SHIZUOKA, Jul 18, 2025 (News On Japan) - A massive amount of seaweed has washed ashore on a popular beach in Ito City, Shizuoka Prefecture, turning the shoreline into a green carpet and causing concern just days before the summer swimming season begins.
The affected area is Orange Beach, located on the eastern coast of the Izu Peninsula facing Sagami Bay. Known for its calm waves, the beach is usually packed with families during the summer months. According to the Ito City government, the unusual incident was first observed on July 11th.
"Just as you can see, the entire beach is covered, and with the official opening coming up soon, we’re in a tight spot," said Takayuki Tsuchiya, a tourism official from the city. "Cleanup and transportation alone are likely to cost over 1 million yen."
The seaweed in question is known as juzumo, a type of filamentous algae commonly found along Japan’s coasts. Residents and business owners near the beach expressed surprise at the volume of seaweed that had come ashore.
"I saw this mass of blue stuff piling up and didn’t know what it was. I was shocked," said Kazuo Yamada, who runs a local dried fish shop. "It’s the first time we’ve seen anything like this."
"It really smells," added his daughter, Eri Yamada. "Even when you’re just walking nearby, you catch the stench. Plus, a lot of dead sea creatures have come up and dried out, adding to the odor."
Although the city hired a private contractor to clean the beach the day after the seaweed appeared, another wave of it washed ashore the following day. When reporters visited the site on July 16th, large quantities of seaweed were still visible, some of it already turning white and emitting a foul smell.
Local residents, while not alarmed, were puzzled by the phenomenon. "It doesn’t seem dangerous since it’s just seaweed. It’s more rare than scary," said one. Another commented, "It’s such a strange sight. I wish we could find some use for it."
Drone footage, taken with city permission, revealed that large swaths of seaweed were still floating offshore. According to locals, juzumo is not usually found in this area.
Hirokazu Yamada, head researcher at the Izusan branch of the Fisheries and Ocean Technology Research Institute, suggested that the seaweed may have been brought ashore in bulk due to swells caused by an approaching typhoon. However, he added that the exact cause remains uncertain—especially since the first wave came before Typhoon No. 5 passed by eastern Honshu earlier this week.
The city has advised against consuming the seaweed and is planning another beach cleanup on July 18th, just ahead of the official beach opening scheduled for July 19th.
Source: FNN
