Small wooden boats filled with unidentified dead sailors, assumed to be North Korean fishermen, keep washing up on the shores of Japan.

The so-called ‘ghost ships’ have been regularly washing up on the shores of Oga, a city in the peninsular Akita Prefecture. This year, however, has already seen a dramatic rise in the number of discoveries.

Since December, the remains of 35 people have been found aboard 103 wooden boats that drifted onto Japanese shores or were discovered in its territorial waters. A total of 13 of the dead have yet to be identified.

One of the somber overturned boats in Oga was captured in eerie drone footage by RT’s Ruptly video agency.

Some North Korean fishermen have been found alive aboard the vessels, while the remains of others have been discovered in a partly skeletal condition.

"Over there, there was the ship that was washed ashore, in the Kusakata area. These both happened at the same time, but in the ship over there, was six or seven North Korean people still alive and they were rescued," said Oga fisherman Hiyama Hiromi.

On November 26, eight corpses were found on a wooden boat in Oga, with two more skeletal remains found washed ashore on December 7. At that time of year temperatures can drop to below freezing and sea conditions are so stormy it is “impossible” to safely sail in the boat these fishermen are using, says Hiromi.

Oga's authorities have requested that the city’s Tosenji temple temporarily accept the remains of the unidentified dead sailors, whose ashes have been kept in urns, as well as some DNA samples, in case North Korea or family members ever need to identify the deceased.