A humpback whale has been spotted in waters off Howth, north Co Dublin.

The Irish Whale and Dolphin Group (IWDG) said it was the first sighting of a humpback in the eastern Irish Sea in almost 20 years.

The mammal, which tends to have a preference for shallow coastal waters according to Pádraig Whooley, sightings co-ordinator with the group, is believed to be sub-adult “or a teenager in human terms”.

The mammal was photographed within metres of the Cardinal marker off Howth Head, between Ireland’s Eye and Howth harbour yesterday afternoon.

The photographer, Sean Pierce of Shearwater Sea kayaking, said: “It stayed around Cardinal Mark off Howth for over two hours. [It] just seemed to be lolling about pushing head into trailing weed and perhaps scratching itself.”

Neil Cramer spotted the humpback off Skerries on Wednesday evening.

"The whale was just astern of our committee boat which was anchored while doing race management for our usual Wednesday night racing in the bay, he said, adding: “The whale remained in close proximity to the boat for about 20 to 30 minutes and came to within touching distance of the boat, and in fact could be felt rubbing off the underside on a few occasions.”

Boats should maintain a 100 metre distance from the whale, keep speeds to less than seven knots and maintain a parallel course with the mammal if travelling with it, the IWDG said.