by Leann Zotis

Created on: July 12, 2011   Last Updated: November 26, 2011

It’s a rare beach lover who hasn’t spotted a jellyfish or two washed up on shore after a storm or when the tide goes out.  Whether you regard them are beautiful or frightening, jellyfish are undeniably magnificent creatures of the deep.  Jellyfish can be found in all the oceans of the world.  Some swim near the surface; others lurk far below near the ocean floor.  There are hundreds of known

jellyfish species, with hundreds more swimming the ocean depths yet to be classified and named. 

Jellyfish are strange creatures, to be sure.  They have a very minimalist physical structure.  Ninety-seven percent of their bodies are made of water.  They lack a brain, digestive system, respiratory system or a clear circulatory structure.  Most of them can’t even see the world around them.  They can eat and smell and detect the world around them through a nerve net that allows them to detect stimuli. 

Jellyfish can range in size from thumbnail size to hundreds of feet in diameter.  A few can be deadly while most others inflict an uncomfortable sting that can be treated and goes away quickly. 

The most commonly found jellyfish is the Moon Jelly or Aurelia Aurita.  A visit to your local aquarium will usually allow a glimpse of this saucer shaped jellyfish.  Their near transparent bodies reveal four pink horseshoe shaped markings that provide the only color they give off.  They grow to about 6 to 8 inches in length, 20 inches in diameter and may inflict a non-fatal sting if molested.

Another common jellyfish is the Cannonball Jelly or Stomolophus meleagris.  This jellyfish often shows up in fishing nets.  They do not possess the typical tentacles so characteristic of jellyfish; rather they have little fingers protruding from their arms.  They may grow to be 8 to 10 inches in diameter and are completely harmless.

One of the more interesting species of jellyfish is the Portuguese Man of War or Physalia physalis.  It always attracts attention and excitement when spotted in the ocean waters.  While not a true jellyfish, its bell is purplish blue in color and can grow to ten inches in size.  They are feared for their sting that, though rarely fatal, can be quite painful, leading to shock, chills, fever and rash.

Another noteworthy specimen of the jellyfish world is the Lion’s Mane or Cyanea capillata, so named because of its appearance.  Its bell is 6 to 8 inches wide and it has reddish arms.  Eight clusters of tentacles hang from these arms.  Its sting is mild, leading to a rash.

Jellyfish are just one group of the many intriguing and interesting creatures in the waters of the planet.  They are not deliberately aggressive but are quite able to defend themselves when threatened.  There are hundreds of species to observe and each one promises to reveal something unique about its existence to those who care to examine their underwater world.

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