Scientists from a Scottish university have discovered a previously unknown species of fish in one of the deepest points in the world's oceans.

The party from Aberdeen University have returned from seven days of ocean sampling to the north of New Zealand, near the Kermadec Islands at depths of between half-a-mile and four miles. They took more than 6500 photographs of deep-sea fish and caught about 100 fish.

They discovered a species of eelpout, an eel-like fish, a member of the ray-finned fish family, more than two-and-a-half miles down.

They also established new depth records of nearly three-and-a-half miles for a rattail fish, which has not previously been caught in the south-west Pacific; and depth records of more than two miles for large cusk eels.

The expedition involved scientists from the university's sub-sea research centre, Oceanlab, the National Institute of Water and Atmospheric Research and Museum of New Zealand Te Papa Tongarewa. They used landers with cameras that free-fall to the seafloor, as well as baited fish traps.

Voyage leader Dr Alan Jamieson, from Oceanlab, said: "What makes the whole experience even more personally satisfying is that all the equipment used in these research cruises was designed and constructed at Oceanlab."