A group of eight fishermen claiming to be from North Korea washed up in northern Japan after drifting there when their wooden vessel developed problems, authorities said today. Television footage from a pier in the city of Yurihonjo on Japan's northwestern coast showed a wooden boat rigged with bare light bulbs, used to attract fish and squid. "We understand that the eight individuals are reporting that they came from North Korea for fishing, but drifted there after their ship experienced (mechanical) troubles," said Hachiro Okonogi, chairman of the National Public Safety Commission. Local police told AFP they were alerted about the group early today and took them into custody. The men were able to walk unaided, according to national broadcaster NHK. Dozens of North Korean fishing vessels wash up on Japan's Sea of Japan coast every year. Sometimes their occupants have already died at sea, with their vessels delivering headless skeletons and rotten corpses to Japan's fishing ports, with media occasionally calling them "ghost ships." In late 2015, at least 14 weathered vessels - some badly damaged or capsized - with almost two dozen bodies reached Japanese shores or were found floating in regional waters. Experts say some North Korean fishermen take risks to travel far out into the Sea of Japan, which is known on the Korean peninsula as the East Sea, in order to satisfy government mandates for bigger catches. But their old and poorly equipped vessels are prone to mechanical and other problems, including running out of fuel, and there are few credible options to call for rescue. Often surviving drifters are fishermen who request to be sent home, but some of them are defectors who are eventually sent to South Korea. In September 2011, the Japanese coastguard rescued nine North Koreans on a small boat, included three children, who asked to be sent to South Korea. Japan and North Korea have stormy relations, with Pyongyang routinely issuing verbal threats as well as firing missiles near or above Japan. But the Japanese coastguard occasionally rescues North Korean fishermen in maritime accidents in regional waters. The coastguard last week saved three out of 12 North Korean fishermen after their boat capsized in high seas. The survivors have been returned home as they wished. The Japanese coastguard also found another capsized boat last week in the Sea of Japan with four bodies inside, with media reporting they were also North Korean fishermen.