Researchers using baited camera traps recorded an unknown species of snailfish more than 5 miles (8 kilometers) deep just off the coast of Japan. These are the deepest fish ever caught on film.
A team with the Tokyo University of Marine Science and Technology and the University of Western Australia recently released the footage, which was collected in September 2022 in the Izu-Ogasawara Trench, which is just south of Japan. Cameras captured the unknown snailfish that belongs to the genus Pseudoliparis at 8,336 meters (5.1 miles) underwater, according to a press release from the University of Western Australia.
Here’s a video of the fish floating around. It looks kind of like a large, pale tadpole with fins on the side:
A few days after recording the footage last year, researchers also managed to catch two Pseudoliparis belyaevi snailfish in the area. They were caught in traps set at around 8,022 meters (4.9 miles) deep. This is the first time that fish have been collected at a depth of more than 8,000 meters, according to the university. Previously, this snailfish species had been spotted at 7,703 meters (4.7 miles), back in 2008.
The snailfish found in the Izu-Ogasaware Trench do not have any scales. They’re covered in a gelatinous layer and do not have a swim bladder like other fish species do, The Guardian reports. This allows them to live under the extreme pressure found in the deepest parts of the ocean.
The expedition was part of a 10-year study into the deepest fish population on the planet. Researchers set out to study the Izu-Ogasaware, Ryukyu, and Japan trenches—all of which are over 7,000 meters (4.3 miles) deep. According to researchers, the recently released images show how different the Pacific Ocean’s trenches are to others around the world. Alan Jamieson, a chief scientist in the expedition, explained in the UWA release that, in the Mariana Trench, the deeper researchers look, the less fish there are. But in the trenches around Japan, there are a lot of fish to be found even at extreme depths.
“The real take-home message for me, 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, in fact until this expedition, no one had ever seen nor collected a single fish from this entire trench,” Jamieson said.