A team of Australian and Japanese scientists succeeded in capturing on camera the deepest-swimming fish ever recorded. The fish, an unknown snailfish species of the genus Pseudoliparis, was recorded at a depth of 8,336m in the Izu-Ogasawara Trench, south of Japan.

University of Western Australia Professor Alan Jamieson, founder of the Minderoo-UWA Deep Sea Research Centre and chief scientist of the expedition, worked with a team from the Tokyo University of Marine Science and Technology to deploy baited cameras in the deepest parts of the trenches. 

“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,” said Professor Jamieson.

“In other trenches such as the Mariana Trench, we were finding them at increasingly deeper depths just creeping over that 8,000m mark in fewer and fewer numbers, but around Japan, they are really quite abundant.”

What allows deep-sea snailfish to survive at such depths? 

While many species of snailfish live in shallow water, research has shown that the deep-sea snailfish diverged from a shallow-water relative about 20 million years ago and accumulated genetic adaptations that make its bones softer and more pressure-tolerant.

Unlike many other types of fish, snailfish don’t have swim bladders. Instead, they produce a gelatinous substance that keeps them buoyant.

They have adapted to living in habitats with overwhelming pressure due to genetic adaptations. Their genes protect their genome and make their bones softer.

Temperatures are freezing miles below in the deep seas, especially in the Arctic and Antarctic regions where some snailfish reside. Some species have anti-freezing proteins in their DNA sequence that keep them from freezing to death.

This is the Deepest Fish Ever Recorded in the Ocean

Thanks to Alaric Bond for contributing to this post.