Scientists have captured video footage of a previously unknown species of snailfish living in the deepest depths of the northern Pacific Ocean.
Researchers discovered the tadpole-like fish of the genus Pseudoliparis during a two-month mission last summer aboard the research ship DSSV Pressure Drop, according to a University of Western Australia (UWA) press release. The mission was part of a 10-year joint study between UWA and the Tokyo University of Marine Science and Technology focusing on the deepest fish populations in the world.
Snailfish are so-named because of their gelatinous bodies, which appear similar to snails. They have loose thin skin, tiny eyes, and no scales, according to AZ Animals.
The expedition team, led by Professor Alan Jamieson of UWA, deployed cameras at the bottom of the Izu-Ogasawara and Ryukyu trenches off the coast of Japan to capture the footage of these creatures.
The researchers recorded the video of the fish at a depth of 27,349 feet. The previous record for the deepest-dwelling fish discovered was the Mariana snailfish found in the Mariana Trench at a depth of 26,716 feet. Jamieson said the scientists had found snailfish in other trenches but they appeared to be fewer in number than those off the coast of Japan.
“The Japanese trenches were incredible places to explore; they are so rich in life, even all the way at the bottom,” Jamieson said, according to the press release.
The scientists said the subject of this discovery was a very small juvenile of the species. They noted that these juveniles tend to live in the deeper end of their depth ranges, which is the opposite of other deep sea fish.
The depth where this species of fish was discovered is double the average depth of the Pacific Ocean and just under 9,000 feet from the deepest known point of the seabed. The Challenger Deep, located at the southern end of the Mariana Trench, is between 10,902 and 10,929 meters (35,768 and 35,856 feet) deep.
“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,” Jamieson said.
Two days after capturing the video, the researchers managed to trap two snailfish of a different species, Pseudoliparis belyaevi, in the Japan Trench at a depth of 8022 meters (26,318 feet). These were the first fish to be collected from the ocean at depths greater than 26,000 feet.
“The real take-home message for me, is not necessarily that they are living at 8,336 meters [27,349 feet], but rather we have enough information on this environment to have predicted that these trenches would be where the deepest fish would be. In fact until this expedition, no one had ever seen nor collected a single fish from this entire trench,” said Professor Jamieson.
Although what became of the captured Psuedoliparis belyaevi fish was not mentioned in the UWA press release, scientists have documented that other snailfish taken from the deep depths of the sea had “melted” or “exploded” due to changes in temperature and pressure, according to AZ Animals.