叉尾斗鱼仔鱼饵料选择与摄食强度

Food selection and feeding intensity of Macropodus opercularis larvae

采用实验生态学方法,研究了叉尾斗鱼仔鱼对不同类别饵料的选择及其摄食强度。结果表明,2—3日龄刚开口摄食的仔鱼对桡足类无节幼体有明显正选择,对轮虫表现为明显的负选择,而对枝角类和桡足类则完全不摄食。4—6日龄仔鱼主要以桡足类无节幼体为食物,7—11日龄的仔鱼主要以枝角类为食物,而12—25日龄仔鱼则主要摄食桡足类。仔鱼口宽或全长与摄食饵料个体大小呈线性或曲线正相关。2日龄仔鱼开口摄食发生率达47%,而3日龄以上则保持100%;2日龄仔鱼平均摄食量仅为0.0017 mg,而25日龄仔鱼平均摄食量已达0.3795 mg。最高饱食率出现在25日龄,达到60%,而消化道饱满系数以5日龄最大,达13.13%。但之后消化道饱满系数逐步下降,11—25日龄仔鱼消化道饱满系数在1.46%—2.79%之间波动。

Food selection and feeding intensity of Macropodus opercularis larvae were studied in the laboratory .The results showed that index of food selection of Macropodus opercularis larvae at the age of 2-3 days on copepod nauplii was greater than 0, and index on rotifers was less than 0, but larvae did not eat cladocera and copepods. The larvae at the age of 4-6 days mainly fed on copepod nauplii. The larvae mainly fed on cladocera at the age of 7-11 days and mainly fed on copepods at the age of 12-25 days.There was a positive correlation between the average body length of diet and mouth width and total body length of larvae. Larvae began to eat at the age of 2 days with the feeding incidence of 47%, and starting from the age of 3 days, it reached 100%;the average feeding amount of 2 days old larvae was only about 0.0017 mg, but that the average feeding amount of 25 days old larvae reached 0,3795 mg. At 25 days after hatched, fullness rate of larvae reached maximum value （60%）, and satiation coefficient of larvae at the age of 5 days reached maximum value （13.13%）.But there was a gradual decline in satiation coefficient after the age of 5 days. the satiation coefficient of Macropodus opercutaris larvae at the age of 11-25 days fluctuated between 1：46%-2.79%.