LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTOR OF THE WHITE BREAM (Blicca bjoerkna) IN THE DANUBE RIVER NEAR BELGRADE (1168-1170 RKM)

Abstract

White bream is an important species in commercial and sport fishing that is caught in nets throughout the year. The analyzed samples of white bream (n = 377) came from commercial catches carried out between December 2014 and May 2015 at two locations in the Danube near Belgrade, Jojkića Dunavac (JD) – an armlet of the Danube, with slow water flow and Veliko ratno ostrvo (VRO) – the main channel of the Danube, with fast water flow. Total body length (TL, cm) and body weight (BW, g) of each fish were measured, and Fulton's condition factor (K = W/L3 x 100) was calculated. Average TL of the fish samples from the JD and VRO were 23.1±1.7 and 23.8±2.4, respectively, and average BW were 164.4±42.2 and 201.0±73.0, respectively. In general, fish from VRO were in better condition (K=1.44±0.16) compared to sample from JD (K=1.31±0.11). Individuals in the sample from JD had a negative allometric growth (a = -1.79, b = 2.93, r² = 0.85), while those from VRO have a positive allometric growth (a = -2.22, b = 3.28, r² = 0.89). Based on the results of this study, positive allometric growth (b > 3) and fish condition indicated that individuals from VRO increased body mass more than body length. The source of food, its availability, and better habitat conditions at VRO could be the reason for the differences in the growth and condition of the fish from the investigated locations.