'It's urgent': Research shows right whales may not survive ocean warming and human impact
Doug Fraser Cape Cod Times
Published Sep 13, 2021
A trio of recently published research papers paint a grim picture for the critically endangered North Atlantic right whale.
Caught between climate change impacts that have warmed the Gulf of Maine faster than just about any other marine ecosystem on Earth, and fatal interactions with ships and fishing gear, the right whale — the most endangered great whale in the world with less than 360 individuals remaining — may be headed for extinction.
One research paper showed that a slowdown in the Atlantic Meridional Overturning Circulation (AMOC) was largely responsible for the increased warming in Gulf of Maine waters.
AMOC is a massive, planetary-scale system of currents that help equalize global temperatures by moving warm water from the tropics north on surface currents like the Gulf Stream. The water cools, condenses and drops to the ocean depths around Greenland, Iceland and the North Sea, returning south as a cold-water-bottom current.
But some researchers have found that a large mass of freshwater from melting glaciers and ice sheets may be interfering with the cold saltwater's descent to the bottom — in theory slowing what is sometimes known as The Great Ocean Conveyor Belt.
Andrew Pershing, director of climate science at Climate Central, explained that the slowdown of the AMOC allowed the warm surface currents to expand their footprint in the northwest Atlantic. Pershing said he believes that warm water enters the Gulf of Maine through the Northeast Channel that runs by the easternmost tip of Georges Bank and is the main entry point for Atlantic water into the gulf.
Study from June:Endangered right whales are shorter than they used to be.
Until recently, Pershing was the chief scientist at the Gulf of Maine Research Institute and was a co-author of one of the papers published in the online journal Elementa that reviewed observed and expected changes to the Gulf of Maine ecosystem out to 2050.
Co-authors included researchers from the Gulf of Maine Research Institute, Colby College and the University of Maine all located in Maine; the Department of Fisheries and Oceans Canada; the Bedford Institute of Oceanography, Fisheries, and Oceans in Nova Scotia; Rutgers University in New Jersey; the Anderson Cabot Center for Ocean Life at the New England Aquarium; and Owen Nichols from the Center for Coastal Studies in Provincetown.
North Atlantic right whales on the move
Normally, a cold current from Labrador and Newfoundland chills the Gulf of Maine, creating what is considered a subarctic ecosystem. Researchers found that the last five years were the warmest on record in the Gulf of Maine. For cold-water species like cod, haddock, northern shrimp and lobster that thrive in the subarctic ecosystems, the warming waters have been troublesome.
Scientists noticed species are on the move, generally north to find cooler water, or west into the deep basins in the Gulf of Maine.
Those loving a more temperate ecosystem are moving in, like black sea bass, longfin squid, green crabs and tunicates that carpet the ocean bottom. Scientists are concerned about new shellfish pathogens and toxic blooms of new algae species that like warmer water.
Conservation groups:NOAA didn't go far enough in protecting right whales in latest plan
For the right whale, the big impact has been the negative affect on the population of their preferred prey, the lipid-rich zooplankton (Calanus finnmarchicus) that prefer a subarctic ecosystem and feed on cold-water phytoplankton blooms.
While right whales can go in search of the copepods blooming in cooler waters, lower calving rates and thin whales demonstrate that it has not been a successful hunt. Up until 2010, the right whale population had been slowly rebuilding amid what was a Calanus population bloom.
But Pershing and others believe that what is known as a regime shift — an abrupt persistent change to an ecosystem — occurred in 2010 that resulted in warmer temperatures in the Gulf of Maine. From that point on, the Calanus finnmarchicus zooplankton populations dropped and right whales were on the move.
Dropping numbers
Right whales largely disappeared from the Bay of Fundy, where they were known to summer, and were found in unexpected areas, like the Gulf of St. Lawrence in Canada and south of Martha's Vineyard and Nantucket.
In Cape Cod Bay, record numbers started showing up earlier than usual. They may have been loading up on other species of copepods that weren't as rich in the oils that the right whales crave, but at least were food. Pershing thinks they also may be eating a different species up in Canada, and to the south of the Cape.
This caused problems for those trying to protect right whales, as Canadian fishermen and their shipping industry didn't have the regulations and closed areas used to safeguard whales along the U.S. coastline. Significant mortality resulted as right whales showed up in unfamiliar areas and were hit and entangled in large numbers.
North Atlantic right whale numbers have been dropping since 2010 and are now estimated to be around 357 individuals — down from 488 in 2011 — with fewer than 100 breeding females.
Scientists estimate that less than one right whale per year can die from human causes if the species is to avoid extinction.
But NOAA data showed that over the past four years, 50 have been confirmed dead or injured seriously enough by entanglements in fishing gear or collisions with ships that they are likely to die.
Daniel Pendleton, a research scientist specializing in spatial distribution and population ecology at the Anderson Cabot Center, was co-author of a research paper, also published in Elementa. That research looked out to 2050 and found a decline in habitat suitability in historical foraging areas like the Bay of Fundy and Cape Cod Bay.
Surveyed by Center for Coastal Studies:Flight crew observes 89 North Atlantic right whales near Sandy Neck
Pendleton worked with researchers from Maine's Bigelow Laboratory for Ocean Sciences; the Bedford Institute; and Charles "Stormy" Mayo of the Center for Coastal Studies.
Right whale habitat decline in the Gulf of Maine was true under most climate change emissions scenarios, researchers found, and that large areas of the Gulf of Maine would no longer be foraging areas in July and none by August.
The right whale message
While areas to the north, like the Scotian Shelf off Nova Scotia, might see notable Calanus blooms in some months, there were unknowns. Right whales, for instance, rely on currents and bottom contours to condense the blooms and make feeding suitably efficient.
"The right whale message is that overall, the right whale habitat in the Gulf of Maine seems to be declining, but at the same time we're seeing whales appear in unexpected places," said Pendleton.
The problem, Pendleton and other researchers concluded, was that management to protect right whales is reactive, effecting change only after deaths have occurred.
Computer models that look at habitat change, he said, can help tell researchers and managers where to put their efforts in surveys and in proactive measures to prevent harm.
Pershing said the models used in the research showed that trend potentially lasting for decades or longer, with consequences beyond 2050 growing exponentially depending on how much mankind can limit emissions now.
Video:Watch as two North Atlantic right whales do a 'hug' in Cape Cod Bay
Pershing and Pendleton co-authored an essay published in the journal Oceanography that expressed the concern that even if the right whale did learn how to find the food they need, the pace of climate change would likely mean they would relatively quickly be put in the position of having to adapt again.
Whales would need to be healthy to make it through tough times as they looked for new foraging grounds. But their health was continually being compromised by ship collisions and entanglements.
Stopping human impacts
"Under these conditions, the right whale population can only grow if there are no deaths from ship strikes or from entanglements in fishing ropes," they wrote in the essay. But the reality is that federal regulators have not reduced the deaths of right whales from ships and fishing gear to levels where the species has a chance to recover.
"Climate change is one of two things affecting right whales," Pendleton said. "We can stop the human impacts — that is within our field of control on the timescales that matter right now."
"Just as it is super-urgent to figure out how to get our economy off fossil fuels, it's urgent to find out how to live in an ocean with right whales. It's very disconcerting that we haven't figured that out yet," Pershing said.
On Friday, the Conservation Law Foundation, Center for Biological Diversity and Defenders of Wildlife announced they had filed updated litigation against NOAA for failing to protect right whales from entanglements in the vertical lines used primarily to mark lobster pots, but also crab and other fishing gear.
In their updated lawsuit in U.S. District Court, the District of Columbia, the plaintiffs, contended that NOAA's new right whale protection rule unveiled at the end of last month would still result in around 32 right whales a year becoming entangled in fishing gear.
