Pearl culture

Pearl culture

 Pearl fisheries-   pearl is a white highly shining globular concretion found within the shell of oyster.The natural pearls are rare due to the mode of formation. Scientist have succeeded in producing pearls of the same substance. This is known as the pearl fisheries.

History of pearl industry-  The idea of pearl culture was evoked in Japan and was carried out at South coast of Hansoo in the Bay of Japan. Kokichi Mikimoto is said to be the father of pearl industry in Japan.

Pearl producing Molluscs- High quality of pearls are obtained from Pinctada. A number of species of genus Pinctada like P. valgaris, P. chemnitzi, P. atropurpurea are pearl producing molluscs. All these species are marine.

Pearl producing places in India- Natural habitat of pearl oysters are ridges of rocks or dead corals at a depth of 18-22 metres at a distance of 19 kilometres from the shore. The pearl oysters are obtained from the gulf of kutch , pak bay and Baroda.

Pearl beds on the east coast are more extensive and productive than those on the west coast.

Pearl formation- Pearl is a natural secretion deposited by the mantle epithelium around some foreign body which happens to enter between the shell and mantle and produces irritation. Pearl formation occurs only in bivalved molluscs and the pearls formed in pearl system are large, shining and valuable.

Per chance if any foreign body either a sand grain or some living minute organism finds its way in between the shell and mantle,it cuasca irritation in mantle.The cells of mantle epithelium surrounding it pinch off as sac. The epithelium cells of this sac secrete nacreous substance which is deposited around the foreign body in several concentric layers and thus pearl is formed. The foreign body inside the pearl is known as nucleus and the concentric layers of nacre are known as mother of pearl.