A small group of North Atlantic right whales, including a mother and calf, were photographed on Sunday swimming about 20 miles south of Martha’s Vineyard by New England Aquarium scientists conducting an aerial survey, according to an aquarium spokesperson.

“As the pair surfaced, the calf remained in very close contact with mom as it circled around her. It was an incredible experience to document a mother and calf pair given how crucial they both are to the recovery of this critically endangered species,” said Katherine McKenna, a research assistant at the aquarium’s Anderson Cabot Center for Ocean Life, in a statement.

The aquarium has identified the mother whale as Catalog #2420, who was first sighted with her newest calf on Jan. 11 off Ponte Vedra Beach, Fla. This is #2420’s fifth calf. She has been spotted several times over the years in the calving grounds off the southeastern United States, but this is only her second sighting with a calf in northern waters.

“With only four sightings north of the calving ground in 27 years, we know little about where this female right whale feeds. This recent sighting adds an exciting piece to that puzzle,” aquarium senior scientist Philip Hamilton said in a statement.

The 37-plus-year-old whale is a rarity for the critically endangered species, according to the aquarium, because she has no scars from entanglements — one of 14 per cent of the species’ population, which numbers only 356 individuals, without such scars. This suggests she may feed in areas with less fishing activity.

The National Oceanic and Atmospheric Administration (NOAA) has extended its volunteer speed restriction for boaters south of Nantucket and the Vineyard through March 22 after the Aquarium survey team’s most recent right whale sightings. NOAA is encouraging mariners to avoid the area or reduce speeds to 10 knots or less while traveling through it.