What to Do About Jeju Sea's Salinity Loss Due to China's Heavy Rain... Emergency Over Fishery Damage

Yangtze River Flood Discharge 53% Above Average

Due to heavy rainfall concentrated in southern China, a large volume of Yangtze River water has flowed into the sea, putting Jeju Island on alert. This is because damage to fishing grounds is inevitable if salinity drops.

The Jeju Marine and Fisheries Research Institute predicted that around the 29th, a mass of high-temperature and low-salinity water with temperatures above 28 degrees Celsius and practical salinity units (psu) below 26 would flow into the sea about 30 km southwest of Marado. The practical salinity unit psu refers to the amount of dissolved salts (g) in 1 kg of seawater. The average summer salinity of Jeju's sea is 30 to 31 psu, and the water temperature ranges from 23 to 25 degrees Celsius. Low-salinity water is lighter than seawater with higher salinity, so it floats on the surface in the form of water masses for a long time, exposed to strong sunlight, causing the temperature to rise.

The low-salinity water flowing into Jeju is mostly created by the mixing of a huge amount of freshwater from the Yangtze River due to heavy rainfall with seawater, flowing through the East China Sea of China. Recently, due to heavy rain in China, the outflow of the Yangtze River has exceeded 72,000 tons per second, a 53% increase compared to the average (47,000 tons).

This situation is similar to that of 2016. At that time, in August and September, a large amount of high-temperature and low-salinity water with salinity levels of 23 to 26 psu and temperatures of 30 to 31 degrees Celsius flowed into the western sea of Jeju, causing massive deaths of shellfish such as turban shells, abalones, and red sea cucumbers in Andeok-myeon and Daejeong-eup of Seogwipo City, and Hangyeong-myeon of Jeju City. Earlier, in 1996, high-temperature and low-salinity water flowed into village fishing grounds in Daejeong and Hangyeong areas, causing enormous damage worth approximately 6 billion KRW.

Jeju Province, administrative cities, the Marine and Fisheries Research Institute, the National Institute of Fisheries Science, and the Fisheries Cooperative Federation officials plan to conduct observational surveys in the affected waters, disseminate phased situation updates based on low-salinity water monitoring information, and strengthen surveillance of aquatic organisms in village fishing grounds to respond accordingly.

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