10 years ago, a deep-sea scientist from the University of Western Australia predicted that fish could be discovered at depths of 8,200m to 8,400m. After a decade of research conducted worldwide, this prediction has been proven correct.

Image source: Minderoo-UWA Deep Sea Research Center

A special discovery was made by scientists who recorded a fish swimming at a special depth in the ocean. This species, identified as the Pseudoliparis snailfish, was observed at a depth of 8,336m (27,349ft) by an atomomas lander.

The discovery was made in the Izυ-Ogasawara Trench in southern Japan, one of a series of trenches up to 11,000 meters (36,000 feet) below sea level on the western edge of the Pacific Ocean, where the Pacific Plate lies. 4,200 meters (13,780 feet) above the ocean surface, different bottom plates will merge.

This marks the deepest observation ever of this fish, and it likely won’t be surpassed, as it was made at or very close to the maximum depth at which any fish can survive.

Professor Alan Jamieson, the scientist who made the prediction a decade ago, told BBC News that if the record is eventually surpassed, it will likely be by a very small margin, perhaps just a few metres.

The deepest previous fish observation was made at a depth of 8,178m in the Mariana Trench, further south in the Pacific Ocean. The next discovery in the Izυ-Ogasawara Trench surpassed this depth record of 158m.

The fish swimming at this particular depth is seen in the video below in the first 15 seconds.

Video source: Minderoo-UWA Deep Sea Research Center

The sailfish was filmed using a camera system attached to a weighted frame released from a ship, onto which bait was added to lure in marine life. While the species of the specimen could not be confirmed because it was not caught, several other fish species were trapped slightly higher at a depth of 8,022m in the nearby Japan Trench.

These fish were dubbed the Pseυdoliparis belyaevi snailfish, setting a record for the deepest fish ever caught.

Some gobies were picked up from a depth of 8,022m – this is the deepest catch ever. Image source: Minderoo-UWA Deep Sea Research Center

Tuna are an impressive group of creatures, with more than 300 species, most of which live in shallow waters such as estuaries. However, some species of snailfish have also evolved to survive in the frigid waters of the Arctic and Antarctic, as well as withstand the harsh pressures of the deepest oceans on Earth.

Their gel-like bodies enable them to live at depths of 8km, where they can withstand pressures of more than 80 megapascals, 800 times greater than the pressure at the ocean’s surface. Also helping them is the fact that, in contrast to many other fish, snailfish do not have a swim bladder, which is a gas-filled organ designed to control activity.

Furthermore, seabass are simple feeders consisting of small crustaceans, an abundant food source in the trenches.

Onboard cameras are deployed along with bait to attract fish into their field of view. Image source: Minderoo-UWA Deep Sea Research Center

According to Professor Jamieson – head of the Minderoo-UWA Deep Sea Research Center, which collaborated with a team from Tokyo University of Marine Science and Technology on the mission – the discovery of a fish living at greater depths than those. The Mariaпa Trench is likely located in slightly warmer waters than the Izυ-Ogasawara Trench. He further explained that the research team was hoping to discover the deepest fish in this area and it would be a type of snail fish.

Jamieson emphasized that we possess a significant amount of knowledge about the deep sea and that our knowledge of it is expanding rapidly.

“I feel frustrated when people tell me we know nothing about the deep sea. We do. Things are changing very quickly.”