Noisy ocean drilling

Northern bottlenose whales swim off the coast of Nova Scotia. There are only an estimated 130 of the mammals left on the Scotian shelf. Nova Scotia's population of northern bottlenose whales made Canada's endangered species list recently, because scientists fear noise from oil and gas exploration will kill them off.

The Committee on the Status of Endangered Wildlife in Canada upgraded the friendly, deep-diving whale from a species of special concern because seismic testing is expected to encroach on the three underwater canyons where the bottlenose lives. Whales sense their environment through sound. They communicate through sound and as noise increases, it's like living in a fog. During seismic testing, boats trail long lines that blast air guns, sending sound waves that bounce back off the ocean floor. Seismic patterns are used to map geological formations under the surface.

Exploration activity is most intense in summer, with blasts going off every 10 seconds for hours at a time, they can be heard thousands of kilometres away. That, along with ocean liners and other ship traffic, makes the sea an increasingly noisy place and while there's little scientific data on how noise pollution affects the bottlenose in Canada, their relatives, also known as beaked whales for their distinctive snouts, have turned up dead elsewhere. Nova Scotia's pocket of northern bottlenose whales is one of a few scattered across the North Atlantic.

The mammals are known to dive as deep as 1,000 metres searching for squid. They are also known to enjoy contact with humans, a trait that has almost destroyed the species. They are extremely friendly animals and don't have to be chased by either whalers or scientists. They go to boats so the whalers found it very easy to kill them. The Nova Scotia bottlenose population has been steady at about 130 and most of the whales are found in an area known as the Gully, a 30-kilometre long canyon near Sable Island that's also home to endangered blue whales.

The Fisheries and Oceans Department has been planning to designate the Gully a marine protected area since 1998, but debate continues to drag on over how much human activity will be allowed there. Marathon Oil, meanwhile, is preparing to do seismic testing a kilometre away from the Gully. Marathon appears willing to modify its exploration plans to minimize the impact on the whales but more study is needed to show if those plans would be effective.