Korean fisherfolk say the sea has changed and the catches are small

"The water is hot now. It hasn't been raining, so the seawater turned black. The sea is becoming weird," said Park Myeong-ja, a 64-year-old fisher in Mangdeokpo-gu in Gwangyang, South Jeolla on Sept. 22.

A fisherman holds jeoneo caught in Mangdeokpo-gu, Gwangyang in South Jeolla on Sept. 22. [JOONGANG ILBO]

"The water is hot now. It hasn't been raining, so the seawater turned black. The sea is becoming weird," said Park Myeong-ja, a 64-year-old fisherman in Mangdeokpo-gu in Gwangyang, South Jeolla on Sept. 22.

Higher sea temperatures are changing everything, according to people who making their living in the waters off Korea.

Around 7 a.m. in Magdeokpo-gu, fishing vessels returned to the port in Gwangyang, South Jeolla, but the catch was underwhelming. Over three hours, each boat caught only about 20 jeoneo, known as spotted gizzard shad.

The season has come for the annual jeoneo festival in Gwangyang, but jeoneo are no longer found during the usual fall season. This particular fish is known to be the most active and easily caught in the fall in Korea.

Fishermen board a fishing vessel to catch jeoneo in Mangdeokpo-gu, Gwangyang in South Jeolla on Sept. 22. [JOONGANG ILBO]

Mangdeokpo-gu in Gwangyang, where the Seomjin River meets the ocean, is a favorite spot for jeoneo along the country's south coast.

But fishermen in the area say it is now becoming more difficult to catch this fish due to environmental issues, such as the rising sea temperature and drought.

"Fish that were not found before are getting caught these days due to global warming," said Jeong Seung-hwan, a 61-year-old fisher. "The jeoneo festival should be now held earlier when jeoneo are easily caught."

Climate change is not only shifting the catching season of jeoneo, but changing the standards of the season itself.

September, commonly referred to as the early fall in Korea, is now more like summer.

According to data collected upon request of the JoongAng Ilbo, there were big changes in the duration of the season and the starting day of fall in seven large cities, including Seoul, Mokpo, Busan and Jeju, over the past decade (2011-2020).

The start day of the fall refers to the first day that the average daily temperature drops below 20 degrees Celsius (68 degrees Fahrenheit).

Among the seven cities, the fall season in three cities located in the southern region started in October. The fall began on Oct.1 in Mokpo, Oct. 7 in Busan and Oct. 10 in Jeju, the southernmost city among those studied.

In Seoul, the fall season began on Sept. 29, which is 17 days later than it usually started in the 1911-1920 period.

Data show that the Chuseok harvest holiday, a holiday that represents the fall season in Korea, is becoming more like a summer holiday. According to data that analyzed the average temperature in Seoul on the Chuseok day over the past 30 years, the average temperature was 19.5 degrees Celsius in the 1990s, 20.3 degrees Celsius in the 2000s and 21.2 in the 2010s.

"As the day temperature does not fall much in September, foods are likely to go bad in Chuseok, raising food poisoning risks and also affecting inflation as harvesting periods of fruits vary," said Byun Young-hwa from the National Institute of Meteorological Sciences.

"Climate change not only affects agriculture and fisheries but also directly affects our daily lives, including leisure and fashion."

The rising temperature is also found in seawater. Due to the rising sea temperatures, fishing grounds for jeoneo are moving to the north.

According to Statistics Korea, more jeoneo were caught in the fall than in the summer in 1990. Last year, the catches during the two seasons were about the same.

This fall, the fish became a scarce resource due to the sharply reduced number of fishing days as Typhoon Hinnamnor hit the country.

Jeoneo cannot live in a fish tank for many days, so when catch falls, the market price of jeoneo sharply rises.

"Thirty years ago, it was possible to catch jeoneo even until late November, but because the water temperature is not like before, they are now caught well in the summer and slowly becomes difficult to catch over the months and are no longer seen in October," said Kim Maeng-cheol, from the fishing committee of Gwangyang city.

"There is high demand for jeoneo in the fall, but due to short supply, the fish that cost 8,000 won per kilogram in the summer increases up to 25,000 won to 30,000 won."

The drop in catch during the fall may be due to multiple reasons, such as drought and fishers that give up fishing due to an increase in oil prices.

A sargassum forest seen in Seogwipo, Jeju Island in April, 2018 [GREEN KOREA]

The same sargassum forest seen destroyed in Jeju Island's Seogwipo, in April this year [GREEN KOREA]

The rising water temperature is lethal to the marine ecosystem. Ocean's surface temperature normally cools down slower compared to land, which could be a threat to marine creatures sensitive to water temperature.

This year, the sea surface temperature was high from July 6 to September 7, or 64 days.

The waters off of Jeju Island became a subtropical ocean due to the rapidly rising sea surface temperature, eventually damaging the seaweed ecosystem. Due to this reason, the number of shellfish, such as horned turban snail and abalone, that feed on seaweed fell significantly.

"The ocean that is shallow and good for haenyeo [women divers] to catch seafood is all dead," a haenyeo in Jeju lamented.

"Around 30 to 40 years when I first started my job, sea urchins were exported to Japan in the fall, but now, all these sea urchins are only left with shells in October," said Kim Yeong-nam, a haneyeo who worked at the Gapa Island in Jeju for over 30 years.

"The average water temperature of Gapa Island in August was below 25 degrees Celsius until 2018, but the temperature rose to 27.8 degrees Celsius in just three years last year," said Yoon Sang-hoon, an activist affiliated with Green Korea.

"Seaweed should reproduce in the fall, but if they are exposed to water over 25 degrees Celsius, which is considered as the tipping point of seawater temperature, the seaweed melts and dies, eventually destroying the sea forest."

Aquaculture is another industry that is getting damaged by climate change. Unlike agricultural crops that are planted in the spring and harvested in the fall, the seeding process of seaweed begins in the fall and is harvested in the spring. The seeding process refers to the process of attaching seeds to the net to culture these seaweeds.

In culturing seaweed laver, or gim, in which Korea has the largest market share, the seeding process usually starts near the Chuseok holiday, but this year, no progress was made with the seeding process due to the high water temperature.

The suitable water temperature for the seeding process of seaweed laver has been postponed from early September to late September, and that of seaweed from mid-September to early October, according to a report on the effects of climate change on fisheries released on Sept. 22 by the National Institute of Fisheries Science. The suitable water temperature is when the temperature falls below 22 degrees Celsius.

From 2011 to 2021, the high water temperature accounted for the greatest damage to aquaculture (53 percent), causing 124.1 billion won ($86.7 million) of losses.

Last year, around 5.05 billion won of losses occurred related to seaweed aquaculture due to high water temperatures.

"In 2100, the seeding and production period of seaweed laver will be delayed as the sea surface temperature has risen by 4 degrees Celsius, heavily affecting productivity," said the report.

"Korea's fishing environment is changing five times faster due to the rising sea surface temperature," said Jeong Seok-geun, a marine life professor at Jeju National University. "Scientific measures are needed to predict the change in the fishing industry caused by the climate crisis."

BY CHEON KWON-PIL, PYUN GWANG-HYUN, CHANG YOON-SEO AND KANG CHAN-SU [cho.jungwoo1@joongang.co.kr]