A deadly swarm of jellyfish which once wiped out £1m worth of salmon from a Northern Ireland fish farm is threatening to wreak havoc on our shores again this summer.
Scientists are warning that billions of lethal mauve stinger jellyfish are swimming into waters in the north-east Atlantic as sea temperatures rise and currents change, according to a study in the journal Biology Letters.
People bathing in British waters are in no grave danger at present, according to Richard Kirby, a research fellow at the University of Plymouth and one of the authors of the study.
But experts in Northern Ireland have warned we could well see another invasion of mauve stingers this year, especially if the bad weather that dogged our last three summers makes a return.
The mauve stingers — or Pelagia noctiluca — are tiny but can cover hundreds of thousands of square miles in a single ‘bloom’.
They are normally found in the Mediterranean and Caribbean but three years ago more than £1million worth of salmon were wiped out at a Co Antrim fish farm after a massive swarm descended, suffocating the fish.
Last year, there were also |shocking images of the idyllic north coast beach at Whitepark Bay strewn with jellyfish.
Ulster Wildlife Trust nature conservation manager Ciaran Mullan said: “Going by the pattern of activity over the last few years, it’s quite possible that we will see more and more of these blooms.
“We hadn’t experienced this in previous years in the water round the UK but with predictions for sea temperatures to rise in line with global warning, we expect the repetition of past incidents to occur in future years as well.
However, marine biology lecturer Dr Jonathan Houghton of Queen’s University Belfast believes large blooms of mauve stingers have always been around — they just hadn’t been recorded.
“The ones that hit Northern Ireland are not coming up from the Mediterranean. They hang out by the Rockall Trough north of Ireland and west of Scotland, so these are not necessarily Mediterranean ones spreading up to us,” he said.
“I’ve looked back through the records and mauve stingers have been washed up on the coast of Ireland at least 30 times in the last 100 years.”
Glenarm Organic Salmon director John Russell said the farm is now putting its third generation of young fish into the water since the devastating 2007 attack.
“The jellyfish have been there the last two years but they haven’t really come down as far as the farms in big numbers,” he said.
“We’ve seen them in ones or twos. Northern Ireland Environment Agency and Department of Agriculture and Rural Development are keeping an eye out for us up north but we haven’t seen too much and we don’t want to.”