Japan's recent decision to up its patrols in response to rising appearances of mysterious ships implies there might be a serious problem with North Korea's food supply.

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The Guardian reports that at least 28 North Korean boats washed ashore or were found adrift in Japanese waters, the result of North Korean fishermen's decision to push farther and farther out to sea to make bigger catches for their military, citizens and exports to China. Several of the vessels found were "ghost ships," labeled as such when found with either a dead or missing crew.

Though the number of stray vessels found in Japan this year is consistent with last year’s number, some have expressed concern for the high number of ships found in November compared to the number found last November.

The Washington Post offered possible explanations for the spike in appearances, including food shortages which may be the result of tougher sanctions recently passed against the country.

“North Korean fishermen have to work harder than ever before, and they have to go farther out into the sea, but they don’t have new boats,” said Atsuhito Isozaki, associate professor of North Korean studies at Keio University in Tokyo. “Plus, North Korea doesn’t have enough gasoline anymore, so they’re running out of fuel.”

The concerning state of North Koreans' food supply was highlighted last month following the dramatic rescue of a North Korean soldier who defected while on duty.

Oh Chong Song abandoned his post in November and began to run toward South Korea. He was shot at more than 40 times by his fellow soldiers, and at least five bullets hit him. South Korean soldiers were able to crawl to the area where he lay and he was transportedto a hospital by a United Nations Command helicopter.

While rushing to save his life, trauma surgeon Lee Cook-Jong discovered parasitic worms, some were over 10 inches long, in the soldier's digestive tract.

The worms, which have been discovered in other defectors, indicated the use of a detrimental, government-backed approach to health and agriculture in the country: night soil.

"Night soil" is a fertilizer made up of human excrement and used by North Korean farmers. There is a perception in the country that night soil makes food taste better and the method has even been personally supported by dictator Kim Jong-Un.

The five-hour surgery consisted of removing a bullet, fixing a number of wounds caused by the bullet and removing the parasitic worms that were making their way out of Oh Chong Song's body.

“In my over 20-year-long career as a surgeon, I have only seen something like this in a textbook,” Cook-Jong later said of the flesh-colored parasites he found.