Gas exchange in the carp gills in normoxic and hypoxic conditions.

Respiratory exchange measurements in a teleost fish, Cyprinus carpio, in normoxic and hypoxic conditions are presented. Oxygen pressure in the dorsal aortic blood in normoxic carp was much lower than that in most of teleosts and elasmobranchs in similar conditions. The most evident physiological adjustment to the hypoxic condition was the increased ventilation due to an increased frequency of operation of the branchial pump. Increased perfusion at the gills played a small role in the physiological adjustments.