Facultative Aerial Respiration in an Intertidal Sculpin, Clinocottus analis (Scorpaeniformes: Cottidae)

Abstract

Clinocottus analis, a common tidepool cottid fish occurring in the marine intertidal zone in central and southern California, readily tolerated exposure to air for up to 24 h. Like species of amphibious marine fish, its rate of O₂ consumption during air exposure was not different from that when in water, even after 24 h in air. Aerobic metabolism was suficient to meet resting metabolic needs, as shown by the absence of an increase in aquatic O₂ consumption rate following air exposure and the lack of accumulation of lactate as a result of 6 h of aerial exposure. Aerial release of CO₂ was high, and aerial respiratory exchange ratio (CO₂ released/O₂ consumed) was 0.82, suggesting that respiratory acidosis should not occur during air exposure. These results indicate that C. analis, although it may be emerged only rarely during low tides in nature, is able to respire in air.