Measurements of cardiovascular physiology of the Antarctic fish Pagothenia borchgrevinki and Trematomus bernacchii acclimatized to -1°C and +4°C

This study tested this hypothesis by determining the thermal plasticity of the Antarctic fish Pagothenia borchgrevinki. Fish were acclimated to either -1°C or +4°C for at least 4 weeks.

Fish were exercised in a swimming respirometer using a standardised Ucrit measure of performance at their acclimated temperature and at other temperatures at the opposite end of the range they were acclimated to from -1°C up to 8°C. Cardiac output, heart rate and blood pressure was measured from each fish at rest and during stress (exercise and temperature). Samples of tissue (red and white muscle, heart and liver) were collected from all of the fish and analysed for both anaerobic and aerobic enzyme activity to determine if the fish acclimatized to the new temperatures by determining if their biochemical systems have changed.