Scientists discover hidden 15,000-pound right whale calf, brings endangered species total to 24

Scientists spotted a surprise North Atlantic right whale calf in Canadian waters. They say the discovery is a cause for celebration.

The discovery comes as the critically endangered species continues to face threats from fishing-gear entanglements and vessel strikes. The aquarium estimates that around 380 North Atlantic right whales remain.

On September 25, researchers with the Mingan Island Cetacean Study photographed a mother and calf near Anticosti Island, Quebec, according to the New England Aquarium’s press release.

The photographs were sent to scientists at the aquarium’s Anderson Cabot Center for Ocean Life, which manages the North Atlantic Right Whale Catalog, a database used to identify and track individual whales.

After weeks of comparing photographs and examining sighting records, researchers determined that the calf was new. The calf’s mother was identified as Silt, Catalog #1817, a whale at least 38 years old that has now given birth to six known calves.

Silt had not been seen since February. She avoided detection during boat-based and aerial surveys along the U.S. East Coast throughout the spring and summer.

“This is an exciting discovery for us so late in the year,” said Amy Warren, a scientist at the aquarium’s Anderson Cabot Center, in the news release.

The new calf, estimated at about 15,000 pounds (6,804 kilograms), was identified more than five months after the annual calving season ended, which runs from mid-November through mid-April in the southeastern United States.

Researchers initially documented 23 mother-calf pairs. This surprising discovery off Quebec has increased that total to 24.

A family marked by survival and loss

Silt has had six known calves, three grandchildren, and one great-grandchild, born in 2026.

The aquarium reported that Silt has survived at least five fishing-gear entanglements, some of which left substantial scarring on her head and tail. Two of her offspring died following these encounters.

Division, born in 2022, died this year following a severe entanglement. Her oldest known calf passed away in 2005 after being struck by a vessel. That family history shows the dangers this species faces in the North Atlantic. Researchers hope Silt’s newest calf will not face the same threats.

On a hopeful note

Phys.org described 2025-2026 as the most productive calving season since 2009. The recently discovered calf was welcomed as hopeful news as the species population remains small.

Only about 70 reproductive-age females remain. The species lost about 25 percent of its population between 2010 and 2020. No calves were born in 2018. The population has recovered somewhat since 2020, but right whales still face threats.

The New England Aquarium maintains the North Atlantic Right Whale Catalog in collaboration with researchers and organizations along the eastern seaboard of North America and eastern Canada.

According to the news release, the catalog documents births, injuries, migration patterns, and ages. Scientists reconstruct individual whales’ histories. However, Silt’s newest calf demonstrates that even extensive surveys can miss individual animals.

“It just goes to show you how big the ocean is, and how those animals can get lost out there,” Sears said in Phys. The latest sighting adds another calf to one of the strongest breeding seasons recorded for North Atlantic right whales. It is a promising development for the species.

Source: https://interestingengineering.com/science/scientists-discover-24th-right-whale-calf