Abstract:The effects of different water temperatures (17,20,23,26 and 29℃) on the embryonic development speed,hatching,survival and fry production rates of silver carp Hypophthalmichthy molitrix were investigated in this study.Meanwhile,the relationships between both growth and deformity rate of the larvae and water temperature were also analyzed.The embryonic development time decreased and development speed accelerated with the increasing water temperature.The hatching,survival and fry production rates were significantly affected by different water temperatures (ANOVA,P<0.01).The survival and fry production rates at 17 and 20℃ were significantly lower than those at 23℃ (P<0.05),whereas were not significantly different at 26 and 29℃ from those at 23℃ (P<0.01).At the end of this experiment,the averaged total length of the larvae at 17℃ was significantly lower than that at 23℃,but not different from those at 20,26 and 29℃.Moreover,the deformity of the larvae occurred in all groups and there was no significant correlation between deformity rate and water temperature.The results indicated that the optimal water temperature for early development of silver carp is 23-26℃,the increase of 3-6℃ would not affect the artificial reproduction of the carp,while a sharp decline of 3-6℃ would cause seriously negative influence on the reproduction of the carp.