In Japan’s picturesque Ago Bay, a couple sits in a little hut picking out oysters from a net, cleaning them carefully one-by-one before replacing them gently back in the water. Their hope: in several months, these oysters will produce a glistening white pearl from a cultured farming technique invented in Japan that is in decline as experts die out in the ageing country.
Cultured pearl farming was first commercialised in Ago Bay and spread throughout the world. There are still dozens of farms plying the trade there, which look from the sky like a series of rafts floating between the steep coast and a string of tiny islets.
In 1893, an Ago Bay local called Kokichi Mikimoto became worried the oyster pearls avidly sought in his waters were becoming extinct.
So he began introducing artificial foreign bodies into the oysters in a bid to replicate the natural process in which they secrete thousands of layers of nacre when a grain of sand or shell finds its way inside the pearl pocket.
After several setbacks — including a bacterial virus that decimated his crop — Mikimoto finally hit the jackpot: one day in July 1893 a semi-spherical pearl appeared, clinging to the oyster.
A decade or so later, he had refined his method to produce a perfectly round specimen and immediately patented his technique — the cultured pearl.
Success was not immediate — several viewed the cultured pearl as a vulgar replica of the “natural” variety — but eventually Mikimoto built a global empire and Japan became the reference for the small pearls known as “Akoya.” Around the same time, two other Japanese, Tatsuhei Mise and Tokichi Nishikawa, applied for a patent.
Top five percent
The Sakaguchi family has been crafting these valuable pearls between three and 10 millimetres in diametre for three generations. Kasuhiro, 73, and Misayo, 68, are now supported by daughter Ruriko.
“Our job is to look after the oysters as well as we can for three to four years,” explained the energetic 43-year-old Ruriko, sporting an apron and headscarf. “From harvesting the young oysters, introducing the graft, right up to extracting the pearl,” she added, as she dragged oysters from the net for inspection.
The whole delicate operation rests of the insertion of a nucleus — a small round polished ball made out of shellfish — and the “graft”, a piece of donor mantle tissue from another oyster. Over a period of several months, the oyster reacts to the foreign bodies by secreting thousands of layers of nacre which form the pearl.
The pearls are harvested in December, when the water is around 15 degrees, said Ruriko. “Below this, the pearl will lack strength. Above that, it will lack shine,” she explained.
It is a thankless task. Of the 100,000 oysters harvested annually, half die immediately after the operation.
The vast majority produce either mediocre pearls or nothing at all. Only around five percent of the oysters harvested will result in pearls of sufficient quality to adorn the windows of chic jewellers far away in Tokyo.