Beluga whale seen off County Antrim coast near Dunseverick
Marine researchers have said a beluga whale has been sighted off the County Antrim coast near Dunseverick.
It is believed to be the first time the Arctic species has been recorded in Northern Irish waters.
Dr Peter Evans, director of the Seawatch Foundation, said a fall in sea temperatures could be why the whale strayed so far from its usual habitat.
"A beluga whale is extremely unusual," he said.
"It's the first record that we know for Northern Ireland and in fact there's only been about a dozen in 50 years for the whole of Britain and Ireland.
"On the whole, over the last sort of 10 years, certainly the sea temperatures have been generally warming, but at the same time there have been a number of anomalies where you've got actually significantly cooler waters and that seems to be the case here."
There are just two records of beluga whales off the coast of the Republic of Ireland - one off Clare Island, County Mayo, in 1948 and another at Cobh, County Cork, in 1988.
"This is not the first arctic species to occur in Britain this year. Back in February, the first European sighting of a bowhead whale was captured on a smart phone in the Isles of Scilly," Dr Evans said.
"In that instance it was thought that the fragmentation of floating ice may have resulted in whales typically associated with pack ice, straying much further south.
"Whether the same has occurred in the case of this beluga is not clear but sea temperatures have been unusually low this summer."