A new approach to pearl oyster broodstock selection: can saibo donors be used as future broodstock?

Abstract

Cultured pearl production requires grafting of a pearl nucleus, together with a piece of mantle tissue (‘saibo’) from a donor oyster, into a recipient oyster. The donor mantle tissue is an important factor in determining pearl quality. It is desirable that donor oysters resulting in high quality pearls be used as the basis for future hatchery production to ensure high quality pearl production; however, donor oysters are killed as part of the grafting process. This study was conducted to assess the feasibility of keeping donor pearl oysters alive as potential broodstock. To determine whether mantle tissue could be removed from oysters without mortality, Akoya pearl oysters (Pinctada fucata) were anaesthetised with 500 mg l−1 of benzocaine and had the ventral margin of either their left, right or both left and right mantle lobes removed. Survival after 4 weeks was 100% for all treatments and oysters showed regeneration of excised mantle tissue. After 3 months, histological analyses showed complete regeneration of the mantle and its structures. These findings show that donor pearl oysters recover from removal of mantle tissue and could be used as future broodstock for pearl culture operations.