Whales v the Kaikoura quake: Niwa unintentionally records impact of 7.8 on Cook Strait's marine life video

NIWA

The sounds of whales and dolphins rarely seen in New Zealand waters have been recorded by a NIWA scientist in a pioneering underwater sound project. The acoustic moorings also captured one of the November earthquakes, but the sound was too deep to hear.

Underwater recordings have caught a rare insight into the impact of an earthquake on marine life.

Last year, Niwa marine ecologist Dr Kim Goetz led a programme to deploy seven acoustic moorings in Cook Strait to record the sounds of marine mammals. The aim was to learn more about their migration paths and behaviour.

The seven moorings were underwater when 'the big one' hit off the coast of Kaikoura on November 14.

The sound of the quake was too deep and close to be captured by the instruments, but they did catch an insight into underwater wildlife behaviour when disaster strikes, Goetz said.

Niwa marine ecologist Dr Kim Goetz.
DAVE ALLEN/NIWA

Niwa marine ecologist Dr Kim Goetz.

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"There's a decent amount known about how land mammals respond to earthquakes, but no one knows anything about marine mammals underwater. Just because it goes quiet, doesn't mean they're not there."

This spectogram image of the November 14 earthquake from Niwa were collected on acoustic moorings that were in Cook ...
NIWA

This spectogram image of the November 14 earthquake from Niwa were collected on acoustic moorings that were in Cook Strait to record whale sounds. The sound is inaudible, but the data shows the severity of the noise.

Goetz said analysis will take time and extra staff had been brought in to plough through the six months worth of data.

The devices recorded vocalisations from Antarctic blue whales, Antarctic minke whales and several species of the elusive beaked whale species, including Cuviers, and possibly strapped-tooth and Gray's beaked whales. 

"There is just nothing known about these animals - they are every elusive, deep diving animals which can spend over an hour on a single dive and surface for a very short time so they are not often documented," Goetz said.

Other sounds caught included man-made noises from vessels and industry.

Goetz says the data so far shows that Cook Strait may be segregating different whale populations, with Antarctic blues primarily heard on the east side.

"We have also picked up Antarctic minkes. It matches the time minkes are known to go into Australian waters, but they have never been acoustically recorded here before." 

She said the long-term aim of her research was to assist the consent process for activities in the Cook Strait.

"Right now we don't know what's in the area and that uncertainty makes getting resource consent difficult.

Niwa's research vessel, Tangaroa, was used to distribute the buoys in Cook Strait.
DAVE ALLEN/NIWA

Niwa's research vessel, Tangaroa, was used to distribute the buoys in Cook Strait.

"If we can determine what species are there and when, industry can operate in a manner that accommodates [that] species presence."

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Niwa's instruments went crazy went the November 14 quake hit at 12.02am. Note: the timestamp is incorrect, and about two ...
NIWA

Niwa's instruments went crazy went the November 14 quake hit at 12.02am. Note: the timestamp is incorrect, and about two minutes behind London time.

Sounds of Antarctic blue whales have been captured as part of the project.
DAVE ALLEN/NIWA

Sounds of Antarctic blue whales have been captured as part of the project.

 - Stuff

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