The National Institute of Fisheries Science, along with local governments, academia, fisheries cooperatives, and aquaculture fishermen, held an on-site discussion to address the issue of mass mortality in flounder farming, which has been a major factor in the decline in productivity. The institute has been conducting research to develop the aquaculture industry and flounder species since 1981. The research includes breeding varieties, developing disease treatments, and circulating filtration culture. However, flounder aquaculture production has been stagnant since 2010 due to factors such as new diseases, environmental deterioration, and natural disasters. The institute shared disease trends and reduction measures in the Jeju region, which is home to half of all flounder farming, and discussed future research directions to reduce mass mortality of flounder.