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NEPA warns of venomous Portuguese man o’ war washing ashore in Jamaica

Published:Tuesday | February 11, 2025 | 4:03 PM

The National Environment and Planning Agency (NEPA) is advising the public to exercise caution when visiting coastal areas across the island, following reports of Portuguese man o’ war (Physalia physalis) washing ashore in parts of Portland.

NEPA says beachgoers and individuals engaging in coastal activities should remain vigilant, as the Portuguese man o’ war can still sting even after it is dead, due to a reflex action of its tentacles.

It says while stings are rarely fatal to humans, they can cause intense pain, welts, and irritation that may last one to three hours.

Often mistaken for jellyfish, the Portuguese man o’ war is a siphonophore—a specialised colony of zooids that function together as a single organism.

The agency says it is easily identified by its balloon-like float, which is typically blue, violet, or pink and rises up to six inches above the waterline. Beneath the float, long tentacles and polyps can grow to an average length of 10 metres (about 30 feet), with some reaching up to 30 metres (about 100 feet).

The tentacles of the Portuguese man o’ war are equipped with stinging nematocysts, microscopic capsules containing coiled, barbed tubes that deliver venom. This venom is powerful enough to paralyse and kill small fish and crustaceans.

Portuguese man o’ war are typically found in tropical and subtropical seas. They are transported by ocean currents and winds and often travel in groups, sometimes forming colonies of 1,000 or more.

NEPA advises the public to take the following precautions:

· Avoid touching the Portuguese man o’ war, whether it is in the water or washed ashore.

· Wear protective footwear when walking along coastal areas.

· If stung, rinse the affected area with seawater and remove tentacle remnants carefully using a pair of tweezers. Do not rub the area, as this can worsen the reaction. Seek medical attention if symptoms persist or worsen.

· In the sea, swimmers should not approach them as the trailing stingers can be as much as 20 to 30 feet away from the float at the sea surface.

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