Salinity influence on the survival of mangrove oyster, Crassostrea rhizophorae

Abstract

The effect of salinity on the survival of spats of mangrove oyster,  Crassostrea rhizophorae , was tested by means  of 12 treatments in triplicates corresponding with 5%-intervals over a 5 - 60% o range, with measurements taken during  8 days of cultivation. Each experimental units was stocked with 40 oyster spats averaging 1.17 ± 0.12 cm in length, fed  daily with 250,000 cel.mL -1 of  Chaetoceros muelleri . Results were given as survival rates, together with daily observa - tions on oxygen concentration (mg.L -1 and saturation) and water temperature (°C). The data were analyzed by the ANO - VA and Tukey tests. Significantly higher survival values were observed in 15% o , 20% o e 25% o salinity values, whereas  as 5% o , 10% o , 30% o and 35% o determined lower survival rates along the experiments and did not differ significantly at  the end of the cultivation period. Total mortality of the reared stock started after the 4 th day under salinities above 40% o .  Results from the present study indicate that  C. rhizophorae should be farmed in estuarine areas where salinity varies  from 15% o to 25% o .