The aerobic scope of an antarctic fish,Pagothenia borchgrevinki and its significance for metabolic cold adaptation

Summary Resting weight-specific oxygen consumption of the cryopelagic Antarctic nototheniid Pagothenia borchgrevinki at 0°C was 39.6 ml kg^-1 · h^-1 for a 50 g fish, with oxygen consumption being described by the regression equation: log₁₀ VO₂(ml/h)=–1.104+0.825 log₁₀ M_b (g). These values are considerably below those raported by Wohlschlag (1964a,b). VO₂ max. in forced swimming was described by the regression equation: log₁₀ VO₂ max = –0.507+0.823 log₁₀ M_b. Despite low basal metabolism, factorial aerobic scope is similar to that reported for most other teleost fish, as is the cost of net transport. Myotomal muscles were used only at the highest swimming speeds and once they were recruited the fish fatigued rapidly. After swimming, oxygen debt was repaid rapidly, with a half-time of 20 min.