Anesthetic effect of MS-222 on juveniles of Sebastes schlegeli

The anesthetic effect of MS-222 on Sebastes schlegeli juvenile was investigated.The anesthetic process of experimental fish can be divided into six stages and the recovery process four stages,according to their corre-sponding behaviors.The respiratory frequency of the fish was slightly increased when the fish were in the final an-esthetic stage I～III,and then clearly declined at stage IV.MS-223 at low concentrations exerted slight influence on the respiratory frequency of the experimental fish.There was no remarkable difference in respiratory frequency between the 20～80 mg/L groups and the control group.The respiratory frequency of the sting fish was clearly de-clined,and even stopped in the high concentration MS-222(≥100mg/L).The optimum concentrations of MS-222 on Sebastes schlegeli juvenile was 80mg/L.After up to 12 times of repeated anesthesia,the time needed for anes-thesia and resuscitation of juvenile(TL=59.5mm) would be prolonged,indicating that anesthesia resistance capa-bility can be improved by repeated anesthesia.In addition,the time margin between anesthesia and death was short.The fish should be removed for recovery immediately after being anesthetized to prevent death.