Abstract

Objective: To conduct on sustainable fingerling production technique of endangered Labeo calbasu (Hamilton, 1822) (L. calbasu) based on different protein levels in ponds. Methods: The experiment was carried out under rearing pond in fish hatchery complex with three treatments group each having three replicates under department of fisheries, University of Rajshahi. L. calbasu were stocked at 41 990/ha in T1, T2 and T3, respectively. The initial length of L. calbasu in three treatments were (4.60 ± 0.10) cm and initial weights were (3.48 ± 0.01) g. Fishes were fed with 28%, 30%, 32% protein supplement for T1, T2, T3, respectively. The fishes were initially fed at 10% of body weight on 1st and 2nd fortnight. Then it was decreased at 8% of body weight on 3rd and 4th fortnight. Finally in 5th fortnight they were fed 5% of body weight. The physico-chemical characteristics of pond water were measured fortnightly. Results: The mean final weight gain was found highest in T3 (40.87 ± 0.01) g which was significant compared to T1 and T2. SGR (% bwd–1) was found 2.83 ± 0.02 (T1), 3.04 ± 0.01 (T2) and 3.39 ± 0.01 (T3). The highest survival rate of L. calbasu was found in T3 (90.00 ± 1.00) and the lowest was found in T1 (87.00 ± 1.00). The best FCR (1.54 ± 0.01) was observed in T 3 fed with 32% protein supplement. The highest production was observed in T3 (1 672.20 ± 16.96 kg/ha/75 days) and lowest was observed in T1 (1 055.50 ± 29.04 kg/ha/75 days). The highest net benefit was calculated in T3 (260 663.00 ± 4 326.88 tk.) and lowest was found in T1 (112 831.00 ± 7 383.66 tk.). The CBR was found 0.60 ± 0.04, 0.80 ± 0.02 and 1.16 ± 0.02 in T 1, T2 and T3, respectively. There were significant differences in CBR values among the three treatments. Conclutions: In this study, growth parameters i.e., weight gain, SGR (% bwd–1), length gain, total yield were significantly (P < 0.05) improved in T3 treatment fed with 32% protein supplemented diets.

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