Seismic survey affects on sea life uncertain

Manuel Fernandes
Manuel Fernandes

Seismic testing in Kaikoura waters this month will be 2D rather than 3D as many people in Kaikoura had previously believed.

It is unclear where the misunderstanding arose.

Anadarko corporate affairs manager Alan Seay confirmed last week that the surveying was 2D which involves one streamer being towed from the back of the survey ship, rather than multiple streamers.

Future surveying involving 3D mapping will depend on what is found during the first stage. Mr Seay said there were no definite plans for it.

Many of those opposed to the seismic surveying fear it will put marine life at risk, a theory backed by various studies that have come to light as the survey work gets closer.

Data published in April by international conservation organisation Oceana outlines possible effects to marine mammals like whales from seismic airgun blasts. These include hearing loss, abandonment of habitat, disruption of mating and feeding, beach strandings and even death.

The study said mass mortality events in Madagascar and Peru following seismic surveys may indicate the worst case scenario.

Recent and repeated strandings of pilot whales at Farewell Spit have also been linked to seismic surveys. Climate Justice Taranaki called for urgent research into the strandings. Survey ship Polarcus Alima was carrying out seismic testing about 90 kilometres from Farewell Spit between January 5 and 8.

Between January 6 and 18 more than 50 pilot whales beached on Farewell Spit, a coincidence which the group said was too high to be ignored.

However, an independent environmental consultant, who spent three years studying the effects of seismic testing on Kaikoura's whale population, advises caution when making these links.

Manuel Fernandes has been working on seismic ships since 2007 and was collecting data in Kaikoura when a 2D seismic survey was being undertaken in the Pegasus Basin, where the current survey is being carried out.

He said despite many studies taking place across the world, it was very difficult to verify and quantify the effects of the sound pulses produced by the airguns. Marine mammals can detect the blasts over hundreds of kilometres, he said, but did not necessarily change their behaviour or avoid the seismic ship.

Species such as pilot whales had been found to approach the guns during operations.

This did not mean there were no effects, he said, and it was also important to point out the complexity of underwater acoustics.

There was the possibility that airgun noise could mask the ability of certain mammals to communicate with each other, he said. The most likely species to be affected by masking effects were baleen whales, including the blue whale and humpback, because they sang from a distance to find partner, although the ramifications were still unknown at this stage.

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