This Week's Reefview - Short Shelled Snails are small snails that eat coral. They have thick shells that are very hard to break. The shells get covered and grown over by different kinds of algae that grow around the reef. This covering camouflages the snails so they are almost impossible to see, and until recently were virtually unknown on the reef.
These snails are a favorite food of large spiny lobsters. Lobsters, commonly called crawfish in the Bahamas, have to be two pounds or larger in order to have the strength to crack the snails and eat them.
Because lobsters, especially large ones, have been so completely fished out of the reef, the snail population has been able to spread unchecked.
The snails have moved into the shallow reef and are eating the now endangered Elkhorn coral. This leaves white patches and spots on otherwise orange coral. At first these white patches were thought to be diseases since the snails are so hard to notice. Many times these white areas become diseased as the stressed coral loses its resistance and the chewed areas open the coral tissue to infection.
The relationship between lobsters, coral and Short Shelled Snails is a very good example of how different species interact in the reef environment.
In the short term, specific reef areas can be conserved by searching for and removing all of the snails that can be found. In the longer term and larger picture, large lobsters need to be protected in order to save this species of coral.
About the Author: Fred Riger is president of the Grand Bahama Dive Association. Fred operates Grand Bahama Scuba, and has lived in The Bahamas for 25 years. He can be contacted at email@example.com
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