Photo/IllutrationThe megamouth shark swims in a cage off Tateyama, Chiba Prefecture, on May 22. (Kotaro Ebara)

TATEYAMA, Chiba Prefecture--An ultra-rare megamouth shark caught off the coast here was confirmed dead on May 23, having been unable to survive away from its habitat.

The deep-water fish, which measured between 5 and 6 meters, had been observed vigorously swimming only a day earlier when it was captured.

At around 9 a.m. on May 23, the female shark was lying on the bottom of the sea, faintly breathing, according to TV personality Sakana-kun (Mr. Fish), who is also a professor emeritus of the Tokyo University of Marine Science and Technology.

Later on the fish, whose scientific name is Megachasma pelagios, stopped moving.

“It is regrettable,” said a downcast Sakana-kun. “Having seen her on the previous day I thought she was going to become energetic.”

The shark was trapped in a fishing net early May 22. Later that day, it was transferred to a cage in the ocean.

“If a specimen of her skeleton is created that will be valuable,” said Sho Tanaka, a professor at Tokai University’s Department of Marine Biology. “We should utilize her body for the research.”

The species was discovered off Hawaii in 1976. Since then, there have been around 110 sightings worldwide, about 20 of which were in Japan. In most cases the sharks were already dead when they were caught in nets.

“Technological advances are making it possible to rear sharks at aquariums, which used to be difficult,” said Kazuhiro Nakaya, a professor emeritus of Hokkaido University. “We might be able to rear megamouth sharks at aquariums in the future.”