低温和饥饿对华贵栉孔扇贝幼虫生长和存活的影响

为了弄清我国南方低温季节能否利用自然水温进行华贵栉孔扇贝人工育苗以及饵料缺乏对幼虫的影响,于2008年10月上旬和11月下旬,分别在水温25.5—28.0℃和18.2—22.5℃条件下,研究了低温和饥饿对幼虫生长、存活的影响。实验分两次设置常温、低温和饥饿3个组进行。结果表明,低温情况下,幼虫摄食较少,活力差、绝大部分沉入水底,生长缓慢,发育迟缓,但存活率仍较高;饥饿不但抑制幼虫的生长和发育,同时也显著地降低幼虫的存活率。此外,低温和饥饿的结合会加剧对幼虫生长、发育、存活等的抑制作用。这些结果说明在我国南方水温低于23℃的季节利用自然水温已不适合进行华贵栉孔扇贝苗种生产。

Effects of low temperature and starvation on larval growth and survival of noble scallop Chlamys nobilis Reeve

In order to test whether ambient seawater with low temperature and food availability during the late Autumn and Winter seasons is suitable for artificial seed production of noble scallop Chlamys nobilis Reeve in southern China, studies were conducted to investigate the effects of low temperature and starvation on larval growth and survival of this species at temperatures of 25.5-28.0℃and 18.2-22.5℃ in early October and late November, 2008. Three test groups were set up : (1) larvae were reared under normal temperature (25.5-28.0℃) and fed with enough food, (2) larvae were reared under low temperature (18.2-22.5℃) and fed with enough food, and (3) larvae were reared under low temperature ( 18.2-22.5℃) and unfed. The results showed that larvae fed less, active worse, grew and developed slower under lower temperature than those under normal temperature, but there was no significant difference in larval survival between low and normal temperature groups. Starvation, however, not only significantly affected larval growth and development, but also significantly affected larval survival. When treated with the combination of low temperature and starvation, larvae displayed less survival, slower growth and development than those only under starvation. The present results may suggest that it should be unsuitable to use natural seawater for reproducing artificial seeds of noble scallop when ambient seawater temperature was lower than 23℃ in southern China.