Oxygen consumption rates and lactic acid levels of notothenioid fish to determine the exercise physiology of how a low water temperature has affected their ability to swim

Notothenioid fish live in a relatively constant temperature of -1.86°C. In order to survive at this temperature they have undergone several modifications to their biochemical makeup. The ability of these fish to swim at low temperature was investigated with aspects of exercise physiology examined in order to determine how the low temperature has affected their ability to swim. Pagothenia borchgrevinki (a pelagic fish) and Gymnodrace acuticeps, Trematomus bernacchi and T. hansonii (benthic species) were caught using baited hand lines and kept in still water (or small flow through) aquarium systems. A purpose built tunnel respirometer was used to observe swimming and to determine oxygen consumption values (using oxygen electrodes) of the fish by regulating the speed of water flow in the closed system and hence the swimming ability of the fish (sprint vs endurance vs resting). Blood and muscle samples were taken to determine the anaerobic component of any exercise regime by measuring lactic acid levels. The P. borchgrevinki fish were swum to exhaustion and allowed to recover. Oxygen consumption rates and lactic acid values were monitored over 48 hours to determine the rate of recovery from the exercise. Results were compared between pelagic and benthic species.