A Crippling Threat from the Deep: Portuguese Man-of-War Forces Beach Closures

Recent reports from the Basque Coast and other parts of France have raised alarms as numerous beaches hoisted red flags and were subsequently closed due to the presence of Physalia physalis, commonly known as the Portuguese Man-of-War. These fascinating yet dangerous marine organisms have caused significant disruption, leading to warnings for beachgoers about their potent sting.

Understanding the Threat: The Portuguese Man-of-War

Often mistaken for a jellyfish, the Portuguese Man-of-War is in fact a siphonophore, a colonial organism made up of specialized polyps working together. Its most distinctive and perilous feature is its incredibly long tentacles, which can extend up to 20 meters (approximately 65 feet). These tentacles are equipped with nematocysts, stinging cells filled with a powerful venom capable of causing intense pain, severe skin lesions, and in rare, more extreme cases, even cardiac arrest. The sheer length of these tentacles makes them particularly dangerous, as they can drift far from the main float, posing a hidden threat to swimmers and unsuspecting individuals.

Widespread Closures and Public Safety

In late July 2025, several beaches along the Basque Coast were forced to raise red flags and initiate closures following confirmed sightings of these venomous creatures. The closures extended to nearly a dozen beaches in various locations, impacting summer activities and prompting local authorities to issue urgent warnings. The swift action underscores the serious nature of the threat posed by the Portuguese Man-of-War, prioritizing public safety over recreational access to the affected areas.

What to Do if You Encounter One

Authorities advise extreme caution. If a Portuguese Man-of-War is spotted, it is crucial not to touch it, even if it appears to be dead or washed ashore, as its stinging cells can remain active for weeks. Immediate medical attention should be sought if stung. The presence of these organisms is a stark reminder of the diverse and sometimes dangerous marine life that inhabits our oceans, necessitating vigilance from all beach visitors.

Protecting our coastal environments and ensuring public safety remain paramount as these unsettling visitors continue to make their presence known.