The respiratory physiology of Antarctic fish: resting metabolism, dermal respiration and haemoglobin denaturation investigations

Metabolic studies were made on 4 common species of notothenioids; Pagothenia borchgrevinki, Trematomus bernacchii, T. centronotus, T. hansoni and on one zoarcid species Rhigophila dearborni. Fish were housed in in-flow respiration chambers for at least 24 hours before beginning measurements, which continued for another 24-72 hours. Some Antarctic fishes have reduced the size and/or number of scales, which may improve oxygen uptake across surfaces other than the gills. Fish were placed in partitioned chambers, with the head (and gills) sealed off from the tail area, and rates of oxygen uptake were measured in the two compartments. The stability of Antarctic fish haemoglobin was determined by incubating solutions of purified haemoglobins at 50°C and testing in a spectrophotometer to determine the time at which 50% of the haemoglobin was denatured.