An “unprecedented” number of Portuguese men o’ war have washed up on the Cornish coastline in recent days, causing lifeguards to close a beach on Monday and issue safety advice.

More than 140 of the floating tentacled organisms, which can deliver a painful sting that can be fatal in rare circumstances, have been spotted off the Cornish coast in the last three days, according to the Cornwall Wildlife Trust. They are reported to have been blown in by strong south-westerly winds.

Lifeguards discovered several on Perranporth beach on Monday morning, and decided to close the bathing area from around 10am to 1.30pm as a precaution.

The Marine Conservation Society said there had been other sightings elsewhere in Cornwall, the Isles of Scilly, Wales and Ireland.

While they are often bracketed with jellyfish, Portuguese men o’ war are in fact floating colonies of tiny organisms known as hydrozoa that behave collectively. Their tentacles can reach 50m in length.

MCS’s head of ocean recovery, Dr Peter Richardson, said: “Portuguese men o’ war are ocean-going animals, propelled by the wind on their inflatable sail as they fish the depths with their stinging tentacles. Recent persistent winds have blown them from the Atlantic on to our shores.

“Because a stranded Portuguese man o’ war looks a bit like a deflating purple balloon with blue ribbons attached, children will find it fascinating. So, if you’re visiting west coast beaches in the next few weeks it’s well worth making sure you know what these animals look like and that no one picks them up.”

Cornwall Wildlife Trust described the number of sightings as unprecedented, adding that the previous maximum number of sightings was 40 in 2000. Only three were spotted off the Cornish coast last year.

The Cornwall Wildlife Trust’s marine awareness officer, Matt Slater, said: “This is an unprecedented event and we urge the public to be cautious and to keep an eye out for unusual species being stranded. We may see other rare warm water species washing up. Please report sightings to the trust’s marine strandings network.

“Although the UK media always focuses on the dangers posed by their stinging cells to us humans, stings are incredibly rare and the man o’ war is actually a beautiful life form, wonderfully adapted to life in the open ocean and are only seen in extremely rare cases on our shores.”

The Royal National Lifeboat Institution said it was monitoring beaches in the south-west closely.

It said in a statement: “If sighted, do not touch. If you are stung, please seek assistance from the RNLI lifeguards on duty. Treatment involves removing the tentacles by hand or by spraying with seawater, and immersion in or application of hot water to relieve the symptoms.



“In the majority of cases further medical treatment will not be necessary, but those with any complications or serious stings should be advised to seek further medical assistance.”