"Did You Come to See Dokdo?"... Ulleungdo Sea's 'Parangdom' Increased 10 Times

National Institute of Biological Resources Investigation Results Announced
Tropical and Subtropical Fish Species Rapidly Increasing
"Year-Round Sea Temperature Rising Near Ulleungdo Coast"

In the coastal waters of Ulleungdo, the tropical fish 'Parangdom' has been found to have increased more than tenfold compared to last year. Among all fish species, tropical and subtropical fish accounted for nearly 60% of the total.

Experts predict that the distribution of tropical and subtropical fish will expand along the East Sea coast due to rising seawater temperatures caused by climate change.

The National Institute of Biological Resources under the Ministry of Environment announced on the 21st the results of the 'Ulleungdo Coastal Fish Species Diversity Survey' conducted from 2021 to October this year.

Tropical fish Parangdom found off the coast of Ulleungdo.
[Photo courtesy of the National Institute of Biological Resources]

The waters around Jeju Island, Ulleungdo, and Dokdo in South Korea are clear, allowing fish observation through diving. As a result, more than half (58.5%) of the 131 species observed in the underwater survey were tropical and subtropical fish. This is 1.5 times the proportion of temperate fish (36.9%). Including species recorded in the past, the total number of fish species inhabiting the coastal waters of Ulleungdo reached 174 as of last month, an increase of 20 species compared to last year.

The institute explained that at some survey sites, more than 100 Parangdom, a tropical fish species, were observed, indicating an approximately tenfold increase compared to previous counts. The fully grown Parangdom, about 10 cm in size, is loved as an ornamental fish due to its bright blue body resembling the sea and yellow tail fin. They live in groups around rocky areas at depths of about 20 meters.

Parangdom inhabits waters with temperatures ranging from 16 to 31 degrees Celsius. Originally, they mainly lived in the warm waters around Jeju, but their habitat has now expanded to include the waters around Ulleungdo and Dokdo.

White-tailed yellowback sea bream. [Photo by National Institute of Biological Resources]

The survey also newly discovered juvenile fish such as the yellowish White-tailed Yellowtail Damselfish and the large-spotted Chromis with a red base and black and blue spots. The National Institute of Biological Resources believes that these young tropical fish drifted along the warm currents starting from the Korea Strait and moving northward along the East Coast, eventually remaining in the East Sea.

These changes appear to be due to rising sea temperatures in domestic waters. According to the National Institute of Fisheries Science, the surface water temperature around the Korean Peninsula was 26 degrees Celsius from late August to early September this year, the highest since observations began. During this period, the surface water temperature in the East Sea, where Ulleungdo is located, was 25.8 degrees Celsius, more than 2 degrees higher than the average.

Yongchinollagi.
Photo by National Institute of Biological Resources

Researcher Kim Byung-jik explained, "Young tropical fish drifted along the East Korea Warm Current starting from the Korea Strait and moving northward along the East Coast, eventually remaining in the East Sea. Tropical fish can live in environments where the minimum water temperature is above 15 degrees Celsius. Last year, the annual water temperature near Ulleungdo ranged from a minimum of 8 degrees to a maximum of 28 degrees, creating a suitable environment for tropical fish during summer and autumn."

Accordingly, the institute expects tropical and subtropical fish to spread further along the East Sea coast due to rising seawater temperatures and plans to expand survey areas to include Dokdo and the central East Sea coastal waters.

Having collected comprehensive field data on the species diversity of Ulleungdo fish through a three-year underwater survey, the institute plans to conduct long-term observational research to track changes in fish species diversity along the Korean Peninsula coast in response to climate and environmental changes.

This content was produced with the assistance of AI translation services.