The Portuguese man-of-war (above) and jellyfish can deliver painful stings. Photo provided
By Jan Engoren
Worldwide, more than 150 million people are stung by jellyfish each year (hundreds fatally), according to a July 2019 story in The Washington Post. The snorkel and travel website ProAdventureGuide estimates 200,000 people are stung each year in Florida.
August through October in Florida is peak season for jellyfish, which are present all year long. Warming waters combined with the right currents and wind conditions can bring more to our shores.
Most beachgoers have seen them, as well as the Portuguese man-of-war (Physalia physalis). The latter is not technically a jellyfish but they can be grouped together for purposes of this column.
Scientists say jellyfish have been around for more than 600 million years, predating dinosaurs, trees and fungi. They are the oldest multi-organ animal, surviving all five of Earth’s mass extinction events. More than 2,000 species of jellyfish have been discovered and identified, although some experts believe there could be 300,000 species.
Jellyfish are related to coral; both are members of the same phylum, Cnidaria. They range in size from 0.02 inch in diameter to the world’s largest — the Nomura jellyfish in the Sea of Japan, which weighs up to 440 pounds with a diameter of 6.5 feet.
Lacking brains, jellyfish are composed of 98% water and act on instinct using an elementary nervous system with receptors that detect light, vibrations and chemicals in the water.
Man-of-war, looking like a deflated blue plastic baggie when washed ashore, is actually a colony of organisms working together and characterized by long, thin tendrils which can extend 165 feet in length below the surface of the water. These tendrils can deliver painful stings and leave whip-like red welts on your skin, typically lasting two or three days.
People who are sensitive to the toxin or who get a higher dose or robust sting can go into anaphylactic shock, but most people can treat the sting with hot water. That denatures the toxin.
Molly Pendergast, naturalist at the Sandoway Discovery Center in Delray Beach, encourages people to leave jellyfish in the ocean where they belong and not add them to an aquarium.
“They’re difficult to keep in captivity because they don’t like small, enclosed spaces,” she says, noting that the Sandoway does not keep them for that reason.
Jim Masterson, assistant research professor at FAU Harbor Branch specializing in marine and estuary ecology, remembers walking in 2004 with his 5-year-old daughter on a beach in Melbourne when she poked at a man-of-war washed up on the shoreline and was stung on her finger.
Masterson washed her finger with hot water and applied an antihistamine cream. She soon felt better, although she remembers that sting to this day.
“Be aware,” Masterson says. “If you see jellyfish or man-of-war washed up on the beach, that is an indication they are in the water as well. Enjoy the beach, but just be aware. Even if they are washed up on shore and appear dead, they are still able to sting you.”
Other common jellyfish in South Florida include moon jellyfish (Aurelia aurita), cannonball or cabbagehead jellyfish (Stomolophus meleagris), lion’s mane (Cyanea capillata), Atlantic sea nettle (Chrysaora quinquecirrha) and Caribbean box jellyfish (Cubozoa).
If you are stung, Masterson suggests using vinegar or hot water (not cold, which can activate the venomous cells) to denature the toxin. Another option is an over-the-counter medication for insect bites such as Benadryl, calamine lotion or a hydrocortisone cream.
He also suggests inspecting the injury site for stinging cells and removing them with a tweezers, rather than scraping them off, which can trigger the cells.
According to the Mayo Clinic, unproven and mythical remedies include urine, meat tenderizer and alcohol.
Phil Wotton, division chief at Delray Beach Ocean Rescue, has seen many incidents of people stung by jellyfish and he was once stung by a man-of-war while floating on his back in the ocean. The sting, on his torso, was severe enough for him to have respiratory difficulty, go into shock and seek treatment from paramedics. Wotton says the reaction subsided overnight.
Most reactions are not life-threatening, unless the victim is allergic and experiences anaphylactic shock. The longer the tentacles stay attached to you, the more poison will be in your system, says Wotton.
Wotton has no individual statistics on jellyfish stings for Delray Beach because all incidents and injuries are grouped together.
“If you are stung, don’t panic,” says Wotton. “Get treatment as quickly as possible. Seek help from the lifeguard on duty, and even before you go for a swim in the ocean, make sure there is a lifeguard on duty. Accidents happen when there is no lifeguard in the tower. Come to the tower and ask if there are any concerns today that I should be aware of? We’re here to help.”
Florida lifeguards display purple flags to warn swimmers when dangerous marine life, including Portuguese man-of-war, is present in the area.
The Florida Department of Health recommends leaving the water immediately after a sting and if necessary calling 911 or the Florida Poison Control Centers hotline at 800-222-1222.
Jan Engoren writes about health and healthy living. Send column ideas to jengoren@hotmail.com.
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