Storm Ophelia may have swept Portuguese men o’ war our way

NUI Galway zoologist appeals for reports of sightings of dangerous marine animals

Coast walkers and swimmers have been advised to take extra care following Storm Ophelia. Photograph: iStock

Storm Ophelia’s course from the Azores may have swept lethal Portuguese men o’ war onto the Irish coastline.

NUI Galway (NUIG) zoologist Dr Tom Doyle has appealed to shore walkers, surfers, swimmers and fish farmers to exercise caution. He also appealed for recorded sightings of the marine animals.

The British coast guard has already issued public safety warnings after multiple reports of Portuguese men o’ war over the last several days on beaches in Dorset and Devon.

The poisonous purple/pink animals (Physalia physalis) with a balloon form are not jellyfish but siphonophores, or colonies of zooids.


Although the animals die after stranding, they should not be touched as the sting can remain active for days.

“Each tentacle can carry hundreds of thousands nematocysts or stinging capsules, which are just 10 to 20 micons in size and contain a tiny little protective harpoon with venom,” Dr Doyle has explained.

“The southerly winds we had during Ophelia will have swept many up from the Bay of Biscay area,but as yet we have not received many specific reports,” he said.

Large numbers of Portuguese men o'war were swept onto the Cork and Kerry coasts, and further north, last year. About 700 in total were reported in the autumn from Cork to Donegal, which was "unprecedented" in existing records, he says.

Large numbers were also stranded here in the mid 1940s and in 1968,when 400 were counted in one day alone by the Cape Clear island bird observatory off west Cork.

Dr Doyle said there had been recent sightings of the animals in September, and more over the past week – with up to 200 individuals counted so far.

Research he participated in with the University of Hawaii, which was published earlier this year, states that man o’ war stings are no different than other jellyfish stings, and the best first aid is to rinse with vinegar to remove tentacles and then immerse in hot water at 45 degrees, or apply a hot pack for 45 minutes.

Coastwatch co-ordinator Karin Dubsky says that Storm Ophelia took its toll on marine life, with large numbers of octopuses (octopodes) and other deeper water species washed up on the Irish coastline.

Ms Dubsky, who is based in Co Wexford and lost power at her own home during the storm, said shellfish were also washed up in large numbers on the south coast – which took the full impact of the varying southerly cyclonic winds.

The Coastwatch annual survey began in September and involves large numbers of volunteers. Ms Dubsky and local volunteers in Co Wexford, including children, collected some 51 plastic bottles and 270 lids, along with other intertidal debris, along a 100m stretch of Ballymoney beach after the storm abated. Such was the ferocity of the winds that they found a lifeguard hut upended on the strand.

Ms Dubsky has appealed for public participation in the continuing Coastwatch survey, given the large amount of marine debris swept ashore. The survey is on

Dr Doyle has appealed for information on Portuguese men o'war and other related sightings to be logged by members of the public on the National Biodiversity Data Centre website.

Lorna Siggins

Lorna Siggins

Lorna Siggins is the former western and marine correspondent of The Irish Times