Abstract:To determine the optimal temperature of embryonic and larval development of Procambarus clarkii,we observed the embryonic and larval development process,and recorded the survival rate,development time,biological zero degree and effective accumulated temperature at four temperatures (19℃,22℃,25℃ and 28℃). The results showed that the hatching time,hatching rate and larval development of P. clarkii were significantly affected by temperature (P<0.05). The embryonic development was accelerated with the temperature increasing within the experimental temperature range (1928℃),and the development time at 19℃ was (622.67±6.02) h post spawning,while it was only (349.67±4.63) h at 28 ℃. The embryonic hatching rate firstly increased and then decreased with the temperature increasing,with the highest hatching rate of 91.03%±2.97% and lowest of 40.53%±4.97% obtained at 22 ℃ and 28 ℃,respectively. The larval development time decreased with the increase of temperature,and the development time at 19 ℃ was (304.00±10.73) h,while it was only (194.00±9.03) h at 28 ℃. The larval survival rate firstly increased and then decreased with the increase of temperature,and the highest (94.37%±1.60%) and lowest (82.67%±1.51%) survival rate were obtained at 22 ℃ and 28 ℃,respectively. The biological zero of embryonic and larval development calculated by SandersonPearis formula were 7.32 ℃ and 3.29 ℃.Further,a temperaturedependent developmental model for the P. clarkii embryos and larvae was built. According to the curve fitting equation,the optimal temperature of embryonic and larval development were 22.06℃ and 22.78℃,respectively. Therefore,it is recommended that the optimal temperature range for the embryonic and larval development during artificial P. clarkii breeding process should be set at 2225℃.