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Seismic tests 'low impact'

Paul Bickford
Northern News Services

Hay River (Aug 26/02) - A seismic research company is very pleased with the results of tests on the Mackenzie River.

During July and August, WesternGeco Canada conducted acoustic and biological tests to prove its so-called "air gun" will not harm aquatic life or the environment.

Steve Whidden, the account manager for WesternGeco in Calgary, said preliminary results show the method is a "low-impact, no-footprint technique."

Basically, the method involves the release of compressed air into the water.

The bubble oscillates and creates an sound wave that goes down into the earth. The wave reflects off rock layers and the reflection is recorded by instruments on vessels.

"It's not a big, violent explosion," Whidden said.

The company tested 90-kilometre stretches of the river around Norman Wells, between Fort Good Hope and Tsiigehtchic, and in the Delta.

Whidden says the company didn't believe the $9-million study was necessary, because the method has been proven safe throughout the world. However, it conducted the environmental assessment at the request of the Department of Fisheries and Oceans and other regulatory agencies.

"We had to prove it, and that's OK," Whidden says.

As part of the study, 196 caged fish were placed at various distances - two, 85, 466 and 3,000 metres - from a "gun string" towed behind a vessel.

While four of the fish died, Whidden said they died from handling injuries, noting no fish died from the tests, even at two metres from the air gun.

Monitors hired from local communities reported minimal or no impact to other fish, wildlife or the environment.

Whidden also said the air gun didn't affect the distribution of fish in the water.

The testing began in early July and the vessels and barges involved sailed back into Hay River on Aug. 18.

WesternGeco will make a formal presentation on the test results in mid-September to DFO and the other regulatory agencies. In mid-October, it will make a submission for next summer's work -- a seismic survey of the whole Mackenzie River and the Liard River to the B.C. border.