Home of cultured pearl industry

Press, Volume CXII, Issue 33065, 4 November 1972, Page 11

Home of cultured pearl industry

All the processes involved in making cultured pearls, from the artificial irritation of an oyster through to the finished product, can be seen by visitors to Pearl Island, Japan.

It was on Pearl Island that Mikimoto laid the groundwork for the industry by cultivating semi-round pearls for the first time in 1893. Here the world-famous Japanese Ama girls dive for oysters growing wild on the ocean bed. Visitors are shown the irritant nucleus being inserted into an oyster and the various techniques of classifying pearls and assembling necklaces. Learning how the pearls are actually grown calls for a cruise on peaceful Ago Bay, the centre of Japan’s multimillion dollar pearl industry. The bay, nurturing hundreds of floating pearl farms, is part of the beautiful Ise Shima National Park at the southern end of Japan’s central island, Honshu. Here tourists can examine cultivating rafts where prepared oysters are kept in wire cages, and chat to Japanese workers cleaning shells in floating houses. Most of them buy pearl samples, such as pendants, for as little as $2. Divers for 2000 years The local girls have been divers for more than 2000 years. The zigzag chain of mountains dropping to the sea on these islands leaves almost no land for cultivation. Because of the sea water which is wanner here than in most other areas of Japan all the inhabitants make their living from the sea. The men are deep-sea fishermen and the women work in Ise-Shima National Park, mostly as divers. They begin diving after finishing primary school, even practising in the open sea, but the experienced divers who get the biggest catch are usually aged between 30 and 40. Catches vary according to the season, but generally they are all kinds of edible sea weeds, mother-of-pearl shells, ear shells, top shells, and sea urchins. The girls wear goggles and full cotton bathing outfits, believing from ancient times that white protects them from shark and dolphin attacks. Those in shallow water come up by their own skill and put their catch into a tub kept floating on the sea above by a rope tied to their waists. In deep water they carry a 401 b weight to go down

quickly and to surface they signal with a tug on the line. The girl must be able to stay down at least one or two minutes. To avoid injury to heart and lungs by breathing out suddenly on surfacing, they let out a loud plaintive whistle. Pearl pioneer At least 300 companies have pearl farms on Ago Bay, each one having about 10 employees. Mikimoto was Japan’s pearl pioneer. When he was 20 he visited Yokohama and saw Chinese merchants selling pearls (for medicine) which he knew came from oysters in his native port town of Toba. Learning about the process of pearl formation from an authority on aquatic animals, he became a pearl cultivator in 1890. How are pearls made in nature? Briefly, sand grains or shell chips lodge in a pearl oyster and irritate its membranes. The oyster then lays down calcium carbonate in countless layers which solidify into natural pearls. In pearl cultivation an irritant is necessary, and beads cut and polished out of clam shells are used. There beads or nuclei come from the Mississippi River oysters (before the war oysters from the Yangtze River in China were used). They are shaped into spheres and polished. Inserting the nuclei is a delicate tissue-grafting operation. Skilled hands cut the mantle (which secretes the calcium carbonate) from a second live oyster, and place this and the irritant inside the cultivating oyster after inducing a valve to open. In theory, the mantle develops new cells which keep growing till they cover the whole surface of the irritant, forming a pearl sack around it through countless layers of mother-of-pearl. Cultivating rafts After the operation the oysters are planted in wire cages and submerged in sheltered waters for a month to six weeks. Then they are examined, dead ones removed and the cages are transferred by barge or motor boat to the permanent bamboo cultivating rafts, here to remain for one to five years feeding on plankton. The cages protect them from enemies like octopuses, devilfish and eels, also barnacles and clinging seaweeds which prevent them taking nourishment. Three or four times a year, the oysters are

raised and cleaned to ensure they can feed, and are put in freshly tarred cages. Cold currents are one of the worst dangers. To overcome this, cultivators at Ago Bay shift their oysters for several months of the winter to warmer sites. Even so, with all the care only about half the beds yield a harvest and about 40 per cent of total Japanese production has a market value. | Suble variations No more than 10 per cent of pearls in each season are fine-lustred and perfectly spherical. Cultured pearls are commonly classified as silver, blue, pink, white, cream, yellow (or golden) and black. In fact, the colour distinction is not very definitely marked and the variations (except for black and yellow), are so subtle that only specialists can usually distinguish them. The yellow or golden pearls are quite distinctive, as are the so-called black pearls which are really dark bluegrey or gunmetal in shade. Large-sized pearls take up to six years to grow, are fairly rare and therefore expensive. To see Japanese girls rolling hundreds of pearls on to black Velvet to study shape, size and shade under strong light is to appreciate all this work and patience that goes into a necklace.—A Qantas feature.