黑龙江黑斑狗鱼的食性及其随体长和空间的变化

Feeding Ecology and Variation With Body Length and Region of Amur Pike Esox reicherti Dybowski in Heilongjiang River

为了解黑斑狗鱼(EsoxreichertiDybowski)的食性及其随体长和空间的变化,2022年10—11月用网目2~8cm的流刺网和网目0.9~3.5cm的定置刺网在黑龙江抚远和呼玛江段采集到138尾黑斑狗鱼,鉴定和测量其体长和体质量及胃含物种类与重量,研究摄食习性及其随体长和空间的变化。结果表明:这些黑斑狗鱼的饵料生物共有27种(包含未鉴定种),分为5个类群:鱼类、两栖类、甲壳类、水生昆虫和其他饵料,其中鱼类为黑斑狗鱼最主要的食物类群,数量在食物中占90.17%,然后依次为两栖类、水生昆虫和甲壳类。食物类群随着黑斑狗鱼的体长增加存在不显著的差异。体长350~450mm组黑斑狗鱼主要摄食幼鱼;体长450~550mm之间时开始摄食的饵料鱼个体增大,还摄食两栖类和少量水生昆虫;550~650mm体长组的黑斑狗鱼则全部以鱼类为食。不同空间的黑斑狗鱼食物组成无明显差异。平均饱满指数和空胃率结果显示,黑斑狗鱼的摄食强度随着其体长的增长显著变化,摄食的高峰期在450~550mm体长组之间,摄食强度无明显的空间差异。

In order to understand feeding habits and changes with body length and regions in Amur pike Esox reicherti Dybowski,the stomach contents were identified and analyzed in 138 samples of Amur pike collected by drifting net gills with mesh size of 2~8 cm and fixed net gills with mesh size of 0.9~3.5 cm in Fuyuan and Huma River sections of Heilongjiang River in October and November 2022,and changes in their feeding habits with body length and regions were also investigated.The results showed that there were 27 species(including unidentified species)of live food organisms,which were divided into five groups,namely fish,amphibians,crustaceans,aquatic insect and other food organisms,in Amur pike in Fuyuan and Huma River sections of Heilongjiang.Fish was the most important food group for Amur pike,accounting for 90.17%of the food,followed by amphibians,aquatic insect and crustaceans,without significant difference in food groups with the increase in body length of Amur pike.Amur pike with body length from 350 mm to 450 mm mainly fed on juvenile fish and large fish at body length of 450~550 mm,with amphibians and a small number of aquatic insect.Amur pike with body length from 550 mm to 650 mm fed on fish,without significant difference in the food composition in different sampling sites.The average fullness index and empty stomach rate showed that the feeding intensity of Amur pike changed significantly with the growth of its body length,at feeding peak between the 450~550 mm body length groups,without significant spatial difference in feeding intensity.