Efeitos da salinidade e densidade de estocagem no crescimento e sobrevivência larval da ostra do mangue Crassostrea rhizophorae (Guilding,1828) sob diferentes tempos de troca de água

Abstract

The combined effect of salinity, storage density and water exchange time on growth and larval survival of Crassostrea rhizophorae were studied in two experiments corresponding to the period from day 1 to day 6 (experiment 1) and day 7 to day 14 (experiment 2) after Of D-véliger larvae. Two salinities (25 and 35) and three densities (3, 6 and 12 larvae.mL-1 - experiment 1) and (2, 4 and 8 larvae.mL-1 - experiment 2) were tested under three water exchange times (24, 48 and 72h). Response surface diagrams were generated for survival and larval growth data for estimation of optimal conditions. The salinity above 32.5 provided the highest larval survival in the first week (≥ 50%), but this was not different from the saline range between 25 and 31 with water changes above 70h. Between the 7th and 14th day of larvae survival was higher at salinities below 26 (≥ 14%). Growth was higher in the two experiments at salinities below 27. Water changes greater than 36 h increased growth and larval survival in the two experiments. All densities used in both experiments were not statistically different for growth (P> 0.05). However, survival was highest in experiment 1 at densities of 6 (32.56%) and 12 larvae.mL-1 (37.1%) and in the second all densities were statistically the same. Based on the results of this study, it is recommended that larvae of C. rhizophorae be cultivated at salinities of less than 27 and water changes above 36 h with densities of 12 mL-1 larvae and 8 mL-1 larvae, first and second week, respectively.