Washed-Up Little Aliens from the Sea
Cannonball Jellyfish on Emerald Isle, NC —
photo by Patti Wren Byrd - June 2023
Why Do We Find These Creatures on Our NC Beaches?
On the hottest days of the summer and into early autumn, our beaches often become dotted with semi-clear, gellotine-like creatures that roll up from the shoreline waves, left to slowly dry in the sun’s unforgiving rays.
Cannonball Jellyfish (stomolophus meleagris), also sometimes called Cabbagehead Jellyfish, are a common sight along the southeastern coastline of the United States during these hotter months. These smaller sized jellyfish have round, dome-shaped bells that range from an average of seven to ten inches in width and roughly five inches in height. The bell of the Atlantic Cannonball Jellyfish is semi-translucent and milky, often featuring brown rim around the base of the bell. Very short and thick, protruding semi-translucent white oral arms with secondary mouth folds (scapulets) that are covered with mucus for trapping small prey, can be found under the base of the bell. When I was first seeing these washed-up jellyfish as a young child, I believed that sharks must have bitten off the iconic long tentacles, given their stubby appearance.
Cannonball Jellyfish on Hammocks Beach State Park — Photo by Patti Wren Byrd - June 2023
Drawn to the warmth of the shallow waters, meeting their preferred temperatures of 68° to 76° farenheit (20° to 24° celsius), Cannonball Jelleyfish hunt these shoreline waters for zooplankton and red drum larvae. Aggregating in large groups called “blooms,” this specific species of jellyfish makes up over 16% of the coastline’s biomass during this time of the year, making it the most prominent jellyfish on the coast of the southeastern U.S.
When it comes to jellyfish, most people seem to mainly be concerned about the level of pain that they might be unfortunate enough to experience if stung by one. When disturbed or threatened, the Cannonball Jellyfish secretes a toxic mucus from its nematocyst (a specialized cell in its tentacles containing a venomous of barbed coiled thread that can be projected to capture its prey or in self-defence) that can harm small fish and drive away most predators, such as crabs and the endangered Leatherback Sea Turtle; their main predator. The good news is that the sting of the Cannonball Jellyfish, while being among the most common causes of stings to humans in the US and Caribbean waters, is mostly harmless to humans, and minor compared to most other jellyfish. The bad news is, however, that their toxin is capable of causing cardiac problems in both humans and animals.
