Warmer Seas, Shrinking Catches and Deadlier Voyages Put South Korea's Fishers at Risk

Five crew members never escaped

A fishing boat off Jeju Island overturned after a powerful wave struck from two directions, creating a whirlpool. Five of its 10 crew members were asleep below deck and never made it out. Before dawn, news of the disaster reached the owner, Hong Suk hui, who also heads the Jeju Fishing Boat Owners Association. He rushed to the shore, where his hopes for a long voyage gave way to grief.

Hong described his reaction to the loss:

When I heard the news, I felt like the sky was falling.

The tragedy forms part of a sharp rise in deaths at sea. Official figures show that 164 people were killed or went missing in South Korean waters in 2024, about 75 percent more than the previous year. Most were fishermen aboard vessels that sank or capsized.

South Korea's fishing communities face several pressures at once: warmer seas, declining catches of familiar species, longer journeys to fishing grounds, and weather that captains describe as increasingly difficult to predict. Boats must travel farther to earn a living, leaving crews farther from shelter when conditions deteriorate.

Hong said changing winds have become a constant concern for people working at sea:

"The weather has changed, it is getting windier every year. Whirlwinds pop up suddenly. We fishermen are convinced it is down to climate change," Mr Hong said.

Scientists are examining how warming affects dangerous winds and waves, while accident investigators have identified growing risks for fishing vessels. The changes also reach beyond boats: fish farms are losing stock during heat waves, seafood prices are rising, and coastal communities are searching for ways to keep working as the ocean changes.

Farther from Jeju, farther from safety

Jeju's main harbor remains a place of daily work and mounting worry. Crews move between the quay and their boats with fuel and gear. Owners check radios, charts, and forecasts before voyages whose costs and dangers are becoming harder to manage.

Hairtail, the silvery fish that once provided a dependable source of income, has become harder to find near the island. Boats now pursue it farther offshore, sometimes as far south as Taiwan. That distance can remove the option of returning quickly when a weather warning arrives.

Kim Seung hwan, a boat owner aged 54, described the fear accompanying those trips:

"I am always afraid something might happen to the boat, the risks have increased so much. The winds have become more unpredictable and extremely dangerous," said 54 year old owner Kim Seung hwan.

Kim said the disappearance of hairtail from nearby grounds leaves owners choosing between safer routes and the journeys needed to pay their bills:

Since we are operating farther away, it is not always possible to return quickly when there is a storm warning. If we stayed closer to shore it would be safer, but to make a living we have to go farther out.

Longer voyages consume more fuel and leave crews exposed to rough weather for more time. Equipment failures are also harder to address far from harbor. A warning can reach a skipper promptly while still leaving too little time to reach shelter.

A warming sea and more weather warnings

Average sea surface temperatures around South Korea rose by about 1.58C between 1968 and 2024. The global increase over the same period was roughly 0.74C. Korea's surrounding seas therefore warmed by more than twice the global average.

Warmer water adds energy to the ocean and atmosphere. That energy can intensify tropical weather systems such as typhoons and create conditions for sudden squalls and dangerous waves. Small vessels can be caught in rapidly changing conditions.

Government investigators reviewing recent accidents found that the marine environment around the Korean Peninsula had become riskier for fishing. Marine weather warnings covering gales, storm surges, and typhoons increased by about 65 percent between 2020 and 2024.

The dates behind the changes show how several pressures have developed together:

• 1968 to 2024: Average sea surface temperatures around South Korea increased by about 1.58C.
• 2020 to 2024: Marine weather warnings increased by about 65 percent.
• 2023: Almost half of South Korean fishers were older than 65.
• 2024: Deaths and disappearances in South Korean waters reached 164.
• February 2025: A large trawler sank off Yeosu, killing 10 crew members.
• July 2025: The fish and shellfish price index was 7.6 percent higher than a year earlier.

Professor Gug Seung gi, who led the accident review, said small fishing boats face particular danger when changing catches push them into longer voyages:

Unpredictable weather is leading to more boats capsizing, especially small fishing vessels that are going further out and are not built for such long, rough trips.

Professor Kim Baek min, a climate scientist at Pukyong National University, described the evidence on sudden gusts and the need for longer observation:

Climate change is making strong, sudden wind gusts more likely, but more research and long term data is needed before we can establish a clear trend.

Evidence is growing that climate change creates conditions favorable to sudden wind gusts and marine heatwaves, periods when ocean temperatures stay unusually high. Some weather patterns still need more research and longer records before scientists can describe their trends firmly.

Squid and anchovy catches collapse

Squid landings in South Korean waters have fallen by about 92 percent over the past decade, while anchovy catches have dropped by about 46 percent. Those declines leave fishing communities with much less of two species that have supported their earnings.

Warmer seas are changing where marine life can live. Many species move toward cooler water or deeper layers. Along the south coast, fishermen say hairtail and other familiar catches have shifted offshore and southward, extending journeys and reducing the time available to seek shelter.

Anchovy skipper Park Hyung il recently hauled up nets filled with jellyfish rather than fish. He separated just two boxes of anchovies, too little to cover fuel costs, much less crew wages.

Park compared the catch with what his boat once brought back:

"In the past, we would fill 50 to 100 of these baskets in a single day. This year the anchovies have vanished and we are catching more jellyfish than fish," Captain Park said.

Park described the financial result of the outing:

The haul is basically worthless. The sea is a mess, nothing makes sense anymore.

Longer records of coastal and offshore catches show a shift from species that favor cold water, including walleye pollock, toward species suited to warmer conditions. Pollock have thinned or disappeared from important South Korean fishing grounds. Squid, an economic pillar for many ports, have also struggled as ocean conditions change.

Sardine and anchovy catches vary with temperatures and currents. Recent anchovy declines have been especially difficult for small trawlers, whose fuel and wage bills continue even when nets bring back little that can be sold.

New fish and changing habitats around Jeju

A survey conducted over several years used underwater drones and environmental DNA to detect 167 fish species along the Korean coastline. Environmental DNA is genetic material that organisms leave in the water, allowing researchers to identify species without catching each one.

The monitoring found a growing presence of tropical and subtropical fish, particularly around Jeju. It also detected 13 species that had not previously been recorded in South Korean waters, an early sign of new arrivals as waters warm.

Jeju's seabed is changing too. Scientists have documented shifts among sessile benthic communities, the organisms that live attached to the sea floor. Coral species such as Alveopora japonica are expanding while some temperate macroalgae, or large seaweeds, decline.

Winter sea surface temperatures, water clarity, nutrients, and local water movement strongly influence where these foundation species grow. They shape the habitats used by fish and other marine animals. Their changing distribution is producing a different patchwork of habitats from the one present a generation ago.

Tropical and subtropical visitors are therefore part of a wider change in Jeju's marine community. The mix of species in the water and in fishing catches is shifting alongside the plants and corals that help form their habitat.

Older crews and gaps in safety training

Almost half of South Korean fishers were older than 65 in 2023, compared with less than one third a decade earlier. Younger workers face long hours, uncertain income, and dangerous conditions, making it difficult for the industry to attract replacements.

Many skippers hire deckhands from Vietnam and Indonesia to keep their vessels operating. Some crews receive limited safety training, while language barriers can make urgent instructions difficult to follow in rough weather.

Woojin Chung, South Korea's representative at the Environmental Justice Foundation, said the financial and safety pressures reinforce one another:

When you combine more extreme weather with the pressure to travel further, the increased fuel costs this brings, and the need to rely on cheap, untrained foreign labor, you have a higher chance of meeting disaster.

Owners face fuel bills that rise with distance, while poor catches reduce the money available to meet them. Crews must then work through longer voyages, sometimes with limited preparation for an emergency. Safety decisions made before departure carry consequences for everyone aboard.

A Yeosu sinking puts owners' decisions in focus

A large trawler sank off Yeosu in February 2025, killing 10 crew members. Conditions were so cold that falling into the water likely meant hypothermia, a dangerous loss of body heat.

Smaller boats had been held back that day, but the trawler sailed. The cause of the sinking remained unclear as of October 24, 2025.

Ean, whose father Young mook died at age 63, believes owners have a duty to judge weather risks and maintain older vessels. She described the difference between a company's financial loss and a family's loss:

"Ultimately it is their call when to go out. Companies have insurance, so they get compensated after a boat sinks, but our loved ones cannot be replaced," she said.

Families are pressing for better decisions on land as well as stronger protection at sea. The condition of a vessel and the choice to depart affect a crew's exposure before any rescue operation becomes necessary.

Research identifies the fisheries most exposed

A national analysis using data from 1993 to 2023 found that rising sea surface temperatures, higher carbon dioxide levels, and changes in rainfall were associated with declines over time in coastal and offshore catches.

The study also found that past production helps predict current output over shorter periods, and that temperature shocks can affect stocks after a delay. Fish populations can respond through changes in where they live, difficulties during spawning and early life, and disruptions to food webs that benefit some species while harming others.

A separate assessment examined 36 species and 24 fisheries. It measured their sensitivity to warming and their exposure under a scenario with high emissions by 2100. Offshore fleets ranked as more vulnerable than coastal fleets.

Fisheries relying heavily on species with low productivity, limited movement, or narrow habitat ranges faced the greatest risk. Such species have fewer ways to replace losses or move into suitable conditions. Offshore fleets also face longer distances, particular target species, and limited alternatives when fishing conditions deteriorate.

The assessment's authors called for priority attention to the most vulnerable fisheries and for climate stress to be included in quotas, fishing seasons, and gear rules. Those measures govern how much can be caught, when fishing takes place, and which equipment may be used.

Seafood prices bring the changes ashore

South Korea's fish and shellfish price index rose 7.6 percent in July 2025 from a year earlier. Yellow croaker prices increased by more than 13 percent, while mackerel and oysters rose by more than 12 percent. Wholesale flatfish prices climbed by about 21 percent.

The general inflation rate was much lower, meaning seafood costs were rising faster than many other household expenses. Price swings make favorite dishes harder to afford during peak heat and complicate menu planning.

Repeated heat waves are causing higher mortality in aquaculture pens, particularly among flatfish and rockfish raised for sashimi. Aquaculture means farming aquatic species rather than catching them in the wild. Losses at farms can reduce the supply reaching markets.

Imports of some seafood products have increased as domestic production of certain species falters. At sea, fishers face higher fuel costs from longer trips and the possibility that weather will close ports before they can land their catch.

Policymakers are directing more money toward smart aquaculture models, automation at existing fish farms, and fisheries restructuring that includes reducing vessel numbers. The aims are to stabilize supply, improve safety, and give ecosystems time to adjust.

Safety reforms and alternatives for coastal livelihoods

A government taskforce has urged owners to install safety ladders, require life jackets whenever crew members are on deck, and provide mandatory safety training for all foreign crew. It also wants faster weather updates tailored to local conditions and better search and rescue coverage.

Inspectors have increased unannounced checks of safety equipment aboard working boats. These measures address both preparation before departure and the chances of surviving an emergency at sea.

Some local governments offer small payments for jellyfish brought ashore, helping clear nets and remove the mass of jellyfish clogging coastal waters. Squid skippers are being offered loans and retirement packages to prevent bankruptcy during poor seasons. Vessel reduction programs aim to reduce fishing pressure where stocks remain strained.

South Korea is already a world leader in seaweed farming, especially gim. Seaweed requires no feed, can improve water quality, and can provide steadier income with less exposure to storm risks than mobile fishing. Investment in seed quality, farm design, and new markets can create coastal jobs while easing pressure on wild fish stocks.

Environmental DNA sampling with underwater drones offers a faster way to track where species are present. Incorporating those observations into stock assessments can speed warnings about arrivals of warm water species or risks to important stages of marine life.

Policymakers are also considering harvest rules that account for climate change, more marine protected areas in nursery and spawning grounds, and programs to replenish stocks with resilient species suited to future conditions.

Changing fisheries cross national boundaries

Marine heatwaves have become more frequent over the past three decades, and warming is shifting the ranges of commercial fish stocks. When fish move across national boundaries, countries can disagree about how to divide the catch, as happened with North East Atlantic mackerel.

Fisheries that plan for changing ocean conditions, closely monitor stock movements, and coordinate with neighboring countries are better able to keep catches sustainable. Rules built around older patterns need to account for where fish now live and reproduce.

South Korea's fleets also operate far from home. In 2024, vessels from Norway, China, and South Korea caught around half a million tonnes of krill in Antarctic waters. Demand for krill oil and feed for farmed salmon has made the fishery more lucrative.

Krill feed whales, seals, penguins, and seabirds. They also help store carbon by transporting it into the deep sea. Scientists warn that overfishing and warming can weaken this keystone of the Southern Ocean, a species on which many others depend.

International negotiations to update conservation measures have struggled in recent years, increasing the risk that catches become concentrated in sensitive areas. South Korea's seafood future is connected to those decisions as well as to the changing waters around Jeju.

Agreements that share catches fairly and keep fishing within limits guided by science, together with stronger domestic safety and training standards, can help protect coastal livelihoods. The challenge reaches from individual decisions about whether to leave harbor to international rules for fisheries in a warming ocean.

Key Points

• South Korean waters recorded 164 deaths or disappearances in 2024, about 75 percent more than the previous year, mostly involving fishing vessels.
• Sea surface temperatures around Korea rose about 1.58C from 1968 to 2024, compared with roughly 0.74C globally.
• Marine weather warnings increased about 65 percent between 2020 and 2024 as some boats traveled farther to find fish.
• Squid landings fell about 92 percent over a decade, while anchovy catches declined about 46 percent.
• Monitoring detected 167 fish species, including 13 not previously recorded in South Korean waters.
• Almost half of fishers were older than 65 in 2023, and safety concerns include training gaps and language barriers among migrant crews.
• Research links changing climate conditions with declining catches and identifies offshore fisheries as more vulnerable than coastal fisheries.
• Seafood prices rose sharply in July 2025, while heat waves caused losses at fish farms.
• Proposed responses include life jackets, safety ladders, crew training, better forecasts, fewer vessels, and investment in aquaculture and seaweed farming.
• Shifting stocks and Antarctic krill fishing connect South Korea's coastal livelihoods to international conservation decisions.