The influence of body weight on gas exchange in the air-breathing fish, Clarias batrachus

Abstract

Abstract: The oxygen consumption of Clarias batrachus varies as a function of weight and access to air. The metabolic rates of Clarias in air and water with access to air are essentially the same, but the V̇O2 of forcibly submerged fish is lower. C. batrachus is a facultative air breather and at aquatic oxygen tensions exceeding 40 mm Hg. an oxygen regulator. Aerobic metabolism is primarily utilized during forcible submergence. The critical oxygen tension of Clarias is proportional to body weight and about 1/3 the value for bimodally-breathing salamanders. The number of air breaths per unit time doubles at night and is inversely proportional to body weight. The sensitivity of its naked skin to desiccation and the low bicarbonate buffering capacity of its blood limit the terrestrial activity of Clarias to rainy nights when a cutaneous film of water can be maintained. © 1976.