Jan 26 (NHK) - A new -- and large -- kind of deep-sea fish found off central Japan has been named "yokozuna iwashi," in reference to the highest rank in sumo wrestling.
Researchers from the Japan Agency for Marine-Earth Science and Technology captured four previously-unknown large fish in waters more than 2,000 meters below the surface of Suruga Bay in 2016.
They say all four measured more than a meter across, with the largest over 1.3-meters-long and weighing some 25 kilograms.
Analysis showed the fish are a variety of "sekitori iwashi." Sekitori means a ranking sumo wrestler. The researchers gave their new find the "yokozuna" label in reference to the grand champions of sumo.
The researchers say the fish, which have bright blue scales, top the food-chain in the deep waters of Suruga Bay.
The group has also recorded video of the top predator swimming near the seabed.
JAMSTEC researcher Fujiwara Yoshihiro says it is unusual to discover a new type of large-sized fish.
He says it is important to preserve deep-sea ecosystems and their unknown biodiversity, especially as deep-ocean fishing increases.