Food and feeding habits of silver carp, Hypophthalmichthys molitrix (Val., 1844) in Gobindsagar Reservoir, India

Abstract

Investigation on the food and feeding habits of silver carp in Gobindsgar reservoir indicated that the diet of silver carp was dominated by Cyclotella spp. (diatom) followed by Chlorophyceae, Cyanophyceae, Crustacea, Dianophyceae and Rotifera. The size range of Cyclotella spp. varied between 5-25 μm indicating that silver carp is capable to collect the food particles smaller than distance between its gill rakers. Probably, excretion of mucus plays an important role in collecting such small particles. By applying Costello method, it was concluded that Cyclotella spp. is very important food item while the others are general food items in the diet of silver carp in this water body. Study of diet overlap index of different size groups of silver carp revealed that the value of "D" varied between 0.461 (moderate) to 0.972 (high), indicating that the diet of small size groups was significantly different from those of large size groups. The present observations indicated that the diet overlap index between female and male specimens of silver carp was very high (0.915), clearly indicating that the diet of male and females specimens did not differ significantly. Analysis of gut contents of silver carp indicated that zooplankton comprised only 7.7% by number and 19.3% by volume in the foregut contents of this fish, hence, silver carp can be considered as microphytoplankton feeder.