Transatlantic Match Confirms Rare Movement for Endangered Species
Scientists have confirmed that a critically endangered North Atlantic right whale photographed in Donegal Bay, Ireland, in July 2024 is the same individual resighted off the coast of Massachusetts near Boston on Nov. 19, 2024. The Center for Coastal Studies (CCS) announced the match on Dec. 3, 2024, after aerial observers documented the whale during a routine survey.
This sighting represents the first verified case of a right whale first recorded in the eastern North Atlantic and later resighted in the western North Atlantic — a transatlantic journey of roughly 3,000 miles.
How the Match Was Made
CCS observers Ryan Schosberg and Annie Bartlett were conducting an aerial survey east of Boston when they deviated briefly to photograph a group of humpback whales. While circling the area, they photographed a lone right whale feeding at the surface — the Center's first right whale sighting of the 2025–2026 monitoring season.
"The first sighting of the year is always exciting, but we didn't yet realize just how remarkable this one would turn out to be," said Schosberg in the CCS press release.
Because North Atlantic right whales are critically endangered — with fewer than 400 individuals remaining (current estimates are about 370) — CCS compares each sighting to entries in the North Atlantic Right Whale Catalog. The photographed animal did not match any cataloged individuals, so CCS contacted the New England Aquarium in Boston, which curates the photo-identification database.
Researchers at the New England Aquarium compared the new images with archived photographs and identified matching natural markings and callosity patterns from photographs taken in July 2024 in Donegal Bay by the Irish Whale & Dolphin Group. The earlier Irish photos had been considered too limited to confirm identity on their own; the November images provided the additional detail needed for a positive match.
Conservation Significance
The transatlantic resighting provides direct evidence that some right whales may undertake much wider movements than previously documented while searching for food and suitable habitat. Six right whales previously photographed in North America have later been seen in European waters, but this is the first confirmed instance of an animal moving from east to west across the Atlantic and being resighted.
"Seeing a whale photographed in Ireland reappear off Boston is extraordinary," said Dr. Daniel Palacios, director of the Right Whale Ecology Program at CCS. "Encounters like this highlight both their resilience and the importance of international cooperation to support their recovery."
Aerial monitoring in Massachusetts runs from December through mid-May, with additional fall flights added in recent years to track early arrivals. The program operates with support from the Massachusetts Division of Marine Fisheries, NOAA, and other partners. Photo and survey work are conducted under NOAA permit 25740-03. Photo credit: Center for Coastal Studies (NOAA permit 25740-03).
Researchers say this confirmed transatlantic movement underscores the need for coordinated international research, data-sharing and management measures — such as vessel speed restrictions, fishing gear modifications, and protected areas — to reduce human-caused threats and support recovery for a species with a precariously small population.
