2024.07.01 - 502 viewed
This trial aimed to evaluate the effects of stocking densities of 5-9 fish/m3 on the growth, survival rate and economic efficiency of Blackspotted croaker (Protonibea diacanthus) cultured in sea cages in Quảng Ninh province. The fish had an initial length of 16-18 cm and an average weight of 82.0 ± 0.3g/fish. [OA1] Fish were experimentally reared in cages measuring 3 x 3 x 4m. The experiment was designed with 3 treatments corresponding to 3 rearing densities: 5; 7 and 9 fish/m3, treatments were repeated 3 times. Fish was fed slow-sinking artificial pellets with a protein content of 45-48%. Water quality parameters, including temperature, DO, salinity, and pH were measured [OA2] once a week. Fish were sampled every 30 days for length and weight measurement. The costs of fish culture were recorded to calculate economic efficiency. The reseach results show that environmental paramater are suitable for the growth and development of Black spotted croaker. After 18 months of culturing, fish raised at a density of 5 fish/m3 had a length and weight higher than the density of 7 and 9 fish/m3 (P<0.05). However, the density of 7 fish/m3 given higher productivity and profit rate than the other 2 densities. At a treatment density of 7 fish/m3, the fish size reached 3,545.96 ± 125.26 kg/fish, survival rate was 75.2%, average productivity was 18.6 kg/m3, FCR was 2.2 and the rate of the profit rate was 29%. There were no significant differences in survival rate and FCR indices in the 3 treatments. The research results provide a significant scientific basis for developing a technological process for culturing Black-spotted croaker in sea cages.
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