Food and feeding habits of the juvenile and adult Common carp (Cyprinus carpio) in Lake Ziway, Ethiopia

Abstract

Cyprinus carpio (common carp) is one of the most commercially important fish species in Lake Ziway. Even though the species is economically important, there is no data on the feeding ecology of the fish for the lake. The present study aims to investigate the food and feeding habits of the juvenile and adult common carp collected for five sampling months from April to August 2017.The juveniles were collected using a beach seine net and the adult fishes were purchased from catches of the fisher men. A total of 315 common carp (75 juveniles and 240 adults) specimens ranging from 5.2 to 55 cm were examined that have a total weight (tw) from 4.6 to 1610.2 g, respectively. Among the total number of juvenile and adult common carp, 71 (94.5%) and 180 (75%) fish samples had food content in their guts, respectively, which were analyzed using the frequency of occurrence and volumetric analysis methods. Volumetrically, the major food items found in the juvenile guts were zooplankton (34.2%), insects (26.3%), and detritus (25.8%) while adults fed on detritus (31.4%), macrophytes (30%) and insects (20%). Juveniles fed largely on animal origin food items whereas plant origin was more important for adults. However, both juveniles and adults were omnivores feeding on plant and animal origins. Schoener's Overlap index revealed the absence of significant dietary overlap between juveniles and adults corroborating ontogenetic dietary shift of the common carp. The study provides an insight on the diet of common carp which is a vital input in developing sustainable management strategy options in the multispecies fishery and provides data for diet formulation for aquaculture.