Growth performance of the mangrove oyster (Crassostrea gasar) under continuous and periodic submergence in tidal ponds

Abstract

Growth of the mangrove oyster (Crassostrea gasar) under continuous and periodic submergence in tidal ponds was investigated using rack and cage method. Two ponds, A and B were used for the study. Oysters in pond A were always submerged; while those in Pond B were submerged during flooding at high tides only (oysters in Pond B were exposed to air at ebb of tides). Five Netlon© cages were stocked with oyster spats and placed on rack stands in ponds A and B respectively. The initial stocking density in each pond was 375 spats, distributed equally among the cages at 75 spats each. Initial mean length and weight at stocking was 19.3 ± 4.38 mm and 1.0 ± 0.51 g, and 20.4 ±5.92 mm and 1.1 ± 0.75 g in Ponds A and B, respectively. No significant differences (P > 0.05) were recorded between the final mean length and weight of oysters of 50.3 ± 6.68 mm and 20.8 ± 6.53 g in pond A and, 52.3 ±7.14 mm and 18.8 ±5.73 g in pond B. The implication of these results is that both continuously submerged and periodically submerged culture systems for oyster production are favourable for good growth of oysters.