Portuguese men-of-war, which look like jellyfish and whose sting can cause severe pain and, in rare cases, death in humans, has been seen on beaches in Waterford and Cork, and may yet reach Kerry coasts.
The Irish Water Safety organisation yesterday warned swimmers, surfers and other beach users that Portuguese men-of- war have been seen in Tramore, Ardmore, Inchydoney and Schull, and that there is a risk they may drift farther north.
The invertebrate and carnivore creature is a siphonophore, which means it is made up of a colony of organisms working together.
Its float is about 30cm long and 13cm wide and it has tentacles that can reach 50m in length.
The stinging venom-filled nematocysts in the tentacles cause severe pain to humans, leaving whip-like red welts on the skin.
A sting may lead to an allergic reaction. There can also be serious effects, including fever, shock, and interference with heart and lung function. Stings may also cause death, although this is extremely rare.