THE INFLUENCE OF GRADUAL WATER ACIDIFICATION ON THE OXYGEN-CONSUMPTION PATTERN OF FISH

1. Carp (Cyprinus carpio) and tilapia (Oreochromis mossambicus) were k ept in a flow-through respirometer for a week, while continuous oxygen consumption measurements were carried out, at a constant water O2 con centration. 2. Our measurements showed that tilapia decreased its stan dard metabolic rate (SMR), its average oxygen consumption, and its max imum metabolic rate in acid water (pH 4.0), whereas carp did not. 3. I t is proposed, based on our results, that carp and tilapia probably ha ve different strategies to survive pH depression episodes: whereas til apia avoids the additional stress of exercise, carp tries to escape th e acid conditions.