(Yes, you are seeing double - double feature! No mistake, Week Four has two articles. See the other one here.)
One of the great things about islands is that they often have beaches. St. Catharines Island is no exception. Although there are a number of beaches here, the one most accessible to me is the aptly - if not creatively - named North Beach. This is where I found myself Monday afternoon, when I went for one of my frequent seashell hunts (a new obsession). As I crested the last row of dunes, I was puzzled to find that the beach's usually smooth complexion had broken out in a bumpy purplish rash. I used my camera's zoom to see if I could get a closer look. Still unable to get a clear view, I walked out to the pimply anomaly.
Hundreds and hundreds of cannonball jellyfish - scientifically known as Stomolophus meleagris - had been stranded ashore. Some of them were still pulsing in a weak attempt to swim through the surf that had abandoned them. It was a challenge not to step on one while picking my way across the littered shore. The scene reminded me of a similar experience I had years ago in San Diego when thousands of small, red crabs covered the beach for days, eventually needing to be bulldozed away. As I tried to pitch a few of the jellyfish back into the water (with a gloved hand, of course), my mind swam with possible explanations. Had there been an ecological disaster? Had an offshore storm caused them to change course? Agal bloom? Mass suicide?
A big part of why animals (including humans) do what they do has to do with two very strong motivations; food and sex. So a great way to figure out what's going on with a group of animals is to take a look at what they eat, what eats them, and how they make more of themselves. Cannonball jellyfish eat a lot of things, but mostly fish eggs, zooplankton, and copepod larvae. I know next to nothing about ichthyology, but it seemed like the wrong time of year for fish eggs to be abundant. So I crossed "feeding frenzy" off of my list. On the flip side of the food chain, we have humans and leatherback sea turtles as the main consumers of these jellies. While it isn't a common menu item found in Georgia restaurants, jellyfish export to Asia is a multimillion dollar industry. Between five and ten thousand tons of these squishy side dishes get shipped overseas annually. But since it's the wrong time of year for leatherbacks and I don't know of any commercial jellyfish enterprises nearby, I crossed "avoiding predators" off of my list too.
That leaves us with sex, but I hit a dead end here too. There isn't much to a cannonball jellyfish aside from an opening - which functions as anus, mouth, and reproductive apparatus - surrounded by wiggly tentacle bits. So, when they mate, males release a cloud of sperm and females swim through the cloud, drawing in the sperm to fertilize their eggs. As unromantic as it is, this event doesn't normally take place until summer or early spring. Although the seventy-degree weather might be deceiving, it's still the first of February. There are two remaining, very plausible, reasons for the mass stranding of jellyfish on North Beach this week. One is simply that this type of jellyfish kinda sucks at swimming. One might imagine that an organism whose body is ninety-eight percent water would have no trouble navigating the ocean. But, jellyfish strandings are quite common because a strong current will easily throw a bloom (that's what a flash mob of jellyfish is called) off course and maroon them when the tide goes out. The other very possible factor involved here is environmental degradation (Here's a quick video about that). I may never know for sure why I found a beach full of jellies, but the thrill of discovery will keep me hunting for answers.