Machias Seal Island is a tiny dot on maps of North America. But the uninhabited, fogbound rock is significant for its location in an area known as the "Grey Zone" – the site of a rare international dispute between Canada and the United States.

The two neighbours and long-time allies have each long laid claim to the island and surrounding water, where the US state of Maine meets Canada's New Brunswick province – and with that claim, the right to catch and sell the prized local lobsters.

John Drouin, a US lobsterman who has fished in the Grey Zone for 30 years, tells of the mad dash by Canadian and American fishermen to place lobster traps at the start of the summer catching season each year.

"People have literally lost parts of their bodies, have had concussions, [their] head smashed and everything," he says.

The injuries have been caused when lobstermen have been caught up in each other's lines. He says one friend lost his thumb after it became caught up in a Canadian line, what Mr Drouin calls his battle scar from the Grey Zone.

The 277 square miles of sea around Machias Seal Island has been under dispute since the late 1700s – and in 1984, an international court ruling gave both the US and Canada the right to fish in the waterway.

It has stood as a quirk – an isolated area of tension in what had been, until now, an otherwise close relationship between the two countries.

But that could all be about to change.

US President Donald Trump's return to the White House, steep tariffs on Canadian imports and rhetoric about making the country the 51st state has sparked a series of fresh flashpoints, with the possibility that he may ultimately wish to subsume Canada into the US hanging over everything. Amid the biggest shift in the relationship between the two countries in decades, the question is, what does he really want from Canada?

Cutler, Maine, is the closest US town to the Grey Zone. It has a collection of scattered houses, one supply store and, for good reason, a lobster wholesaler.

Aside from a few big-city retirees and holiday-goers, Cutler owes its existence to the bountiful crustaceans that inhabit the offshore waters. And for the lobstermen of Cutler, the international limbo of the Grey Zone is their everyday reality, as they scatter their traps along the bottom of the Gulf of Maine to catch the prized lobsters and bring them to market.

During lobster season, the Grey Zone is packed with boats and buoys marking the location of their traps. When the waters get crowded and livelihoods are at stake, things can get ugly.

"Do we like it? Not in the least," says Mr Drouin. He has caught lobsters in the Grey Zone for 30 years. "I will continue to complain about it until I can't breathe anymore."

Another Maine lobsterman, Nick Lemieux, said he and his sons have had nearly 200 traps stolen in recent years – and he blames their rivals to the north.

"This is our area, and it's all we have to work with," he said. "Things like that don't sit very well with us."

Americans accuse the Canadians of operating under a different, more accommodating set of rules that allow them to catch larger lobsters.

Canadians counter that the........

© BBC