A fish has been captured by researchers swimming at never-before-recorded depths of over five miles below the ocean’s surface off the coast of Japan, researchers announced.
The unknown species of snailfish was caught on camera swimming 27,350 feet underwater by a deep ocean vessel in the Izu-Ogasawara trench, south-east of Japan, the Guardian reported.
Scientists from the Minderoo-University of Western Australia Deep Sea Research Centre and the Tokyo University of Marine Science and Technology spotted the alien-looking creature — which belongs to the genus Pseudoliparis — while on a two-month expedition that began last year.
Days after the new snailfish was filmed, scientists caught two other snailfish from species Pseudoliparis belyaevi in the trench at 26,318 feet. Researchers told The Guardian these fish are the first to have ever been collected from a depth greater than 8,000 meters — or 26,246 feet.
The research team was exploring trenches off the Japanese coast with a baited unmanned craft known as a lander as part of a 10-year study into the deepest populations of fish on the globe.
There are over 400 known species of snailfish, which are found at nearly all depths of the sea.
The species found near the ocean floor have adapted over eons to survive more than 1,000 meters deeper than the next known deep-sea fish, according to Prof Alan Jamieson, the expedition’s chief scientist and founder of the Minderoo-UWA Deep Sea Research Centre.
“When you picture what the deepest fish in the world should look like, the chances are it’s gnarly, black, with big teeth and small eyes,” Jamieson told The Guardian. “Chances are it’s got nothing to do with deep sea – that has to do with being dark.”
But obvious physical adaptations are less at extreme depths, he said.
“One of the reasons [snailfish] are so successful is they don’t have swim bladders,” he continued. “Trying to maintain a gas cavity is very difficult at high pressure.”
At 8,000 meters below the surface, pressure is 800 times greater than at the ocean surface.
The pinkish, almost winged-looking creatures do not have scales like most fish, but have a gelatinous layer around their bodies that Jamieson called a “physiologically inexpensive adaptation”.
Unlike other fish species, the youngest snailfish are typically found at greater depths.
“Because there’s nothing else beyond them, the shallow end of the range overlaps with a bunch of other deep-sea fish, so putting juveniles at that end probably means they’ll get eaten,” Jamieson told the newspaper. “When you get down to the mega deep depths, 8,000 plus [metres], a lot of them are very, very small.”
The new discovery shatters the previous record of the deepest fish ever discovered by 158 meters, or about 518 feet. Jamieson also made that discovery in 2017 —.a Mariana snailfish in the Mariana trench.