Levels of CO2 in arterial blood of carp under carbon dioxide anesthesia

The application of carbon dioxide anesthesia to fish has been studied in order to find a method of transport of live fish. In the continuation of this study, the levels of arterial PaO2, PaCO2 and pH were examined in carp anesthetized with carbon dioxide. In the initial stage of the anesthesia, both PaO2 and PaCO2 increased. In the following stage, PaCO2 gradually decreased. An increase or decrease in PaO2 seems to depend on the levels of PaCO2 during anesthesia. On the other hand, ECG (electrocardiogram) profiles of anesthetized carp indicate that a gradual increase in `R-R interval is coupled with a gradual decline of the opercular rate.