Growth of Juvenile Brazilian Flounder, Paralichthys orbignyanus, Cultured at Different Salinities

The Brazilian flounder, Paralichthys orbignyanus, is found in coastal and estuarine waters of the Western South Atlantic Ocean. It is being considered for aquaculture due to its high market price and wide environmental tolerance. In this study, the hypothesis of enhanced growth of Brazilian flounder at a salinity equivalent to its isosmotic point was tested. Hatchery raised juveniles were cultured during 12 months at three salinities: 2,11, and 30 ppt in a semi-recirculation system (15-20% daily water renewal). Every 15 days, length and weight were measured. At the end of the study, flounders were sacrificed and their gonads sampled to determine sex and to ascertain gonad development. A greater proportion of males (approximately 90%) was observed at all salinities. All individuals were mature, but females contained no gametes beyond oocyte III. Growth was significantly higher at 30 ppt when compared to 2 ppt, but no differences were observed for flounders reared at 11 ppt. Thus the hypothesis that growth of Brazilian flounder could be enhanced in a isosmotic environment was refused. These results suggest that Brazilian flounder may be a suitable candidate for estuarine and coastal aquaculture, but additional information will be required before aquaculture facilities are developed in Brazil.