These images provide a rare look at the unique characteristics that allow deep-sea species to survive in such an extreme environment.
Swimming at a depth of 8,336 meters right next to the sea floor, a tiny sea snail became the fish photographed at its deepest depth ever by scientists during an investigation of trenches in the North Pacific Ocean.
Scientists from the University of Western Australia and the Tokyo University of Marine Science and Technology released images of sea snails last Sunday, captured by marine robots in deep trenches off Japan.
In addition to photographing a sea snail at its deepest depth ever, scientists actually captured two more specimens at 8,022 meters and set another record for the deepest capture.
Previously, the deepest sea snail ever seen was at 7,703m in 2008, but scientists have never managed to catch the fish anywhere below 8,000m.
“The important thing is that it shows how deep a particular type of fish can sink in the ocean,” says marine biologist Alan Jamieson, founder of the Mindero Center for Deep Sea Research, who led the expedition.
These two fish were found at a depth of more than 8,000 meters in the Japan Trench in the North Pacific Ocean. Image: University of Western Australia
Scientists filmed in trenches off Japan to conduct a 10-year study of fish populations that live in the world’s deepest waters. Snails belong to the family Liparidae, and while most of them live in shallow waters, others live in some of the deepest depths ever recorded, according to Jamieson.
During the two-month survey last year, three Landing – Automated marine robots with high-resolution cameras – dropped into three pits – those in Japan, Izu Ogasawara and Ryukyu – at varying depths.
In the Izu-Ogasawara trench, footage showed sea snails in the deepest places floating quietly alongside other crustaceans on the sea floor.
Jamison classifies the fish as juveniles, and said smaller sea snails are often kept as deep as possible to avoid being eaten by larger predators that swim in shallower depths.
Another clip, filmed at a depth of between 7,500 and 8,200 meters in the same trench, showed a colony of fish and crustaceans biting a bait attached to an underwater robot.
Images of the captured sea snail — identified as Pseudoliparis belyaevi — provide a rare glimpse into the unique characteristics that allow deep-sea species to survive in that harsh environment.
They have small eyes, a transparent body, and a gas bladder that helps other fish float and works for them, Jamison says.
The professor says the Pacific Ocean is particularly conducive to intense activity because of its warm southerly current, which encourages marine organisms to go deeper, while abundant marine life provides a good source of food for bottom eaters.
Scientists would like to know more about the creatures that live at great depths, Jamieson said, but cost is the biggest limitation, adding that each robot costs them more than €180,000 just to assemble and operate.
“The biggest challenge was that the technology was very expensive and scientists didn’t have a lot of money,” he says.
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