Portuguese man-of-wars found at Fort Wetherill

A Portuguese man-of-war at Mackerel Cove in 2015.

A Portuguese man-of-war at Mackerel Cove in 2015.

At least five Portuguese man-of-wars have been spotted at Fort Wetherill, according to Beavertail Aquarium intern Cam Chadronet.

One of them has been put on display at the aquarium.

The Rhode Island Department of Environmental Management said the Portuguese man-of-war “is a dangerous sea creature with long tentacles and a painful sting.” Although it is often erroneously referred to as a jellyfish, the so-called floating terror is a siphonophore, a colony of different organisms working together as a single, specialized animal to live in the water column. It is a predatory species that uses its feeding tentacles to sting and paralyze its prey. The species can be found in Rhode Island during this time of the year when a warm-core ring has peeled off from the Gulf Stream.

Swimmers should be vigilant because the tentacles of a man-of-war can grow to 30 feet. They contain stinging nematocysts, which are “microscopic capsules loaded with coiled, barbed tubes that deliver venom capable of paralyzing and killing small fish and crustaceans,” according to the National Oceanic and Atmospheric Administration.

These stings should be treated by carefully removing remaining tentacles with fine tweezers or with a gloved hand, then rinsing the affected area with white vinegar to prevent any remaining stinging cells from firing. The affected skin should then be soaked in water that is roughly 110 degrees Fahrenheit, or sting victims could take a hot shower for 20 minutes since the heat should denature the protein in the venom.