Absence of metabolic acclimation to cycling temperature conditions in the goldfish.

Studies of whole organism metabolism have failed to confirm an effect of cyclic acclimation in fish while studies at the hematological level show clear changes due to cyclic thermal regimes. To reevaluate the effect of cycling temperatures on fish metabolism, oxygen consumption was measured in goldfish acclimated to either a constant temperature (28 degrees C) or a diurnal sinewave cycle (20-36 degrees C). Fish from both acclimation conditions were tested at one of three temperatures (20, 28, 36 degrees C). Oxygen consumption increased with temperature but did so independently of the acclimation regime. Thus, cyclic acclimation did not alter metabolic sensitivity.