Voyage to study impact of commercial fishing on vulnerable ecosystems

Photo / Dean Purcell

The impact of commercial fishing on vulnerable ecosystems in a unique area of the South Pacific will go under the microscope during a five-week scientific voyage.

NIWA's flagship research vessel Tangaroa will leave Wellington on Friday for the Louisville Seamount Chain, about 1000km northeast of New Zealand.

The chain, a series of underwater mountains and volcanoes, is one of the longest in the world, stretching about 4300km from the Pacific-Antarctic Ridge north-west to the Tonga-Kermadec Trench.

NIWA marine ecologist Dr Ashley Rowden said there was concern that fragile ecosystems, which could exist on the chain, were being affected by commercial fishing, as the area supported extensive trawl fisheries for orange roughy.

New Zealand was leading initiatives to improve fisheries management in the South Pacific but there was limited information about the distribution and characteristics of the vulnerable marine ecosystems of the seamount chain, he said.

"This voyage will make a substantial contribution to furthering understanding that will help to preserve these ecosystems."

Scientists at NIWA and the Marine Conservation Institute in the US have developed "habitat suitability models" to predict the whereabouts of various sea animals that indicate the presence of a vulnerable marine ecosystem.

But while the models were useful for designing effective fishing management plans, it was important they were checked and verified to ensure their effectiveness, he said.

"The fishing industry needs to know these models are accurate and this survey represents one of the first examples of validating habitat suitability models that are to be used for fisheries management."

Tangaroa will survey three areas along the chain, with an underwater camera to be towed behind the ship to provide evidence of vulnerable species.

The camera system, known as DTIS or Deep Towed Imaging System was designed and built by NIWA staff and is attached to the Tangaroa by a conducting wire that enables researchers to see a live video feed, control the camera and lights and see information on depth and distance from the seabed.

"We are using the camera because we want to be as non-destructive as possible but the specimens we do collect will help improve our understanding of the evolution of marine species in the Pacific, as well as the genetic connections between populations."