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Cruising at a depth of 8,336 metres (more than 27,000 feet) just above the seafloor, a young snailfish has become the deepest fish ever filmed by scientists during a probe into the depths of the North Pacific Ocean.
Scientists from the University of Western Australia and the Tokyo University of Marine Science and Technology on Sunday released footage of the snailfish filmed last September by marine robots in deep trenches off Japan.
In addition to filming the deepest snailfish, scientists physically captured two other specimens at 8,022 meters and set another record for the deepest capture.
Previously, the deepest snailfish ever observed was at 7,703 meters in 2008, while scientists had never been able to capture a fish at a depth of less than 8,000 meters.
“What’s important is that it shows how far down in the ocean a particular type of fish can go,” said marine biologist Alan Jamieson, founder of the Minderoo-UWA Deep Sea Research Centre, who led the expedition.
Scientists are filming the trenches off Japan as part of a 10-year study of the world’s deepest fish populations. Snailfish are members of the family Liparidae, and while most live in shallow waters, others survive at some of the deepest depths ever recorded, Jamieson said.
During last year’s two-month survey, three “landers” – automated marine robots equipped with high-resolution cameras – were dropped into three trenches – Japan, Izu-Ogasawara and Ryukyu – at different depths.
In the Izu-Ogasawara Trench, footage showed the deepest snailfish hovering calmly alongside other crustaceans on the seafloor.
Jamieson classified the fish as juvenile and said younger deep-sea snailfish often stay as deep as possible to avoid being eaten by larger predators swimming at shallower depths.
Another clip shot between 7,500 and 8,200 meters in the same trench shows a colony of fish and crustaceans nibbling on bait attached to an underwater robot.
Images of the two captured snailfish – identified as Pseudoliparis belyaevi – offer a rare glimpse into the unique characteristics that help deep-sea species survive in an extreme environment.
They have tiny eyes, translucent bodies and their lack of a swim bladder, which helps other fish float, works in their favor, Jamieson said.
The professor said the Pacific Ocean is particularly conducive to vibrant activity because of its warm southern current, which encourages sea creatures to move deeper, while its abundant marine life provides a good food source for bottom-dwelling fish.
Scientists would like to learn more about creatures living at extreme depths, but cost is the constraint, Jamieson said, adding that each lander alone costs them $200,000 to assemble and operate.
“The problem is that the technology is expensive and scientists don’t have a lot of money,” he said.
cnn
