POSTEXERCISE METABOLIC-RATE IN ATLANTIC COD AND ITS DEPENDENCE UPON THE METHOD OF EXHAUSTION

This study tests whether or not post-exercise oxygen consumption rates (MO(2)) in fish are dependent upon how exhaustion is induced. A group of eight Atlantic cod (Gadus morhua) were each exercised using (1) a critical swimming speed (U-crit) protocol, (2) an exercise protocol designed to measure anaerobic capacity of fish (U-crit) 3, and (3) a protocol in which the fish were chased to exhaustion manually. MO(2) was measured for a 2-h period following exhaustion induced by all three exercise regimes (U-crit, U-burst and chase). Post-exercise MO(2) following exhaustion from the U-burst and chase protocols were significantly higher than post-exercise MO(2) following the U-crit protocol. Each fish during the U-crit protocol exhibited maximal MO(2) during exercise rather than during recovery, yet 75% of the fish during U-burst recovery and 100% during chase recovery exhibited MO(2) higher than that measured during U-crit exercise. These results, as well as the large interindividual variations in MO(2) among the eight fish, show that post-exhaustion MO(2) is specific to the exercise regime employed, thus, investigators must exercise caution when combining results from different exercise protocols and/or individuals. (C) 1995 The Fisheries Society of the British Isles