Feeding frequency and stocking density for fat snook juveniles reared in net cages

Abstract

In order to evaluate the effect of feeding frequency and stocking density on the zootechnical parameters, juvenile fat snook (3.0 ± 0.96 g and 6.8 ± 0.67 cm) were distributed in 12 groups of fish in four treatments: (T_1A) 100 fish m^-3 and 2 meals day^-1; (T_1B) 100 fish m^-3 and 4 meals day^-1; (T_2A) 200 fish m^-3 and 2 meals day^-1 and (T_2B) 200 fish m^-3 and 4 meals day^-1. Food was offered until apparent satiation during the experimental period of 90 days. Fish weight and length were determined every 30 days. At the end of the experiment, survival rates ranged from 85 to 89%, with no difference among the treatments (p>0.05). Total length and condition factor values were similar among the treatments (p>0.05), being 12.6 ± 0.27 cm and 0.98 ± 0.05, respectively. Weight gain varied between T_2A and T_2B treatments (p<0.05). Apparent feed conversion started to differ from 60-days of cultivation between the treatments with juveniles stocked at 100 and 200 fish m^-3 (p<0.05), being better at the lowest density (2.2). It is recommended to use the feeding frequency of 4 times daily and the stocking density of 200 fish m^-3 during the nursery phase, as at this density, although the worst conversion rate was observed (3.1), final biomass value was 2 times higher (3.5 kg) when compared to the lowest stocking density (1.75 kg).