中华绒螯蟹在实验室条件下的成蟹阶段蜕壳与生长观察

Observation on molting and growth of adult Chinese mitten crab reared in the laboratory condition

在实验室条件下,进行了中华绒螯蟹成蟹阶段（200 d）的个体蜕壳与生长观察。在观察的4次蜕壳中,实验河蟹蜕壳后的体重平均增长率分别为48.7%、69.1%、80.1%和64.8%,壳长平均增长率分别为21.3%、17.0%、29.5%和16.7%,壳宽平均增长率分别为17.4%、18.3%、28.2%和18.1%;雄蟹每次蜕壳后的体重、壳长和壳宽均高于雌蟹,但从第3次蜕壳开始,雌雄间才呈现出显著的生长差异（P〈0.05）。第1-4次的平均蜕壳间期分别为37、38、29和41 d。在前两次蜕壳,其蜕壳后的生长变异系数较大,而在后两次蜕壳,其蜕壳后的生长变异系数相对较小。起始体重对每次蜕壳后体重有显著影响（P〈0.05）,第3次蜕壳后的体重与其他次数蜕壳后体重呈显著相关（P〈0.05）。研究还发现,壳长、壳宽与生长水温有显著的相关性（P〈0.05）,体重与生长水温的相关性略显著（r=0.917~0.923,0.05〈P〈0.10）。以上研究结果表明：河蟹成蟹阶段在第3次蜕壳时的增长率最高,对生长影响较大,应注意此阶段的饲养与管理;同时,在生产上为提高成蟹的养成规格应选取规格较大的蟹种。

In this study,observation on molting and growth of Chinese mitten crab（ Eriocheir sinensis） at adult stage（ 200 days） was carried out under laboratory conditions. The results showed that the average growth rate of body weight at the first to fourth molting stages was 48. 7%,69. 1%,80. 1%,64. 8%, respectively; the average carapace length growth rate was 21. 3%,17. 0%,29. 5%,16. 7%,respectively; the average carapace width growth rate was 17. 4%,18. 3%,28. 2%,18. 1%,respectively. The body weight,carapace length and carapace width of male individuals were higher than those of female individuals at each molting stage,and the significant differences（ P 0. 05） were found since the third molting time. The average molting period was 37 days,38 days,29 days and 41 days for the first to fourth molting stages, respectively. The coefficient of variation of growth was higher at the first two molting stages than that at the latter two molting stages. The initial weight had significant effect（ P 0. 05） on the weight gained after each molting. There was significant difference（ P 0. 01） in weight,carapace length and carapace width among each molting stage,and the body weight after the third molting stage had significant correlation（ P 0. 05） with the weight at other molting stages. This result also showed the carapace length and carapace width had significant correlation（ P 0. 05） with the culturing temperature,however,the body weight had slightly significant difference（ r = 0. 917-0. 923,0. 05 P 0. 10） with the culturing temperature. Generally,the present study showed that the growth rate was the highest at the third molting stage,indicating its important effect on the growth and culture practice at this stage. Meanwhile,the results showed that the larger size of juveniles,the larger size of adults would be.