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Cruising to a depth of 8,336 meters (more than 27,000 feet) just above the seafloor, a young snail became the deepest fish ever filmed by scientists during a probe into the northern abyss of the ‘Pacific Ocean.
Scientists from the University of Western Australia and Tokyo University of Marine Science and Technology on Sunday released footage of the snail filmed last September by marine robots in deep trenches off Japan.
In addition to filming the deepest snail, scientists physically captured two other specimens at 8,022 meters and set another record for the deepest capture.
Previously, the deepest snail ever observed was at 7,703 meters in 2008, while scientists had never been able to collect fish below 8,000 meters.
“What’s significant is that it shows how far down a particular type of fish will go in the ocean,” said marine biologist Alan Jamieson, founder of the Minderoo-UWA deep sea research centre, who led shipping.
Scientists are filming in the trenches off Japan as part of a 10-year study of the world’s deepest fish populations. Snails are part of the Liparidae family, and while most snails live in shallow water, others survive at some of the greatest depths on record, Jamieson said.
During the two-month investigation last year, three “landers” – automatic marine robots equipped with high-resolution cameras – were dropped into three trenches – the Japan, Izu-Ogasawara and Ryukyu trenches – at different depths.
In the Izu-Ogasawara Trench, images showed the deepest snails hovering calmly alongside other crustaceans on the seafloor.
Jamieson classified the fish as a juvenile and said young deep-sea snails often stay as deep as possible to avoid being eaten by larger predators that swim at shallower depths.
Another clip shot between 7,500 and 8,200 meters in the same trench showed a colony of fish and crustaceans munching on bait attached to an underwater robot.
Images of the two captured snails – identified as Pseudoliparis belyaevi – offer a rare glimpse into the unique traits that help deep-sea species survive in an extreme environment.
They have small eyes, translucent bodies and their lack of a swim bladder, which helps other fish float, works to their advantage, Jamieson said.
The professor said the Pacific Ocean is particularly conducive to dynamic activity due to its warm southerly current, which encourages sea creatures to sink deeper, while its abundant marine life provides a good source of food for bottom 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 challenges are that the technology is expensive and scientists don’t have a lot of money,” he said.