Pacific Pearl-oyster

• It is the source of Tahitian black pearls, the economic mainstay of much of French Polynesia.
• The dark border of the nacre, from which it takes its name, is what gives the pearls their green, grey and aubergine tones.
• Before pearl farming it was harvested on a huge scale for its shell, the raw material for buttons and marquetry.
• This is the oyster of the Tahitian black pearl. The dark rim of its shell carries the same pigment as the nacre, so the colour of the pearl forms inside the animal and is never dyed.
• The pearl is obtained by grafting in a nacre nucleus and a piece of donor mantle; the oyster coats it over twelve to twenty-four months.
• It is one of the giant shells of tropical seas: an adult reaches 30 cm and weighs more than 5 kg, and there are individuals of up to 9.
• Together with Pinctada maxima it produces around half the world market in cultured pearls.
• Its farming has been an economic mainstay of French Polynesia and the Cook Islands since the 1990s; in 2000 the Cooks exported 18 million dollars' worth of pearls, a figure that later fell because of the international price and an epidemic on Manihiki.
• The larva lives between sixteen and thirty days in the plankton before settling.

Habitat and environment

Indo-Pacific reefs and coral lagoons, from 0 to 40 m

Sources consulted: Wikipedia (es): Pinctada margaritifera