First-ever footage of the incredibly rare 'ghost shark' has emerged in oceans off Hawaii and California - a very long way from home.

The pointy-nosed blue ratfish, known as Hydrolagus trolli, has never been seen in the wild and only caught near Australia, New Zealand and New Caledonia in 2002.

The discovery by an unmanned submersible operated by the Monterey Bay Aquarium Research Institute extends the strange fish's range by more than 6,000 kilometres.

First ever footage of the incredibly rare 'ghost shark' has emerged in oceans off Hawaii and California

Video released by the MBARI along with a paper in science journal Marine Biodiversity Records showed the sharks swimming 1,640 metres below the surface.

Like sharks their skeleton is made of cartilage not bone and the ratfish is named for the fusing of its jaw to its skull giving its face a rat-like appearance.

It and similar species in its family are also famous for having a retractable penis on their forehead, though it is not known exactly how they are used.

Dave Ebert, program director for the Pacific Shark Research Center at Moss Landing Marine Laboratories, said the sharks were discovered by accident as the MBARI was not actually looking for them.

The discovery by an unmanned submersible operated by the Monterey Bay Aquarium Research Institute extends the strange fish's range by more than 6,000 kilometres

'Normally, people probably wouldn’t have been looking around in this area, so it’s a little bit of dumb luck,' he said.

'It’s almost a little comical. It would come up and bounce its nose off the lens and swim around and come back.'

Researchers still needed to catch one to confirm through DNA if the six they recorded were pointy-nosed blue ratfish or a completely new species of chimaera.

'This is much easier said than done, because these fish are generally too large, fast, and agile to be caught by MBARI's ROVs,' the institute's Lonny Lundsten said.

Video released by the MBARI along with a paper in science journal Marine Biodiversity Records showed the sharks swimming 1,640 metres below the surface

The group of 38 species is named after the chimaera from Greek mythology, which had a goat's head, a serpent's tail, and a lion's head.

Unlike regular sharks they don't have jagged teeth to tear flesh from their prey , which includes molluscs and worms, and so chews them up instead.

Mr Lundsten said similar animals were spotted in the Indian Ocean and off the coasts of South America and Southern Africa but not yet identified.

'This is another example of how little we know about the deep sea,' he said.

Hydrolagus trolli was named after Alaskan artist Ray Troll because of his fascination and appreciation for chimaeras that appeared frequently in his paintings.