While many communities, in cluding the Vineyard, have seen extreme declines in lobster populations over the years, the species has rebounded further north in a disputed area on the border of the United States and Canada. Fueled by warming waters due to climate change, this newly robust lobster area is being claimed by both countries, and it’s been dubbed the gray zone.

Lobster War, a new film about the building tension in the gray zone off the coast of Maine, will screen on Saturday at 4 p.m. at the Martha’s Vineyard Film Center. Film director and Boston Globe reporter David Abel will appear for a question and answer session via Skype. He will be joined by Tubby Medeiros and Wes Brighton of the Martha’s Vineyard Fishermen’s Preservation Trust, both of whom lobster in the waters around the Vineyard.

Speaking with the Gazette by phone, Mr. Abel said he learned about the gray zone through his environmental reporting for the Boston Globe.

“I’m interested in telling stories that look at how climate change affects us and how it’s not an abstract threat, but it’s having a real impact on people’s lives,” he said.

Whereas most areas have seen a decline in lobsters, warming waters in the "gray zone" has led to a 1,500 per cent increase since 2002.

And in the story of the gray zone, the effects of climate change collide with international relations.

“Borders are sort of bizarre when you’re on the water,” Mr. Abel said. The 277 square miles of ocean in the disputed gray zone surround the tiny Machias Seal island. Since 2002, lobster catch in the area has grown by 1,500 per cent due to warming seas.

“Both countries have claimed the island and the waters around it since the Revolutionary War, and both countries have a long line of arguments for why they believe they should rightfully own the island and the waters,” Mr. Abel said.

The zone is increasingly crowded with lobster boats from both countries, and the clash of fishermen governed by separate regulations, seasons and methods has made the work even more dangerous than it typically would be.

Mr. Abel and his partner Andy Laub began filming last year, embedding on lobster boats with Canadian fishermen from Grand Manan Island and with American fishermen from Cutler and Lubec Maine.

Many of the fishermen in the film do not seem to notice the cold or the damp as they go about their physically demanding work, but Mr. Abel said his first excursion on a lobster boat left him laid out sick for several days.

“It was in June, and I thought the weather would be warmer. I was out for 12 hours, maybe 14 hours. By the end of the day, I was holding the heat pump in the bowels of the lobster boat trying to stay warm,” he said.

Unforgiving weather conditions are not the only danger on a lobstering vessel. In the film, Patrick Feeney, an American lobsterman, tells the story of how he lost a thumb trying to untangle traps after a run-in with a Canadian boat.

“[The trap] was either going to haul me overboard or my arm off, so I braced off,” he said. “I fell over backwards and then I sat up real quick, and I looked and it had ripped my glove and my thumb was gone. It was just, there was nothing left.” Steering his lobster boat, the fisherman later added, “I’m still alive, and I’m still doing what I love to do.”

Though Mr. Abel’s film focuses on lobster fishermen, his reporting for the Globe has left him deeply aware of the impact of lobstering on the North Atlantic right whale. The whales are on the brink of extinction, and entanglements with lines from lobster traps are to blame for many right whale deaths. Mr. Abel said the whales have been known to traverse the gray zone, though the issue is more pressing in other areas.

“There are seven million of these lines all through the gulf of Maine, and those are waters that right whales, which number at about 400 and are critically endangered, those are waters they transit,” Mr. Abel said.

As the climate continues to change, lobster fisheries off the coast of Maine are not guaranteed to last long, and the lobstermen know that. But something drives them to keep at it, something that seems innate. The film samples audio from a recording of essayist EB White, who wrote about lobstering in the 1950’s.

“A boat does not merely transport a man to his traps in the sea. It carries him in some degree to where all men want to go: toward a destination that gives the illusion of security and strength. The boat is a living prop to the spirit of the man,” Mr. White narrates.

“It’s a fierce independence, it’s a love of the sea, and it’s also, especially right now, a really good way to make money,” Mr. Abel said.