How big: The area in question is roughly 21,000 square kilometres shaped in a triangle that extends from the Alaska-Yukon border to the edge of the U.S. and Canada’s exclusive economic zones.
Why: Canada claims the 1825 Treaty of St. Petersburg – signed by Russia and the U.K. – puts the maritime boundary along the 141st meridian. That treaty indicates that the meridian line should serve as the border between Alaska and the Yukon “as far as the frozen ocean.” Canada claims it should apply to the sea as well. The U.S. says the boundary should be guided by the principle of equidistance, which would create a line that is perpendicular from the coast, and one that slants east of the line claimed by Canada. Oil-and-gas deposits in the Beaufort Sea mean the disputed territory is highly valuable to both countries – and could make this dispute the most difficult to resolve.
But if the continental shelf extends significantly beyond 200 nautical miles, resolving the dispute could become much easier, Dr. Byers said.
Using the U.S. equidistance principle, the maritime boundary slants to the east until it reaches the edge of the exclusive economic zone. But if it were extended further, the presence of Banks Island in the Northwest Territories would push the U.S. boundary back towards the west and onto the other side of Canada’s preferred meridian boundary.
Dr. Byers, who co-authored a recent paper on the dispute with James Baker, said he believes the only reason the dispute hasn’t yet been resolved is that both governments are still collecting data about the outer limit of their extended continental shelves. (The U.S. has not signed on to the International Convention on the Law of the Sea, but supports the treaty in principle.)
“I showed the map two years ago to [then foreign affairs minister] Lawrence Cannon, and a big smile went across his face,” Dr. Byers said. “He recognized it was a win-win.”
Who: Canada vs. U.S.
What: The section of water between the Alaska panhandle and Haida Gwaii, formerly the Queen Charlotte Islands
How big: The disputed waters cover roughly 2,750 square kilometres.
Why: In 1903, an international tribunal set the southernmost land boundary for the Alaska panhandle. Canada argues the line the judges used to determine which land masses belonged to each country should also be used as the maritime boundary – leaving Canada with the entire Dixon Entrance. The U.S. wants the waters to be divided equally between the two countries.
Donald McRae, a law professor at the University of Ottawa who worked on boundary water disputes for British Columbia in the 1970s, said it’s possible to find arguments that support both countries’ claims. “The arguments are sort of evenly balanced,” he said. “There’s support on both sides rather than one being absolutely right and one being absolutely wrong.”
Juan de Fuca Strait
Who: Canada vs. U.S.
What: The dispute is over a section of the Pacific Ocean to the west of the Juan de Fuca Strait, the body of water that runs between Vancouver Island and Washington State.
How big: Combined, the two sections of water total an area of about 50 square kilometres.
Why: Both countries have agreed on their shared maritime boundary inside the strait. To the west of the strait, they each use the principle of equidistance to claim exclusive fishery zones, but calculate the line using different baselines. The result is two main pockets of disputed water, one of which is in the area of the salmon- and halibut-rich Swiftsure Bank fishery.
Machias Seal Island
Who: Canada vs. U.S.
What: Machias Seal Island, a small, mainly uninhabited island in the Bay of Fundy and the Gulf of Maine, and some of the surrounding water.
How big: The island is six hectares and the maritime area in dispute is about 720 square kilometres.
Why: In the 1980s, Canada and the U.S. asked the International Court of Justice to resolve the maritime boundary that would separate Maine from New Brunswick and Nova Scotia. But they deliberately excluded the area around Machias Seal Island and Gull Rock and North Rock, two islets nearby, which both countries say should be theirs.
The U.S. argument is bolstered by the proximity of the island to Maine. New Brunswick has kept an active lighthouse on the island since 1832, and the Coast Guard has a navigational aid at North Rock. The economic value of this island is minimal. It is mainly used by birdwatchers and researchers.
“Every now and then it crops up as an issue between the two parties, and then they just simply try to put aside because I don’t think either side is interested in dealing with it,” Prof. McRae said.