Kesennuma Bay on 7 June (left) and 30 July (right), 2025. While wave patterns appear in both, the disrupted formations on 30 July may reflect tsunami activity linked to the Kamchatka earthquake. © Sentinel-2
On 30 July, one of the strongest recorded earthquakes struck in the Pacific near Russia’s Kamchatka Peninsula, prompting tsunami warnings across Pacific coastlines. Some aquaculture infrastructure was damaged along parts of Japan’s north-eastern coast.
According to a report by The Japan News (Yomiuri Shimbun), the coastal city of Toba in Mie Prefecture saw waves of up to 40 centimetres, resulting in damage to at least 372 of the roughly 2,000 floating oyster rafts in the bay. Local officials from the Toba Isobe Fisheries Cooperative warned that even rafts that remained afloat might be compromised due to tangled hanging ropes, which could have cracked developing oysters.
“The oysters were growing well this year, and we were looking forward to winter shipments, so this is a big blow,” the chairman of an oyster farmer cooperative told The Japan News.
The news website also reported that Kaneki Suisan’s oyster and scallop farm in Kesennuma suffered extensive damage, as more than half of the company’s 60 rafts were impaired due to the waves. The company had previously rebuilt its operations following the 2011 Great East Japan Earthquake and tsunami.
“It’s frustrating that we have to start all over again after finally getting back to the way things were before the disaster,” the owner told the publication.
Further north, in Iwate Prefecture, recovery work was also underway in Ōfunato City. According to a broadcast by TV Asahi, local fishermen deployed three boats early on 2 August to restore longline oyster culture facilities. While seven units were found displaced, no oyster loss was reported.
While no fatalities were reported, the event underscores the vulnerability of Japan’s aquaculture sector to seismic and climate-related disruptions. The devastating 2011 tsunami was estimated to have caused ¥100 billion in damage to the industry, with oyster and brown seaweed (Undaria pinnatifida) cultivation particularly hard hit.
