The thought of canyons typically conjures up images of the American Southwest, where the Colorado River chisels its famous path through the majestic Grand Canyon. However, WWF conservationists in the Arctic region are now calling attention to a set of lesser-known—yet ecologically and economically important—undersea canyons in Alaska.
In the middle of the Bering Sea—where shallow waters become deep sea—sits the continental shelf break and multiple submarine canyons. Two of the biggest are the Zhemchug Canyon and Pribilof Canyon. Few humans have ever explored these canyons or know what lives in them.
Oceanographers know that upwelling funnels nutrient-rich deep waters to the top of the continental shelf where a variety of animals eat, and that canyons create eddies that contribute to one of the most biologically productive large marine ecosystems in the world, and also one of the biggest fishing grounds on Earth.
Advocating for change
The biodiversity and productivity of the canyons are threatened by the use of certain types of commercial fishing gear and the amount of fishing in the area.
Trawlers, in particular, fish the area heavily and touch the bottom of the Bering Sea frequently, knocking over corals and other species attached to the benthos. Heavy fishing challenges the productivity encouraged by the canyons, in addition to robbing marine mammal populations (like those of the Steller sea lion and Northern fur seal, both of which are suffering severe declines in numbers) of prey.
WWF is advocating for conservation of habitat from the deep Bering Sea canyons to the edge of the continental shelf. Testifying before the North Pacific Fishery Management Council at its June meeting, WWF urged Council members to consider conservation actions such as setting aside habitat from fishing effort. In doing so, WWF argues, the Council would allow depleted fish species to recover and could reduce bycatch of certain species.
Equally important, if this richly productive area is allowed to function as an intact ecosystem, it could continue to serve as an engine of vitality in the Bering Sea, supporting commercial fisheries and wildlife alike.
An area of biological productivity
At the canyons, sunlight reaches into the top layers of nutrient-rich water, enabling photosynthesis on a grand scale. This process—as well as the organic matter transport, sediment flushing, and plankton migration that come with it—allows the marine environment to support an astonishingly diverse array of wildlife. At the shelf edge, conservationists and scientists call this area of massive productivity the Bering Sea “Green Belt.”
Margaret Williams, managing director of the WWF Arctic field program was at the meeting and had the following to say about these ecological treasures:
“The Bering Sea canyons and the continental shelf break nearby comprise an amazing ecosystem. The North Pacific Fishery Management Council's decision shows the Council's recognition of the value of the canyons, but stops short of a decisive conservation action. WWF will encourage the Council to consider specific measures that would set aside this area from fishing pressures and allow biodiversity to thrive. By investing in that ecosystem, the Council can ensure that people, wildlife and commercial fisheries will reap the benefits for years to come.”