Effects of temperature, hypoxia and activity on the metabolism of juvenile Atlantic cod

Standard metabolic rate (SMR), active metabolic rate (AMR) and critical oxygen saturation (S-crit) were measured in Atlantic cod Gadus morhua at 5, 10 and 15 degrees C. The SMR was 35.5, 57.0 and 78.2 mg O-2 kg(-1) h(-1) and S-crit was 16.5, 23.2 and 30.3%, at 5, 10 and 15 degrees C, respectively. Previously reported SMR for Atlantic cod from arctic waters at 4 degrees C was twice that measured at 5 degrees C in the present study. A possible intraspecific latitudinal difference in the SMR is discussed. The AMR was 146.6, 197.9 and 200.4 mg O-2 kg(-1) h(-1) and the critical swimming speed (U-crit) was 1.6, 1.7 and 1.9 at 5, 10 and 15 degrees C, respectively. The maximum oxygen consumption was found to be associated with exercise, rather than recovery from exercise as previously reported in another study of cod metabolism. (C) 1997 The Fisheries Society of the British Isles.