PROVINCETOWN — This year, May 15 marked the beginning of the lobster fishing season on the Outer Cape. The fishery is not an insignificant one here. There are 42 fishermen on the Outer Cape who collectively land about 830,000 pounds of lobster every year, according to data on the Mass. Lobstermen’s Association website. This represents about 5 percent of the Massachusetts fishery.

While overall the fishery seems stable, some lobstermen are seeing changes that have them worried about its future. Scientists are looking into what role the changing climate may be playing in those changes, but they don’t have definitive answers.

“It’s horrible,” said Mike Rego, a lobsterman and owner of the F/V Miss Lilly who operates out of Provincetown. “Last year was the worst year I ever had.”

Dana Pazolt, another Provincetown lobsterman who owns the F/V Black Sheep, said that the last four years have been slim for lobsters around the Outer Cape. “You’ve got to hunt for them,” he said. “I can’t tell you why that is.”

The surface waters of the Gulf of Maine are warming at a rate of about one degree per decade, faster than 99 percent of the world’s oceans, according to the Gulf of Maine Research Institute.

Meanwhile, in other areas, warming has already had an effect — it played a major role in causing the collapse of the lobster fishery in Long Island Sound in 1999.

Lobsters do appear to be shifting their range north. From 1985 to 2016, Maine experienced a 650-percent increase in its lobster population, according to data from the Maine Dept. of Marine Resources. This may be due in part to the decline in Atlantic cod, a lobster predator, but it is also likely due to warming temperatures making lobster conditions more favorable farther north.

At the same time, the lobster fishery south of Cape Cod has declined drastically, according to the Atlantic States Marine Fisheries Commission. Between 1994 and 2014, the fishery in southern New England declined by 78 percent, and in Long Island Sound in a similar timeframe, between 1999 and 2014, the decline was 97 percent, according to the Connecticut State Council on Environmental Quality. In that same period, the average bottom water temperature increased by about 2 degrees Fahrenheit, which caused low-oxygen conditions and weakened lobsters, making them more susceptible to disease.

Not Just ‘One of Those Years’?

When it comes to Cape Cod Bay, “we do have some concerns about changing environmental conditions,” said Owen Nichols, director of marine fisheries research at the Center for Coastal Studies in Provincetown. Whether these changing conditions — and the apparent changes to the lobster fishery that Pazolt and Rego have noticed — are signs of an impending fishery collapse is still unclear.

Nichols said hypoxia, or low oxygen, is a major concern for the lobster fishery here. The Independent reported that large patches of low-oxygen water appeared near Provincetown last summer. Nichols describes these hypoxic patches as normal in deeper water later in the season, “but what we’ve now seen is it spreading to shallower water.”

The cause of the hypoxia is not fully understood, said Nichols, but a combination of warming surface waters and weaker winds preventing oxygen-rich surface water from replenishing oxygen levels in the depths, plus algal blooms consuming oxygen, are likely to blame. Nichols said what was observed was unsettling, although last year’s lobster catches improved later in the season.

Nichols said that other fishermen he works with have confirmed Pazolt’s experience that lobsters have been turning up in surprising places in recent years. “It doesn’t mean they don’t ultimately catch them, but it’s just not what they’re used to,” he said.

In the past, Nichols said of his work with fishermen here, “We’d have ‘one of those years’ every few years.” After which they would conclude, “That was a weird year.” But lately, he said, “It seems like every year is one of those years.”

Rego shared many of Nichols’s concerns. One worry is that warming waters and hypoxia will push lobsters deeper into Cape Cod Bay. “My fear is eventually we’re not going to have an inshore fishery,” he said, referring to the fishery within nine miles of shore and at depths of less than 100 feet. This year, he set some of his first traps in 120 feet of water. “I’ve never fished that deep early in the season,” he said.

Another change Rego noted: the peak season seems to have moved from July into early August, and the season seems to be getting shorter and later.

David Stamatis, a lobsterman who owns the F/V D-Tails and runs Billingsgate Charters out of Wellfleet, is also concerned about the effects of climate change. “I’m not completely convinced that we’re losing our industry,” he said, but “warming water is definitely going to affect us.” He has noticed more tropical species like triggerfish showing up in his traps.

Still, there are reasons for optimism. Rego, for one, is hopeful that this year will be a good one — the water is still cold, he said, and strong winds out of the east this spring may help circulate oxygen into the deeper water that lobsters occupy.

A Population Problem

Pazolt, meanwhile, is more concerned about a lack of young lobsters. The Atlantic States Marine Fisheries Commission found that, between 2016-18 and 2020-22, the number of young lobsters declined by 39 percent.

Harvesting practices in other areas may be to blame. In the Outer Cape Cod management zone, the minimum carapace length that a lobster must be before harvest is 3 5/16 inches, but elsewhere in Massachusetts and in Maine the limit is only 3¼ inches. While this difference is small, it may be important — enough to give female lobsters more time to grow and reproduce. That could increase egg volume by 40 percent, said Dan McKiernan, the Mass. Div. of Marine Fisheries director, in a press release.

The AMFSC is increasing the minimum length to 3 5/16 inches across the board in 2025, then increasing it again to 3 3/8 inches in 2027.

Pazolt is strongly in favor of these increases, and he suspects that addressing this issue is what’s needed to help the lobster fishery recover. He doesn’t think climate change poses a significant threat to the industry.

Stamatis is also in favor of these increases but is concerned that they are being implemented too quickly. “We expect an incredible loss” when these size restrictions are put in place, he said, and “they’re not giving lobstermen time to recover” before the second increase.

Rego, meanwhile, said the lack of juvenile lobsters could also be in part due to bottom trawlers, which catch lobsters as they tow their nets along the ground. Addressing the lack of juvenile lobsters will require regulating these other sources of lobster mortality, too, he said.

Priced Out

David Casoni, secretary and treasurer of the Mass. Lobstermen’s Association and a lobster fisherman out of Sandwich, agrees with Pazolt that climate change has not yet affected lobster populations. “There is a change, but I haven’t seen it in Cape Cod Bay,” he said. “Could it happen? Yeah.”

For Casoni, Stamatis, and Pazolt there is one issue that is more immediate than warming waters: the rising costs of doing business. “The bait, the fuel, the equipment — everything has gone disproportionate,” Casoni said.

Pazolt said the costs are especially devastating for young lobstermen, who he said often take on significant loans to start their businesses. Pazolt said they are “bleeding money.”

Rising costs have caused a dramatic decrease in the numbers of lobstermen statewide. “There are fewer than 700 active lobstermen” in Massachusetts, said Casoni. “When I started 50 years ago, there were just under 2,000.”