ARTIFICIAL PROPAGATION OF TANK-CULTURED CHINESE GIANT SALAMANDER(ANDRIAS DAVIDIANUS)

Chinese giant salamanderAndrias davidianus (Blanchard),Which is the largest species in amphibian, is found in 17 provinces of China. The resources of salamander are declined remarkably because of inordinate catching by men. Therefore, the artificial domestication and propagation of salamander are widely developed in the present time. In this paper, the results of propagation for artificial domesticated brood in Chinese giant salamander are reported. The salamanders for the test were caught from Hubei and Sanxi Provinces. The area of each tankfor domestication was 16m2 and the depth of water was 0.20m. In each tank, 12-40 salamanders are cultured in static water, which came from tap water. The water was changed once in 1-2 days. The temperature of water changed from 5 to 26 ℃in all year. The feed was fresh 533 fish. In the condition of artificial domestication, it takes 5 yearsfor the Chinese giant salamander to attain gonad maturity and the gonads can be normally developed. Its reproductive cycle is once a year and fastigium is 6-8 month in each year. Its ovulation and spermiation can be induced byLHRH-A or HCGinjection. Individual differences were observed in gonad development within the population. During the reproductive fastigium, only about 60 % brood salamanders can lay eggs after hormonal injection. It takes 10-20 days more for male thanfemale to attain gonad maturity. The phenomenon is often observed that the gonad of some individuals in the population attaining progenitive age cannot attain maturity. When the filial generations coming from artificial propagation attain maturity, their individual differences of gonad development are also observed. If they were not induced by exterior hormone, the mature individual under the condition of artificial domestication would not take ovulation and spermiation. Furthermore, their gonads will degenerate and absorb naturally. After induced by hormone, fe-male salamanders can lay eggs naturally in tank, but copulatory action is not observed. The reactive time for salamander spawning is related with different hormone and water temperature. The reactive time of LHRH2A was longer than that of HCG. The lower the water temperature was; the longer time needed. If the water temperature declines 1 ℃, the reactive time will delay 10 hours. Induced by the extender of LHRH2A and HCG, the reactive time of female was about 96-120h and sperm could be extruded in male after 80h. The quantity of eggs laid by each brood salamander was about 400-500, with an average of 430. The ovulated quantity of repetitious spawning brood was more than that of first spawning brood. The method of inducing ovulation was that exterior hor-mone was directly injected into the celomof salamander. The effect of once injection was better than that of more than one injec2 tion. No significant effects were found upon the gonad development and spawning rate by using low doses of hormones for induc2 ing maturation. On the contrary, low doses of hormones could lead to the abortion of some brood salamander.