Comparative studies of the respiratory functions of mammalian blood X. Killer whale ( Orcinus orca linnaeus) and beluga whale ( Delphinapterus leucas)

Abstract

Respiratory characteristics of blood from two adult killer and two adult beluga whales were studied. Both of these are dolphins; killer whales attain weights up to 7000 kg and belugas up to 700 kg. Oxygen dissociation curves of the blood were constructed at 37 °C and corrected to a plasma pH of 7.40. Beluga whale blood had a significantly higher (P < O.01) oxygen capacity than killer whale blood (25.8 ± O.6 vs 21.8 ± O.5 vol%). The mean P 50 values were 25.2 ± O.5 and 24.4 ± O.1 mm Hg, respectively, for killer and beluga whale blood and these are significantly different (P < O.05). The Bohr factor for killer whale blood (− O.602 ± O.148 Δlog P O 2 / ΔpH) was not significantly different than that for beluga whale blood (− O.782 ± O.073), but the Haldane effect for killer whale blood (7.0 vol%) was smaller than for beluga whale blood (9.4 vol%). The concentration of 2,3-diphosphoglycerate in killer whale blood was significantly higher (P< O.01) than in beluga whale blood(15.12 μmol/g Hb vs 11.49 ± O.63 μmol/g Hb). Starch gel electrophoresis showed that killer whale hemoglibin has two major components and beluga whale hemoglobin has only one major component. The fast-moving component of killer whale hemoglobin and the single major component of beluga whale hemoglobin migrate at the same rate as human A hemoglobin. A relationship between body weight and blood oxygen affinity, which is seen in land mammals, is not apparent in the published data for aquatic mammals.