This is the second story in a series on Canada-U.S. cross-border measures to protect North Atlantic right whales.
Off the tip of Cape Cod, on the bay side of the national shoreline, a North Atlantic right whale and her four-month-old calf swim in a synchronized dance. The mother’s oil slick of a body breaks the surface first, then the calf’s smaller silhouette emerges beside her.
From the flybridge of the RV Shearwater, right whale researcher Ryan Schosberg tracks their movement, his trained eye recognizing a distinctive callosity – white, rough patches of skin that serve as a whale’s unique fingerprint – on the mother’s head. Her name is Nauset, after a local lighthouse, because of the shape of the marking.
“At first, you don’t realize what you’re looking at,” Mr. Schosberg says, recalling the moment in late March when he spotted the pair swimming close to shore between Herring Cove and Wood End Lighthouse. “Did they move funny? Is that another part of their body? Oh no, it’s two bodies. There’s a little body there.”
For Mr. Schosberg and his colleagues at the Center for Coastal Studies’ (CCS) Right Whale Ecology Program in Provincetown, Mass., every sighting of a North Atlantic right whale mother and calf is a victory because they are among the most endangered large whales in the world. But this sighting in particular – the latest of Nauset and her calf, which are the first pair of the 2025 calving season and the first spotted on these feeding grounds – offers hope that motherhood could help the species rise again.
Since 2017, North Atlantic right whales have been caught in what the U.S. National Marine Fisheries Service of the National Oceanic and Atmospheric Administration (NOAA Fisheries) calls an “Unusual Mortality Event.” More than 20 per cent of the population is sick, injured or has been killed.
As a mother, Nauset is one of the most crucial members of her species. With fewer than 70 reproductively active females remaining in a population of 370 whales, scientists consider these mothers the key to the species’ survival. “Reproductive females are the limiting factor for North Atlantic right whales,” says Kate Silverstein, a spokesperson for NOAA Fisheries. That’s why the federal department’s population viability analysis focuses on this cohort of the population.
Once they sexually mature by the age of 10, right whale females should birth a single calf after a year-long pregnancy, with three years between births considered a healthy interval. But stressors such as entanglements, vessel strikes, declining prey and ocean noise have disrupted this cycle. The average calving interval has stretched to six to 10 years, a devastating slowdown for a species that is dying faster than it can reproduce.
When it comes to entanglements, scientists have found they disproportionately affect females, reducing their calving capacity and preventing them from starting to breed. Females are also twice as likely as males to die from minor entanglements.
Scientists warn that if the loss of six to seven breeding females a year continues, the number of reproductive females will soon drop below the quasi-extinction threshold of 50 individuals – a tipping point from which recovery may be impossible.
North Atlantic right whale mothers and calves
Population numbers
Calves
Mothers
100
90
80
70
50 mothers would mark the
quasi-extinction threshold
for the species
60
50
50 calves per year for
many years would allow
population recovery
40
20 calves per
year would be a
productive year
30
20
10
0
1990
1995
2000
2005
2010
2015
2020
THE GLOBE AND MAIl, source: NOAA FISHERIES
Despite these grim realities, Nauset represents resilience. At 31 years old and rearing her fifth calf, she’s a seasoned mother. Her previous calves were born in 2005, 2011, 2013 and 2021, making her a rare success story in a population where there are more males than females, and dozens of females that should be becoming mothers are failing to do so.
“Nauset and her family are a relatively robust right whale story in the face of ongoing trauma. Her run of five calves in an adult life of about 20 years is remarkable for their world today and shows that they can still reproduce with minor trauma,” says Michael Moore, a veterinary scientist at the Woods Hole Oceanographic Institution in Woods Hole, Mass.
Nauset and her newest calf have already defied extraordinary odds. Their journey together began hundreds of kilometres away, in the calving grounds off the coast of Georgia. On Dec. 1, 2024, the first day of their aerial survey season, the Clearwater Marine Aquarium Research Institute identified them as the first mom-calf pair of the 2025 calving season near Sapelo Island.
“As giddy as we are in the plane the moment a right whale mother-calf pair is seen, it is equally as incredible to learn that they have made it to their feeding grounds,” says Melanie White, a right whale researcher with the institute.
Travelling north, the whales navigate a gauntlet of threats from ship strikes; entanglements in fishing gear; climate change, which is altering their migratory patterns and feeding areas; and ocean noise, which may affect their ability to communicate, find food and navigate. By reaching Cape Cod Bay – another first, as they were the first mom-calf pair spotted on the feeding grounds earlier in March by the CCS aerial survey team – Nauset and her calf have arrived in one of the few refuges where, for a short time, they can enjoy relative safety.
From February to May, these waters are protected by seasonal fishing closures and vessel speed restrictions, reducing the risks from human effects. Nauset can nurse her calf here without the immediate threat of ship strikes, and she can feed at depth without the risk of entanglement in the vertical ropes that connect surface buoys to traps on the ocean floor. And mother and calf can gain the strength they need for the next leg of their migration – as far north as the Gulf of St. Lawrence.
The archives at the Center for Coastal Studies in Massachusetts have decades-old photos of North Atlantic right whales, including Nauset’s mother, #1013, last sighted in 2007.Lauren Owens Lambert/The Globe and Mail; Courtesy of Ryan Schosberg, Center for Coastal Studies (NOAA permit 1014)
Although Nauset’s (#2413, the code which identifies her in the North Atlantic Right Whale Catalog, maintained by the New England Aquarium) story is largely one of success, she and her family have not evaded crisis. Of her four older calves, only two – Monomoy, a 12-year-old female (#4313), and her four-year-old son who hasn’t been named (#5113) – have been seen in recent years.
While her 2005 daughter, Canaveral (#3513), survived for 10 years, she died shortly after reaching breeding age, her lone 2013 calf (which made Nauset a grandmother) also dying, never to be catalogued. Nauset’s 2011 son, who did not survive the migration north during his first six months of life, was also never catalogued.
“Between Nauset and her family, these whales have experienced a combined eight entanglements and four vessel strikes. Fortunately, most of the events resulted in only minor injuries,” the aquarium reports in its 2025 calving update. However, these are considered a minimum number of events because not all events cause scarring.
Even so, Monomoy brings some optimism. The whale – named after a nearby island – has been seen in surface-active groups, gatherings where whales engage in playful and mating behaviours. Last month, the aerial survey team observed her interacting with three adult males in Cape Cod Bay.
“She might have calves of her own soon,” Mr. Schosberg says.
If Monomoy continues her mother’s and grandmother’s lineage (Nauset’s mother, #1013, birthed at least six calves in her observed lifetime), she will join the ranks of breeding females – a crucial step toward stabilizing the population.
Monomoy, a 12-year-old female and Nauset's oldest living offspring, was in Cape Cod Bay in March with three adult males, a promising sign for future calving seasons.Center for Coastal Studies Aerial Survey Team (NOAA Permit 25740-02)
Nauset and Monomoy’s stories are rare bright spots in an otherwise dire picture. The number of right whale births each year remains too low to recover the population.
NOAA Fisheries estimates that 20 calves a year would mark a “productive” season. Yet, since the Unusual Mortality Event started, the annual average is 11 calves a year, compared with the long-term average of 15 calves a year from 1990 to 2024. In the 35-year record, only 11 years have produced 20 or more calves.
And to truly reverse the species’ decline, scientists believe that 50 calves a year are needed – a number that has never been reached in the species population record. The closest the species came was in 2009, with 39 calves born.
“Last year, we had a total of 20 mother-calf pairs. Right now, we’re standing at 10, so that’s not a great number,” Ms. White says of the 2024 and 2025 calving seasons.
“Is it better than zero? Absolutely. Is that 10 going to let this population rebound to where it needs to go? No, but it’s a start, and every single whale counts,” she adds.
To save North Atlantic right whales, NOAA Fisheries reports in its 2025 calving update, “the only solution is to significantly reduce human-caused mortality and injuries, as well as stressors on reproduction.”
Efforts to do that are already under way on both sides of the Canada-U.S. border, including ship-speed limits, fishing area closures and the use of on-demand fishing gear that reduces entanglement risks.
Yet, as Dr. Moore notes, “We can do better. These whales should not have to live a life of trauma. They should be able to swim free and prosper.”
The Long Point lighthouse sits at the end of the peninsula in Provincetown. Nauset the whale is named for another lighthouse farther south in Eastham.Lauren Owens Lambert/The Globe and Mail
“It’s heartbreaking. It’s devastating,” says Brad Lopes, a member of the Wampanoag peoples’ Aquinnah Wôpanâak Tribe, which has lived alongside these whales for centuries, and an educator with the Mashpee Wampanoag Education Department on Cape Cod.
“Because they’re our cousins, I see the reflection of our own people. Ours is a matriarchal society and culture. Oftentimes, I see these mothers as I see our own mothers and grandmothers. I see their fight. The reason why we’re still here as Wampanoag people is our women.”
For now, in the quiet sanctuary of Cape Cod Bay, Nauset and her calf – whose sex remains a mystery until the right photo opportunity arises – continue their ancient rhythm, breaking stride only when the mother dives to feed at depth, her calf lingering at the surface.
But soon, they must move on.
By May, warmer waters will draw them further north, leaving the relative safety of the Cape Cod Bay feeding grounds to venture into a more dangerous world – one where their survival will depend not just on their instincts, but on the choices humans make.
“Nauset and her children give me lots of hope. I see reflected in their continuance this fight, this spirit, about not disappearing from their home waters and to hang on. I find inspiration in that,” Mr. Lopes says.
This story is part of a series produced in partnership with the Pulitzer Center’s Ocean Reporting Network.
Editor’s note: An earlier version of this story incorrectly stated that 39 calves were born in 2003. It has been corrected to say they were born in 2009.
The sex of Nauset's latest calf – known by a temporary ID, 2025Calfof2413 – remains a mystery until researchers have visible evidence.Lauren Owens Lambert/The Globe and Mail (NOAA permit 25740-02)