Climate change drives up shark activity off Korea’s east coast

Authorities provide shark repellent to beach lifeguards


The iconic line from the 1975 film “Jaws” — “You’re gonna need a bigger boat!” — is taking on new resonance in Korea.

Rising sea temperatures, a result of climate change, have led to a sharp increase in shark sightings along the nation's east coast. The National Institute of Fisheries Science (NIFS) reports a significant rise in shark activity, with the number of sharks hauled in by fishing boats as unintended catch in the East Sea climbing from just one in 2022 to 44 last year. As of late July, 22 additional cases have already been reported this year.

The increase has provoked unease in coastal communities, particularly as more visitors venture into open waters during the summer holiday season. In response, local governments are stepping up safety measures.

For the first time, Gangwon Province allocated 45 million won ($32,500) this year to install protective nets at 14 major beaches along the East Sea. The nets are intended to keep sharks, jellyfish and other marine threats away from people in the water.

The east coast city of Gangneung has also deployed shark deterrent devices for lifeguards at major beaches. Previously, the city used repellents mounted on jet skis that emitted electrical currents. This year, it introduced wearable devices that release magnetic pulses.

The devices work by targeting sharks’ sensitivity to electric fields. Receptors near their snouts detect minute signals, and when exposed to such stimuli, sharks typically swim away.



A great white shark lies on a dock after being caught off the coast of Yeongdeok, North Gyeongsang Province, April 14, 2017. Courtesy of Korea Coast Guard Station Pohang

“A lifeguard injury during an emergency could hinder rescue efforts, so we’ve provided shark repellent specifically for lifeguards,” a Gangneung city official said.

The recent increase in shark sightings along Korea’s east coast is largely attributed to warming waters, which have attracted more warm-water fish species that sharks feed on.

According to NIFS, surface water temperatures in Korea’s surrounding seas have risen by 1.58 degrees Celsius over the past 57 years. The East Sea recorded the sharpest rise, with surface temperatures climbing by 2.04 degrees — higher than in the West Sea or South Sea.

Among the 81 sharks accidentally caught off Korea’s east coast between 2023 and July this year, shortfin makos accounted for the largest share with 40, followed by 23 salmon sharks, 12 blue sharks, three great whites, two copper sharks and one hammerhead. All six species have been classified by the NIFS as posing a high risk of attack.

Many of the sharks were notably large. Of the 58 whose length was confirmed, five measured over 3 meters. Thirteen were between 2.5 and 3 meters, and 17 ranged from 2 to 2.5 meters.

NIFS told The Korea Times that shark sightings are likely to increase as sea temperatures rise, and their presence could become more common throughout Korean waters if warming trends continue.

“Sharks are apex predators that help maintain ecological balance by preying on mid-level species like mackerel,” the institute said. “But a sudden surge could reduce coastal fish populations as prey species alter their behavior to avoid them, while also damaging fishing nets and threatening vessels.”

The institute also noted the need for stronger monitoring systems, including environmental DNA tools that detect genetic traces of marine life in the water.