INVESTIGATION ON strongGROWTH RATEstrong AND FOOD CONVERSION RATIO OF WELS.pdfVIP

171 Bulgarian Journal of Agricultural Science, 14 (No 2) 2008, 171-175 National Centre for Agrarian Sciences INVESTIGATION ON GROWTH RATE AND FOOD CONVERSION RATIO OF WELS (SILURUS GLANIS L.) IN CONTROLLED CONDITIONS A. ZAIKOV, I. ILIEV and T. HUBENOVA Institute of Fisheries and Aquaculture, BG-4003 Plovdiv, Bulgaria Abstract ZAIKOV, A., I. ILIEV and T. HUBENOVA, 2008. Investigation on growth rate and food conversion ratio of wels (Silurus glanis L.) in controlled conditions, Bulg. J. Agric. Sci., 14: 171-175 The aim of this study was to establish the growth rate and food conversion ratio of wels (Silurus glanis) when fed with carp (Cyprinus carpio). The experiment was carried out under controlled laboratory conditions for a period of 30 days in two variants, by two replicas each, differing by the initial weight of the wels. For each variant 7 wels were used, at initial ratio between the biomass of the predator and the prey 1:3. The preys had an average body weight of 5-7 g. As a result of the experiment, the growth rate of S. glanis was established for the investigated period, which for the first variant is 25.43 g or 25.56%, and for the second – 9.56 g or 19.2%. (The linear growth rate for the first variant is 0.52 cm or 2.25% and for the second variant 0.46 cm or 2.45%). The food conversion ratio of wels when fed with carp was 4.3 for variant 1 and 4.7 for variant 2. Key words: Silurus glanis, food conversion ratio, growth rate Introduction than 100 years now (Linhart et al., 2002). As com- pared to pike and pike-perch, the wels is consider- The wels (Silurus glanis L.) is one of the most ably unassuming towards environmental factors. In the highly preferred predatory fish for cultivation, which fi