A South Korean fisherman disappeared Wednesday night after falling off a fishing boat operating into the Sea of Japan, the Japan Coast Guard said Thursday.

Choi Jong Hae, 40, fell from the 51-ton South Korean boat Dong Bang Ho around 9 p.m. Wednesday in waters 87 km northwest of Hagi, Yamaguchi Prefecture, western Japan, coast guard officials said.

The coast guard and the South Korean maritime police are jointly searching for Choi. The boat had a permit to operate in the area, which is within Japan's exclusive economic zone, they said.