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Pearl oysters

Pearl oysters. Caitlin Marsh. Taxonomy. Genus: Pinctada Includes most of the pearls found in fashion. Pinctada maxima South Sea pearls Pinctada fucata Akoya pearls (classic) Pinctada margartifera Tahitian peals (black). Economic Importance. Billion dollar retail industry

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Pearl oysters

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  1. Pearl oysters Caitlin Marsh

  2. Taxonomy • Genus: Pinctada • Includes most of the pearls found in fashion. • Pinctada maxima • South Sea pearls • Pinctadafucata • Akoya pearls (classic) • Pinctadamargartifera • Tahitian peals (black)

  3. Economic Importance • Billion dollar retail industry • Sold all over the world • Price depends on rarity and quality • $50 Pair of freshwater pearl earings to $100,000 strand of South Sea pearls.

  4. Life Cycle

  5. Reproduction in Captivity • Thermal stimulation induces spawning. • Breeded from healthiest looking oysters. • Larvae are allowed to float freely in the water under controlled conditions until they are a few weeks old. • Once the larvae develop into baby oysters they are moved to a “nursery” area. • Remain in nursery for about 1-2 years, until they are large enough to be grafted.

  6. Grafting • A nucleus/grain (usually mother of pearl) is inserted with a piece of donor mantle tissue into the pearl pocket. • If it is rejected then can create deformed “Keshis” • Number of times an oyster can be seeded depends on species.

  7. Growing • Raft Culturing • Appropriate for sheltered bays • Long-line culture method • Cages are hung from horizontal ropes or chains connected to floats. • Oysters are threaded at onto a small thread or rope that is hung from a raft. • Good for open ocean environments • On-bottom culture • Can only be used in areas of granite or coral sand composition of the sea bottom.

  8. Harvest • Akoya pearls are harvested after 8 months – 2 years. • All other pearls are harvested after 2 – 6 years. • Harvesting is done in the winter months, when the pearl luster is highest. • An x-ray can be used to determine pearl size before harvest. • Harvested pearls are then cleaned, polished, and treated.

  9. Extensive Aquaculture • Most food is supplied by filtering water wherever they’re located. • In larval and nursery stage, fed with microalgae and algae. • Most labor is devoted to grafting and insuring good pearl growth.

  10. Water Chemistry • Temperature • 20 – 25C • Salinity • Prefer higher salinities, but tolerate wide range. • Bottom • Gravelly • Avoid sandy or muddy bottoms, reduce pearl quality. • Depth • Optimum depth at ~ 15m

  11. AdvantagesDisadvantages • Almost 100% of new pearls come from aquaculture • Almost any size, color, luminosity, shape, etc. • Largely extensive. • Limited production of more expensive pearls. • Time consuming • In competition with imitation pearls. • Can be effected by weather or natural disasters.

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