London, Apr 5 (IANS): At a depth of more than 8 km underwater, a fish filmed by a team of researchers from Japan and Australia has been certified by the Guinness World Records as the deepest fish in the ocean to be observed.

Scientists mainly from the Tokyo University of Marine Science and Technology and the University of Western Australia on August 15, 2022, filmed the unknown snailfish species of the genus Pseudoliparis at a depth of 8,336 metres, near the bottom of the Izu-Ogasawara Trench off southern Japan in the western Pacific, reports Xinhua news agency.

According to the Guinness World Records, the unprecedented depth -- more than double the vertical extent of Mount Fuji -- is approaching what is thought to be the biological bottom line for fish.

Hiroshi Kitazato and co-researchers from the Tokyo University of Marine Science and Technology received their Guinness certificate on Tuesday.

According to the joint scientific expedition, the observation was made 158 metres deeper than the previous record of 8,178 metres in the Mariana Trench, where living fish were confirmed in 2017.

The Mariana snailfish was observed in the Mariana Trench on May 18, 2017.

Kitazato stressed the significance of having filmed fish at such a depth and expressed hope of finding fish even deeper in the ocean.

The chief scientist conducting this field study was UWA Professor Alan Jamieson, founding director of the Minderoo-UWA Deep-Sea Research Centre.

Professor Jamieson is arguably the world's leading authority on hadal organisms -- those that live deeper than 19,685 ft -- and has made numerous record-setting discoveries over his career.

These include the deepest squid (20,381 ft), the deepest octopus (22,825 ft), the deepest decapod (25,272 ft) and the deepest hydrozoan (33,015 ft).