Abstract:Effects of different photoperiods on reproduction performances and accumulation of main biochemical components in the fertilized eggs of the red claw crayfish , Cherax quadricarinatus , were investigated. Crayfish were divided into five groups , group Ⅰwas nature light , group Ⅱto group Ⅴwere 12 h light/12 h dark, 14 h light/ 10 h dark , 16 h light/ 8 h dark , and 18 h light/ 6 h dark respectively. Results showed that during the one2 and two2month periods spawning rate , weight gain rate , gonadosomatic index , and hatching rate of all experimental crayfish changed hyperbolically , with group IV exhibiting the highest values for each of these four endpoints, specifically, 61. 54 % for one2month period spawning rate , 92. 31 % for two2month periods spawning rate , (29. 48 ?0. 51 ) % for weight gain rate , (5. 38 ?0. 25 ) % for gonadosomatic index,and (46. 99 ?3. 15) % for hatching rate. Additionally , the total weight of eggs per female crayfish , the average spawning number and the average weight of individual eggs per female were the greatest in group Ⅳ. Significant increases in total amino acids (essential and non2essential amino acids ) of the fertilized eggs and main amino acids (Leu , Arg and Glu) were also found in group Ⅳ. Total lipids of fertilized eggs (dry weight and wet weight) in groups Ⅲ and Ⅳ were the highest and each significantly differently from those of the other three groups. Photoperiod had no effect on the proportional accumulation of neutral lipids and phospholipids. The content of neutral lipids in each group was approximately twice as much as that of phospholipids. Both neutral lipids and phospholipids of all experimental crayfish were found to be mainly composed of C18∶1ω9 , C18∶2ω6 , C16∶0, and C16∶1 fatty acids. For crayfish of group IV , the content of C20∶4 was slightly lower whereas the contents of 16 h light/ 8 h dark is the ideal light regime for reproduction performances in this crayfish. C20∶5ω3 and C22∶6ω3 were slightly higher than those for the other groups. These results suggest that photoperiod can significantly affect reproduction performances and the quality of the fertilized eggs of Cherax quadricarinatus and