光周期条件对罗氏沼虾幼体存活率及体长生长率的影响

Influence of Photoperiod on Survival and Growth of Macrobrachium rosenbergii larvae

用４Ｌ：２０Ｄ、８Ｌ：１６Ｄ、１２Ｌ：１２Ｄ和２４Ｌ：０Ｄ四种光周期条件培养罗氏沼虾状幼体，观察其存活率和生长、发育情况．研究结果表明，随着光照时间的延长，特别是在连续照明的条件下，与最短的光照条件相比，幼体的存活率及体长生长率分别提高１５．７％和２．２％／ｄ，而育成Ｐ１（仔虾）的时间却相应缩短了１０ｄ．

The experiments were carried out on the iceal larvae of Macrobrachium rosenbergii(De Man) to exadrine the effect of photoperiod on survival and growth in body length.The larvae were reared from first iceal stage to postlarval stage under 4L:20D,8L:16D, 12L : 12D and 24L:0D photoperiods, separately.There were significant differences in survival and growth rate. Reared in long-day especially under continuous illumination, rates of survival and growth of larvae were 15.7% and 2.2%/d higher respectively. Metamorphosis was 10 d faster than that in short -day.