河口区凡纳对虾亲虾培育及其生长和蜕皮

Growth, molt, and maturation of shrimp brood stock Penaeus vannamei cultured in the river mouth area in Shanghai

首次在上海河口地区成功进行了凡纳对虾的亲虾培育和育苗 ,并重点研究了凡纳对虾亲虾的生长和蜕皮规律。通过一套自行设计的水循环系统来培育亲虾 ,盐度为 9～ 12的自然海水加盐度为 10 0～ 12 0的浓缩海水调配至盐度 2 8～ 30。 2 0 0余尾亲虾 (雌∶雄为 1∶1)经过近两个月的培育 ,成活率达 90 %左右 ,暂养 12d后 ,切除雌虾单侧眼柄促使亲虾成熟。手术后 3d ,即可观察到雌虾卵巢开始发育 ,7d后开始产卵 ,但未受精。 30d后 ,雌、雄虾出现追尾、交配现象 ,得到受精卵并孵化出无节幼体。试验结果表明 ,利用河口区低盐海水兑配高盐浓缩海水在水循环系统中培育亲虾 ,最终生产出健康的苗种是完全可行的。切除眼柄前亲虾完成一个蜕皮周期需要 14～ 15d ,手术后 ,卵巢开始发育 ,蜕皮周期延长到 2 0d左右。凡纳对虾亲虾在整个实验期间一直持续生长 ,切眼柄前雌虾的平均日生长率为 0 .2 5mm ,较切眼柄后的 0 .17mm快 ,雄虾的平均日生长趋势与雌虾相似 ,前期为 0 .2 0mm ,后期为 0 .15mm。文中还讨论了有关切除眼柄后亲虾生长减慢。

A recirculating system was designed for shrimp brood stock Penaeus vannamei culture indoor in the low salinity area of the river mouth in Shanghai. The natural seawater with salinity of 9-12 was mixed with concentrated seawater with salinity of 100-120, which made the culture water salinity reach 28-30. About 200 shrimp brood stock (female∶male was about 1∶1) were cultured in the recirculating system for two months, and the survival rate of the shrimp was about 90%. Unilateral eyestalk ablation of female shrimp was done for stimulation of the ovary maturation. Three days after the operation the ovary development could be observed clearly, and one week later, a part of shrimp began to spawn, but the eggs were not fertilized. One month later fertilized eggs appeared and nauplius were obtained. The results showed that shrimp brood stock P. vannamei cultured in this recirculating system could live healthily and spawn successfully. The regularity of molting and growth in shrimp brood stock P. vanamei was investigated. Before ablation of eyestalk, the mean molt interval was about 14～15 days, and after that, the mean molt interval extends to about 20 days due to ovary development. With molting the body length of shrimp brood stock increased continuously, whether before or after ablation of eyestalk, but the mean daily increase of body length before ablation (female:0.25mm, male: 0.20 mm) is greater than that after ablation (female:0.17mm, male:0.15). The reasons of lower growth rate and longer molting interval were discussed.