The pearl-cultured pearl oyster larvae “unprecedented mass death”, unknown cause September 4, 15:02
The nation's best pearl production area On the Uwakai coast of Ehime Prefecture, it can be seen that a large number of young pearl oysters are used for pearl farming, and the prefectures are investigating the actual state of damage and investigating the cause.
According to Ehime Prefecture, in late July, there was a report from the prefecture's fishery officials saying that more oyster oysters were dead than ever before.
According to the prefecture, it was confirmed that a large amount of pearl oysters were killed at a farm from Uwajima City to Ainan Town.
The pearl oyster is a shell used for pearl farming, and after raising the young shellfish to the mother shell for about two years, the core that becomes the core of the pearl is put in, and the pearl is finished and shipped from about half a year to about a year and a half.
The pearl oysters along the Uwakai coast have died in the past due to the redness of shellfish that turns red, but this time it is not a redness and the cause is unknown. In addition to examining the actual state of damage in detail, we are also investigating the causes of environmental changes in seawater and the occurrence of infectious diseases.
At the time of the day, Ehime Prefecture has the highest pearl production amount of 7664 kilograms in the country, and mother shellfish production of 1242 tons, accounting for nearly 90% of the nation. Has also been shipped.
This mass death of juveniles may affect the production of pearls nationwide from the next year onwards, and prefectures and other organizations are planning to support producers by securing new juvenile shellfish.
Even in the birthplace of pearl farming
In Ago Bay, Shima City, Mie Prefecture, we know that a large amount of pearl oysters are used for aquaculture, and the prefecture is investigating the cause.
The Ise-Shima area in Mie Prefecture is the birthplace of pearl farming and is also known as one of the nation's leading production areas.
According to the Mie Fisheries Research Institute, in July, it was found that the cultured pearl oysters in Ago Bay, Shima City, died in a state where the so-called mussel string called “Gaito Membrane” was shrunken. The same damage was confirmed in the neighboring Minami Ise Town.
The institute surveyed about 300 contractors that were farming in Ago Bay, and more than 80% of the respondents responded that the pearl oyster had died.
The cause of the death of the pearl oyster is currently unknown, and the institute is now urgently identifying the cause by asking the government to investigate.
In Ehime Prefecture, pearl oyster clams are damaged, while in Mie Prefecture, mother oysters that are made into pearls with pearl cores are also damaged. So, according to the Mie Prefecture Pearl Culture Liaison Council, shipments of pearls in the prefecture are expected to decrease after that.
Isao Kuriyama of Mie Prefectural Fisheries Research Institute says, “It seems that it will take time to investigate the cause because there has never been before, but I would like to search for a countermeasure while investigating the contractor.