All eight crew members of a fishing boat are missing after it capsized 600 kilometers off Hokkaido on Tuesday, the Japan Coast Guard said Wednesday.

An overturned vessel found by a search aircraft east of Nemuro on Tuesday was confirmed to be the Keiei Maru No. 65, a 29-ton saury fishing boat belonging to a fisheries cooperative in the town of Taiki, according to the coast guard. The crew members are men between the ages of 43 and 74.

At the coast guard's request, the Maritime Self-Defense Force dispatched a plane to search for them throughout Tuesday night. Coast guard boats also joined the rescue effort.

The coast guard said Wednesday that it had discovered a lifeboat near where the fishing boat was found, but that no one was on it.

According to the authority, it received a report at around 11:30 a.m. Tuesday that operators had lost contact with the vessel after its crew notified another boat that they had been hit by a high wave. The report was said to have been made that morning via a satellite phone.

The vessel had recently been operating in areas farther out than usual due to a record-poor catch of saury, according to the cooperative.

It said the boat had left Nemuro on Sept. 12 and was set to return possibly on Wednesday.