Tourists were warned to be wary in the water after swarms of dangerous Portuguese man o’ wars hit Mediterranean resorts.
Holiday hot-spots including Mallorca, Menorca and Ibiza have suffered infestations of the jellyfish-like creatures – whose sting can prove fatal.
Portugal has also issued a summer-long warning for the whole of its coastline.
Man o’ wars can grow tentacles of up to 30 metres which act like lashes and can cause an allergic shock on contact. The venom in their barbed tubes is used to paralyse and kill fish.
In humans, it can lead to fever, shock, heart failure or respiratory arrest – closing the airway and choking the victim to death. The sting lasts for up to an hour.
Scientists say they are moving into new areas because of global warming and that the explosion in numbers is down to plastic in the ocean killing turtles that normally feed on them.
The first death in Europe from their sting was near Sardinia in 2010.
A Spanish government spokeswoman said: “Due to climate change, we will have to get used to them.”
