The cannonball jellyfish are very common along the beaches of Hilton Head.
The cannonball jellyfish looks like it’s straight out of a science fiction movie. Its round, leathery body can grow up to 12 inches in diameter with hundreds of tentacles trailing behind it. Despite its intimidating appearance, it is actually quite harmless and considered a delicacy in some parts of the world! In fact, this jellyfish has become an important part of the global seafood trade.
This jellyfish is also an incredible survivor—it can thrive in a wide range of temperate and tropical waters from the Caribbean to Alaska! Its unique design helps it survive in both shallow and deep waters, allowing it to forage for food wherever its travels take it. With its ability to adapt to so many different environments, the humble cannonball jellyfish is sure to remain a common sight in ocean waters for years to come.
Also known as the cabbagehead jellyfish, the cannonball derives from its dome-shaped bell, similar to a cannonball in shape and size.
Underneath the body is a cluster of oral arms that extend out around the mouth. These arms function in propulsion and as an aid in catching prey.
Cannonballs eat mainly zooplankton such as veligers, and also all forms of red drum larvae. They have a symbiotic relationship with the portly spider crab, which also eats the small zooplankton. The crab feeds on the prey captured by the cannonball and also on the medusae of the jellyfish.
They can reproduce both sexually and asexually. During sexual reproduction, cannonballs shoot sperm out of their mouth. The sperm are then caught by another cannonball through the mouth and fertilization happens. The embryo begins to develop in specialized pouches found on the arms around the mouth. After about 3–5 hours the larvae fall to the bottom and attach themselves to a hard structure. There they develop into polyps and catch small prey that swims by. After several days the polyp will detach and become a swimming ephyra, and will eventually turn into an adult jellyfish.
When disrupted, the cannonball secretes a mucus out of its nematocyst that contains a toxin.
The toxin harms small fish in the immediate area and drives away most predators, except for certain types of crabs. Although cannonballs do not commonly sting humans, they do have toxins that can, but not usually, cause problems in animals and humans. However, cannonball jellyfish are mostly harmless to humans. Contact with them may cause the skin to itch slightly, or minor eye irritation.
One of the main predators of cannonball jellyfish is the endangered species of leatherback sea turtle. Cannonball jellyfish are also commercially harvested as food for humans.
So don’t be scared of this weird-looking creature. So whether you’re in the market for a snack or a conversation starter, look no further than the cannonball jellyfish!