Temperature effects on hematological responses of adult bluegill were examined for constant vs fluctuating temperature regimes, for ambient vs high temperature, and for intake vs discharge temperatures at an operating power plant. Multivariate statistical methods were used to determine temperature effects. Different hematological responses were observed between different constant temperature regimes, between different fluctuating temperature regimes, and between ambient and high temperatures, but not between intake and discharge areas of a power plant. Red blood cell roundness increased by 11 to 15% with the higher temperatures, but only accounted for approximately 17% of the total variation on the average. The hemotological responses were complex in all cases with 5 to 10 variables contributing to at least 80% of the total variation. (ERA citation 08:047464)