Portuguese man o’ war sightings force French beach closures

Several popular beaches in south-west France were closed to swimmers on July 25 due to sightings of Portuguese man o’ war, a venomous marine species often mistaken for jellyfish. Several of the sites have now been reopened but officials say the situation is being continually monitored and beaches may need to be closed again. 

The pink-purple creatures whose stinging tentacles can be several metres long are carried in by the wind and currents. Marine scientists note that shifting ocean temperatures and wind patterns may be contributing to their spread. 

They have appeared sporadically before in earlier years depending on weather patterns. Some were spotted, for example, in 2017 in Brittany and in 2011 more than 800 cases of people being stung were reported.

Red no-swimming flags were raised on Friday across the Basque and Landes coasts, where authorities confirmed the presence of Physalia physalis - known in French as vessie de mer or galère portugaise - an organism capable of delivering painful, sometimes dangerous stings.

The commune of Bidart (Pyrénées-Atlantiques) was among the worst affected, with five beaches - including Pavillon Royal, Ilbarritz, and Erretegia - shut to the public. 

In neighbouring Biarritz and Anglet, access to beaches such as Marbella, la Milady, and Petite Chambre d’Amour was also suspended.

Further north, in the Landes department, three beaches - Le Penon and l’Agréou in Seignosse, and Cap de l’Homy in Lit-et-Mixe - were closed following similar sightings.

What is a man o’war?

Usually found in the temperate waters of the Atlantic, it floats on the surface and is carried ashore by wind and current. 

It is not a single creature, but a colony of specialised polyps functioning together, feeding on small fish, molluscs, small crustaceans, and zooplankton. 

Its translucent sail can appear blue, pink or violet, while its trailing tentacles - some extending beyond 10 metres - are lined with stinging cells.

Though recent specimens found on the French coast were small, their tentacles remain active even after death and can cause serious reactions. 

These range from skin irritation to systemic symptoms including vomiting, respiratory distress and - in rare cases - cardiac arrest. Children and allergy sufferers are particularly vulnerable.

Local hospitals and emergency services advise against touching the creature or affected areas with bare hands. 

If stung, rinse the site with seawater, apply shaving foam, and gently remove tentacle fragments without touching them directly. 

Fresh water, sand or rubbing the skin may worsen the reaction. Medical attention should be sought if symptoms persist or escalate.

Man o’war in French waters

Physalia physalis is not uncommon on the French Atlantic coast but rare in the Mediterranean, where its presence is largely limited to the coasts of Spain and Morocco.

However, the species was observed last summer as far north as Spanish Catalonia, and in early July this year in Brittany. 

In Nouvelle-Aquitaine authorities have introduced warning signs and are monitoring local conditions. 

Some communes have created specific alerts for man o’ war sightings alongside standard lifeguard flag systems.

Swimmers and beachgoers are urged to remain vigilant, to avoid approaching the creatures, and to report all sightings to local authorities, such as the nearest lifeguard or local mairie.