Victoria University of Wellington marine biologist Professor James Bell said the discovery of the red coral forests was made while the researchers were working on a project to explore and map marine life in Fiordland’s deep waters.
They were working about 4km north of the entrance to Doubtful Sound/Patea on board the Department of Conservation vessel Southern Winds, using a remotely operated vehicle (ROV) to collect video footage of reefs at depths of greater than 100m in areas that have not previously been filmed.
He had never seen the coral in such large numbers.
"It’s fair to say, we were very excited to see this.
"While we do sometimes find red corals when we are using the remotely operated vehicle in the fiords and rarely when we are diving, I have never seen so many at one time.
"There were literally thousands and thousands of them.
"The most incredible find — unlike anything we have seen elsewhere."
"In other parts of the country, we usually find reefs at these depths are dominated by sponges.
"In this area off the Fiordland coast, red corals dominated.
"The water was also incredibly clear down at 100m and we could see the reef from a distance of about 30m-40m."
The coral species, Errina novaezelandiae, was commonly known as red coral, but it was not a true coral. It was actually a related animal called a hydrocoral.
Marine biologists had been exploring these deep reefs inside Fiordland for many years, but were rarely able to work on the open coast outside the fiords because of the weather.
"On our most recent trip in January, the weather was finally on our side."
Video footage of the reefs showed thousands of large red corals, along with a range of animals, including larger black corals which are also a protected species under the Wildlife Act.
"Filming the animals that live on these deep-water reefs provides us with more information about the extraordinary biodiversity in our seas.
"This information is crucial to decisions about the use and protection of our marine environment.
"While much of Fiordland’s inland waters are protected, this is not the case for the open coast.
"In fact, most deep-water reefs around Aotearoa are not protected in marine reserves."
Doc senior science adviser Lyndsey Holland said our understanding of protected coral distribution in Fiordland was previously dominated by black corals.
"Other protected corals in the area haven’t been studied as extensively, so this finding is a breakthrough.
"We do know that New Zealand boasts a diverse array of cold-water corals offshore, so this discovery validates the need to survey and monitor Fiordland corals so we can best protect them."
