Resort island of Jeju raises stink over fetid algae invasion

Stinky ginger-colored algae have appeared on the shorelines of Jeju Island, turning emerald-blue waters an unpleasant dark orange. The arrival of the algae, named sargassum horneri, harms the natural scenery and distresses local commercial fishers.

Sargassum horneri gathers on the sand at Iho Tewoo Beach in Jeju Island on Monday. [CHOI CHOONG-IL]

Stinky ginger-colored algae have appeared on the shorelines of Jeju Island, turning emerald-blue waters an unpleasant dark orange.

The arrival of the algae, named sargassum horneri, harms the natural scenery and distresses local commercial fishers.

On Monday, the three-meter-long (9.8-foot-long) algae covered the white sand at Iho Tewoo Beach. Volunteers removed 500 large bulk bags of sargassum in just a single day.

The fishy aroma emitted as the algae decay on land makes the job even more disagreeable.

Iho Tewoo Beach in the northern part of the island was not the only victim. The algae's presence is an island-wide problem.

On May 16, sargassum arrived on the coastline in Aewol-eup, in the island's northwest.

Local fishers were stranded on land for fear that their boats could suffer engine failure if the algae got tangled in their motors.

Often dubbed an “unwelcomed visitor,” the algae has been hitting the shores of Jeju Island in greater volume this season.

This year, the island has already removed over 800 tons of algae, nearly double the previous year’s collection of 414 tons. In 2022, approximately 502 tons of algae were collected.

Before 2022, Jeju Island suffered from enormous amounts of the algae, with collections of 5,181 tons and 9,755 tons in 2020 and 2021, respectively.

The latest algae invasion alarms Jeju authorities ahead of the summer peak season, prompting the provincial government to invest “all administrative forces to clear the sargassum.”

Jeju Island is one of Korea's most popular travel destinations. Its economy is largely dependent on tourism, which accounted for 21 percent of the island’s gross domestic product in 2020.

Sargassum horneri appear in ocean waters near a port in Aewol-eup in Jeju Island on May 16. [CHOI CHOONG-IL]

A task force dedicated to clearing the algae has been up and running since May 2.

State-run marine-related agencies, such as the National Institute of Fisheries Science and Korea Marine Environment Management Corporation, have joined forces with provincial and county-level offices.

Each agency has been removing the sargassum based on real-time monitoring.

The Kuroshio current, a warm northeasterly ocean current flowing from waters near the Philippines and southern China to Japan, carries algae to Jeju Island in springtime, mainly between March and June. The algae showing up in Jeju are mostly from Chinese waters.

Although some algae are edible, this specific sargassum horneri is too tough to be digested.

“A total of 269 volunteers are participating in the algae removal,” said Chang Jae-cheol, head of the provincial government's Maritime Affairs and Fisheries Bureau. “The local authorities will find ways to utilize the collected sargassum as an agricultural fertilizer, and what remains will be discarded as trash.”

BY CHOI CHOONG-IL, LEE SOO-JUNG [lee.soojung1@joongang.co.kr]