Exploring links between seismic vessels and New Zealand's marine mammals

KATIE KENNY
Last updated 16:17 04/01/2017
BRADEN FASTIER / Stuff.co.nz

A beached sperm whale lies dead after washing up on Rabbit Island, near Nelson

Whale removed from Caroline Bay

FOREST & BIRD
New Zealand is home to more than half of the world's whale species, and each beaching is a lesson to be learnt, says marine expert Anton Van Helden.
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An oil exploration ship off Wellington's coast.
JOHN BISSET/FAIRFAX NZ
A beaked whale washed up on Timaru's Caroline Bay died despite rescue efforts. Derek Cox and Alan McDonald from DOC are pictured preparing the sling.

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It's time to look at the impact of seismic surveying on New Zealand's marine mammals, according to experts.

New Zealand is a globally significant whale hotspot, with nearly half of the world's whales, dolphins, and porpoises found in the country's waters. It's also the site of several multi-millon dollar seismic surveys, which are a vital part of exploring for oil and gas.

While seismic surveyors say there is no evidence to suggest the sound from their vessels has harmed marine species, marine biologists say there hasn't been enough research done to make such claims.

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RULES AND REGULATIONS AROUND SEISMIC SURVEYING

In 2012, the Department of Conservation [DOC] developed a voluntary code of conduct for minimising acoustic disturbance to marine mammals from seismic survey operations.

In 2013, the code was brought into regulatory effect, which helped improve the data collection process. At the time, DOC committed to a review of the code after three years. That review began early 2015, and is ongoing. 

RECENT STRANDINGS

Recent strandings in the context of large surveying projects has caused concern among environmentalists.

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A sperm whale was found stranded and dead on Rabbit Island, near Nelson, on December 30. DOC duty officer Simon Bayly at the time said it was unclear how the whale died and it was too late for an autopsy. 

A blue pygmy whale washed up on a remote beach near Rahotu, South Taranaki, on December 28, was thought to have been dead for several weeks. 

Around the same time, a shepherd's beaked whale beached itself on Timaru's Caroline Bay. Despite rescue efforts, the whale died.

It's impossible to know what caused the strandings, and no autopsies were performed on the whales.

WHAT'S THE ISSUE WITH SEISMIC SURVEYING?

Forest and Bird marine advocate Anton van Helden said the loud noises produced during seismic surveys can and do harm marine mammals. 

"Whales, dolphins and porpoises rely on sound for navigation, foraging, and communication so one thing we could do to help them is protect their habitats and migratory paths from these activities," he said. 

New Zealand's current marine mammal sanctuaries still permit seismic surveying, with the future prospect of sea bed mining.

It's not just the noise that's an issue, but also the pollution, ocean acidification, collisions with boats, and indiscriminate fishing practices, he added. 

Surveys are being carried out in Cook Strait south of Taranaki and in eastern Cook Strait, he said, and these could have played a part in the whale stranding near Nelson.

THE NEED FOR MORE AUTOPSIES

Otago University marine biologist Professor Liz Slooten told Radio New Zealand beaked whales and sperm whales were usually found in waters at least1000 metres deep. 

She said seismic noise could travel hundreds of kilometres and there had been instances overseas where sperm and beaked whales stranded near vessels operating sonar equipment. She hoped autopsies would be done to provide more information. 

Sea Shepherd, a radical environmental group, said the fact the strandings coincided with the largest activity of intensive seismic surveying ever seen in New Zealand waters set off "alarm bells".

Michael Lawry, Sea Shepherd's New Zealand director, said it shouldn't be up to scientists, iwi, NGOs, and the public to "kick up a stink" to ensure autopsies were done. 

If anyone comes across a whale or mammal in distress, they can call the emergency DOC hotline on 0800 DOC HOTLINE.

- Stuff

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