Tribute to R. G. Boutilier: The effect of size on the physiological and behavioural responses of oscar, Astronotus ocellatus, to hypoxia

The physiological and behavioural responses of two size groups of oscar (Astronotus ocellatus) to hypoxia were studied. The physiological responses were tested by measuring M(O(2)) during decreasing environmental oxygen tensions. Larger oscars were better able to maintain oxygen consumption during a decrease in P(O(2)), regulating routine M(O(2)) to a significantly lower P(O(2)) threshold (50 mmHg) than smaller oscars (70 mmHg). Previous …