Marine scientists have sunk to new lows and recorded fish at the deepest ever level

Scientists have delved eight kilometres below the ocean’s surface to film a fish, and set new records in the process.

While exploring the Japan, Izu-Ogasawara and Ryukyu trenches as part of a decade-long study into the world’s deep sea fish populations, teams from the Universities of Western Australia and Tokyo University of Marine Science and Technology spotted a snailfish (genus Pseudoliparis) cruising at a depth of 8,366 metres.

It’s the deepest recording of a fish yet taken by humans.

Pseudoliparis are a genus first described midway through last century, and known to inhabit the farthest depths of the Pacific Ocean’s deep trenches. They are ray-finned fishes and part of the same animal order as lionfishes.

The records weren’t over, however, with the study team trapping two Pseudoliparis belyaevi at 8,002 metres – a record catch depth for this species.

“It is not necessarily that they are living at 8,336m but rather we have enough information on this environment to have predicted that these trenches would be where the deepest fish would be,” says the study’s chief scientist, Professor Alan Jamieson.

“Until this expedition, no one had ever seen nor collected a single fish from this entire trench.

“We have spent over 15 years researching these deep snailfish; there is so much more to them than simply the depth, but the maximum depth they can survive is truly astonishing.

“In other trenches such as the Mariana Trench, we were finding them at increasingly deeper depths just creeping over that 8,000m mark in fewer and fewer numbers, but around Japan they are really quite abundant.”