Those tiny, colorful clams with two siphons poking our of their shells that emerge quickly once the waves wash gently ashore are known as coquina (ko-KEE-nah) clams. These bivalves rarely exceed an inch long and are indicators of a healthy beach. If eroding beaches are constantly being renourished, coquina clams, as well as other sand dwelling invertebrates (i.e., mole crabs), could become buried under the extra sediment. Many beaches have to be renourished because the natural supply of sand from rivers and other sources from the mountains have been impeded by dams and reservoirs. Coquina clams can usually recover their populations if a beach has not been renourished in a year or two.
They tend to feast upon single-celled detritus or algae. Fish, shorebirds, and humans tend to feast upon them. That’s right, coquina clams are found around the world and are enjoyed steamed with butter or even as ‘the basis for a great potato puree‘. In Australia there is a commercial fishery for the meat (God help those processors).
In Florida, you can visit one of my favorite places, Blowing Rocks Preserve, and see the coquina rock outcrop. The coquina rock is a soft rock that is made up of the coquina clam shells (as well as other materials). But, what makes this rock outcrop so unique is that it is part of the largest section rock, known as the Anastasia Formation, from the Pleistocene epoch (2.576 million years ago).