Taking Part in Seto Inland Sea Cleanup Campaign with Four Governors, 1,000 Volunteers, Collecting 26 Tons of Marine Debris (1)
Published on August 21, 2025
Some 240 volunteers participate in an ocean cleanup campaign held on an island in Marugame City, Kagawa Prefecture, on July 5, 2025, under the “Setouchi Oceans X” project.
This was one of four cleanup events that took place simultaneously in Kagawa and three other prefectures that together encircle the Seto Inland Sea. About 1,000 people took part, including the governors of the four prefectures.
On July 5, I took a 6:55 a.m. flight to Takamatsu, Kagawa Prefecture, to participate in a rally to collect plastic and other marine waste from beaches on a small island in Marugame City in the western Japanese prefecture.
This was one of four cleanup events under the “Setouchi Oceans X” project that took place simultaneously in Kagawa and three other prefectures－Hiroshima, Okayama and Ehime－that together encircle the Seto Inland Sea.
The campaign was launched by The Nippon Foundation and the prefectures in 2020, aiming to achieve the world’s most beautiful inland sea. In April 2024, we extended the campaign, originally scheduled to last until March 2025, by three years to March 2028.
The day’s rallies were joined by a total of about 1,000 people, including the prefectural governors－Mr. Toyohiko Ikeda of Kagawa, Mr. Ryuta Ibaragi of Okayama, Mr. Hidehiko Yuzaki of Hiroshima and Mr. Toyohiko Nakamura of Ehime－alongside members of local fisheries cooperatives and companies, junior and senior high school students, and other local volunteers.
In choosing the event sites, we prioritized coastlines, estuaries and other places where the topography and climate make it easy for debris to accumulate.
These spots are hard for local residents to access, so cleanup campaigns have been rare. We used landing craft (private ferries) to transport special vehicles, heavy machinery and other equipment. In one day, the participants in the four rallies collected a total of roughly 26 tons of debris.
According to the 2023 Journal of the Japanese Association for Coastal Zone Studies, the four prefectures generate a total of roughly 388 tons of trash annually, of which approximately 302 tons is collected by local governments and other entities. This means that each year more than 86 tons of debris needs to be collected under Setouchi Oceans X by March 2028 if we are to reduce the amount of debris in the Seto Inland Sea－now the goal of the project.
At a kickoff ceremony at the Kagawa rally that was linked online with the three other prefectures, I stated: “The Setouchi Oceans X project was launched with the endorsements of the governors of Okayama, Hiroshima, Kagawa, and Ehime prefectures, committed to achieving the most beautiful sea in the world. I look forward to working together with everyone to make the Seto Inland Sea a model for the rest of the world by March 2028.”
The Kagawa event took place on Teshima island in Marugame City. The islands off the coast of Kagawa Prefecture have coastlines where debris from cities tends to accumulate as a result of seasonal winds and tides, and Teshima is no exception. On the day of the cleanup, we transported two garbage trucks and another truck to the island by ferry to directly load household trash and fishery-related debris into them.
Closing the cleanup activities, Governor Ikeda told the participants: “Today we have collected a large amount of debris in cooperation with The Nippon Foundation and the three other prefectures, but these activities need to continue. With regard to Kagawa Prefecture, I would like to step up our human resource development and other measures to address residential trash and collect debris from difficult-to-access remote islands.”
(To be continued)
