CANNONBALL JELLIES
By Dr. Joe Richardson
Unfortunately, this is the month when we have to be concerned with
jellyfish because August is when Sea Wasp Jellyfish show up around here.
And their sting isn’t any fun. To learn more about them, check page 26 of
last year’s August issue on line at: http://tybeebeachcomber.com/media/TBAUG
2017Issue-Web.pdf . This year, I want to deal with a friendlier, harmless
jellyfish we see around here, the Cannonball Jellyfish.
If you’ve been on Tybee’s beach a few times, chances are you have run
across Cannonball Jellies washed up. They might show up any time of the
year. Generally when they do, it’s not just one or two individuals, but dozens
of them. Offshore, they occur in groups of hundreds or more; so when the
currents bring a group close to the coast, we will see lots of them washing
up.
A Cannonball Jelly is stiffer and firmer than most other jellies. It feels
like rubber or plastic rather than soft and jelly like. It will still be slimy. Its
name comes from its spherical ball shape, and it is about the size of a big
grapefruit, or a cannon ball. It is creamy-white with a broad reddish-brown
band around it. Hanging down from the middle of its ball-shaped bell is its
mouth which actually has many small openings or mouths.
Lots of jellyfish have long, frilly, finger-like mouthparts hanging from the
middle of the bell, but those aren’t the tentacles. The stinging tentacles
actually hang from the outer edges of the bell. And if you look at a Cannonball
26 TYBEE BEACHCOMBER | AUG 2018
Jelly, you see that there aren’t any tentacles hanging from around the edge
of the bell. So there’s nothing there to sting you! For this reason, Cannonball
Jellies are pretty much harmless. If you really, really want to feel a Cannonball
Jelly’s very mild “tingle,” you would have to put your finger way up inside,
where it has some very short tentacles lining the inside of its bell.
Cannonball Jellies are my favorite jellyfish for two reasons. First, they don’t
sting. And second is that sometimes when you find one, you might find a
prize inside! Since it won’t sting you as long as you just handle the outside of
it, you can pick it up, turn it upside down, and look down inside there and see
if yours is carrying around a small, dark brown Spider Crab. Don’t worry, the
Spider Crab’s pinchers are tiny. Often when a Cannonball Jelly washes up,
the Spider Crab might crawl out, trying to figure out what is going on! And
shore birds, like seagulls, know about these crabs, so when a Cannonball
Jelly washes in, a bird will tear a hole in the jellyfish’s bell to poke around
and see if there is a crab in there to eat.
So, be careful with jellyfish this month. But if you see a Cannonball Jelly
washing up, don’t worry about it. Check it out, and you might find a hitchhiking
Spider Crab inside!
Dr. Joe Richardson (Ph.D. Marine Sciences) is a retired marine science
professor with 40 years of research and teaching experience along GA, the
southeastern coast and Bahamas. Besides research, he conducts Tybee
Beach Ecology Trips (www.TybeeBeachEcology.com) and frequently posts
pictures of their findings on his Tybee Beach Ecology Trips Facebook page.
Beach Walks
with Dr. Joe
/(www.TybeeBeachEcology.com)