Last week, several beaches on the French Atlantic coast were closed to the public after the sighting of the Portuguese man o’ war (Physalia physalis), a venomous marine species that has also been detected on Spanish coasts in recent years.
Local authorities decided to ban swimming in areas of Biarritz, Anglet, Bidart, and Seignosse, although some sections have already been reopened under strict surveillance.
What is the Portuguese man o’ war and why does it pose a risk?
Although often mistaken for a jellyfish, the Portuguese man o’ war is actually a colony of organisms that moves thanks to its bluish floating bladder, easily visible on the surface. Native to tropical and subtropical zones, its presence in the European Atlantic is increasing, possibly favored by global warming and changes in ocean currents.
Its venom can cause:
- Intense skin irritation
- Sharp pain and vomiting
- Respiratory difficulties
- In extreme cases, severe reactions or risk of drowning
Recommendations for a sting: what to do and what to avoid
Health authorities in the Balearic Islands and southwestern France recommend following these steps:
- Get out of the water immediately if you spot a Portuguese man o’ war nearby
- Remove the tentacles with tweezers or a rigid object (like a card), without touching the area with your hands Only rinse with seawater, never with fresh water, vinegar, ammonia, or urine
- Apply indirect cold (ice pack wrapped in plastic) for 10–15 minutes, rest for five, and repeat if necessary
- Do not rub, scratch, or use towels or sand on the affected skin
- Do not assume the specimen is dead: it remains venomous
In case of any severe symptoms, seek immediate medical attention.
Impact on tourism and constant monitoring
Last Friday, red flags were raised along the Basque and Landes coasts. Among the affected beaches are:
- Bidart: Pavillon Royal, Ilbarritz, Erretegia
- Biarritz and Anglet: Marbella, Milady, Petite Chambre d’Amour
- Seignosse and Lit-et-Mixe: Le Penon, l’Agréou, Cap de l’Homy
Although many have already been reopened, authorities insist on exercising caution, avoiding contact with these organisms, and reporting any sightings to emergency services.
Climate change and displacement of marine species
Experts in marine biology warn that the rise in water temperature is facilitating the arrival of tropical species in temperate zones. The Portuguese man o’ war is one of the most visible examples of this phenomenon, posing new challenges for coastal safety and environmental management in tourist destinations.
“While it is fascinating to observe them, it is essential to know how to act if you encounter a Portuguese man o’ war,” reminded the Landes prefecture on social media.
