An American fishermen plying disputed lobster grounds off the East Coast says he too has been stopped and questioned by U.S. Border patrol agents, much like his Canadian counterparts who complained they were being targeted in the same area near Machias Seal Island.

John Drouin of Cutler, Maine, said Friday that he was out about two weeks ago when U.S. patrol agents came alongside his boat in the so-called Grey Zone to him to ask where he was from and to see his paperwork.

The veteran fisherman said he was slightly bemused by the encounter, having rarely seen patrol boats in the area over four decades of fishing the rich lobster grounds, something Canadian fishermen also said was a new and unusual phenomenon.

"They asked me for a driver's licence and identification and I kind of chuckled -- I said I'm not driving my vehicle, so I don't have my licence," he said in an interview from his home.

"We are in a different time and Border Patrol is patrolling...Their presence is a lot more visible."

The 53-year-old fisherman, who has seen a patrol boat only once or twice over the last many years, said he asked the agents what they were doing and said he was told only that they were there to "document who was in the area."

U.S. Customs and Border Protection said in an email late Thursday that agents were enforcing "immigration laws and other violations of federal law that they may encounter in the course of their duties during the operation in June."

Drouin said his two sons were also recently stopped when they were fishing in the contentious area around Machias Seal Island, which is about 19 kilometres southwest of Grand Manan Island and east of Maine. It is in a disputed area known as the Grey Zone, where lobster fishermen from both Canada and the United States have long fished side by side.

Drouin, a member of Maine's lobster advisory council, said he witnessed three other vessels that were also stopped and questioned, and has seen several Border Patrol vessels in the area over the last month.

"I honestly do not know what's going on," he said, adding that a directive to patrol the area may be linked to a broader culture change with the election of U.S. President Donald Trump. "We're in a different time. We know he's doing a wonderful job pissing off the rest of the world."

A Canadian fishermen's group said this week that over the last two weeks at least 10 fishing boats from New Brunswick have been intercepted by U.S. patrol agents while fishing around Machias Seal Island.

Laurence Cook of the advisory board for Lobster Fishing Area 38 said some Canadian vessels were boarded by American agents who asked about possible illegal immigrants.

"There's been a bit of a misunderstanding there somewhere," Cook said. "They're in international waters, so border patrol shouldn't be boarding Canadian vessels."

A spokesman for Global Affairs Canada has said it is contacting U.S. agencies about the encounters, but that the federal government considers its sovereignty over the area to be "long-standing" and grounded in international law.

The small island is a flat, treeless piece of rock, which includes a large colony of puffins and a lighthouse staffed by two Canadian lightkeepers year-round.

However, both Canada and the United States claim sovereign jurisdiction over the island and the surrounding waters at the mouth of the Bay of Fundy.

As lucrative lobster catches have increased in the zone, competition between fishermen has intensified in the past decade.

Stephen Kelly, a research scholar at Duke University in Durham, N.C., said neither country accepts that there is a Grey Zone and that "it's created more tension in the area over the last decade."

Drouin said the area has been "inundated" with Canadian lobster fishermen since 2002.

"The resource is being overexploited," he said. "In our viewpoint, the Canadians are not managing the resource anymore."