Observation on the growth of hatcherypropagated Japanese pearl oyster Pinctada martensii spat cultured in the tropical sea area

Cultivation of the Japanese pearl oysters Pinctada martensii was carried out in the tropical sea area-Lingshui, Hainan Island, using hatchery-propagated spat of 2.0 mm. The average shell length reached 59.2 mm, the average shell height 59.7 mm, the average shell width 20.7 mm and the average body weight 34.8 g after one year's culture. After 90 days' culture, the average increment of shell length, shell height and shell width were 11.9, 11.2 and 5.9 mm, respectively, with relative increment ratios being 55.4%, 61.2% and 190.3%, respectively. These observations demonstrated that the Japanese pearl oysters grow fast in the region and can be transplanted for pearl farming.