Fig. 2. (A) Oxygen consumption (_O2) and (B) cardiac output () of resting (•) and swimming () sockeye salmon during an acute temperature increase of 2°C h^–1. For swimming fish, an initial resting value at 15°C was obtained prior to swimming (). At the end of the acute temperature increment, water velocity for the swimming fish was immediately decreased to the resting level and the temperature was decreased to 15°C over an hour before a recovery measurement was recorded for both groups. All values are means ± s.e.m. Different letters indicate significant differences between temperatures within the same group. An asterisk indicates a significant difference between resting and swimming fish at a given temperature.