Marine underworld discovered in Fiordland

An underwater wonderland has been disovered in Fiordland. Photo / Supplied

Undersea environments teaming with previously undiscovered life has been captured on film in Fiordland.

Niwa and Environment Southland recently used a remote-operated robot vehicle to film footage of undersea sills in Dusky and Doubtful Sounds.

They discovered an array of thriving marine life, including rare and protected red coral, rock lobster and dense schools of fish.

Ken Grange, Nelson regional manager for Niwa, said the mission had uncovered new species of sea pens, corals, sea squirts and sea cucumbers and previously undescribed habitats.

"The scientists were surprised with what is down there. It's pretty amazing.

"We know that the fiords are globally unique and have some of the highest marine diversity in New Zealand, but the discovery of these sill communities was outstanding. We can't wait to get back and survey more of them."

Mr Grange said the footage showed the danger a booming cruise ship industry could pose to the marine environment of Fiordland.

This year, 87 cruise ships are set to travel through Fiordland and next year the number is set to rise to 90.

A few of those drop anchor near the sills where significant wildlife has been discovered, Mr Grange said.

Some of the areas currently marked as safe to for the cruise ships to anchor would need to be changed, he said.