Proposed sonar would be “orders of magnitude” less noisy than U.S Navy system blamed for beaching whales

By JOHN THOMPSON

Underwater drones equipped with high-tech sensors could one day patrol the icy waters of Canada’s eastern Arctic, to help keep an eye on the region’s growing shipping traffic—and to be on the lookout for foreign submarines.

It’s part of a plan that Canada’s Department of National Defence calls its All Domain Situational Awareness Science & Technology Program.

Last month, the department issued two contracts, worth about $7 million, to GeoSpectrum Technologies Inc. of Dartmouth, Nova Scotia, to work on two underwater projects tied to this program.

The first project aims to develop a very-low-frequency sonar system that could be used in Arctic waters to both detect ships and submarines and to transmit information via coded pulses. It would be light and small enough for an underwater drone to carry beneath sea ice, and powerful enough to detect vessels and transmit information beyond 1,000 kilometres.

The second project is a long, bendable, cable-shaped sensor rigged with special underwater microphones, designed to be towed behind an underwater drone to help detect ships and submarines across long distances.

One big question raised by these gadgets is how they could impact whales and other marine mammals in the region. Loud blasts of very-low-frequency sonar, in particular, have been blamed for spooking whales and causing them to become stranded on shore.

As a result, last year the U.S. Navy lost a court battle over its use of this technology to hunt for submarines.

But the project being designed for Canadian Arctic waters would be “orders of magnitude” less noisy and would be designed with the health of marine mammals as a top-of-mind concern, said Paul Yeatman, president of GeoSpectrum Technologies.

“We’re acutely aware of the importance of the Arctic for a number of different species, and how disruptive things like seismic activity or naval activity can be. What we’ve been working on is coming up with ways to transmit information or do detection without putting masses of sound in the water,” he said.

“The less energy you put in the water, the less impact you have.”

The proposed sonar system would put roughly one watt of energy in the water, said Yeatman. “One watt is more power than your cellphone uses. But if you look at a light bulb, even an LED bulb uses more than a watt.”

“If you look at traditional marine seismic testing, they’re putting a megawatt of energy in the water. Or if you look at some of these super-high-power sonars, in particular that the U.S. Navy has used, it would put 100 kilowatts or so—I don’t know exactly—in the water. Even then, they’re being restricted from doing that anymore, and these programs are going by the wayside because of the impact they have.”

GeoSpectrum Technologies specializes in building underwater sensors and has experience designing devices to limit the impact on marine mammals, said Yeatman. The company will be partnering with Hines Ocean Science and Technology, Jasco Applied Sciences and Dalhousie University for these defence projects, providing them with additional expertise in tracking whales and other marine mammals and “trying to understand how sound impacts them,” said Yeatman.

GeoSpectrum Technologies will build and field test both devices as terms of the contract. But it remains to be seen whether the sonar will be tested in Arctic waters. Yeatman said this will ultimately depend on cost, logistics and winning the necessary regulatory approvals.

“A large part of our contract has nothing to do with equipment,” he said. “It has to do with acoustic modelling, propagation modelling, understanding what’s happening under ice.” The company will then deliver to the government a report, proposing “what we believe is the right approach,” said Yeatman.

Yeatman acknowledges the dangers posed to marine life by conventional seismic testing, which involves shooting loud blasts of compressed air at the seabed to reflect back information about oil and gas deposits. These blasts can frighten whales, as well as damage their hearing—a sense that’s critical to their survival.

Yeatman credits Inuit for raising public awareness about these risks during the recent legal battle successfully waged against seismic tests planned off Baffin Island.

“The Inuit have certainly raised their voices, and it’s had a big impact. I think when they started they were alone on that, but now they’re just one voice among many, because people are realizing something is going on now. And I’m impressed even the U.S. Navy has been shut down because of environmental concerns over some of the things they were doing. It means that the world has been changing a bit.”