When Jellyfish Attack

Warm water expands their range and brings them closer to shore. If you get stung, should you ask a friend to… well, you know?

Photo: iStock

Everyone remembers their first jellyfish sting. It came without warning. You’re floating there, minding your own business, when, out of the blue, a quick dart to the skin, a sharp pain, your slow happy day in the surf turned to crisis. As soon as you could, you were out of the water, the pain pulsing into agony. Laying there in the sand, you thought, now what?

It’s a common belief that urinating on a jellyfish sting will alleviate the pain. This, says Kelly Robinson, a biological oceanographer with a focus on jellyfish at the University of Louisiana, is a myth, although one with a wee bit of truth. Urine contains urea, a nitrogen-based chemical which does help in alleviating stinging pain, but the stuff is simply too diluted by other components to have any effect. In fact, applying urine may make matters worse; the difference in the salt concentration between seawater and urine can actually aggravate the sting. “It can cause the harpoon still stuck in your skin to fire,” Robinson says.

The first step to relief is to remove any jelly tissue—tentacles or stinging barbs called nematocysts—preferably with a tool like tweezers. Lacking such an instrument, skin can also be scraped clean using a credit card or ID. Then rinse the area with vinegar, the chemical composition of which can soothe skin pain. For the well-prepared, there are commercial anti-stinging products like Sting No More which work pretty well, Robinson says. Ignore any impulse to cool the wound. Heat, which acts as a pain reliever, is your friend. Soak the affected area in hot water or apply a hot pack and wait it out. The length of pain varies—depending on type of jelly, how much of it got you, and your own body—but it typically lasts a couple of hours. Take an aspirin or two. Also watch out for allergic reactions.

Stinging jellyfish belong to the phylum cnidaria, as do corals. There are thousands of species. Jellyfish exist in every body of salt water on earth; there’s even one freshwater variety, Craspedacusta sowerbii, which can be found, among other places, in Alabama. Some jellies lack skin-piercing power. Others can be fatal to humans.

In the southeast, the most common stingers are sea nettles. They can be painful but are not going to hospitalize anyone. Closer to Florida, unlucky swimmers might encounter box jellyfish. Though they deliver a much harsher punishment than nettles, American box jellies pales in comparison to their Australian cousins, which can cause fatalities. According to Robinson, there are no American jellyfish that can reliably kill humans.

Robinson’s favorite jelly species is the pink meanie, a bubble gum-bright species in the Gulf which preys on other jellyfish. When collecting them, she has to store the biggest meanies in fifty gallon trash-cans (a meanie also gave the biologist her worst sting ever, under the armpit). Portuguese Man o Wars, notoriously painful, are one of the most feared stinging sea creatures. They’re related to jellyfish, but are actually siphonophores, a sea-faring colony of tiny organisms working in unison.

Of course, the only way to fully avoid jellyfish is to avoid the water. But if taking the risk, wearing a tee-shirt or wetsuit can be preventative. Be vigilant: August, with its warm air and water temperatures, is the height of jellyfish season. While sea nettles, which bloom from May to July are waning, moon jellies, which have a slight sting, peak now through September. Around 150 million people are stung by jellyfish a year. You might be one of them. Now you know what to do.