Swimming has been repeatedly interrupted since late July along beaches on the Aquitaine coast from Arcachon Bay to the Basque coast due to physalia.
The marine invertebrate, nicknamed the Portuguese man o' war, has stinging filaments, news outlet ICI reported. Local authorities have called on vacationers to exercise caution and avoid touching the organisms.
The prefecture of Pyrénées-Atlantiques warned that a sting can be very painful and lead to serious health effects. Officials advised people never to touch a physalia even if it is dead, because the organisms remain stinging after death and present a danger both in the water and stranded on the sand.
Health Risks and Symptoms
Native to tropical waters, physalia resemble jellyfish and are recognizable by their bluish color. The organisms are not fatal, but their stings can cause very acute pain. Their slightly translucent filaments can measure up to 20 meters long, making them difficult to spot in the water and hard to predict.
The filaments release a stinging substance that can cause burns, muscle weakness, and vomiting. If contact occurs, victims should not rinse the burn with fresh water because doing so risks worsening the sting.
The best solution after contact is to quickly alert the nearest lifeguard station so that lifeguards can remove the filaments. Lifeguards have called on beachgoers to respect safety instructions without panicking, noting that severe symptoms remain rare.
Medical Complications and Lifeguard Advice
A doctor from the poison control center at Bordeaux University Hospital told AFP in 2025 that severe complications occur in only 8 to 10 percent of cases. These severe complications include muscle or respiratory tetany, which can potentially lead to drowning.
