"Woah - Jellyfish!" or ... everything you ever wanted to know about Cnidaria
By Alice Bain - The Abaconian - 15 August 2002

I started swimming backwards toward the beach, as fast as I could. "What"s wrong?" asked my boyfriend.

"Jellyfish!" I yelled, scrubbing at my leg while I swam, "we have to get out of the water now!"

Summer in the Bahamas"jellyfish season. My boyfriend and I and a friend of ours had driven to Treasure Cay to swim at the beach and eat hamburgers at a little beach side bar. We had been in and out of the water for at least two hours without incident when my leg started burning with the characteristic cold fire of a jellyfish sting. There"s nothing quite like it. If you touch an ice cube or if you burn your hand on a hot skillet the sensation is instant and you jerk away reflexively.

Jellyfish stings are "soft" - the pain creeps up on you like someone turning up a dimmer switch on your nerve endings. So there I was, hopping up the beach with my leg on fire, heading towards the resort office where a lady kindly provided me with a product with a name like "sting-away" or "sting-eze" that contained papaya extract to kill any remaining sting cells that were lodged in my skin. It helped a bit.

The sting itself didn"t really come up until the next day. A patch of skin roughly two and a half inches in diameter turned an angry purple color with two short tentacular-looking extensions pointing towards my ankle. The burning had ceased the first night and was replaced with an itch almost rivaling that of poisonwood inflammation. I say "almost" because I was able to restrain myself from scratching itwith poisonwood, I often wake up in the morning to find I have been scratching the area in my sleep.

Scientists group jellyfish, along with corals, sea anemones and hydras (soft corals), into a phylum known as "Cnidaria." I wonder if Roald Dahl had the Cnidaria in mind when he invented the jellylike extraterrestrial Vermicious Knids to be the villains of his book Charlie and the Great Glass Elevator! Cnidaria are, in general, gelatinous and possess stinging cells called "nematocysts." Under a microscope, a nematocyst looks like a cigar tube with a spiral coiled inside it. When my leg brushed the jellyfish, the trapdoors at the ends of thousands of these cigar tubes popped open, and the coiled stings shot through my skin and injected me with venom meant to paralyze and digest a hapless fish. Luckily, I am too large for most jellyfish to digest, although some of the more venomous varieties (such as sea wasps) would have made a more thorough attempt. My sting was painful and certainly looked alarming but was not anywhere near as severe as the lash inflicted by the sea wasp. I never saw the jelly that stung me (I was too busy swimming away!) but the sting pattern and the level of severity seems to indicate that it was probably a "sea nettle." The most commonly seen jellyfish on Abaco is the Cassiopeia, or "upside-down jellyfish." Any mangrove creek system will have areas almost entirely carpeted with these jellies, and I have seen them in every harbour I"ve looked into. They sit on the sea floor, upside down on their flattened "bells," with an array of eight short, stubby tentacles spread to the sky.

Cassiopeias house symbiotic algae in their cells and get most of their nutrients from photosynthesis"although they do also catch and digest small animals with classic jellyfish nematocyst cells as well. Most people do not feel a Cassiopeia sting, although some may find they have sensitivity to it.

Another jelly I remember from my childhood in Nassau was the "sea thimble""in the summer great schools of these tiny, pulsating brown jellies would wash in and out with the tides. Swimming through them was painless but produced a rash resembling measles the next day! In Abaco"s tidal areas, around docks that see a lot of current (e.g. in the cut between Sugarloaf Cay and Eastern Shores) I have seen moon jellies in great abundance. These are hemispherical, transparent with a milky tinge and sport a fringe of eyelash-like tentacles around the rim and a "four-leaf-clover" at the apex of the bell.

Sea nettles and sea wasps are unfortunately more often felt than seen since they are more regularly found in the ocean than the calm Sea of Abaco. True pelagic or ocean-going jellies grow much larger than our local varieties"for example, tropical species of the "lion"s mane" jelly can grow tentacles up to 60 feet long!

The sting on my leg stopped itching within a few days although the purple welt didn"t fade for over a week. Even now, two weeks later, I can still see the outline of it. Because I"m a Bahamian and I"m stubborn, I refused to let the sting deter me from my birthright of swimming in the sea between Labour Day and Columbus Day. But last week while swimming and throwing a tennis ball in the water for a friend"s Labrador to retrieve, my hand brushed something unseen and gelatinousand I thought it best to get out!