斜带石斑鱼仔鱼的摄食节律及日摄食量

鱼类的日摄食节律分为白天摄食、晚上摄食、晨昏摄食和无明显节律四种类型。为了解斜带石斑鱼早期发育阶段的日摄食量及昼夜摄食规律,对孵化15天的仔鱼(全长4.86±0.38mm)在不同昼夜节律下的日摄食量和摄食节律进行了研究。结果如下:实验包括自然昼夜组(对照组)、持续光照组和持续黑暗组,各组对轮虫的日摄食量分别为142个/尾、156个/尾和47个/尾;白天摄食量比例分别为总摄食量的91.3%,80.5%和71.7%。对照组在正午(14:00)出现一个明显的摄食高峰;持续光照组在下午(16:00～18:00)出现明显的摄食小高峰;黑暗组则未出现明显的摄食峰。持续光照组在夜间的群摄食率明显高于对照组;黑暗组在白天的群摄食率明显低于对照组。持续光照组摄食强度小幅度增加,日摄食量为对照组的109.9%;而黑暗组摄食强度则明显下降,日摄食量为对照组的33.1%。综上所述,斜带石斑仔鱼摄食节律明显,属于典型的白天摄食类型;仔鱼的摄食与光照有着紧密的关系。

Studies on feeding rhythm and daily feeding amount of larval Epinephelus coioides

The daily feeding rhythms of fish were classified into four groups , named daytime feeding , night feeding , morning2dusk feeding and rhythmless feeding. In order to characterize the daily feeding rhythm and daily feeding amount of larval Epinephelus coioides , the fifteen2day2old larvae (4. 86 ?0.38mm,total length) were used for study. The obtained results were as follows : experiments consisted of natural day2night group (control group ) , continuous light group and continuous dark group , the daily feeding amounts of rotifer were 142/ larva , 156/ larva , 47/ larva respectively and the amount of daytime feeding were 91. 3 % , 80. 5 % and 71. 7 % of that of total daily feeding amount , respectively. In the control group , an apparent feeding peak appeared at 14 :00 PM. Similarly , in the continuous light group , the feeding peak presented at 16 :00 -18 :00 PM. Bycontrast,inthecontinuousdarkgroup,apparentfeedingpeakdidnotexist. Intheevening,thefeeding incidence of the continuous light group was higher than that of control group , in contrast with this , at the daytime , the feeding incidence of continuous dark group was much lower than that of control group . In the continuous light group , daily feeding amount increased slightly and it was 109. 9 % of that of control group , however , in the continuous dark group , daily feeding amount decreased obviously and it was 33. 1 % of that of control group. Taken together, our results showed that the feeding rhythm of larval Epinephelus coioides was identical with the daytime feeding. The feeding behavior of larval Epinephelus coioides had close relationship with light .