19 Apr 2018

What lurks deep in the southern fiords

From Afternoons, 1:38 pm on 19 April 2018

Researchers are on a mission to find out what lurks in the seldom-explored Fiordland waters.

A Victoria University team explored the waters of  Doubtful, Dusky and Breaksea Sounds, and made some surprising discoveries.

“It’s just so deep, which really limits our ability to get down to these areas and study the organisms that are there,” says Victoria University associate professor James Bell, who led the research.

Video courtesy Dr Joseph Marlow

The scientists submerged a deep-water camera attached to a frame with a large light and a bait pot in silty waters 300m-400m deep.

“Its a bit murky, then the light suddenly comes on, and nothing’s happening, then all of a sudden these shadows appear out of the dark and start attacking the bait pot.”

One of the fish captured on an underwater camera in Fiordland.

Photo: Screengrab / Victoria University of Wellington

They encountered hapuku, spiny dogfish, blue cod, tarakihi, sixgill and seven-gill sharks, red gurnards and hagfish.

The crayfish were huge, and some of the sharks were up to 2 metres in length, Bell says.

“Anybody who’s swimming in the fiords next time, have a think about what’s lurking in below because there are certainly some big sharks there.

"Crayfish are scavengers, so you might have expected to see them, but we didn’t expect to see such large crayfish and we didn’t expect them to attack the baits with the ferocity they did.”

Their work is aimed at monitoring and assessing any changes that might occur in the fiords as a result of human activity, such as climate change or pollution.

As well as the baited video system, the researchers also used a remotely-operated underwater vehicle to survey shallower areas of the fiords, down to 130m.

That footage shows a diverse range of anemones, sponges, coral and brachiopods (shellfish that look similar to clams).

James Bell

James Bell Photo: Supplied

Most intriguing for the team were the different kinds of marine life on the underwater cliffs, and how they change at increasing depth.

“We found large colonies of black coral – some of these are up to 2 metres in height," Bell says.

“They’ve been spotted before, but with this video footage we should be able to quantify their abundance at all depths."