[Chiba, Kujukuri] Risk of Explosion and Infectious Diseases! An Overwhelming Stench of Decay… On-Site Photos of the “17-Meter Giant Fin Whale” That Was Washed Ashore

A Dangerous Carcass

“I heard the beached whale might explode. It’s surprising that such a huge creature would wash up on the shore right in our neighborhood. Ropes had been strung up to keep people from getting too close,”

said a resident of Sosa City, Chiba Prefecture. It was on September 19 that a fin whale, approximately 17 meters long, washed ashore at Kujukuri Beach in the city. When a reporter visited the scene a few days later, the massive body lay at the water’s edge (photo).The carcass swayed with the incoming waves, and pieces of subcutaneous fat and skin that had peeled off floated on the surface of the water. Standing downwind, a pungent stench of decay assaulted the nose.

“The beached fin whale is believed to be a young male, as its penis has been identified. Due to the approaching typhoon, recovery and disposal efforts were delayed, and the carcass remained untouched for more than 10 days after it washed ashore. Decomposition has progressed, and the head has flattened and begun to crumble,” said a reporter from the social affairs department of a national newspaper.

The fin whale is one of the world’s largest whales, reaching a length of 25 meters and a weight of 60 metric tons as an adult.They migrate thousands of kilometers annually, and the waters off the Boso Peninsula lie along their route. Their meat is of high quality and highly valued for consumption; in 2024, they were added to the list of species subject to commercial whaling, and their capture—the first in about half a century—drew significant attention.

However, beached carcasses pose certain risks, according to Genta Yasunaga, a senior researcher at the Japan Whale Research Institute.

“Generally speaking, there are three potential dangers to consider. First, there is the risk of being crushed by the massive body—weighing tens of metric tons—if you get too close and are swept by the waves. Second is the risk of infectious diseases. The whale may have died from an illness, so touching it without protective gear is extremely dangerous.

Third is the risk of explosion. Methane gas accumulated inside the body can, in very rare cases, explode. While it’s not a large-scale explosion like gunpowder, bones and other internal parts can be scattered, potentially causing injuries.”

The fin whale that washed ashore at Kujukuri Beach was examined by experts and dissected on September 30.

In Japan, there are reportedly about 300 documented cases of whales and dolphins washing ashore each year. Given the risks of infectious diseases and explosions, it is important for the general public to stay away.

The October 2 issue of *FRIDAY* (October 16 edition) and the paid version, *FRIDAY GOLD*, provide detailed explanations of past incidents involving beached whales and the costs associated with their disposal. They also feature images of the fin whale that washed ashore at Kujukuri Beach.

Click here to view the full article and additional photos↓

From the October 16, 2026 issue of “FRIDAY”