不同光周期条件下罗氏沼虾幼体摄食量及发育的研究

于１９９１年３－５月，在光周期Ｌ：Ｄ为４：２０，８：１６，１２：１２和２４：０四种条件下以卤虫无节幼体作饵料，在三角烧瓶中对实验室孵化的罗氏沼虾通状休进行单只培养，测定各期状幼体的日摄食量和总摄食量，并观察幼体的发育情况，结果表明，随着光照时间的延长，特别是连续照明的条件与最短的光照时间条件相比，幼体的日摄食量增加４０％－１５０％，育成的Ｐ１体重增大４０％，且育成Ｐ１的时间缩短９ｄ，而幼体完成整个

INFLUENCE OF PHOTOPERIOD ON FOOD CONSUMPTION AND DEVELOPMENT OF MACROBRACHIUM ROSENBERGII LARVAE

The effect of photoperiod on food consumption and development of the larvae of Macrobrachium rosenbergii (DE Man) were examined from March to May, 1991,in the Tokyo University of Fisheries. After the larvae hatched in laboratory, they were fed with Artemia nauplii and individually reared from the firs zoeal stage to postlarval stage under four L:D photoperiods: 4:2O, 8:l6, 12:12 and 24:O. Groups under different experimental photoperiods showed significant differences in molting behaviour and development rate The larvae reared under continuous light condition molted at all times in 24h, but most ecdysis (47%) were observed at 12:(X) - l8:00. For the other be groups, ecdysis mostly (93% - 97%) occurred at 00:00 - 06:00 in darkness. There were 1O-16 instars before metamorphosis in all groups. Short-day larvae tended to pass through an extra stage, e.g. larvae at UD 42O passed 3 instars more in average than those reared at 24:O. The intermolt period was each in each group however, accumulated zoeal duration was 6- 10d longer in the 42O group than in other groups. Food consumption was also significantly different in different photoperiod groups. Daily food consumption was higher with increasing lilght period, especially in the 24O group Which was 40% - 15O% higher than that of the 42O group in the same instars. The total food consumption of an larval development instars in the four groups was in the order 8:l6>12:l2>42O>24O. The larval growth also increased with increasing light period, especially under continuous light condition. Metamorphosed postlarvae growth was 4O% higher than that of the 42O group if growth is expressed in dry weight. Since higher accumulated food consumption and lower growth was noted in the 42O group, their food conversion efficiency was markedly lower than that of the other groups. The Study showed that continuous light condition is an important favorable factor accelerating the lawae development.