The mission was the seventh to take place as part of HADEEP, a collaborative research project between the University of Aberdeen's Oceanlab and the University of Tokyo's Ocean Research Institute, supported by New Zealand's National Institute of Water and Atmospheric research (NIWA).

The University of Aberdeen said these latest discoveries helped shed new light on life in the depths of the earth.

Oceanlab's Alan Jamieson, who led the expedition, said the findings, which revealed diverse and abundant species at depths previously thought to be void of fish, would prompt a rethink into marine populations at extreme depths.

"This expedition was prompted by our findings in 2008 and 2009 off Japan and New Zealand where we discovered new species of snailfish known as liparids inhabiting trenches ... at depths of approximately 7000m - with each trench hosting its own unique species of the fish," Jamieson said.