Something fishy going on five miles below the sea … the world's deepest living animal

A STAGGERING five miles below the surface of the Pacific Ocean, scientists had been hoping, at best, to film a solitary fish able to exist in the deepest reaches of the world's seas

And they assumed anything they succeeded in capturing on film would almost certainly be a "monster" – a weird and ugly specimen similar to the shrivelled samples of deep-sea species preserved in the world's marine research institutes.

But a team of marine biologists, led by scientists at Aberdeen University's world renowned Oceanlab, were left dumbfounded when their cameras picked up the first signs of life "beyond the abyss" – 7,700 metres down in the uncharted depths of the Japan Trench.

More Nemo than Moby Dick, their sophisticated cameras captured a family of surprisingly cute, foot-long fish swimming happily in the darkness – a discovery that could lead to a breakthrough in helping scientists unlock the mysteries of the deep.

Instead of a lonely fish trying to survive on scraps of food falling to the seabed, the scientists were staggered when a shoal of 17 creatures, a type of snailfish, swam into view, feeding in the deepest reaches of the oceans ever explored on film.

"These are the deepest living backboned animals and it is the first time anyone has ever seen them alive," said Professor Monty Priede, the director of Oceanlab.

"These are the deepest ever pictures obtained of living fishes and it's going to open up a whole new area of our understanding of life at the limits."

He added: "The snailfish, pseudoliparis amblystomopsis, which we filmed is a species first discovered in the 1950s by Russian researchers, but there are only five specimens in existence and they are lying dead in various museums.

"So we really hit the jackpot when we were able to film 17 of them alive, all at once, and several hundred metres deeper than they had previously been filmed.

"We thought that we might just see one or possibly two fish living at the limits of what is possible in the deep ocean. But to have found a thriving big group of fish feeding quite actively was staggering.

"And what also fascinated all of us is that we expected that anything which could live so deep would look quite weird and ugly. But, amazingly, they are quite cute and they were jumping about."

The video has smashed the previous record of 6,500 metres for filming a live fish.

Dr Alan Jamieson, Oceanlab project leader, said: "These videos vastly exceed all our expectations from this research. We thought the deepest fishes would be motionless, solitary, fragile individuals eking out an existence in a food-sparse environment.

"But these fish aren't loners. The images show groups that are sociable and active – possibly even families – feeding on little shrimp, yet living in one of the most extreme environments on Earth."

FACT BOX

THE footage was captured as part of Oceanlab's "Hadeep" project – a collaborative research programme with Tokyo University to investigate life in the "hadal" region of the ocean, which is anything below 6,000m.

The hadal zone accounts for almost half the oceans' depth and consists of a series of extremely deep and very narrow trench systems.

Submersible camera platforms, known as "landers", took five hours to reach the seabed to capture the snailfish alive for the first time.