A rare whale has been recorded off the County Donegal coast, according to the Irish Whale and Dolphin Group (IWDG).

It was spotted swimming near Sliabh Liag on Monday.

North Atlantic right whales are among the planet's most critically endangered large ocean mammals.

It is believed fewer than 350 remained as of 2023 and they could be extinct within 20 years.

This is an exceptionally rare record for the eastern Atlantic, where this species has been largely absent for decades, if not longer,” the group said.

“We can make a convincing argument that the last positive identification of this species in Ireland dates back to 1910.”

In situations where rare species are recorded, the IWDG said it consults “far and wide to make sure the information is accurate”.

The sighting was verified by the New England Aquarium - which curates the North Atlantic Right Whale Photo ID catalogue - in the United States.

“This is an exceptionally rare record for the Eastern Atlantic, where this species has been largely absent for decades, if not longer,” the IWDG said.

The group can make a “convincing argument” that the last positive identification of this species in Ireland dates back to 1910.