An unknown species of snailfish has been spotted at a record depth of 8,336 meters in the Izu-Ogasawara Trench, southeastern Japan.
The animal, which belongs to the genus Pseudoliparis, represents the first ever specimen caught swimming beyond 8,000 meters.
Scientists from the Minderoo-University of Western Australia Deep Sea Research Center and Tokyo University of Marine Science and Technology had set out to explore Japan’s Izu-Ogasawara and Ryukyu trenches-which lie at depths of 8,000, 9,300 and 7,300 meters, respectively-as part of a 10-year study of the world’s deepest fish populations.
Using unmanned submersibles known as landers, researchers deployed cameras with bait in the deepest part of these trenches.
There are more than 400 known species of snailfish, living in a wide variety of habitats ranging from shallow waters to the darkness of the ocean depths.
The expedition’s lead scientist and founder of the Minderoo-UWA Deep Sea Research Center, Professor Alan Jamieson, said some specific adaptations have allowed some species of snailfish to live at depths of about 1,000 meters.
At 8,000 meters depth, the pressure is 800 times that of the ocean surface.
“When you imagine what the deepest fish in the world looks like, it’s likely to be gnarled, black, with big teeth and small eyes,” Jamieson said. But “one of the reasons why snailfish have successfully adapted is that they don’t have swim bladders.” In addition, snailfish do not have scales, but have a gelatinous layer that Jamieson describes as a “physiologically economical adaptation.”
The imaged specimen is a juvenile fish. In fact, juveniles are generally found at greater depths than adults.