SREL Reprint #1219




Predator-Induced Changes in Thermoregulation of Bluegill, Lepomis macrochirus, from a Thermally Altered Reservoir

Robert U. Fischer Jr., Edward A. Standora, and James R. Spotila



In the absence of a predator, small bluegill (Lepomis macrochirus) had a mean upper avoidance temperature of 30.0C as compared with 29.8C 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 33.9C, respectively, while large bluegill had a mean upper avoidance temperature of 33.8 and 33.1C.  The preferred temperatures of large bluegill (X=26.3C) were statistically higher than that of small bluegill (X=25.2C).  There was no significant difference in the preferred temperatures for bluegill from heated and normothermic sites.


SREL Reprint #1219

Fischer, R.U., E.A. Standora, and J.R. Spotila. 1987. Predator-induced changes in thermoregulation of bluegill, Lepomis macrochirus, from a thermally altered reservoir. Canadian Journal of Fisheries and Aquatic Sciences 44:1629-1634.

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