According to NIFS, last year recorded the warmest average water temperature since the 1990s, when NIFS started its monitoring of ocean surface temperature in Korean waters using satellites. 

Since the 1990s, NIFS has gathered the satellite－based data of ocean surface temperature and provided it on a daily basis to identify the impact of climate change on Korean waters and the changes in fishing ground environments. 

The analysis on the satellite-monitored data showed average ocean surface temperature 2023 recorded the warmest 19.8℃. In particular, June, September, and November experienced the highest water temperature, which was 0.6℃ higher than the average water temperature for the past 20 years (2001~2020). 

The anomalies occurred due to the temperature increase by expansion of North Pacific High and the impact of increased influx of warm waters from the Western Pacific Ocean by Tsushima Warm Current (TWC). The increase of ocean surface tempertature was distinctive in the East Sea rather than the West and South Sea.

In research vessel (R／V) ocean monitoring in Korean waters, NIFS also confirmed that last year’s water temperature was 0.8℃ higher than Climate Normals (1991∼2020). 

Last year’s record－high water temperatures have been reported across the globe including Korean waters. The NOAA Global Climate Report said 2023 recorded the warmest global ocean surface temperature since the beginning of modern meteorological observation, and in particular April－December 2023 set a new record in a row.

The sudden changes in physical characteristics of marine environment can affect fisheries resources and marine ecosystem, such as mass mortality of aquatic organisms, chages in habitat environment, deteriorated productivity, decreased biomass of small marine life including phytoplankton.