Thursday, November 4, 2010

The Floating Mouth

Seems like a lot of people see a jellyfish and get the heebie-jeebies. On that account, there are certainly times when walking on the beach or swimming in the ocean are definitely not something those folks want to do. Jellyfish don’t bother me very much, and I’m not particularly concerned I might be stung when swimming in the ocean. Though I’ve been spared, it does happens on occasion; people get tangled up with a jellyfish and come out of the water none too happy. Where I’m situated on Florida’s eastern coast, it isn’t a problem that anyone need worry too much about. Painful encounters with jellyfish are not that frequent. More often than not, the jellyfish one sees on this stretch of beach are washed up onto the sand in a very visible blob, and easily avoidable. The photographs here are what you see a fair amount of on the beach, depending on currents and tides. There must have been a huge colony of them in the drift last night, because I passed a hundred or more of them on my walk this morning.

The common jellyfish in these parts is the Aurelia aurita, more commonly called the moon jelly or jellyfish, sometimes the saucer jelly. It is from five to forty centimeters in diameter, and depending upon the stage or phase of life, either clear jelly throughout, or colored by pink or purplish patterns. Most conspicuous are the four reddish gonads forming a clover-like shape in the center of the body mass.

The jellyfish is capable of only limited movement on its own, and even when swimming gets most of its movement from ocean currents. The animals’s primary aim is to stay near the water’s surface, whether by current or its own swimming. Food is most plentiful near the surface. Jellyfish are carnivorous animals and feed on plankton, which includes mollusks, crustaceans and young worms. They will also feed on other jellyfish. The tentacles, with their stinging cells are sometimes used to catch small fish.

Like anemones and corals, the moon jellyfish is an invertebrate, with a sac-like body, mouth and tentacles. It is made up of more than ninety-five percent water, and basically just a floating mouth and digestive system. They have no brain, no blood and no nervous system; have neither lungs or gills or tracheal system of any kind. They get oxygen by diffusion through their thin membrane. Aurelia jellyfish rarely live more than several months.

Fishermen do not always appreciate the presence of jellyfish, because they eat the larvae of commercially important fish. Jellyfish can also cause an outbreak of algae blooms, which neither fishermen nor tourists like.

Remember that the bell-shaped body of a jellyfish cannot sting, though it may be sticky with mucus. Should you be stung while swimming, aside from the pain, the sting is usually harmless. The best treatment for a jellyfish sting is household vinegar or—of all things—urine.

The movement of these strange creatures is truly beautiful to watch. Take a look at the short YouTube clip below.

1 comment:

  1. Those jelly fish are truly beautiful to watch. Their movements are so graceful; but, having been stung by one once upon a time, I am afraid of them. Vinegar does relieve the sting, but not immediately, so there is stinging pain for quite a bit. Beautiful......yes, but not friendly. Beverly


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Oak Hill, Florida, United States
A longtime expat relearning the footwork of life in America