Japan’s oyster farmers face ruin amid rising sea temperatures: ‘dying en masse’

Oysters in Japan are dying en masse in parts of the country’s top production area, likely due to warmer sea temperatures, officials said on 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 per cent of cultivated oysters are dead.

“I’ve never experienced this in my whole career,” said Tatsuya Morio, who has farmed oysters for more than 20 years.

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 along Hiroshima’s coast from July to October – an important period for oyster cultivation – were 1.5 to 1.9 degrees Celsius higher than the 1991-2020 average, according to prefecture data.

Sea temperatures are rising globally due to climate change.