The winged pearl oyster, Pteria penguin, is cultured primarily to produce half‐pearls (mabé). The mabé quality is influenced by culture techniques, but there is limited information in this field. P. penguin with mean (±SE) dorso‐ventral height of 250 ± 6.5 mm were used to investigate the influence of culture period and nucleus position on mabé quality. Oysters were relaxed using 1‐propylene phenoxetol, and five nuclei were glued at different positions to the inner surfaces of the oyster shells; three on the more concave left valve and two on the right valve. Nucleated oysters were then cultured for 10 months under commercial pearl farming conditions at Savusavu in Fiji. Nacre deposited at the base and top of the nuclei was measured monthly, from the 6th to the 10th months of culture and the different qualities of mabé produced at different positions were scrutinized. Nacre thicknesses at the base and top of the resulting mabé were significantly different at different months (P < 0.05) and the rate of nacre deposition was highest during the warmer months. The different positions of nuclei on the valve greatly affected the quality of mabé formed. After a 10‐month culture period, around 1 mm of nacre covered the nuclei although the best quality mabé were obtained after 9 months. 相似文献
Cultured pearls produced with Pinctada margaritifera, using the surgreffe method (implantation of a second nucleus following pearl harvest) were studied for the first time to: (1) examine family effect on nacre thickness, nacre weight and nacre deposition speed and (2) compare variation in these three traits with that obtained from the cultured pearls previously harvested after the corresponding initial grafts. A surgreffe experiment using 783 recipient oysters was realized in Rangiroa atoll (French Polynesia). After 24 months of culture, 389 cultured pearls were harvested. Significant donor family effect was found for the harvested pearl rate from surgreffe (P = 0.046). Highly significant donor family effect was recorded for nacre thickness (P = 0.004). Very highly significant donor family effects were recorded for nacre weight and nacre deposition speed (P < 0.0001). Comparison between surgreffe and initial graft showed: (1) no significant effect for the average cultured pearl rate harvested (P = 0.052) and average cultured pearl nacre deposition speed (P = 0.622) and (2) very highly significant differences (P < 0.0001) for the average cultured pearl nacre thickness and nacre weight. This study highlighted three major implications for pearl industry management: (1) donor family effect was maintained from initial graft to surgreffe, for nacre thickness, weight and deposition speed, (2) the persistence of the pearl sac metabolic activity over three years of culture and (3) the relation between harvested pearl rate and the size of the nucleus inserted in the pearl sac. 相似文献