Kathmandu, Dec. 1 -- Oysters in Japan are dying en masse in parts of the country's top production area, likely due to warmer sea temperatures, officials said Monday.In some coastal areas surrounding the Seto Inland Sea in western Japan -- an area that accounts for more than three quarters of Japan's farmed oyster production -- around 90 percent of cultivated oysters are dead.

"I've never experienced this in my whole career," Tatsuya Morio, who has farmed oysters for more than 20 years, told AFP.

Shoichi Yokouchi, an official in the Hiroshima area, which borders the Seto Inland Sea, said he suspected "high water temperatures, together with other factors, are the culprit of oysters dying en masse".

This year average water temperatures al...