低盐度条件下罗氏沼虾人工育苗试验

Artificial seedling of Macrobrachium rosenbergii at lower salinity

在水温30的条件下,用8个盐度梯度(4、7、10、13、16、19、22、25)的育苗用水进行罗氏沼虾人工育苗对比试验,结果表明:在7￣13的盐度范围内,罗氏沼虾幼体生长发育正常,变态时间均值为181d,而过高或过低盐度明显延长变态时间,且存活率很低;用淡水孵化罗氏沼虾幼体,每天增加盐度2￣10,幼体的生长发育和变态与育苗盐度始终保持在10的对照组相比没有显著差异;罗氏沼虾在盐度为10的水体中孵化并发育到第期后,每天降低盐度2直到变态,幼体变态时间平均缩短2￣3d,且变态同步性较高。研究表明,罗氏沼虾幼体对盐度变化有较强的适应能力,因此在低盐度条件下进行罗氏沼虾生产性育苗是可行的,本研究可明显节约罗氏沼虾育苗过程中的海水用量,降低育苗成本,为内陆地区大面积推广罗氏沼虾养殖提供了一定的技术依据。

Effects of salinity (4、7、10、13、16、19、22、25 ) on breeding of Macrobrachium rosenbergii were determined at the water temperature of 30 .The results showed that M. rosenbergii grew normally and metamorphic time was 18 1 days with salinity ranging from 7 to 13 . However, either higher or lower salinity resulted in longer metamorphism and lower survival. No significant differences in growth and metamorphism were observed between controls (breeding at salinity 10 ) and M. rosenbergii breeding at fresh water, which grew in water where salinity was increased daily 2 until 10 . Metamorphism shorted by 2￣3 days when salinity decreased daily 2 after M. rosenbergii breed and grew at salinity 10 until stage , and very close metamorphic time was observed in these M. rosenbergii. Results suggested that M. rosenbergii breeding at lower salinity was feasible because of its higher adaptability to salinity. Our study helped to reduce the cost and amount of sea water,and provided technological support for M. rosenbergii breeding and culture in inland regions.