RESPIRATORY ADAPTATIONS OF SACRAMENTO BLACKFISH, ORTHODON-MICROLEPIDOTUS (AYRES), FOR HYPOXIA

1. 1. Resting routine oxygen consumption rates of adult Sacramento blackfish increased from 41.18mg O2/kg/hr (10°C) to 190.74mg O2/kg/hr (30°C) under normoxic conditions. 2. 2. Significant metabolic depressions were measured under 40 torr Po, hypoxia at 25°C (P < 0.05) and 30°C (P < 0.01) compared with normoxia values at the same temperature. 3. 3. High oxygen affinity, a significant Bohr effect, a hyperbolic blood oxygen dissociation curve, and an extraordinarily small temperature shift characterize the oxygenation dynamics of the blackfish hemoglobin(s). 4. 4. The above respiratory adaptations indicate successful habitation of many hypoxic environments including culture ponds. © 1979.