Ask any outsider what Maine brings to mind, and the response might well be: Bone-chilling winters. Forests. Moose. Quaint fishing villages along a rocky coast. Flannel shirts and Bean boots. And lobsters—lots of lobsters.
These cold-water-loving, bottom-feeding crustaceans are top of mind for many Mainers too, including Monique Coombs. She’s the director of community programs for the Maine Coast Fisherman’s Association, in Brunswick. She’s also the wife of Maine lobsterman, Herman Coombs, and the mother of 16-year-old Joceylne, who’s going into the family trade. Homarus americanus—the American lobster—is what keeps bread on the Coombs’ table.
Last year during the pandemic shutdown, Maine didn’t get its usual blast of summer visitors, but there were plenty of lobsters. Signs are promising for a revived tourism season in 2021, and Monique expects it to be another good year for lobsters.
But that doesn’t stop her from worrying. The waters off Maine’s coast are warming, and no one knows what that’s going to mean for the state’s half-billion-dollar-a-year lobster industry—the largest single-species fishery in North America. Some fear that continued warming could cause the lobster population to collapse.
The Gulf of Maine—an ocean body brimming with marine life—is cradled by Cape Cod in the south and the Bay of Fundy in the north, and bounded in the east by two underwater shoals, George’s Bank and Brown’s Bank. In 2015, climate scientist Andy Pershing, formerly of the Portland-based nonprofit Gulf of Maine Research Institute, published a paper in Science concluding that the gulf was warming faster than “99% of the global ocean.”
That eye-popping revelation was enough to keep fisheries managers and a whole lot of Mainers awake at night.
Despite professional scrutiny and doubts about Pershing’s claim (some scientists said he cherry-picked data and that only surface water temperatures were factored in, giving an incomplete picture), the Gulf of Maine is warming at least as fast as any other part of the world’s oceans. Between 2004 and 2013, surface waters in the gulf warmed by 5.4° Fahrenheit (3 degrees Celsius).
Climate change, brought on by human activities, is why Arctic ice is melting faster, oceans are becoming more acidic, and the movements of water and air currents such as the Gulf Stream and the polar jet stream are harder to predict. Scientists are scrambling to make sense of the effects of this warming on Maine’s most popular shellfish and other marine life.
There are no clear answers.
To understand what’s happening to the ecosystem of the Gulf of Maine, says Glen Gawarkiewicz, an oceanographer at Woods Hole Oceanographic Institution, in Massachusetts, you have to look beyond it—see how it’s affected by the atmosphere, ocean currents, and rivers that flow into it.
Starting in the winter of 2011-2012, the jet stream didn’t bring cold air down to the gulf the way it usually does, and the water cooled only half as much as normal. Then a summer marine heat wave hit. After a second marine heat wave, in the summer of 2017, “historical patterns were out the window,” Gawarkiewicz says. Fishermen “were catching exotic fish they’d never seen.”
Pershing says warming alone wouldn’t likely be the cause of a future lobster collapse. Rather, it will be sudden “wild card” secondary events. “The system will get pulled apart, untied in ways we can’t anticipate,” he says. “Climate is a threat multiplier. It isn’t in-and-of-itself the threat—it just makes everything else worse. Pollution is bad, and then you add warming on top of it, and it just makes it harder. It adds stress to the system.” Put simply, if warming is too rapid, lobsters in the Gulf of Maine may not have time to adapt.
For now at least, the warmer waters appear to be causing a lobster boom. It spurred Steneck and colleagues in 2019 to publish a paper in Global Change Biology titled “The Brighter Side of Climate Change.”
Some effects of the warming are counterintuitive. Steneck says that in the southern and western parts of the gulf, warming near the surface is creating a thermal barrier that keeps deeper waters colder than usual. He doesn’t yet know how this might affect the behavior and movements of lobsters.
Five years after Pershing’s nerve-jangling 2015 paper, the Gulf of Maine is still “experiencing warming rates that few other ocean ecosystems have ever experienced,” he says.
“I think that climate change has forced the fishing industry and the scientists to interact in ways they hadn’t done before,” Glen Gawarkiewicz says. Mutual concerns about the oddities they’re witnessing (Gulf Stream flounder, for example, normally found in warmer waters) are pushing them to puzzle out what’s happening and try to adapt to a new normal. He calls this “the positive side.”
Many argue that the Gulf of Maine is bigger and deeper than Long Island Sound and that even though it’s getting warmer, lobsters can find colder water in deeper areas if they need. But, Pershing and others note, it remains to be seen whether there’s enough light or food in those deeper waters to support lobsters’ life cycles from egg to adult.
The modeling suggests the lobster boom in the Gulf of Maine won’t last. With continued warming, the population will fall off by about 2050, Pershing says. “It will decline back to pre-boom levels—what the fishing was around the year 2000, which was still vibrant and productive.”
1996-2015 National Geographic Society