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Alaska Oil And Gas Activities

Walruses in Bering Sea ice.  Courtesy of USGS.

WMRS | Marine Mammal Protection Act and Litigation Highlights

The Beaufort and Chukchi Seas in Alaska are home to a variety of marine mammals, including polar bears and Pacific walruses. Because the Beaufort and Chukchi Seas are also rich in oil and gas resources, companies have long targeted these areas for potential exploration, development, and production. Since 1991, the oil and gas industry has made a practice of requesting “incidental take” authorization before proceeding with oil and gas activities in the Beaufort and Chukchi Seas, and the Fish and Wildlife Service has issued incidental take regulations covering these activities in Pacific walrus and polar bear habitat in these areas.

Thunder Horse oil platform.  Courtesy of U.S. Minerals Management Service.Concerns over global climate change and the consequences of a warming arctic for ice-dependent species like polar bears and Pacific walruses have prompted recent litigation challenging the Fish and Wildlife Service’s issuance of incidental take regulations in the Beaufort and Chukchi Seas.

Polar Bear Impact.

Worldwide, there are 19 polar bear subpopulations, distributed throughout the arctic and subarctic, with a population estimate of 20,000 to 25,000 individuals. The polar bear is listed under the Endangered Species Act as “threatened” throughout its range. Two polar bear stocks occur in Alaska, the Chukchi-Bering Seas stock and the Southern Beaufort Sea stock.

Polar bears are ice dependent and subject to the movements and coverage of the pack ice and annual ice, which they rely on as a platform for hunting (mainly ringed seals). Polar bears are widely distributed within their range and are generally solitary animals. Polar bears can swim long distances across open water, but they are not adapted to a pelagic existence, and typically remain closely associated with sea ice or coastal zones during open water season.

Pacific Walrus Impact.

Pacific walruses are represented by a single stock of animals that inhabit the shallow continental shelf waters of the Bering and Chukchi Seas. The population ranges across the international boundaries of the United States and Russia. Walruses tend to be found in large groups that are distributed in a non-uniform fashion.

Walrus distribution varies markedly with the seasons and is closely associated with the presence of pack ice. Like polar bears, walruses are an ice-dependent species. They rely on floating pack ice as a substrate for resting and giving birth and generally require ice thicknesses of 50 cm or more to support their weight. Where pack ice is unavailable, walruses haul out to rest on land. They spend about one third of their time hauled out on land or ice. Walruses are social animals and tend to travel and haul out in groups. Although capable of diving, walruses are mainly found in shallow waters of 100 m or less. They are not adapted to a pelagic existence.

Fish and Wildlife Service Mitigation Measures to Minimize Impact.

Through incidental take regulations and letters of authorization, the Fish and Wildlife Service (FWS) has imposed mitigation measures to minimize the impact of oil and gas activities on polar bears and walruses. Persons seeking take authorization for particular projects must apply for a letter of authorization. Letters of authorization include mitigation, monitoring, and reporting requirements specific to each activity. For example:

  • Offshore exploration activities may only be carried out during the open water season to avoid seasonal pack ice.
  • Before beginning onshore activities, steps must be taken to avoid known polar bear denning areas or coastal walrus haulouts.
  • A separate letter of authorization is required for each activity, (i.e., geophysical survey, seismic activity, and exploratory drilling).

The impacts of oil and gas activities on polar bears and Pacific walruses are expected to be limited to minor, short-term, behavioral responses, like diving or moving away from the activity. Killing or intentionally taking a marine mammal is prohibited under the regulations.

Recent Litigation.

Litigation over oil and gas activities in the Beaufort and Chukchi Seas has focused on legal topics such as:

  • the meaning of “small numbers” and “specified activity”
  • the sufficiency of mitigation and monitoring efforts
  • scientific challenges (e.g., assessing the cumulative impact of climate change on polar bears and Pacific walruses in the context of incidental take regulations that are only valid for a period of five years).


Updated May 15, 2015

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