A "faceless fish" and other weird sea creatures have been discovered by scientists during an expedition to Australia's eastern abyss – a habitat 4,000 metres below the ocean which has remained unexplored until now.
The fish is 40 centimetres long and had only been seen once before by the pioneering scientific crew of HMS Challenger off Papua New Guinea in 1873.
"It hasn't got any eyes or a visible nose and its mouth is underneath," Tim O'Hara from Museums Victoria, the chief scientist of the mission, said in a statement.
The appearance of the fish is not so surprising. So far below water, it is pitch-dark and animals often have no eyes. They sometimes produce their own light through a process of bioluminescence.
Other strange-looking species recovered by O'Hara and his colleagues include bright red spiky rock crabs, a 'dragon-fish', blind sea spiders and deep sea eels.
These discoveries are part of a month-long mission aboard a research vessel called the Investigator to undertake a series of deep water biodiversity surveys along Australia's east coast.
Led by Museums Victoria, the expedition will come to an end mid-June, after surveying 13 sites, including seven marine reserves.
The scientists hope that by then, they will have succeeded in documenting many new species and in improving their understanding of the creatures that populate the darkest, deepest corners of Australian sea. They also want to find out more about the ecological processes that sustain these strange species.
"This will assist in the conservation and management of Australia's deep sea habitat and will help to protect it from the impacts of climate change, pollution and other human activity," O'Hara said.