South Korea and China have agreed to resume joint patrols to crack down on illegal fishing.
Seoul's oceans ministry says patrol boats from both countries will scour the joint fishing zone in the West Sea over the next six days.
Only authorized fishing boats from the two countries are allowed to fish in the zone.
Each side will share the results of their patrols.
More than 30 illegal Chinese fishing boats have been caught by the two sides since the joint patrol started in 2014.
South Korea alone has seized more than 90 illegal Chinese fishing boats so far this year.