NIWA scientists have made the rare discovery of a days-old ghost shark during a recent survey off the east coast of the South Island.

The neonate - or newly hatched - deep water shark was collected at a depth of about 1200m on the Chatham Rise.

Also known as chimaeras, ghost sharks are cartilaginous relatives of sharks and rays.

Their embryos develop in egg capsules laid on the sea floor, feeding off a yolk until they are ready to hatch.

NIWA Fisheries Scientist Dr Brit Finucci was part of the team that made the discovery and says it is a very rare and exciting find.

"You can tell this ghost shark recently hatched because it has a full belly of egg yolk. It's quite astonishing. Most deep-water ghost sharks are known adult specimens; neonates are infrequently reported so we know very little about them.

Ghost shark egg capsules.

"From better studied chimaera species, we know that juveniles and adults can have different dietary and habitat requirements. Juveniles also look dissimilar to adults, having distinctive colour patterns. Finding this ghost shark will help us better understand the biology and ecology of this mysterious group of deep-water fish."

Dr Finucci says further tests and genetic analysis will need to be carried out to determine the exact species.

The specimen was discovered during a recent trawl survey to estimate abundance of hoki.