Diet composition and feeding habits of common bleak (Alburnus alburnus L.) in the Gruža and Gazivode reservoirs

Abstract

This paper presents the feeding habits of specimens of the fish Alburnus alburnus (L.) that inhabit the Gruža and Gazivode reservoirs. The diets of 37 specimens from Gruža reservoir and 44 specimens from Gazivode reservoir were analyzed. The common bleak from Gazivode reservoir fed more diversely on eight different prey items, while six different prey items were identified in specimens from Gruža reservoir. The most common prey in the diet of specimens from both reservoirs is Bosmina sp., which was present in every digestive tract studied. Very common prey items are also Daphnia sp. and Cladocera. In contrast to the specimens from Gruža reservoir, the specimens from Gazivode reservoir feed on both Leptodora kindtii and insects. The specimens from Gazivode reservoir also feed on Ostracoda at a much higher percentage than the specimens from Gruža reservoir. Numerous reports in the literature have confirmed that common bleak feed mainly on zooplankton and often on insects, as shown by our results.