man o war

Falmouth resident and scientist Dr. Sidney Tamm found the venomous jellyfish on Monday. It is about the size of a light bulb, he said. Beaches on the south side of Martha’s Vineyard were closed recently after an unusually large number of man o’ war washed up there.

A Falmouth resident found a Portuguese man o’ war on Fay Beach over the holiday weekend, the first such sighting of the jellyfish-like marine animal in at least four years.

Sidney L. Tamm, a biologist at Marine Biological Lab, on Monday, September 7, was casually walking the beach as he does often, scouting for sea glass when the blue creature caught his eye.

“At first I thought was a beautiful blue glass bottle, but on closer inspection I saw is was a Physalia,” he said, referring to the scientific name for Portuguese man ‘o war.

Dr. Tamm, who has been researching the comb jellyfish for 40 years, said this is his first man o’ war sighting, and wanted to photograph it. He took it back to his home using a molted horseshoe crab shell to carry it.

“The float was still inflated with gas, which means some of the cells or part were still alive.”

Incidentally, “blue bottle” is one of the man o’ war’s nicknames. Another one is floating terror.

The tentacled creature can cause extreme pain if the tentacles brush exposed skin. According to National Oceanographic and Atmospheric Administration, the species is highly toxic and is covered in venom-filled nematocysts used to paralyze and kill fish and other small creatures. For humans, a man o’ war sting is excruciatingly painful, but rarely deadly. It can leaves welts on the skin and can cause burning, swelling, cramping and sweating.

“They are episodic in our waters,” David Remsen, director of Marine Research Services at MBL said.

“They do show up here and have been doing so for a long time. Every few years wind and sea conditions are right that they get blown up this way.”

He recalls them here in 2013, 2014 and 2016.

“If one shows up then there are likely more.”

Found mostly in tropical and subtropical seas, men o’ war are propelled by winds and ocean currents.

They resemble an 18th-century Portuguese warship under sail and are recognized by its balloon-like float, which may be blue, violet, or pink and rises up to six inches above water. Below the float are tentacles that grow to an average of 30 feet.

“I imagine, like many other southern marine species, they are inadvertently carried north with the Gulf Stream, which passes fairly far to the east of us,” Mr. Remsen said.

He said they could end up off Falmouth by way of warm core rings, a piece of warm gulf stream water that breaks off the main flow and comes inshore, depositing whatever it is carrying in our local waters.

(1) comment


Thank you for publishing this important news. My daughter was stung by one in Bermuda and it is horribly painful and leaves immense scar. Be careful in the ocean

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