Visitors to the ocean this summer should think twice before handling the colorful and cuddly octopuses they come across or find on the end of their fishing lines.
Highly toxic blue-ringed octopuses that can kill a human with a single bite have been spotted recently in Kanagawa and Chiba prefectures, even though the small creatures normally inhabit waters near Kyushu and farther south.
"Touching it because one considers it a small and beautiful object will lead to a major problem, so extreme caution should be used," an official with the Research Institute of Marine Invertebrates said.
Researchers believe that increases in ocean temperatures have led to a spread of the octopuses farther north than their usual habitat.
According to officials of the Research Institute of Marine Invertebrates in Tokyo's Chuo Ward, the blue-ringed octopuses grow to about 15 centimeters long. While the animals are normally brownish in color and docile, they turn a brilliant yellow when attacked, and their bodies become covered with fluorescent blue spots. The octopus produces venom containing tetrodotoxin, the same toxin found in deadly fugu or blowfish. One or two milligrams of the venom can kill a human.
The octopuses normally inhabit reefs in subtropical regions stretching from Japan to Australia. However, the animals have been increasingly spotted in the Kanto region in recent years.