Feeding Habits of Hemibagrus pluriradiatus (Vaillant) in Yuanjiang River

DU Xiao-tian,ZHU Bang-ke,ZHANG Jia-bo,TIAN Zhi-fu (College of Fisheries,Huazhong Agricultural University,Wuhan 430070,China)

Hemibagrus pluriradiatus (Vaillant) ;Feeding habit;Food composition;Feeding intensity;Feeding morphology;Seasonal variation;Yuanjiang River

This paper dealed with the food composition,feeding intensity and feeding morphology of Hemibagrus pluriradiatus (Vaillant).251 individuals,with body-length ranging from 109 mm to 295 mm and body-weight ranging from 14.6 g to 273.5 g,caught by electric shock from Yuanjiang River in Yunnan Province,China,from June 2008 to May 2009,were analyzed.The results showed that H.pluriradiatus is a euryphagous fish feeding on a wide range of food items including small fish (mainly loaches),aquatic insect larvae (mainly Cybister),aquatic and terrestrial insects,mollusc,annelida,crustacean,fish eggs,frogs,rotifers,cladoceran,copepoda,cereals,macrophytes,algae and etc.Small fish had an average occurrence rate of 64.2% and accounted for 46.90% in weight in the stomach content.Aquatic insect larvae had an average occurrence rate of 73.8% and accounted for 40.00% in weight together with insect imago.This indicated that small fish and aquatic insect larvae were the most important food items for H.pluriradiatus.H.pluriradiatus is also a guttler.Its stomach fillness index can reach 11.6% ～ 16.2% at satiation.As the body-length increase,its food composition simplified and feeding intensity decreased,the occurrence rate of aquatic insect larvae decreased and of imago increased.Terrestrial insects appeared in the stomach of individuals with body-length over 160 mm.The seasonal variation of food composition was obvious while that of feeding intensities was less obvious.In conclusion,H.pluriradiatus though it takes in more animal food,is a bottom feeder omnivore.