Does Saint Lucia Have Jellyfish? (Types, Photos & Stings Explained)

Set in the southern Windward Islands of the Lesser Antilles between Martinique in the north and Saint Vincent and the Grenadines in the south, the volcanic island of Saint Lucia is famed for its scenic beauty and alluring beachfronts. 

Those swimming off the calm Caribbean coast or braving the rougher Atlantic waters on the eastern seashore may have jellyfish—those semi-transparent, tentacled drifters feared for their stings—in the back of their mind.

So let’s take a look: Does St. Lucia have jellyfish? And how bad or common are jellyfish stings in St. Lucia?

Photo by Terry Ott/Flickr

Many different kinds of jellyfish populate the waters of St. Lucia. However, stings (especially severe ones) are exceedingly rare, and most beachgoers and swimmers need not concern themselves with jellyfish, beyond appreciating their beauty and importance to the ecosystem!

Some of the jellyfish that may be found near St. Lucia include:

  • Moon jellies
  • Upside-down jellies
  • Cannonball jellies
  • Thimble jellies
  • Box jellies or sea wasps
  • White-spotted jellies
  • And the Portuguese Man o’ War (technically not a jellyfish!)

Let’s take a closer look at these species, photos to identify them, and how how common jellyfish stings are in St. Lucia.

Types of Jellyfish in Saint Lucia

Jellyfish are the simplest of all swimming creatures and yet exquisitely adapted enough to the ocean realm—and even some freshwater environments—to have survived for better than 500 million years.

(Human beings, needless to say, are evolutionary pipsqueaks by comparison!) 

There’s still a lot scientists don’t know about jellyfish, including the exact geographic distribution of many species.

Jellies can drift long distances on ocean currents, and many species are hard to precisely distinguish from one another. Furthermore, as a testament to the ocean’s vastness and the inconspicuousness of many sea jellies, new species are doubtless waiting to be scientifically documented.

(Indeed, as we’ll get to, one of the most recently described kinds of jellyfish—only classified and christened in the 21st century—can be found in Saint Lucian waters.)

All of that’s to say that the following list of Saint Lucia jellyfish is far from definitive or exhaustive. But here are some of the species likely found in local or regional waters, at least occasionally.

Moon Jelly

By Alexander Vasenin – Own work, CC BY-SA 3.0

The moon jelly is quite easily recognized with its clear, ovalish body showing off four horseshoe-shaped glands in the center and rimmed with very short and fine tentacles. 

Widespread, common, and prone to large “blooms,” moon jellies are nonetheless basically harmless:

Their stings are so mild that many people don’t even register them.

Some folks may have more adverse reactions, but in the case of the moon jelly that’s likely to be nothing more than a low-grade burning sensation.

Upside-down Jellyfish

CiXeL at English Wikipedia, CC BY 3.0, via Wikimedia Commons

The upside-down jellyfish is well named:

It positions itself bell down on the seafloor—as in seagrass “lawns” and muddy bottoms—with its stubby tentacles facing up. 

Mostly subsisting on the energy produced by symbiotic photosynthesizing dinoflagellates, this little jelly is thought to also potentially consume small prey that’s paralyzed by the globs of stinging cells it releases.

Research suggests those stinging globs—called cassiosomes, technically speaking—may explain the “stinging water” some people who’ve swum near upside-down jellyfish have reported.

This is a mild reaction, though—nothing to particularly fret about.

Cannonball Jelly

Judy Gallagher, CC BY 2.0, via Wikimedia Commons

The hefty and handsome cannonball jellyfish—also known as the “cabbagehead”—is also aptly labeled, given its brownish or reddish circular ball.

Beneath this bell, short oral arms extend, but no long tentacles. 

Onshore currents may drive large numbers of cannonball jellies into beaches, lagoons, and other coastal settings.

They’re considered essentially harmless to people, though in parts of their range—including off the U.S. East Coast—they’re infamous for fouling fishing nets.

Thimble Jellyfish

Thimble jellyfish are quite numerous and widespread in the Caribbean, and are sometimes reported off Saint Lucia.

These are tiny little sea jellies, growing to less than an inch in diameter, with columnar bells. 

Although they don’t pack potent venom by any means, thimble jellies probably account for a goodly portion of the jellyfish stings received in the Lesser Antilles.

These often manifest as the rash commonly called “seabather’s eruption.”

Studies pinpoint the thimble jellyfish as the likely main culprit for this usually extremely mild, if annoying, skin reaction in the West Indies as well as the Gulf of Mexico and the southeastern U.S.

(A sea anemone is thought to be the prime suspect, meanwhile, farther north up the U.S. Atlantic Seaboard.) 

In the case of seabather’s eruption, miniscule thimble jellyfish—including in larval form—get stuck to swimmers, especially under swimsuits.

Pressure from waistbands and other close-pressing parts of swimwear, or simply the jelly drying-out process, results in the activation of the jellies’ stinging cells (nematocysts). 

Rather than a truly painful sting, the result is typically just itchy redness, though rarely somewhat more pronounced effects, including nausea and fever, have been reported.

Box Jellies/Sea Wasps

Guido Gautsch, Toyota, Japanderivative work: Mithril, CC BY-SA 2.0 via Wikimedia Commons

The most potentially dangerous jellyfish in Saint Lucian waters are box jellies or “sea wasps.”

Indeed, these are the most infamous jellyfish in the world, although fortunately the truly lethal species known from spots such as Australia and the Philippines aren’t found here. 

Box jellies potentially found in the region include the mangrove box jellyfish, a tiny creature that may or may not represent much of a threat—its venom isn’t particularly well understood, and its diminutive size (less than an inch in diameter) lessens the likelihood of a truly serious sting.

Mangrove box jellies are named for their habitation of mangrove ecosystems, in which, some research suggests, they congregate around mangrove prop roots during the day while heading for the muddy seafloor at night.

Of likely greater concern is the little-known and legitimately lovely Bonaire banded box jellyfish, first observed in the late 1980s and not scientifically described until 2011.

A larger box jelly belonging to a completely different genus, this species has been seen not only off Bonaire (where it’s been most frequently identified) but also Saint Lucia, as well as other corners of the Caribbean Basin such as the U.S. Virgin Islands, Honduras, and Mexico. 

The Bonaire banded box jellyfish is named for its strikingly patterned tentacles and also distinguished by its warty body.

A number of serious (though non-fatal) stings have been attributed to the species, with sharp pain and skin damage reported among the symptoms; at least one victim of the Bonaire banded box jelly ended up hospitalized. 

White-spotted Jellyfish

By Papa Lima Whiskey at English Wikipedia, CC BY-SA 3.0

Like box jellies, the white-spotted jellyfish is rather infamous, but not for its sting (which is considered very mild).

Instead, this species is dreaded on account it’s a notorious invasive organism that’s popped up far beyond its native range in the Indo-Pacific. 

The Caribbean is among the ocean basins where this exotic invader, which possesses a large, brownish bell, has been documented, with the potential for ecological impacts and—thanks to the white-spotted jelly’s major blooms—fouled-up fishing nets.

A Jellyfish Lookalike: The Portuguese Man o’ War

By Image courtesy of Islands in the Sea 2002, NOAA/OER. – U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Public Domain,

The beautifully blue or purplish Portuguese man o’ war is often called a jellyfish, though it’s not actually a true jelly:

Instead, it’s a colonial organism known as a siphonophore, composed of many subsidiary animals called zooids.

It shares the medusa form of true sea jellies, however; indeed, some looser definitions of “jellyfish” refer to any such medusoid creature and thus include siphonophores. 

Anyhow, whether you want to call it a jellyfish or not, the Portuguese man o’ war is a super-impressive invertebrate.

Besides the flashily hued, sail-like float—the resemblance of which to a warship explains the organism’s common name—the man o’ war boasts extremely long tentacles that may be dozens of feet long. 

As with true jellyfish, those lengthy tentacles of the Portuguese man o’ war boast nematocysts for stunning and killing small prey, and they can deliver a potent and painful sting to human flesh.

That said, man o’ war stings are rarely fatal, though there’s no question they’re highly unpleasant.

The Portuguese man o’ war may “sail” long distances, and onshore winds or currents may beach individuals or whole assemblages. 

Jellyfish Season & Sting History in Saint Lucia

Jellyfish stings occasionally occur off St. Lucia beaches, though the vast majority are very mild.

Natural jellyfish population cycles and movements as well as trade-wind patterns mean that spring through fall is the generally most likely window for Saint Lucia jellyfish stings.

In the Caribbean as a whole, seabather’s eruption tied to thimble jellyfish is most often reported in the spring and summer months.

Periods of winds, currents, or jellyfish blooms may bring large numbers of sea jellies close to shore, though these are temporary phenomena.

In September 2020, for example, several stings on Saint Lucia were reported off Vigie and Choc beaches with good quantities of an unidentified jellyfish in nearshore waters. 

Beachgoers may be stung by jellyfish out of the water, too: Stranded sea jellies can still sting on contact, including for awhile after death. 

Avoiding Jellyfish Stings (Tips & Things to Know)

For most people, jellyfish stings aren’t a major cause of concern in Saint Lucia.

There aren’t any truly deadly jellyfish native here, though the box jellies are nothing to play around with, and the most common sea jellies deliver sensationless to minor stings. 

To reduce your chances of being stung, pay heed to any advisories issued by authorities regarding jellyfish, and consider steering clear of the water if you see large numbers of jellies washed ashore or floating in the surf.

Don’t touch beached jellyfish with bare flesh; as we mentioned, they can still sting you. 

Wearing a shirt while swimming or snorkeling can cut down on your vulnerability to mild jellyfish stings (and protect you from sunburn!).

Wetsuits or “stinger suits” are sometimes worn where dangerous sea wasps are more common, which is something to consider if you’re exceptionally paranoid about the Bonaire banded box jelly. 

An application of vinegar is usually sufficient to quickly treat jellyfish stings.

Antihistamines and topical corticosteroids can be used to combat the seabather’s-eruption rash caused by thimble jellyfish.

Seek medical attention if you or a member of your party experiences an allergic reaction to a jellyfish sting; it’s a good idea to do the same in the rare event of a box-jelly sting.

Because of the length of the tentacles, close encounters with a Portuguese man o’ war can result in numerous stings that may cause enough pain or inflammation to warrant a check-in with a doctor.

Saint Lucia medical centers that can treat jellyfish stings include Victoria, Tapion, and Owen King European Union hospitals.

Wrapping Up

It’s worth noting here at the close that jellyfish play an important role in the marine ecosystem of the Windward Islands and are certainly nothing to resent.

Indeed, jellyfish such as cannonballs and sea nettles are the preferred food for one of the most magnificent denizens of Saint Lucia: the mighty leatherback sea turtle, one of several sea turtles that nests on the island. 

For most visitors and vacationers in St. Lucia, there’s no need to fear jellyfish.

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Hope this helps!