Size distribution and organ development of the hooded oyster, Saccostrea cucullata (Born, 1778) from Libong Island, Thailand

Abstract

The hooded oyster, Saccostrea cucullata, is an economically important bivalve in Thailand with great potential for aquaculture production. Since its histological development remains unknown, we examined the organ development of field-collected S. cucullata associated with their shell size distributions from Libong Island, Thailand. The water quality parameters were not significantly different between the sampling areas except for the water temperature (p < 0.05). S. cucullata from the Stone Bridge (SB) site had smaller shell lengths and higher condition factors than those from Dugong Tourism by Drones (DT) except for the size of the organ. Histologically, the highest mean length of gill lamellae was 192.1±3.92 µm in 2.1-3 cm group. The thinnest of the mantle epithelium (73.78±3.08 µm in 4.1-5 cm group) of S. cucullata showed statistically significant difference between the sampled locations (Specific F value = 0.1783 and 0.8605 when p < 0.01 and p < 0.0001, respectively). The density of mucous-secreting cells (Msc) was more prominently distributed in the digestive gland than in other tissues. The 2.1-3 cm group or bigger had mature gonads with protandric characteristics, showing the rapid sexual differentiation in SB. Results obtained from this study improve the current knowledge of S. cucullata from natural environments, which potentially contributes to the establishment of its aquaculture.