A late-found right whale calf lifts the season’s tally to 24

North Atlantic right whales lost roughly a quarter of their population between 2010 and 2020, then began a slight rebound. Now a calf that researchers had not counted has improved the record of their strongest breeding season in 17 years—a welcome addition for a species whose recovery still depends on keeping mothers and young alive.⁠¹

The previously undocumented calf, photographed beside its mother, Silt, off Quebec’s Anticosti Island in September, raises the 2025–26 calving-season tally from 23 to 24. That makes the season the most productive since 2009 and the fourth highest on record. This is a late identification, not evidence of an autumn birth: New England Aquarium scientists believe the calf was likely born during the winter calving season, months before it entered their records.⁠¹⁠²

The aquarium announced the identification on November 2, 2026, after analyzing photographs and sighting data from Canada. One photograph, taken on September 25 by Mathilde Laverdière of the Mingan Island Cetacean Study, places Silt and her calf in the Jacques-Cartier Passage, in the Gulf of St. Lawrence. The dated image establishes that encounter; it does not necessarily mark the first time anyone saw the pair.⁠²⁠⁵

Silt is 38 years old and known in the photographic catalog as number 1817. This is her sixth known calf. For researchers following a population with so few breeding females, identifying the mother connects a surprise sighting to a long reproductive history rather than leaving it as an anonymous glimpse of a young whale.⁠¹⁠²

Right whales usually give birth in winter off the southeastern United States, then travel north to feed in New England and Canadian waters. Silt briefly appeared in those southern calving grounds in February 2026, but observers did not document her there with this calf. The pair also escaped documentation during boat and aerial surveys along the U.S. East Coast through spring and summer.⁠¹

That leaves an important distinction between what the photographs show and what scientists infer. The calf was alive alongside Silt in September. Its exact birth date and birthplace remain uncertain. The aquarium’s conclusion that it likely belongs to the winter season is an assessment, not a witnessed birth or a precisely established age.⁠¹⁠²⁠⁵

“Silt was briefly seen in the southeastern U.S. calving grounds in February 2026, so it’s possible she had the calf there but snuck away before they were documented together,” said Amy Warren, a scientist at the aquarium’s Anderson Cabot Center. Her explanation offers a plausible route through the gap in the record, not confirmation that the birth happened there.⁠¹

Extensive photographic cataloging makes an unrecorded right whale birth unusual. Yet a catalog, however carefully maintained, can contain only the encounters observers manage to document. The Canadian photographs changed the interpretation of a season that had already ended—not because a new birth had necessarily occurred, but because researchers finally had evidence of one they had missed.⁠¹⁠²

Sears, founder and director of the Mingan Island Cetacean Study, was describing the limits of observation. Nothing in the documented encounter establishes that the calf had been separated from Silt or was in distress. The missing piece was in the human record.

Even before this identification, the aquarium had recorded 23 mother-calf pairs, already the highest seasonal total since 2009. Annual documented births have exceeded 20 only a few times since 2010; in 2018, no births were recorded at all. Against that history, a 24th calf is a meaningful improvement in an unusually productive season.⁠¹⁹⁠¹

But a birth tally is not a survival tally, and neither is it the population’s net change. Adding this calf does not mean the species has gained 24 surviving animals. That requires knowing what happened to the season’s young, as well as accounting for deaths across the wider population. The September photograph supplies evidence of this calf’s survival to that encounter, not a guarantee of what comes afterward.

NOAA’s 2026 calving-season information puts the species at approximately 380 whales, including about 70 reproductively active females. Those are estimates, not exact head counts. The small breeding population helps explain why scientists track individual mothers so closely: the species has little margin for losing animals capable of producing its next generation.⁠¹⁵

The slight population rebound since 2020 also needs to be kept in view. The earlier decline has not continued uninterrupted, but improvement does not remove the dangers. Ship collisions and entanglement in fishing gear remain severe threats, while warming ocean conditions have shifted whale movements beyond protected waters. Silt herself has survived multiple fishing-gear entanglements. Her sixth known calf is evidence of reproductive success by a mother who has also faced the hazards that can undo it.⁠¹⁠³

The discovery deserves its good-news status without being asked to prove more than it can. Researchers now know of one more calf in an exceptional breeding season. Whether that season becomes a lasting step toward recovery depends on how many of those young whales live—and whether births can outpace deaths.