Ireland’s whale-watching season has now extended from a one- to a “three-season” activity, Irish Whale and Dolphin Group sightings co-ordinator Pádraig Whooley has said.

Mr Whooley had “lost count” of the number of minke whales spotted off west Cork this week and had observed five to seven humpback whales on almost every trip in the past fortnight.

A pod of humpbacks that normally frequents west Kerry has been focusing on west Cork this month , while Boomerang, the humpack that has returned regularly to Irish waters since 2001, has been spotted this season off Helvick Head in Waterford.

Mr Whooley said a change in ocean activity in recent years had seen whales arriving here as early as April, as opposed to the autumn months.

“Mostly they are seen from five to six miles out, depending on the feeding grounds, but there is obviously some very good feeding here this week,” he said.

The number of minke whales in waters between Union Hall in west Cork and Galley Head was “exceptional”, he said.

Humpbacks grow to a maximum 15.24m (50ft) and are known for their spectacular breach and “lobtailing” with their flukes or tails. Their distinctive tails have allowed for photographic identification of up to 80 of them by the Irish Whale and Dolphin Group.

Humpbacks are known for “singing” in their warm-water breeding grounds and are believed to have different songs and dialects in different regions.

They migrate between summer feeding and winter breeding grounds. They were hunted in Irish waters more than a century ago for Norwegian-owned whaling stations in Co Mayo, with six recorded kills between 1908 and 1922.

Mr Whooley said the population was clearly recovering from human exploitation, at a rate of up to 7 per cent a year.