Compensatory growth response of Catla catla (Hamilton, 1822) juveniles, stunted with varied stocking density and photoperiod, in subsequent grow-out phase
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Stunted juveniles of Catla catla (Hamilton, 1822) were produced through 150 days of stunting with five combinations of density and photoperiod. These stunted juveniles were subsequently polyculturedÂ in grow-out ponds for eight months along with rohu (Labeo rohita) and mrigal (Cirrhinus mrigala). In grow-out trial, the five treatments with different combinations of stocking density and photoperiod comprised, Â control (20 m-3, 12L/12D), T-1 (30 m-3, 12L/12D), T-2 (40 m-3, 12L/12D), T-3 (20 m-3, 6L/18D) and T-4 (20 m-3, 0L/24D). After eight months of culture, growth curves of stunted catla in all treatments were non-convergent and inferior to control, indicating no compensatory growth response. Although survival (70-73%), average body weight, (ABW; 667-755 g) and weight gain (648-729 g) in grow-out phase were statistically similar in the groups with different stocking density (Control, T-1 and T-2) (p>0.05), the grow-out survival was relatively higher in T-2 (73.3%), indicating its positive correlation with higher stunting density. In contrast, juveniles stunted with reduced photoperiod (T-3 and T-4) showed significantly lower ABW and weight gain (p<0.05). The poor survival in T-3 and T-4 (40-43%) indicated significant effect of stunting with reduced photoperiod on subsequent grow-out survival and yield performance. Based on the results, the study recommend the use of rearing density up to 40 m-3 for juvenile stunting in catla.
Keywords: Catla, Compensatory growth, Fish culture, Mixed fish farming, Stunted fish