British holidaymakers in the Canary Islands are being warned to keep well away from the Portuguese man o' war after several recent sightings at beaches across the islands.
A sting from the creature can cause severe pain and, in rare cases, serious medical complications, Spanish news site Canarian Weekly reports.
What is the Portuguese man o' war?
Despite resembling a jellyfish, the Portuguese man o' war is not a jellyfish. It is a floating colony of specialised organisms that work together as a single unit.
The creature cannot swim by itself. It drifts across the ocean carried by winds and currents, with its distinctive blue body acting like a sail.
Recent reports of more frequent appearances are thought to be linked to rising sea temperatures, which are allowing the species to spread into areas where it was previously uncommon.
Painful sting
While the bright blue body is easy to spot, the tentacles responsible for its sting are harder to see. The tentacles typically reach up to 10 metres and, in some cases, may extend as far as 50 metres.
The tentacles contain millions of microscopic stinging cells that inject a powerful venom with neurotoxic, cytotoxic and cardiotoxic effects, allowing the colony to immobilise its prey within seconds.
Symptoms of a sting include severe burning pain, intense itching, red raised skin lesions, nausea, vomiting and fever.
What to do if you are stung
Anyone stung should leave the water immediately, carefully remove any visible tentacles without touching them directly, rinse the affected area with seawater, and immerse it in warm water. Medical assistance should be sought if symptoms are severe or if the person has difficulty breathing, feels faint or shows signs of an allergic reaction.
Tourists are encouraged to follow instructions from lifeguards. If warning flags are displayed or a beach is closed, visitors should stay out of the water until it is declared safe again.
Even if a man o' war appears stranded on the sand, it should never be handled, as its tentacles can still deliver a painful sting hours after washing ashore.
Advice for holidaymakers
Never touch a Portuguese man o' war, even if it seems dead. Keep well away if you see one floating in the sea, and move away in the direction it is drifting from rather than swimming behind it, where long trailing tentacles may be invisible beneath the surface.
