A warning is in place for all visitors to Gwynedd beaches to be extremely vigilant whilst visit the coastline due to the numbers of Portuguese Men-o-War that have been washed up on our shores recently.

The species which is found mainly in the Pacific Ocean, are blue and purple in colour, and have many hanging tentacles that are typically over ten meters long.

Despite its appearance, the Portuguese man o’ war differs from single organisms like jellyfish as they are siphonophores, a colonial organism made up of many specialized, though genetically distinct, parts called zooids.

Portuguese man o’ war have no means of propulsion, and move passively, driven by the winds, currents, and tides. Strong winds may drive them into bays or onto beaches. Often, finding a single Portuguese man o’ war is followed by finding many others in the area.

Stings

Because they can still sting while beached, even if they are dead, the discovery of a man o’ war should be treated with caution.

Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin that normally last two or three days after the initial sting, though the pain should subside after about 1 to 3 hours (depending on the biology of the person stung). However, the venom can travel to the lymph nodes and may cause symptoms that mimic an allergic reaction, including swelling of the larynx and airway blockage.

Other symptoms can include fever and shock, and in some extreme cases, even death, although this is extremely rare. Medical attention for those exposed to large numbers of tentacles may become necessary to relieve pain or open airways if the pain becomes excruciating or lasts for more than three hours, or if breathing becomes difficult.

Barry Davies, Gwynedd Council Maritime Officer said: “If you come across a Portuguese Man-o-War, please do not touch it. The tentacles are toxic and will cause a painful sting.

“If anyone gets stung, please seek medical help immediately and report the incident to the Council’s Maritime Service.”

More of the creatures could be washed up following the recent strong winds, and we urge the public to take care whilst visiting our beaches.

Please report any sightings to Gwynedd Council’s Maritime Service on 01758 704 066.