NIFS said that the Cold Water Mass with 5~7℃ lower temperature than that of surrounding areas occurred for the first time this year in the mid part (Samcheok, Gangwon Province/ Yeongdeok, North Gyeongsan) and the south part (Seokbyeong, Guryongpo, Pohang/ Gijang, Busan) of the East Sea. 

NIFS projects the cold water mass would last for a week. The coastal upwelling caused by southerly wind is the reason for the cold water mass, which has the variations in water temperature and the repeated life cycle under the wind directions ; occurrence by southern wind and disappearance by northern wind. 

NIFS urged people to take precautions for rearing management, as the radical change in water temperature can lower aquatic organisms' immunity and increase the chance of disease. 

When the cold water mass occurs, it is required to reduce the influx of breeding water, stop feeding, and minimize the stress imposed on the aquatic organisms by providing enough oxygen. In addition, even after the cold water mass disappears, aquatic organisms still need close monitoring and high-quality feed with nutritional additives including vitamin for their health recovery.