Experts baffled by explosion of lion’s mane jellyfish on the west coast

MORE lion’s mane jellyfish than cuckoos have been recorded on the west coast of Ireland this year, in what may represent a seismic shift in the natural environment of Ireland.

Massive and sometimes dangerous lion’s mane jellyfish are normally confined to the east coast, commonly in waters north of Dublin, and confirmed sightings on the western seaboard are usually non-existent.

Figures obtained from the National Biodiversity Data Centre show that there have been 157 recorded sightings of lion’s mane jellyfish this year in Donegal, Sligo, Mayo, Galway, Clare and Kerry, compared with just 122 recorded sightings of cuckoos.

There were 61 sightings in Galway alone, where the lion’s mane was the most commonly recorded wild animal by the National Biodiversity Data Centre.

According to Damien Haberlin, of the Centre for Marine and Renewable Energy at University College Cork, marine scientists are at a loss to explain why this is happening.

“It is highly unusual in our experience. A lot of lion’s mane on the west coast is a very unusual thing. In fact, up to about two years ago, we would have told people that you don’t get lion’s mane on the west coast.

“But this year that sort of thinking has been proven totally wrong,” he said.

“We have been getting reports of lion’s mane from all over the country. Up to now, the thinking was that lion’s mane were pretty much restricted to the Irish Sea and you’d hardly get any of them below Dublin.

“This year has blown that out of the water. We just don’t know what’s going to happen. Maybe next year it will go back to a more normal distribution.”

Meanwhile, a new report by Inland Fisheries Ireland has revealed the changing diets of pike. Research carried out on Lough Conn, Co Mayo, and Lough Derravaragh, Co Westmeath, in 2016 showed pike appear to have changed their prey preference, from brown trout and perch, and now predominately eat roach. Inland Fisheries Ireland chief executive Dr Ciaran Byrne said the study was important as it gives an idea of the interaction between pike and brown trout in Irish waters.

A lion’s mane jellyfish at the Forty Foot in Sandycove, Dublin, where they are traditionally sighted, but giant ones were seen across the west coast, like this one below, spotted by Pauric Collins on Traught Beach, Co Galway. Photo: Justin Farrelly