferred temperatures for bluegill from heated and normothermic sites. -Authors