Observations on the haematology and oxygen transport of the New Zealand fur seal, Arctocephalus forsteri

Red cell count, haemoglobin concentration, haematocrit, mean cell volume, and mean cell haemoglobin concentration were recorded for the fur seal Arctocephalus forsteri (Lesson). The data did not indicate haematological adaptations for deep diving nor for extended periods of submergence. Two distinct haemoglobin types were isolated from the red cells by electrophoresis. The oxygen affinity of the blood was low as measured by half‐saturation values ( p 50) of 42.3 mm Hg at pH 7.1 and 26.2 mm Hg at pH 7.4 and 37°C. The low oxygen affinity was mediated by erythrocytic 2,3‐diphosphoglycerate, and on this basis a high turnover of oxygen to the tissues is postulated. The role of the blood in oxygen transport appears to be suited for feeding near the surface rather than by deep diving.