Comparison of harvested rate and nacre deposition parameters between cultured pearls issued from initial graft and second nucleus insertion in P. margaritifera |
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| Authors: | Jonathan Demmer Philippe Cabral Chin‐Long Ky |
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| Affiliation: | 1. Ifremer, UMR EIO241, Labex Corail, Centre du Pacifique, Taravao, Polynésie Fran?aise;2. Gauguin's Pearl Farm, Rangiroa, Polynésie Fran?aise |
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| Abstract: | 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. |
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| Keywords: |
Pinctada margaritifera
surgreffe family effect cultured pearl nacre weight nacre thickness |
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