A North Atlantic right whale swims along the surface Sunday near boaters off Long Sands Beach in York, with Nubble Light in the distance. Right whales are one of the Earth’s most endangered marine mammals.

Scientists from the New England Aquarium have concluded that the endangered North Atlantic right whales spotted swimming and feeding off the coast of York County last weekend were not the same animal.

Tony LaCasse, spokesman for the New England Aquarium, which catalogs all right whales, said in a telephone interview Tuesday evening that the scientists used photographs to confirm that the right whale photographed off Long Sands Beach in York was right whale No. 1409.

A North Atlantic right whale spotted off the coast of Wells was a different whale, according to LaCasse.

The York whale is a male born in 1984. Its mother was known as No. 1160. Her death was confirmed in 2005 after her carcass was found floating offshore.

Whale No. 1409 “is definitely an adult male whose length is estimated at 45 feet and weighs around 90,000 pounds,” LaCasse said, dispelling reports from untrained observers that the whale was a juvenile. “The photograph was outstanding.”

Some right whales are assigned names. LaCasse said there is a right whale named Van Halen because the pattern on its forehead looks like an electric guitar.

The scientists, who work for a division of the aquarium called the Anderson Cabot Center for Ocean Life, used photographs of both right whales to determine that they were not the same animal. LaCasse said the whale spotted of the coast of Wells had a distinctly different skin pattern on its head, but the resolution was not as clear and scientists were unable to identify the Wells whale.

Wells police issued an alert last weekend, warning boaters to stay clear of the right whale and not to interfere with its movements. It appeared to be taking a meal break on its slow migration north to Canadian waters.

A boater in York photographed right whale No. 1409 when it surfaced and swam near his boat about a mile off Long Sands Beach.

LaCasse said there are only about 430 individual right whales in the North Atlantic and seeing even one in Maine waters is a rare event.

North Atlantic right whales are so critically endangered that each individual whale has been identified and tracked by researchers at the aquarium.

They do that using the white, raised skin pattern on the tops of their heads. The pattern is as unique as a fingerprint, and researchers are able to build an individual biography of each whale based on where it is spotted, LaCasse said.

LaCasse said right whale No. 1409 has been seen in all the significant feeding habitats, including Cape Cod Bay, Jeffrey’s Ledge off the coast of New Hampshire and York County, and the Bay of Fundy. He has also been spotted in Florida.

LaCasse said it’s uncommon, but not unheard of, to see right whales along the southern coast of Maine as they work their way north from spring feeding grounds in Cape Cod Bay.

North Atlantic right whales, so named because they were the “right” whale to hunt, are among Earth’s most endangered species. They were almost hunted to extinction by whalers, who prized their size and oil-rich blubber.

Scientists now fear the population is headed toward extinction. Among the 430 or so remaining, there are just over 100 breeding females. And, for the first time on record, no right whale calves were born this past winter, LaCasse said. In past years, between 15 and 23 new calves have been reported.

The New England Aquarium is asking anyone with photos of right whales to send them to rwdata@neaq.org or fill out the form at https://form.jotform.com/62625096321150.

People who spot whales can also report them immediately by marine VHF via Ch. 16 to the Coast Guard; to the National Marine Fisheries Service hotline at 866-755-6622; or via the Whale Alert app.