Have you ever been standing on the shore and notice that, after a wave retreats from your feet, a bunch of small clams wiggle their way into the sand?
These clams, called coquina clams, have fascinated students and campers at the field station. They are very small, only about 10 to 25 cm, and can be purple, pink, orange, blue or gray. They are bivalve mollusks which means they have two hinged shells that cover their soft invertebrate body.
Coquina clams move up and down the shore by burying themselves in the sand after each wave moves them. This ability to burry themselves is thanks to their foot. This area where they reside is called the swash zone. They move so frequently so they can get the best feeding opportunities.
They are filter feeders that use two siphons which look like tubes to filter seawater. One extracts oxygen and collects algae, detritus and phytoplankton. The other gets rid of the waste that is in the water.
Fish, crabs and shorebirds feed on coquina clams, and some people even make soup out of them.
Coquina clams are an indicator species because they are sensitive to environmental changes. They allow researchers to know whether or not the environment is healthy or not.
They can live up to two years in the wild, but without moving water for them to filter, they can only survive three days.
The next time you are at the beach, check around your feet to see if any coquina clams are making their way back into the sand when a wave passes!
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