Cannonball Jellyfish on the Beach are a Sign of Spring

The other day there were Cannonball Jellyfish all over the beach, in the marina, and in the creeks. In one of my favorite field guides, (Tideland Treasure) Todd Ballantine calls them the “jelly balls of Easter.” I always love to see them, because they mean the turtles are not far behind!

cannonball jellyfish on the beach at sunrise

Cannonball jellies are identifiable by their maroon bell and the obvious cannonball shape. They have short tentacles that are actually part of the digestive system, giving rise to the name “many mouthed hunter.” While they do have stinging cells, or nematocysts, they lack the long tentacles that many other jellyfish have. As a result, though the toxin can cause problems for people, they rarely sting.  If, like me, you just can’t help touching dead stuff that washes up on the beach, be sure to wash your hands.  Some websites say the cells embedded in the mucus can really irritate your eyes or even cause cardiac problems.

cannonball jellyfish in surf
cannonball jellyfish

Who eats Cannonball Jellyfish?

They can be a food source for a wide variety of other beach visitors: shorebirds and seabirds, and of course loggerhead turtles (which nest here) and leatherback turtles (which migrate near shore.) Last week, SCDNR did a flyover of the state’s coastline and spotted 12 live leatherback and 7 live loggerhead sea turtles.

Birds feed on the decaying jellyfish, which take a few days to break down.  In some parts of the world, they’re eaten by people as well.  Some confluence of ocean currents brings them into shore, perhaps even being chased by those same sea turtles.

Jellyfish often have "Ride-along" friends

In one of my first nature walk videos, (which was double the length I finally settled on) we looked at the relationship between portly spider crabs and cannonball jellyfish.  It’s a great example of commensalism, a form of symbiosis where neither creature is harmed in the relationship.  

Other Jellyfish have More Efficient Stinging Cells

Cannonball Jellyfish are not the only jellies that wash up on our beaches.  Moon Jellies and Lions Mane Jellies are also common, and they have longer tentacles (which will sometimes be missing by the time they wash up on the beach.) Occasionally, the tropical Portuguese Man o’ War will wash up on the beaches, and you definitely want to avoid them.  Sea Walnuts, or comb jellies, are only about 2 inches long and can’t sting at all.

The tiniest cannonball jelly we've found!
comb jelly on the beach