CUTLER, Maine — A nautical “no man’s land” off the coast of Washington County sees Down East and Canadian lobstermen pulling traps side-by-side in waters that have been the focus of an on-again, off-again territorial dispute that dates to 1621.

Nearly 70 square miles of the Gulf of Maine that surround the treeless, 20-acre Machias Seal Island are claimed by both the U.S. and Canada. The so-called “gray zone” encompasses waters where lobster fishermen from both countries set traps, despite the fact that Maine and Atlantic Canada lobstering regulations differ significantly.

The territorial dispute is a contemporary artifact of the treaty that resolved the Revolutionary War. The 1783 Treaty of Paris gave possession of islands within 70 miles of America’s shoreline to the original 13 colonies. As Machias Seal Island is 10 miles southeast of what is now the Washington County community of Cutler, the area was presumed to be within the territorial boundaries of the United States.

The same treaty excluded any island that was once part of Nova Scotia, as defined by a 1621 British land grant that created the province, which was later divided to create New Brunswick. Machias Seal Island is located 12 miles southwest of New Brunswick’s Grand Manan Island, and the Canadian government established a lighthouse there in 1832 as a means of staking its territorial claim to the disputed area. That lighthouse still exists, with two keepers being ferried by helicopter from the Canadian mainland every 28 days. It’s the only Canadian lighthouse that hasn’t been automated.

With Canadian assent, U.S. military forces occupied Machias Seal Island briefly in 1918 during World War I to keep watch for German submarines attempting to enter the Bay of Fundy.

Legally and politically, the disputed claim to the area has been largely a nonissue. The often fog-bound island is a seasonal tourist destination as a sanctuary for Atlantic puffins, razorbills, terns and other migratory seabirds. What has been a lingering issue is the Canadian government bending its otherwise strict lobstering regulations to allow Canadian boats to set traps in the gray zone outside of the established Canadian lobster season that begins in mid-November and runs through June.

“The Canadian boats have been in gray-zone waters for 10 years, and at the start there seemed to be total disregard for the fishermen who were already there,” said John Drouin, a Cutler-based lobsterman who has set 800 traps in the gray zone since 1989. “They would set their gear on top of traps already there. Now we typically see eight to 10 Canadian boats, but they don’t stay long. They don’t fish like we do. During their season, they’re used to very high catch rates around Grand Manan. And when they move over here in July, the catch rates aren’t as high. For them, the money just isn’t there.”

Brian Cates has been lobstering out of Cutler for 35 years and also sets 800 traps in the disputed gray zone.

“It’s an important area to us because it encompasses so much of our fishing bottom,” he said Sunday. “Some years we’ll see 15 or 18 Canadian boats, other years six or seven. For the most part it’s not a problem. When they set over top of gear that’s already there, a few words are exchanged. It irks us, and it makes things difficult.”

What does concern both Drouin and Cates is that Canadian lobstermen are not bound by the same catch regulations as Maine fishermen.

“They can take oversized males, which we have to throw back,” Cates said. “And they’re not supposed to take notched [egg-bearing] females, but we know they do.”

Drouin said he’s not happy that Canadian fishermen can take male lobsters that by Maine standards are oversized and then sell them in the United States.

“We’re throwing them back as broodstock for the fishery, and the Canadians take the same lobsters we’ve thrown overboard and truck them down Route 1 — 10 miles from my house — to send them to market on our side of the border.”

There’s no push by Maine lobstermen to preclude fishing by their Canadian counterparts, and Canadian officials seem firm in their stance on sovereignty. John Williamson, a member of Parliament for New Brunswick Southwest, recently offered this perspective:

“The fishing community on Grand Manan is permitted to fish there on an open-end basis, and it’s our way of laying our claim to this water that is part of the Machias Seal Island dispute,” he said. “I think our claim is sound and is legitimate, but at the end of the day it’s going to come down to the minister in this country and the administration in Washington to settle it. I think it is in the interests of both of our countries to do that.”

Barbara Harvey a spokesperson for Canada’s office of Foreign Affairs and International Trade has said that, as far as Canada is concerned, Machias Seal Island and the waters that surround it are Canadian.

“Canada’s sovereignty over Machias Seal Island and sovereign jurisdiction over the 210-square-nautical-mile surrounding waters is strongly founded in international law,” she said.

Cates said he hopes the Canadian government doesn’t seek any formal ruling on what he perceives as a dormant boundary dispute.

“I’m a little concerned about any push for resolution of this,” Cates said. “I wonder what venue would be used. I hope it’s not the World Court, as everybody hates the United States. To me, it’s a nonissue. Let sleeping dogs lie.”