LOBSTER WAR is an award-winning feature documentary about a conflict between the United States and Canada over waters that both countries have claimed since the end of the Revolutionary War. The disputed 277 square miles of sea, known as the Gray Zone, were traditionally fished by US lobstermen. But as the Gulf of Maine has warmed faster than nearly any other body of water on the planet, the Gray Zone’s previously modest lobster population has surged. As a result, Canadians have begun to assert their sovereignty in the area, fighting with the Americans to claim the bounty.

THERE HAVE BEEN DEATH THREATS on both sides of the watery divide, as lobstermen accuse each other of sabotaging lines, stealing gear, and setting traps atop those already in the water.

The United States and Canada have long shared the world’s longest peaceful border, but a centuries-old conflict over 277 square miles of disputed, increasingly lucrative waters has sown discord and threatens to shatter the tranquility between the neighbors.

Fueling the tension is the rapid warming of the Gulf of Maine and the surging value of lobster, which has attracted more Canadian fishermen to the so-called Gray Zone, the disputed territory fished mainly by Americans until a decade ago. Both countries now allow their lobstermen to fish there, though each claims exclusive ownership of the waters.

“This is a ticking time bomb out here,” says Brian Cates of Cutler, Maine, who has been fishing the contested waters near the Bay of Fundy since he was 9 years old. “It’s just a matter of time before someone gets killed.”

Several years ago, a Canadian patrol boat hauled up his and his son’s traps, after one of his lines drifted into Canadian waters. Cates sped over to the vessel and threatened to ram it if the officers didn’t return his gear, telling them, “I’m going to sink you.”

The Canadians returned his son’s gear.

But Canadian fishermen insist the Americans should get used to their presence.

“It’s our bottom, and we’re going to be there to stress our sovereignty,” says Brian Guptill, president of the Grand Manan Fishermen’s Association, who has been fishing in the area since the 1980s. “I’m going to go there to raise hell for a while.”

He adds, “There are going to be guys on both sides of the border slashing ropes and instigating problems.”

American and Canadian law enforcement authorities, who cooperate and speak with each other regularly as they enforce their respective laws, have worried about the potential for violence.

“The tensions are definitely mounting,” says Mark Murray, a specialist in the Maine Marine Patrol, as he and an armed officer puttered through the disputed waters.

He and his colleagues have heard lobstermen vow to bring guns on the water and have received reports of US and Canadian boats pulling on the opposite ends of the same line. One US lobsterman lost a thumb while trying to disentangle his traps from Canadian lines, they note.

As a result, the Maine Marine Patrol has quadrupled the amount of time its officers patrol the Gray Zone, especially at night, when Canadian laws allow their lobstermen to fish but Maine bans theirs from working.

“We’ve heard guys say that if we won’t do our jobs, they’ll take matters into their own hands,” says Jason Leavitt, a Maine Marine Patrol officer.

The conflict began at the end of the Revolutionary War, when the newly independent Colonies received all islands within about 70 miles of the US shore. But the 1783 Treaty of Paris excluded any island that had been part of Nova Scotia.

The two sides emerged from that deal disputing only one speck of land at the mouth of the Bay of Fundy: Machias Seal Island, a treeless, 20-acre rock about 10 miles from the Maine coast and 12 miles from Grand Manan Island, which is part of New Brunswick. The Canadians say a 17th-century British land grant proves the island was originally part of Nova Scotia.

Both Canadian and US officials insist their countries should have sole sovereignty over the area. In a statement, US State Department officials said: “Our longstanding position is that the Machias Seal Island belongs to the United States.”

Officials from Fisheries and Oceans Canada insist that they have exclusive sovereignty over the area. “Both the waters surrounding Machias Seal Island and the island itself are Canadian,” they said.

For centuries, the conflict remained muted. During World War I, the Canadians agreed to allow a small detachment of Marines onto the island to protect the area from German U-boats. Both US and Canadian boats have ferried tourists there for years to glimpse the southernmost nesting grounds of Atlantic puffins.

Occasionally, people on both sides tried to stoke tensions. For years before he died in 2004, an American tour boat operator, Barna Norton, made an annual pilgrimage to the island to plant an American flag. But instead, the maple leaf flag flies over the island’s lighthouse, which Canadians built and have maintained for nearly 200 years to assert their sovereignty, and politicians occasionally make a show of flying out to visit their constituents, the lighthouse keepers.

Though the two countries have resolved other maritime disputes through arbitration, the Canadians have declined US proposals to do so with the Gray Zone, arguing that their claim is beyond question.

The conflict reignited when Canada relaxed its fishing regulations in 2002 to allow their lobstermen to work in the Gray Zone, including when their lobster season shuts down between July and November.

The rising value of lobster has given Canada even more incentive to assert its sovereignty. In 2016, Maine’s lobster catch was valued at a record $538 million, nearly three times the value of the 2000 catch. In 1950, the catch was worth just $6 million.

In the Gray Zone, US lobstermen in the area caught 23 million pounds in 2016 – nearly five times the amount they landed in 2000. That lobster was worth nearly $88 million in 2016; in 2000, their catch was worth just $18 million.

Since Canadians began fishing the Gray Zone, their catch has surged by nearly 1,500 percent in 2016. The Canadian catch in the area was worth nearly $9 million in 2016, a rise from just $572,000 in 2002.

Americans complain that the congested area now has tens of thousands of traps on the ocean floor and has become more complicated to fish.

“It’s like they want a war,” says Kristan Porter, a lobsterman out of Cutler, Maine, who learned how to set traps in the area’s powerful tides from his grandfather and has been fishing about 400 traps in the Gray Zone for the past 20 years. “They keep trying to ratchet up the pressure and turn the knife. We just want them to leave us alone.”

The US fishermen say many of the Canadians don’t understand how to set traps in the area’s tricky tides, and their traps often get entangled with the Americans’. The US fishermen also complain that the Canadians don’t have to follow US conservation rules, such as throwing back larger lobsters that serve to replenish the population or having to use expensive lines designed to protect right whales.

The Canadians dismiss the Americans’ environmental concerns. They note that Canadian fisherman are limited to 375 traps per license, while most Maine fisherman can set 800 traps at a time.

“It’s Canadian water, plain and simple, [and] if it’s going to be fished, it’s going to be fished by Canadians,” says Lawrence Cook, chair of the lobster-fishing district in Grand Manan, who has defied death threats from Americans since he started fishing the Gray Zone in 2002. “We are there to stay.”

But with temperatures continuing to rise in the Gulf of Maine, scientists worry that the boom times in the Gray Zone may soon go bust as the waters become too warm for lobster.

And they have reason for concern. Since 2012, surveys along the Maine coast have found a steady decline of lobsters less than a year old. Without young lobsters to replace the older generations, the crustaceans could soon become overfished and their population plummet.

That happened in the rapidly warming waters just south of Cape Cod, where temperature gauges have shown an increasing numbers of days when the region’s waters are inhospitable to lobster, which tend to hatch their eggs and thrive in seas that range between 53 degrees and 64 degrees. One station in eastern Long Island Sound, for example, found that there had been nearly 100 days in 2012 when the water was warmer than 68 degrees – dangerously warm for lobster – double the average number of days that exceeded that threshold over the previous three decades.

As a result, the lobster population there has plunged.

Since the 1990s, the region’s lobster catch has dropped by more than 90 percent, forcing hundreds of lobstermen out of the business.

See more about the film at www.lobsterwar.com.