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Pesquisa Agropecuária Brasileira

On-line version ISSN 1678-3921

Abstract

SOUZA-FILHO, José Jerônimo de  and  CERQUEIRA, Vinicius Ronzani. Influence of stocking density on the rearing of juvenile common snook in laboratory. Pesq. agropec. bras. [online]. 2003, vol.38, n.11, pp. 1317-1322. ISSN 1678-3921.  http://dx.doi.org/10.1590/S0100-204X2003001100010.

The objective of this work was to evaluate the influence of stocking density on growth, feed conversion ratio and survival of juvenile common snook (Centropomus undecimalis). Fish were collected from the wild and trained to accept artificial diets. Individuals (13±0.4 cm and 23±0.3 g) were stocked into nine 5-m3 circular fiberglass tanks at three different densities: 3, 6 and 9 fish/m3 during a period of 180 days. Tanks were supplied with seawater and continuous aeration. Total ammonia-nitrogen (0 to 0.5 mg/L), water temperature (23.3 to 30.6ºC), salinity (17 to 34 g/L), pH (7.8 to 8.4) and dissolved oxygen concentration (4.8 to 6.9 mg/L) were similar in all tanks. Feed conversion rate (1.88, 2.06 and 2.31) and survival (100%, 98.9% and 96.3%) were significantly improved for fish stocked at the lower densities (3 and 6/m3). There were significant differences in average weight (110, 87 and 80 g) and length (20, 18.5 and 18 cm) among treatments. Fish stocked at the lowest density (3/m3) showed the highest growth rate, and there was no difference between the others. However, final biomass (332, 511 and 703 g/m3) was directly correlated with density. A low density influences positively growth, survival and feed conversion in common snook rearing.

Keywords : Centropomus undecimalis; saltwater fish; feed conversion; growth rate; survival; rearing techniques.

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