黄颡鱼早期发育阶段摄食的研究

本实验采用实验生态学的方法，分别对池养9、13、17、23日龄黄颡鱼的食物组成，选食行为和昼夜摄食节律进行了研究。结果表明，黄颡鱼早期发育阶段主要摄食浮游动物，其食物组成随仔稚鱼的生长而变化。摄食初期（黄颡鱼9日龄时）主要食物为枝角类和轮虫，其中枝角类数量和重量百分比分别为86.71%和89.65%，占绝对优势。之后，黄颡鱼的摄食范围进一步扩大，从23日龄开始，由主要选食枝角类转为主要选食桡足类，桡足类所占数量百分比也从初期的3.29%上升到23日龄时的26.68%；而且，从13日龄开始，摇蚊幼虫等底栖动物所占比重呈上升趋势，从初期的54.84%到23日龄的69.52%，始终在食物组成中占主要优势。黄颡鱼摄食具有明显的昼夜节律性，9日龄时摄食高峰值出现在20:00（897.7），低峰值出现在19:00（161.8）；13、17、23日龄仔稚鱼胃平均饱满指数均于4:00达最高峰（914.1、1113.1和199.7），于19:00、19:00和16:00达最低值，分别为50.9、60.9和76.6，夜间时段摄食水平显著高于白天时段，黄颡鱼仔稚鱼明显表现为晚上摄食类型。

The feeding of Yellow Catfish, Pelteobagrus fulvidraco in early developmental stages

The diet composition, feeding behavior and the daily feeding rhythm of yellow catfish, Pelteobagrus fulvidraco were studied through the method of experimental ecology for day-9, day-13, day-17 and day-23 in the paper. The results were as following: Larvae and juvenile mainly fed on zooplankton, and occasionally their diet also changed with their growth. Larvae fed on cladocerans and rotifera in the first feeding stage (9th day after being hatched), the abundance and biomass percent of cladocera were 86.71% and 89.65% respectively, holding overwhelming superiority. After that, when the groups of zooplankton in their stomach increased, their selection changed, the main food was cladocera for day-13 and day-17 yet; from 23th day after being hatched, juvenile mainly fed on copepoda, from 3.29% initially to 26.68% for day-23. Moreover, from the 13th after being hatched, the zoobenthos, chironomid larvae et al, occupied the main superiority in food composition. Day and night feeding rhythm was observed apparently in larval and juvenile stages. The highest levels of feeding activity at 20:00(897.7) and the lowest levels at 19:00(161.8) for day-9, after that, The peak means stomach fullness index of all achieved at 4:00 (914.1,1113.1 and 199.7), and got their lowest points at 19:00, 19:00 and 16:00, they were 50.9,60.9 and 76.6, respectively. The feeding levels at night were significantly higher than that in day, the circadian feeding rhythm of yellow catfish belongs to nocturnal obviously.