StoryImage( ‘/Images/Story//Auto-img-116482370129904.jpg’, ‘Photo courtesy of www.oregonstate.edu’, ‘The sea urchin not only provides food for the gourmand, but it has contributed to our knowledge of fundamental biological processes.’);
One of the strangest looking animals occurring along the Atlantic and Pacific coasts of the United States, and in many other parts of the world, is the sea urchin. This animated pincushion, or the marine porcupine, as it is sometimes called, is covered with long, brittle spines that effectively protect it from any of its hungry marine neighbors. In addition to casual protection, the spines of some sea urchins are connected to venom glands offering a more formidable protective shield. The spines are also used somewhat like stilts by which the animal clumsily moves about the bottom of the sea.
When visiting the seashore, one should be careful wading barefooted near piers, jetties, and pilings where these relatives of the sea stars, sea cucumbers and sand dollars frequent. If the spines of the urchin penetrate your skin, they almost always break off and work their way into the deeper tissues. Surgery is frequently required to remove them.
The shell of the sea urchin is composed of rows of calcareous plates that are fitted closely together, forming a rigid, hollow ball flattened on each end. There are numerous holes in the shell through which muscles attach to each spine. Though the spines are easily broken off, they, like the teeth of a shark or rattlesnake, are quickly regenerated.
From the mouth region on one of the flattened sides of the shell, five shiny-white teeth are connected to a complicated structure within the shell that some ancient zoologist named Aristotles Lantern. These mineralized, hard teeth are used for eating sand. Animal and vegetable matter that falls to the bottom of the sea becomes mixed with sand and is ingested by the urchin. The teeth grind up the sand, removing the organic matter for use as food, and eventually the finely-ground sand is cast out.
In France, Italy, Spain, Portugal and in some parts of the Orient, urchins are relished as delicacies. Some years ago, an international incident developed when Japanese fishermen, seeking to ease an insatiable demand for sea urchins in their homeland, ravaged urchin populations off the coast of California. The ecology of the ocean floor in certain areas was devastated by the methods employed to catch the spiny creatures. The Japanese were eventually forced to withdraw from our shores, but not before damage, which required years to repair, was done to the marine environment.
In France, the sea urchin is called la fruite de mer (fruit of the sea) or letoile de mer (star of the sea). On several occasions when I lived in France, I snacked on sea urchin while meandering along the banks of the Seine in Paris. Pushcart vendors offered sea urchins loaded with eggs for about 15 cents each, or those without the roe for about 10 cents. The vendor would remove the spines with a gloved hand, and with a sharp knife cut out a portion of the shell around the mouth. The delicacy was served on a paper napkin along with a plastic spoon to be used to scoop out the internal organs. At that time, sea urchins were so popular in France it was estimated the Marseilles fish market supplied more than 200,000 dozen a year, and those were urchins taken from the Mediterranean and not from the many fishing grounds along the Atlantic.
In addition to providing gourmand food for humans, the sea urchin has contributed to mankinds knowledge of fundamental biological processes. Sea urchins and their relatives are the most advanced of all invertebrate (without backbones) animals and are believed to be the direct ancestors of vertebrates (with backbones). About 130 years ago, when zoologists were studying the processes of fertilization and development, it was found that our spiny friends were excellent experimental subjects. In fact, the first time a human witnessed the penetration of an egg cell by a sperm cell was with sea urchin cells. As a consequence, much of our knowledge of embryology, including our own, was acquired by studying the process in the sea urchin.
Though this creature does not even look like an animal to many, it is and has been of great benefit to mankind. The next time you are in Paris, be adventurous and enjoy La fruite de mer, but expect to pay a bit more than 10 or 15 cents for the pleasure.
Dr. Robert Hedeen is a former resident of Marylands eastern shore and resided in the Chicago area from 1960 to 1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.
From the Nov. 29 – Dec. 5, 2006, issue