A New England ocean science centre says whale watchers off Iceland caught an extremely rare glimpse of an endangered right whale near their country.

The North Atlantic right whale was spotted northwest of Reykjavik (RAY'-kyuh-vik) on Monday.

The Anderson Cabot Center for Ocean Life at the New England Aquarium in Boston says there have been only three North Atlantic right whales identified off Iceland in the last 30 years.

The centre says the whale is called Mogul by researchers and was seen feeding off Marshfield, Massachusetts, in April. Mogul is a 10-year-old male born to Slalom in 2008.

According to a post on the website of the tour company, Elding Adventures at Sea, there have only been three different whales identified off Iceland in the last 30 years. "This sighting truly is a milestone in Iceland's whale watching history," the company said. It was the first time the company had spotted a right whale.

The right whales migrate up the U.S. East Coast every year to feed. But the centre says they have had to change where they feed in recent years because of changes in the ocean. Right whales normally summer in the Bay of Fundy and on Browns Bank off the coast of Nova Scotia. In the last few years, they have become more prevalent in the Gulf of St. Lawrence.

"The northern right whales are the most endangered whales in the world," Elding Adventures said on their website. "It was extremely hunted during the age of whaling when whales were initially hunted for whale oil. The right whale was then a suitable prey of hunters, because of their docile nature, their slow surface-skimming feeding behaviors, their tendencies to stay close to the coast, and their high blubber content (which makes them float when they are killed, and which produced high yields of whale oil). From that fact, it gets the name ‘right’ whale - as it was the ‘correct’ whale to hunt."

There are only about 450 of the whales because they were almost hunted to extinction.