Abstract: Effects of water temperature and sperm species on fertilized egg diameter,fertilization rate and hatching rate were studied in sea urchin hybrids between Strongylocentrotus intermedius（Si） and Anthocidaris crassispina（Ac）,and developing time and length of self propagated and hybridized larvae were compared in the hybrids in order to investigate the pattern of fertilization,hatching and larval development of the hybrids.The results showed that Si had egg diameter of（86.64 μm ± 4.21 μm）,significantly smaller than Ac（95.62 μm ± 3.80 μm）（P 〈0.01）.There was significantly larger fertilizated egg diameter in self propagated hybrid（Si♀ × Si♂） than that in hybrid（Si♀ × Ac♂） at 21 ℃ and 24 ℃（P 〈 0.01）.However,fertilizated egg diameter of Ac was not affected by temperature or sperm species（P 〈 0.01）.Fertilization rates of self propagated sea urchins were significantly lower than those of cross groups in all the experimental temperatures.Fertilization rate of Si♀ × Ac♂ at 21 ℃ was not significantly different from that at 24 ℃（P 〉 0.05）.For hybrid（Ac♀ × Si♂）（38.91% ± 8.25%）,however,fertilization rate at 26 ℃ was significantly higher than that at 24 ℃（0.79% ± 1.11%）（P 〈 0.01）.Hatching rate was significantly lower in hybrid（Si♀ × Ac♂） at 21 ℃（87.96% ± 4.18%） than that in hybrid（Si♀ × Si♂）（99.64% ± 0.81%）（P 〈 0.01）,both fertilized eggs being not hatched successfully at 24 ℃.There was significantly lower hatching rate in hybrid（Ac ♀ × Si ♂）（9.32% ± 4.33%） than that in hybrid（Ac ♀ × Ac ♂）（100%） at 24 ℃（P 〈 0.01）.At 26 ℃,however,fertilized eggs of both hybrids was not hatched successfully.The fertilized eggs of both hybrids（Ac♀ × Ac♂ and Ac♀ × Si♂） developed into eight-armed pluteus larvae 5days post-fertilization at 24 ℃,and 9 days and 12 days at 21 ℃,respectively.The findings suggested that 24 ℃be the suitable temperature for fertil
2015, Vol. 30 
