EFFECT OF TEMPERATURE ON RESPIRATORY AND CARDIAC RESPONSE OF BLUEGILL SUNFISH TO HYPOXIA

1. 1. Bluegill sunfish were acclimated to 30±1, 25±1 and 13±1°C and then subjected to gradually induced environmental hypoxia. 2. 2. Routine oxygen consumption, ventilation rate and heart rate were measured at varying oxygen concentrations. 3. 3. Fish at 25 and 13°C showed varying degrees of oxygen independence. Those at 30°C exhibit oxygen dependence. 4. 4. During hypoxia, ventilation rate increases in both 13 and 25°C fish but failed to do so at 30°C. Bradycardia occured in all acclimation temperatures. 5. 5. The results indicate that the environmental temperature of the bluegill significantly affects its response to gradual hypoxia. © 1969.