Avaliação do desempenho de alevinos de Beijupirá (Rachycentron canadum) submetidos a diferentes densidades de estocagem

Abstract

The present study tested the influence of stocking density on growth, apparent feed conversion rate and survival of cobia (Rachycentron canadum) fingerlings submitted for 64 days to two treatments with stocking densities of 5.5 and 11 fish / m³, under identical diet and water quality. The specimens with total length of 10.78 (± 0.964 cm) and average individual weight of 4.51 (± 1.41 g) were stocked in 8 m³ circular tanks made of fiberglass and supplied with seawater and continuous aeration. The temperature values (25.40 to 26,72ºC), dissolved oxygen (from 10.59 to 6.32 mg / L), salinity (32.17 to 33.18 ppt), pH (8.05 to 8.84 ), total dissolved solids (from 30.01 to 30.33 mg / L) and electrical conductivity (49.18 to 50.58 mS / cm) were similar in both treatments. Feed conversion (1.01 and 1.09) and average individual weight (144.25 and 118.41) showed significantly better differences in treatment with 5.5 fish / m³. Similarly, survival values (91.73 and 87.35) and average total length (27.50 and 26.52) were also better in the treatment with 5.5 fish / m³, but were not significant. The final biomass (4.24 and 5.36 kg / m³) was directly proportional to the stocking density. The lower stocking density favored cobia performance in terms of growth, condition factor, survival rate and apparent feed conversion rate.