An invasion of deadly jellyfish could stretch for hundreds of miles around the Irish coast, an expert said tonight.
Mauve stingers were discovered near Portrush, Co Antrim and as far south as Co Sligo.
Dr John Houghton from Queen’s University said the species was the same as that which devastated salmon farms off the Co Antrim coast last year.
“I have heard reports from people in the south that they stretch from Sligo to Antrim.”
He said it was unclear if they were in isolated bunches or a continuous plume.
The Department of the Environment (DoE) confirmed discoveries in Antrim and Sligo.
Mauve stingers are normally a warm water species. Last November’s catastrophic attack on caged salmon near Glenarm, Co Antrim, caused severe damage to the local industry.
It wiped out £1m-worth of fish at Northern Salmon’s marine farm in Glenarm, with the purple jellyfish covering an area of up to 10 square miles and a depth of 35ft.
The latest outbreak was found by a Northern Ireland Environment Agency (NIEA) worker on the West Strand, Portrush, Co Antrim, as he walked with his family yesterday.
Subsequent tests confirmed their presence on the East Strand and White Rocks as well.
Dr Houghton said: “They occur hundreds of miles out to sea so it is very rare to find them inshore.
“It is to do with the water. If a prevailing wind comes down, they can be carried in.”
Samples of the small purple jellyfish were collected and stored overnight in an aquarium at the NIEA coastal zone before being sent to a laboratory at Queen’s.
NIEA marine communications officer Gary Burrows said of the find: “They were widely dispersed. There were dead ones that had come ashore in previous tides but many of them were alive and washing in.”
Members of the public have been advised not to go near the jellyfish, which are capable of a “nasty, powerful” sting.
NIEA marine conservation officer Joe Breen cautioned: “There is no suggestion at this stage that the catastrophic bloom which happened last year off the Co Antrim coast will repeat itself this year.”
There have been no discoveries further east at Ballycastle.