Scientists filmed the deepest fish on the ocean floor off the coast of Japan

Cruising at a depth of 8,336 meters (over 27,000 feet) just above the ocean floor, the juvenile slugfish has become the deepest fish scientists have ever filmed during their probe into the abyss of the northern Pacific Ocean.

Scientists from the University of Western Australia and Tokyo University of Marine Science and Technology released footage Sunday of a snail filmed last September by a marine robot in deep trenches off the coast of Japan.

While filming the deepest snail fish, scientists physically caught two other specimens at 8,022 meters and set another record for deepest catch.

Previously, the deepest snailfish ever found was 7,703 meters in 2008, while scientists have never been able to collect fish from depths below 8,000 meters.

“What's important is showing how far certain types of fish will go down into the ocean,” said marine biologist Alan Jamieson, founder of the Minderoo-UWA Deep Sea Research Center, who led the expedition.

Scientists filmed trenches off the coast of Japan as part of a 10-year study into the world's deepest fish populations. Snailfish are members of the family Liparidae, and while most snailfish live in shallow waters, others survive at some of the greatest depths ever recorded, Jamieson said.

During a two-month survey last year, three “landers” — automated sea robots equipped with high-resolution cameras — were dropped into three trenches — the Japanese, Izu-Ogasawara and Ryukyu trenches — at varying depths.

In the Izu-Ogasawara trench, footage shows the deepest slug fish floating peacefully with other crustaceans on the ocean floor.

Jamieson classifies the fish as juveniles and says the younger deep-sea slugs often stay as deep as possible to avoid being eaten by larger predators that swim at shallower depths.

Another clip shot between 7,500 and 8,200 meters in the same trench shows colonies of fish and crustaceans munching on bait strapped to underwater robots.

Images of two captured snail fish – identified as Pseudoliparis belyaevi – provide a glimpse into the unique features that help this marine species survive in extreme environments.

They have small eyes, translucent bodies, and a lack of a swim bladder, which helps other fish float, to their advantage, Jamieson said.

The professor said the Pacific Ocean is very conducive to dynamic activity due to its warm southern currents, which encourage sea creatures to go deeper, while its abundant marine life provides a good source of food for bottom feeders.

Scientists want to know more about the creatures that live at extreme depths, but cost is a constraint, Jamieson said, adding that each lander alone costs $200,000 to assemble and operate.

“The challenge is that technology is expensive and scientists don't have a lot of money,” he said.