Short- and long-term cold-anesthesia in carp.

The efficacy of cold anesthesia in the transportation of live fish was evaluated using carp acclimated at 23°C. The carp could be safely maintained in an anesthetic state for 5h in water kept at 4°C and in the anesthetized or sedate state for 24h at 8-14°C. Some anesthetized carp showed signs of convulsion when they received external stimuli, and bled mainly from gills. Hemorrhage became distinct with the decrease in temperature and the duration of the cold treatment. The sedate carp showed no such excitement and bleeding. The sedate state is considered to be adequate for transportation, regardless of the anesthetic time; 14°C seems to be the optimal temnerature when the carp are acclimated to 23°C.