Studies On Anaesthetic And Sex Differentiation Of Cynoglossus Semilaevis Günther

In the paper studies the anaesthetic effect of clove oil and MS-222 on adult Cynoglossus semillaevis Gunther, aim at resolving the difficult problem of artificial insemination and reducing the difficult problem difficult to transport survival percentage low responding to exciting reaction; In the paper gonadal development and differentiation of Cynoglossus semillaevis GUnther were observed by using histological techniques, formation way, sex gland differentiation time having ascertained the partly cunning tonguefish ovary cavity have waited for a data, the research aiming at being Cynoglossus semillaevis GUnther sex control technique has provided. Main result as follows:The frist experiment studies the anaesthetic effect of clove oil on adult Cynoglossus semillaevis GUnther at 20-21℃. According to the behavior characteristic of the fish in the final anaesthetic stage and the recovery process, the anaesthetic degrees could be divided into six stages, and the recovery process could be divided into four stages. The breath frequency of the fish slightly increased when the fish was in the final anaesthetic stage 1～3, and clearly declined until in the stage 4. The effective concentrations of clove oil on adult Cynoglossus semillaevis Gunther were 40-60 mg/L. Within this concentration range, the higher the concentration of clove oil, the shorter was the anaesthetic time needed for reaching stage 4, whereas the recovery time did not show ally significant differences. When the clove oil concentration were 40-60 mg/L, the longest survival time for the fish were over 20 minutes, when the concentration were over 80 mg/L, however, the longest survival time became less than 8 minutes. In addition, the time margin in between anaesthesia and death were very narrow. The fish should be restored immediately after being anaesthetic, otherwise, the fish would die.The second experiment studies the anaesthetic effect of MS-222 on adult Cynoglossus semillaevis Gunther at 23＋0.3℃seawater. The breath frequency of fish slightly increased when the fish was in the final anaesthetic stage 1～3, and clearly declined until in the stage 4. The effective anaesthetic concentration of MS-222 on adult Cynoglossus semiUaevis G u nther were 120～210 mg/L. Within this effective concentration range, the higher the concentration of MS-222 , the shorter was the anaesthetic time needed and longer recovery time of fish was. The exposure time to air in short time and repeated anaesthetic treated fish have no clear effect on the time of fish recovery.In the thrid experiment, gonadal development and differentiation of Cynoglossus semillaevis GUnther were observed by using histological techniques. Gonad remained undifferentiated at 25 days old. The primordial gonads differentiated into ovaries from 55 days old, at 97 days old, the ovarian cavity was formed, at 110 days old, the differentiation of ovarian cavity was completely formed, at 120 days old, the early perinucleolus stage oocytes were accurred. The primordial gonads differentiated into testis from 100 days old, at 120 days old, the formation of eseminiferous tubules fist occurred, at 136 days old, the differentiation of testis was completely formed. The gonadal differentiation in females occurred much earlier than in males. The gonad of Cynoglossus semillaevis GUnther's gonads are dissymmetry.