The swimming ability (mechanics, oxygen consumption, level of hormones, the effects of temperature, lactic acid production) of the Antarctic fish Pagothenia borchgrevinki

Antarctic fish kept in the aquarium system in the wet lab were videotaped while swimming and the data was analysed frame by frame to determine swimming mechanics in these animals. Fish were also introduced to a tunnel respirometer and exercised at a steadily increasing water velocity until they could no longer swim. This is a standard measure known as the U-crit. The respirometer allows oxygen consumption to be measured while the fish is swimming. Blood samples were taken before exercise and immediately following a bout of exercise. All samples were centrifuged to separate plasma from blood cells and analysed for levels of catecholamine’s and lactic acid. The effects of temperature on the swimming ability of Pagothenia borchgrevinki was examined by exercising fish at known temperatures at known speeds in a purpose built exercise tunnel. Swimming ability was determined as was the metabolic rate of the fish at each temperature and each swimming speed. There is an assumption that anaerobic processes have not shown metabolic cold adaptations and as a consequence Antarctic fish are unable to function well under anaerobic conditions. Fish were exercised in the purpose built exercise tunnel respirometer to a standard U-crit regime until the animal fatigued. Blood and muscle samples were taken for analysis of lactic acid production, blood haematocrit levels and the level of aerobic and anaerobic enzymes in fish muscle. Isolated muscle blocks of myotomal (white muscle from the tail section) and pectoral (red muscle from the proximal end) were mounted and stimulated until fatigue occurred. The tissue was collected for analysis of anaerobic enzymes and the level of lactic acid produced.