Beaufort Sea

The Beaufort Sea (pronounced BOH-fərt; in French, Mer de Beaufort) is a marginal sea within the Arctic Ocean. It sits north of the Northwest Territories, Yukon, and Alaska, and lies west of the Canadian Arctic Archipelago. Its name honors Sir Francis Beaufort, a hydrographer. Canada’s longest river, the Mackenzie, flows into the sea’s Canadian portion west of Tuktoyaktuk, one of the few permanent settlements along its coast. The climate here is harsh, and the sea remains frozen for most of the year.

Historically, only a narrow channel up to 100 kilometers (62 miles) wide would open near the shore in August and September. However, due to Arctic climate change, the ice-free area in late summer has grown significantly in recent years. Until recently, this sea was a key reservoir for replenishing Arctic sea ice. Ice would often spin for years within the Beaufort Gyre—the region’s dominant current—building into thick, sturdy multi-year ice.

Claims that people lived along the coast around 30,000 years ago have been largely dismissed. Today, the population density is very low. Beneath the sea’s shelf lie substantial deposits of petroleum and natural gas, including the Amauligak field, discovered between the 1950s and 1980s. Since the latter part of that period, exploring these resources has become the main human activity in the area. Traditional fishing, whaling, and seal hunting occur only locally and have no commercial importance. As a result, the sea hosts one of the largest beluga whale colonies, and as of 2016, hunting this species in the eastern Beaufort Sea was considered sustainable. To prevent overfishing, the United States adopted a precautionary commercial fisheries management plan in August 2009. In April 2011, Canada signed a memorandum of understanding with the Inuvialuit as a first step toward a broader ocean management plan. In October 2014, Canada announced that no new commercial fisheries would be considered until research confirms sustainable stocks, which would then be offered to the Inuvialuit first.

Canada has designated parts of the Beaufort Sea as Marine Protected Areas (MPAs). The Anguniaqvia niqiqyuam MPA surrounds the Parry Peninsula in the Amundsen Gulf, while the Tarium Niryutait MPA lies at the Mackenzie River delta and estuary. These areas are meant to protect species and habitats for the Inuvialuit community.

**Extent** The International Hydrographic Organization defines the Beaufort Sea’s limits as follows: - **North:** A line from Point Barrow, Alaska, to Lands End, Prince Patrick Island (76°16′N 124°08′W). - **East:** From Lands End along the southwest coast of Prince Patrick Island to Griffiths Point, then a line to Cape Prince Alfred (the northwestern extreme of Banks Island), along its west coast to Cape Kellet (the southwestern point), and then a line to Cape Bathurst on the mainland (70°36′N 127°32′W).

**Border Dispute** An unresolved dispute exists over a wedge-shaped slice of the International Boundary in the Beaufort Sea, between Canada’s Yukon territory and the U.S. state of Alaska. Canada claims the maritime boundary follows the 141st meridian west out to 200 nautical miles (370 km; 230 mi), matching the Alaska–Yukon land border. This is based on the natural prolongation principle, which says a nation’s maritime boundary should extend from its land territory along the coast. The United States argues the boundary should be perpendicular to the coast out to 200 nautical miles, following a line of equidistance from the shore. The equidistance principle holds that boundaries should follow a median line equally distant from neighboring coasts. This difference creates a wedge of about 21,000 square kilometers (8,100 square miles) claimed by both nations.

Canada’s position stems from the 1825 Treaty of Saint Petersburg between the United Kingdom and Russia, which set the boundary. Canada, as the UK’s successor, cites the treaty’s wording: the line of demarcation follows the summit of mountains parallel to the coast to the intersection of the 141st degree of west longitude, and then that meridian line extends “as far as the Frozen Ocean.” Canada argues this treaty extends the land boundary into the sea along the meridian. The U.S. rejects this, asserting an equidistance-based line instead—though its position is somewhat weakened by its acceptance in 1867 of similar treaty language and interpretation when it acquired Alaska. Both countries agree they are bound by the 1958 Convention on the Continental Shelf and that the boundary should be “equitable,” as determined by the International Court of Justice. They disagree on what “equitable” means. The U.S. says equidistance is appropriate when no special circumstances exist and it yields an equitable result. Canada argues equidistance would be inequitable because the Yukon coast is concave and Alaska’s is convex, giving the U.S. a significant extension. This dispute has grown more important due to possible natural resources within the wedge.