Scientists in have discovered a newly-hatched which they say could inform their knowledge of the "mysterious" creature.
The ghost shark was found at a depth of around 1,200 metres (about 3,900 feet) on the Chatham Rise, an area of ocean floor off the east coast of the South Island.
The "very rare" discovery was made during a recent survey, the National Institute of Water and Atmospheric Research said in a press release on Tuesday.
A deep water animal, the ghost shark is scientifically known as chimaera, with other names including rat fish, spook fish and rabbit fish, according to the . The ghost shark is closely related to sharks and rays.
They are cartilaginous fish -- having skeletons primarily made up of cartilage -- and their embryos grow in egg capsules laid on the sea floor, and feed off egg yolk until they hatch.
"You can tell this ghost shark recently hatched because it has a full belly of egg yolk," said Brit Finucci, a fisheries scientist who was part of the team that made the discovery, in the press release.
"It's quite astonishing. Most deep-water ghost sharks are known adult specimens; neonates are infrequently reported so we know very little about them," she added.
The exact species of the ghost shark the team discovered is not yet known, and Finucci said further tests and genetic analysis would be needed.
The age of the specimen makes it a particularly rare find, and this will help inform scientific knowledge on juvenile ghost sharks, as Finucci says other chimaera species indicate that juveniles "can have different dietary and habitat requirements" to adults.
"Juveniles also look dissimilar to adults, having distinctive colour patterns," she said of other chimaera species. "Finding this ghost shark will help us better understand the biology and ecology of this mysterious group of deep-water fish."
