Mass Die-Off of Oysters in Hiroshima: A Crisis for Local Fisheries

The coastal region of Hiroshima, Japan, is facing a significant crisis in its oyster production, with reports indicating that up to 90% of oysters are dying in some areas. This alarming trend has been attributed to a combination of rising sea temperatures and the effects of an exceptionally hot summer in 2023, which deprived oysters of essential oxygen and food. The Kure oyster festival, typically a bustling event celebrating local seafood, has seen noticeably smaller and scarcer oysters this year, raising concerns among consumers and businesses alike.

The Guardian

Hiroshima accounts for nearly two-thirds of Japan's farmed oyster supply, producing approximately 89,000 tons in 2023. The fisheries along the Seto Inland Sea, which contribute to 80% of the country's oysters, are experiencing unprecedented mortality rates among the shellfish. Taketoshi Niina, a local fishery operator, reported that about 80% of his oysters are dead upon harvest, marking a drastic increase from the typical 30% to 50% mortality rate. Tatsuya Morio, another oyster farmer with over 20 years of experience, echoed this sentiment, stating, “I’ve never experienced this in my whole career.”

The Guardian

In response to the crisis, Japan's fisheries agency has implemented measures to support struggling oyster farmers, including five-year government loans at nearly zero interest and access to mutual aid programs for aquaculture businesses. Tomonori Uemoto, director of the fisheries promotion office at the Kure municipal government, emphasized the broader implications of the oyster deaths, noting that Kure’s oyster production supports various sectors, including local employment in distribution and food tourism.

The Guardian

Experts attribute the mass die-off to various environmental conditions exacerbated by climate change, such as high air and water temperatures, low oxygen levels, and nutrient shortages. Kazuhiko Koike, a professor at Hiroshima University, highlighted the challenges posed by climate change, stating, “It’s difficult to put the brakes on climate change.” He warned that if the rainy season ends early again, coupled with prolonged high temperatures, the region could face similar low oxygen levels and food shortages in the future.

The Guardian

The impact of the oyster crisis is deeply felt among local families. Niina, who transitioned to oyster farming from a corporate job, expressed concern for the future of his family business, which has been in operation for over half a century. He noted, “This year I’ve begun to really worry whether there is a future for him,” referring to his son, who hopes to take over the business.

The Guardian

• “This is something out of the ordinary.” — Taketoshi Niina, Fishery Operator

The Guardian

• “I’ve never experienced this in my whole career,” — Tatsuya Morio, Oyster Farmer

The Guardian

• “It is possible to say that various abnormal environmental conditions caused by global warming and climate change – such as high air and water temperatures, low oxygen levels, insufficient rainfall, nutrient and food shortages are causing oysters to die en masse,” — Kazuhiko Koike, Professor, Hiroshima University

The Guardian

The ongoing crisis in Hiroshima's oyster production underscores the urgent need for adaptive strategies to mitigate the impacts of climate change on local fisheries.

The Guardian