As the Gulf of Maine’s waters warm, recent studies show the main food source of the endangered North Atlantic right whale is moving north, out of Maine waters. And the whales appear to be following them.

Such findings haven’t escaped the notice of the Maine lobster industry, which has been referencing them in its legal arguments as to why impending new federal restrictions on lobstering gear won’t help save the whales. Its members have pointed to recent studies that suggest the relocation of copepods – small aquatic crustaceans that make up the whales’ preferred diet – is not just a temporary phenomenon but a long-term trend.

The Maine Lobstermen’s Association has filed a lawsuit against the National Marine Fisheries Service arguing that its 10-year conservation plan to protect right whales, primarily by requiring commercial fishing gear modifications such as using breakaway rope and deploying more traps per line, is not based on the best available science. The new gear restrictions are set to take effect May 1 despite ongoing legal challenges by the lobster industry and repeated protests by government officials.

“(The association is) asking the court to require the agency to develop a new plan based on sound science that would protect both the whale and the lobster industry,” said Patrice McCarron, the group’s executive director.

Scientists also warn that rapid ecosystem changes are undermining whale conservation plans that are based on historical data.

Oceanographer Jeffrey Runge, of the University of Maine and the Gulf of Maine Research Institute, said the lipid-rich copepods have been abundant in the Gulf of Maine since Henry Bigelow did his first oceanographic surveys in the early 20th century, but that abundance has dropped by about 70 percent in the past 20 years.

“Historically, the Gulf of Maine has been just a perfect place for reproduction and growth of calanus (a type of copepod) from this supply that comes down (from Canada),” Runge said. “That’s why the Gulf of Maine has been remarkably abundant in this lipid-rich copepod, but with the warmer temperatures, that’s all changing.”

Runge contributed to a report on those findings in 2019 in The Journal of Plankton Research that described abrupt changes to the ecosystem, or “regime shifts,” that resulted in fewer copepods in the Gulf of Maine and Georges Bank in 2010.

Also around 2010, Runge said, the scientific community started noticing a shift in the distribution of right whales out of the eastern Gulf of Maine and into Canadian waters.

“It seemed pretty consistent with the right whales looking for higher concentrations of this prey,” he said.

The ecosystem changes do not appear to be temporary, Runge said, because they  can be linked to a shift in the Gulf Stream bringing a warm, deep current into the Gulf of Maine that blocks off the deep, cold and copepod-rich current from Canada. He said the changes can also be linked to broader climate-driven changes in the North Atlantic ocean circulation patterns.

‘NINE YEARS BEHIND’

Several papers have been published on the apparent trend, including an August 2021 report in the journal Oceanography in which author Erin L. Meyer-Gutbrod also links the climate-driven ocean circulation changes to the whales’ changing foraging locations, reduced calving rates, and greater mortality from ship strikes and gear entanglement.

“The case of the North Atlantic right whale provides a cautionary tale for the management of protected species in a changing ocean,” Meyer-Gutbrod wrote.

A 2019 report by Runge and Nick Record of the Bigelow Laboratory for Ocean Sciences argued that conservation strategies based on the right whale’s historical foraging patterns are undermined by accelerating climate change that is changing marine ecosystems rapidly.

National Oceanic and Atmospheric Administration scientists and fisheries management organizations are aware of such shifts and the challenges of managing species in a way that keeps pace with changing ecosystems.

Janet Nye of the University of North Carolina gave an online presentation in February describing the decline of the right whale’s preferred calanus copepods in the Jordan Basin, about 60 miles west of Nova Scotia, as an example of temperature driving the relocation of a species. It corresponded with fewer sightings of right whales in the Gulf of Maine, she said.

“Now we see more sightings north of the Gulf of Maine, so it does appear that they are following their prey or responding to a change in their prey productivity and shifting their distribution,” Nye said.

John Manderson, a research fishery oceanographer at the Northeast Fisheries Science Center who participated in the February webinar, acknowledged that rapid ecosystem changes require new strategies.

“If you have an ecosystem that’s changing, that’s non-stationary, and then you have academic science that is maybe two to three years behind the ecosystem, and then you have the applied science that goes into assessment, that is five to seven years behind the ecosystem,” Manderson said. “And then you have the governance that’s two years following, (so) you’re nine years behind the ecosystem, and you’re waiting for surveys and information to make these decisions – it’s impossible for you to be right, because the ecosystem is non-stationary.”

DEADLINE APPROACHING

Maine lobstermen, meanwhile, are scrambling to adopt required gear modifications to comply with the first phase of the NOAA’s 10-year right whale conservation plan by adding more traps per line and weakening the rope used to haul them up.

“Maine lobstermen have implemented an array of gear changes over the past 20 years to keep the waters off our coast safe for right whales, and are implementing additional measures May 1,” said McCarron, leader of the lobstermen’s association. “(Lobstermen) have witnessed oceanographic changes and the shift of right whales away from the waters they fish. The last known entanglement in Maine lobster gear was nearly 20 years ago, while observed deaths have spiked in Canada because these whales are now feeding there.”

Steve Train, a Long Island lobsterman who began fishing in the 1970s, said he’s seen a lot of whales: humpbacks, minke whales and pilot whales – even a beluga once – but never a right whale.

Train already had been using a weak buoy line for his traps, but adding the required weak links was a problem for him because the ones he purchased were recalled because they didn’t work as intended.

“I had to return them because they were too weak, and the new ones aren’t in yet,” he said. “So it shouldn’t have been a problem, but the urgency of it forced on us by NOAA is making it hard to comply with now because manufacturing isn’t ready for it – they haven’t perfected the device.”

Gov. Janet Mills and the Maine congressional delegation wrote a letter to U.S. Secretary of Commerce Gina Raimando in March asking to postpone the deadline for gear conversion to July 1 because of the supply issues.

Train said the new studies coming out about copepod decline make a lot of sense to him, based on what he has been observing on the water.

The copepod decline might explain why lobstermen are having to fish farther and farther offshore, he said. Larval stage lobsters, which also eat copepods, might be looking for food in colder, deeper waters.

“If this study is true, it makes a lot of sense to a lot of the problems we’re seeing,” Train said.

THE WIDER PROBLEM

Richard Howland, an Islesford lobsterman who started fishing 23 years ago when he was 15, said he’s seen humpback, minke and finback whales but never a right whale. He fishes 35 miles offshore in the winter, around the Mount Desert Rock area south of Bar Harbor, and about 20 miles out in the summer months.

“Calanus finmarchicus – that’s the one (copepod) that’s primarily been in the Gulf of Maine,” Howland said, the scientific name rolling right off his tongue. “These little organisms that live in the water column that are like 60 to 70 percent body fat, and the whales love them. Actually, lobsters feed on them as well, so this will affect us eventually.”

Howland said he has heard from scientists that these copepods have been moving north, and based on what he is observing out on the water, it makes sense.

He used to see whale-watching boats around Mount Desert Rock but hasn’t seen a single one this summer. Talking to the tour boat captains, he learned they are now going much farther east, almost to the Canadian line.

“The other indication is herring,” Howland said. “Herring feed on those as well, and there aren’t really any schools of herring around like there used to be.”

That touches on a bigger concern for Runge, the oceanographer.

“The right whales are letting us know of these changes in the lipid-rich stage calanus that the whole food web in the Gulf of Maine is dependent on,” he said. 

He said herring and sand lance, which humpback whales eat on Stellwagen Bank, are two foundational species for the whole Gulf of Maine food web, and they both eat calanus.

“These fish support the whole food web (including) cod (and) tuna,” he said, “and so my real concern is the implications for the whole food web down the line. There’s not really a replacement species for calanus.”

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