Anesthetizer of the adult sea cucumber Apostichopus japonicus

Abstract

Anesthetizers were tested on adult Apostichopus japonicus, which expand and contract their bodies, to temporarily fix the body size and allow accurate length measurement. 10% ethyl alcohol seawatersolution saturated with menthol was prepared as the standard liquid. 40% seawatersolution of the standard liquid was the most effective and harmless, with all tested animals returning to normal behavior within 10 hours. In this anesthetizer, animals were motionless, and showed no reaction to pricking with forceps, and all their circumoral-tentacles relaxed externally, regardless of color type, body size or water temperature. While animals were under the anesthetic, the variance of measured body length was smaller than that of animals meagured before anesthetization. Thus we suggest this anesthetic method can be used as a new standard method for body measurement of sea cucumber adults.