CHIBA -- A whale approximately 10 meters long was recently spotted in Tokyo Bay off Tokyo Disney Resort in the city of Urayasu, Chiba Prefecture.

Kazuyuki Kojima, vice chairperson of the eastern Tokyo fisheries cooperative association, captured the whale on video. He said that the whale dived for one to two minutes, resurfaced, occasionally, spouted water, and then dived again, repeating this behavior before disappearing after about 30 minutes.

Kojima was navigating a small boat from the Old Edogawa River toward a fixed net installed by the cooperative off Tokyo Disney Resort when he spotted the animal at around 7:30 a.m. on Dec. 13.

"I was cautious because I had been alerted by a preceding fishing boat about the whale, and I was surprised when the black back of the whale appeared about 10 meters away from the side of my boat, showing its large dorsal fin," he said. "Although I was scared of the possibility of capsizing due to the small size of my boat, I love whales and filmed it. I've seen finless porpoises here sometimes, but this is the first time I've seen such a large whale."

Associate professor Gen Nakamura of the Tokyo University of Marine Science and Technology's Laboratory of Cetacean Biology viewed the video and commented, "The shape of the dorsal fin is clearly visible, and given it was as large as 10 meters long, it is likely an adult humpback whale. In summer, they inhabit the Bering Sea and the Sea of Okhotsk, and in winter, they migrate south for breeding and are seen around Hachijojima Island and the Ogasawara Islands (both south of Tokyo) as well as Okinawa. At this time of year, it is likely on its way south and wandered into the inner part of Tokyo Bay during its migration."

The humpback whale is a species of baleen whale, which belongs to the Balaenopteridae family, and can grow to about 13 to 14 meters in length and weigh up to around 30 metric tons. They primarily feed on krill and small fish.

(Japanese original by Takashi Ishizuka, Chiba Bureau; video provided by Kazuyuki Kojima)