Scientists Capture Footage of Deepest-Ever Swimming Fish – Over 8,000 Meters Below Water!

Clare Fitzgerald|News|10 Apr 2023

Scientists conducting research off the coast of Japan have captured footage of what they believe to be the deepest-swimming fish on record. A type of snailfish, the translucent, gelatinous sea creature was found 8,336 meters below the water’s surface – that’s approximately five miles below sea level!

Map showing the location of the Izu-Ogasawara Trench

Izu-Ogasawara Trench, located off the coast of mainland Japan. (Photo Credit: Peka / Wikimedia Commons CC BY-SA 3.0)

The unidentified species of snailfish was located by a team of researchers from the Minderoo-University of Western Australia Deep Sea Research Centre and the Tokyo University of Marine Science and Technology in August 2022. They were exploring the Izu-Ogasawara Trench with crewed and unmanned underwater vehicles.

To capture the elusive image, the team, led by Alan Jamieson, used an un-crewed vehicle to lay dead fish along the trench floor. This attracted crustaceans, which, in turn, attracted the snailfish. At 8,336 meters below the ocean’s surface, this was a record-breaking discovery.

Just a few days later, the team captured footage of two other snailfish in the Izu-Ogasawara Trench, albeit at just 8,022 meters down. These were subsequently identified as belonging to the Pseudoliparis belyaevi species.

There are over 400 known species of snailfish across the world, ranging from the Arctic to the Antarctic. They’re capable of living in both shallow water and deep-sea environments – locations other sea creatures and predators otherwise can’t reside.

Speaking with Scientific American, Jamieson shared that the Izu-Ogasawara Trench’s relatively warm temperatures have afforded the snailfish an environment in which it can survive and thrive.

In a separate interview with The Guardian, he added that the sea creatures are able to live in such harsh environments because they don’t have swim bladders, nor scales. Instead, they have what Jamieson calls a “physiologically inexpensive adaptation” – a gelatinous layer.

Snailfish swimming on the ocean floor

Snailfish captured 8,336 meters below the ocean’s surface, in the Izu-Ogasawara trench. (Photo Credit: Minderoo-University of Western Australia Deep Sea Research Centre)

The deep-sea exploration was part of a study into the world’s deepest-living fish populations. In a press release, Jamieson shared, “The Japanese trenches were incredible places to explore; they are so rich in life, even all the way at the bottom. We have spent over 15 years researching these deep snailfish; there is so much more to them than simply the depth, but the maximum depth they can survive is truly astonishing.”

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While the team would like to keep exploring the ocean floor, they are currently limited by the financial commitment of doing so. It costs $200,000 to prepare and launch each landing vehicle.