South Florida's East Coast and its Unruly Inhabitants: Portuguese Men-of-War

While seeming completely harmless, the bluish balloon-like man-of-war packs a painful punch, creeping up on unsuspecting beachgoers. With the winter months in full effect and high winds picking up, the presence of these creatures is more apparent than ever. 

The Portuguese man-of-war, while giving the impression of a regular jellyfish, is scientifically known as  Physalia physalis and consists of multiple organisms or polyps. A single polyp fills with gas and can be seen floating above the ocean surface and is recognized by its blue/purple hue while its venomous tentacles sway below the surface reaching 165 feet in length.  

With their long tentacles often going undetected underwater, the Portuguese man-of-war surprises its victims with its sharp sting. 

“When it happened I thought I got cut from something, I didn't realize what was going on at first because I couldn't tell,” said Kaitlyn Flaherty, a student at Florida Atlantic University when recalling her experience getting stung by the man-or-war at Boca Raton's South Beach Park.  

“Honestly one of the most painful experiences of my entire life and I've broken bones, I've done a lot of things and that was genuinely one of the worst pains I've ever felt,” said Flaherty. 

With the coastline littered with washed up men-of-war, it's important to note a Portuguese man-of-war can remain venomous even days after death and beachgoers are advised not to interact with them on the beach.  

Otto Blanco, a lifeguard at Red Reef Beach warns residents on the reality of an encounter with the man-of-war. “When beach patrons come up and ask me what they are, are they dead on the shoreline I always express to them, ‘no they're not, they can still sting.’ Of course I tell them not to pick them up.” 

Getting in contact with the tentacle, or the stinging nematocysts, results in localized pain, rash, swelling, and burning but for some the reaction can be  a lot worse. 

“I've seen little kids you know get stung and it’s no big deal. I try and calm them down right away. I ask them to breathe, take big breaths… I want to make sure that they can swallow and that their esophagus isn't swelling,” said Blanco, who was on his lunch break applying hand salve over his sun dried skin at the picnic tables behind his lifeguard tower. “I ask their parents are they allergic to bee stings or anything like that because they are very dangerous. Some people can go into anaphylactic shock and they may have to be rushed to the hospital and it can affect their breathing and their nervous system.”

With the winter months bringing stronger wind patterns, Portuguese men-of-war are heading to our coast and washing up all along the shoreline.  

“Since these animals cannot swim, they float on the surface and move through the ocean by wind and currents. Since we typically get stronger offshore winds during the winter, the man-of-war will wash up in large groups that time of year through spring. It’s very common to see them on our beaches from November until April,” said Angela Field, an aquarist with the Gumbo Limbo Nature Center in Boca Raton.

Blanco, who has been a part of Florida Ocean Rescue for 41 years, mentioned that he sees the unruly jellyfish “mostly in wintertime.” He said that the winds play a role in their arrival, explaining that the jellyfish are blown out of the water when winds from the east push toward the shore. Blanco describes how they move along the surface of the water. “They vary every year with the wind. When they are here we typically get, you know, a handful of stings every day and it varies by degree of severity.” 

This past January, Boca Raton beaches such as Red Reef Park and Spanish River have seen an abundance of both live and dead men-of-war. “They were lined all the way, the entire way down the beach, they were washed up, there were at least a couple hundred,” said Nicholas Oliverio, a freshman at Florida Atlantic University.  “They were everywhere you stepped on the shoreline.”

According to local residents Joanne Brady and Gabby Bale, this won't be the last we will see of them. “February’s the worst month with the population, I think. I still have pictures of them from the past February [2024] That's when it really peaks,” says Brady, who frequently walks along the shore of Red Reef Beach.  

With how unpredictable these organisms are, Boca Raton Ocean Rescue tries to warn beachgoers of the presence of dangerous marine life.  

Blanco shares how he and his team display warning signs when they are notified of a man-of-war, posting a purple flag indicating to the public there is dangerous marine life present. “We have signs that we post, we try and post them at the entry points of our beach and typically we will get a concerned beach patron, that comes to us and talks to us about them and we advise them, watch for their tentacles. Their tentacles will go 15-30 feet long.” 

With February in full swing, it's likely South Florida will continue to see Portuguese men-of-war both in the waters and along the shoreline as encounters will continue to rise along the east coast.