Seismic tests given the go-ahead

03:00, Dec 28 2011

The Government will offer oil and gas exploration companies the opportunity to conduct further seismic tests off the Kaikoura coast despite a lack of research on its effect on marine life.

The Economic Development Ministry's Petroleum and Minerals department will open up specified ocean spaces around New Zealand to bids from oil and gas exploration companies in the first quarter of next year. Some of the areas may include Pegasus Bay, which lies between North Canterbury and the Wairarapa and extends for several hundred kilometres towards the Chatham Islands.

Initial work for oil and gas exploration included seismic testing, but studies on the effect of the testing on marine life remain largely observational and further research is years away from completion.

Seismic testing conducted in the same area in 2009 involved firing powerful airguns into the ocean at timed intervals. This created low-frequency pulses which echoed back off the ocean floor.

The pulses were recorded and used to create two-dimensional images of the geological makeup of the area. The images were used to help determine the likelihood of gas or oil reserves below the surface, but these can't be confirmed until the area is drilled.

Canterbury University Edward Percival field station marine biologist Manuel Fernandes specialises in sperm whale foraging based on acoustics research, and previously worked as a marine observer on board seismic testing vessels. He said boats emitted low sound frequency pulses that ranged from 200 to 300 hertz.

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Whales could hear the sound from potentially thousands of kilometres away, but how it affected them remained unknown. The only available research was on the direct effects the boats had on the whales, which involved monitoring their movements in regard to the vessel, but not enough was known about their intentions and routines to draw any conclusions.

Studies needed to be conducted on the indirect effects, such as whether the pulses masked the whales' ability to listen for food or communicate with other whales.

"First, we have to be sure there is an effect, but we don't really know," Mr Fernandes said.

"The whales are more likely to be affected than dolphins, due to the whales' low vocalisation frequencies."

A misconception was that seismic testing vessels caused whales to become stranded or rush to the surface too quickly to survive.

This effect was commonly caused by the stronger and higher frequency sonar pulses used by navy vessels.

"There is a very strong correlation and it's very close to being scientifically proven," Mr Fernandes said.

Ministry of Economic Development chief petroleum geologist Richard Cook said the ministry would award an exploration permit to a company based on its planned work programme for the area.

Permits for "blocks" of ocean space off the Kaikoura coast would be opened for bidding in the first quarter of next year, he said.

Explorers would conduct detailed three-dimensional tests on specific areas of interest taken from the broader two-dimensional image tests.

The company would be given five years to conduct its tests and, if successful, would be likely to drill in the area, he said.

Seismic testing vessels had to stop their tests if a whale was spotted within one kilometre of the boat.

"We discussed the testing with Whale Watch [in 2009], and put a 10-kilometre exclusion zone around their activities."

Central government earned about 45 per cent of the profit from a successful exploration company's oil or gas trade, he said.

Te Korowai o Te Tai o Marokura chairman John Nicholls said the coastline protection organisation would seek to negotiate with any exploration company that wanted to conduct seismic testing in Kaikoura.

"[Dr Cook] was at our strategy launch but currently we are looking to work with all those organisations to ensure we don't have any issues arising from it," Mr Nicholls said.

"One would hope that the government would listen to [us] if we can show genuine issues.

"We have strong support from the government for what we are trying to accomplish but they have to look at the big picture – nothing's ever given but if you don't try, you're going to fail anyway."

Green Party MP Steffan Browning said the testing was of concern due to the lack of available research and, if successful, could lead to intensive drilling techniques such as fracking.

"Why bother exploring for something that you wouldn't want to extract anyway," he said.

Kaikoura Star