NIFS said that it clarified the cause of changes in fishing ground formation and environmental changes of largehead hairtail industry in the coast of Jeju Island through Geographic Information System (GIS) analysis. 

  *NIFS Serial Oceanographic Observation (NSO)  

  **Referring to the radio fishery information communication data (National Federation of Fisheries Cooperatives, NFFC) 

It turned out when the water temperature at 20m depth in August reached 21-23℃, the fishing ground formation was distinctive with the catch increasing (2017), but when the temperature rised to 27-29℃, the fishing ground became degraded or dispersed, resulting in the catch decreasing (2015, 2016, 2023, 2024). 

  *Coastal composite fishery is a fishing sector that catches fishery resources by using a wide range of fishing methods such as longline, octopus pot, shellfish shell fishery, etc. by using unpowered or small power boat (under gross tonnage of 10).  

  **Total catch (National): 63,739 tons in 2006 → 44,507 tons in 2024 (30.2% decrease) / Catch of Coastal composite fishery (Around Jeju): 8,149 tons in 2006 → 3,957 tons in 2024 (51.4% decrease) 

Starting in 2026, to project the changes in the fishing grounds by environmental changes in Jeju seas, NIFS will conduct close monitoring* of the marine organisms and environment from surface to bottom layer within approximately 60km of coast in line with the fishing ground formation period of key fish species.

  *Eggs, young fish, water temperature in each water layer, salinity, dissolved oxygen, etc. will be monitored at 40 stations of eight (8) lines in the sea areas of Jeju.