TOKYO -- For decades, residents of Awashima island off northeastern Japan fretted about the possibility of being abducted by North Korean agents. The coastal area of Niigata Prefecture is where a number of Japanese were captured in the 1970s and '80s, including 13-year old Megumi Yokota, who was taken on her way home from school in 1977.
These days, such fears have shifted to the threat posed by the growing number of North Korean "ghost boats" arriving in the area -- wooden boats bearing the corpses of fishermen as well as sick and starving survivors.
"It is no longer someone else's affair," said a self-employed resident of Awashima island in his 30s. "I have small children, and it is scary to imagine running into these illegal entrants."
The possibility of tired, hungry, desperate men breaking into houses in the community is all too real. Several wooden boats have landed in Awashima in recent years, including one with a corpse in it.
In one instance, the fishing town of just 370 residents waited several days for police to arrive from the mainland to take charge of a boat that had been towed into the harbor. Awashima is a one-hour ride by high-speed boat from the mainland.
Since December, two police officers from Niigata have been assigned to patrol the island on a regular basis, traveling back and forth to the police station on the mainland every few days. While the island has a temporary police presence during the tourist season in July and August, there is no full-time presence.
Awashima is by no mean alone in its worries. Ghost boats have been appearing throughout the islands and coastal areas of the region, from the Noto Peninsula in Ishikawa Prefecture, to the northern main island of Hokkaido. In November, eight North Korean men were found on the front porch of a house in the town of Yurihonjo, Akita Prefecture in northern Honshu.
The reason so many North Korean fishermen have gone adrift is that the country sold off its own fishing rights to China in a desperate effort to raise cash. According to the South Korean government, Pyongyang has sold off various rights to China in exchange for foreign currency after its exports of coal and weapons collapsed due to United Nations sanctions.
"Since North Korea sold coastal fishing rights to China, fishermen have had no other choice but to fish farther from their shores," a Japanese government official said, adding that the country's shortage of foreign currency has driven it to illegal fishing.
While North Korean marine products are also on the sanctions list, some experts say Pyongyang is forcing fishermen to operate in winter to cover chronic food shortages, and to gather marine products for smuggling abroad.
A lack of quality fuel, moreover, leads to engine damage, which can leave the boats adrift.
Small boats designed to operate close to shore have been spotted near the Yamato Bank, a prime fishing ground within Japan's exclusive economic zone, suggesting North Korea's fleet is dangerously overstretched.
North Korean poaching in the area appeared to begin increasing around June last year. While the boats withdrew after the Japan Coast Guard stepped up patrols, they returned for the autumn squid season.
That has made Japanese fisherman worried about working in the area, as the many North Korean boats make it "dangerous," according to the Yamagata prefectural fisheries cooperative.
It is even more dangerous for the Koreans themselves.
The Japan Coast Guard said 104 boats washed up on islands and coasts of the Sea of Japan last year, the most since comparable data became available in 2013. Last year's boats carried 35 bodies and 42 survivors, also the most yet.
Half of the survivors found drifting in boats off the Noto Peninsula were rescued and ferried to other North Korean boats.
But those who make it ashore often bring trouble. In November, the crew of a North Korean boat landed on uninhabited Matsumae Kojima island off southwestern Hokkaido.
In the incident that followed, a 67-year-old Japanese fisherman managing a fishing hut of the local fisheries cooperative suffered around 1.15 million yen ($10,400) in damages, including the loss of a motorcycle and some appliances. While he was not present at the time, if he had been at the hut a few hours earlier, he might have run into the North Koreans.
The North Korean captain was later arrested on suspicion of stealing a power generator from the hut, and residents of the area have since been clamoring for greater security.
"I want the police and the coast guard to beef up security," said the fisherman.
The central government decided at a ministerial meeting in December to reinforce its fleet of patrol and survey vessels and introduce new maritime surveillance jets.
"We have increased the number of patrol ships, mainly in waters where many North Korean boats washed ashore," a coast guard spokesperson said.
Japan has about 6,900 islands, more than 90% of them uninhabited, according to coast guard figures.
On Matsumae Oshima island about 50km west of the southern tip of Hokkaido, development is underway of a fishing port scheduled to open in 2020. Once the port is ready, fishermen will be able to take refuge there when they cannot return to the main fishing port in Matsumae town on Hokkaido in stormy weather.
That should increase fishing activities in the area, and with them, greater monitoring of unusual boats, according to an officer of the fisheries section of the Hokkaido Regional Development Bureau.
Yet fishermen have no authority to do anything about suspicious boats and people, noted the fisherman who had been victimized on Matsumae Kojima island. All they can do is to report them to the authorities.
Yoshihiko Yamada, a professor at Tokai University in Tokyo, said there was a need for fisheries cooperatives and maritime public transportation authorities to share eyewitness accounts with the police and the coast guard, and for monitoring by security cameras and satellites.