Cockles and angelwings

Cockles along the beach

Cockles along the beach

Published: Monday, December 23, 2013 at 11:29 AM.

Ever notice how the beach changes from summer to winter? We are now in the “winter beach” and this is the time when shelling is best.

Throughout the summer, sand is deposited on the beaches and the dunes build. The beach becomes higher and wider. In winter, changes in wave height and direction cause sand to be pulled offshore from the beach and deposited in protective offshore sandbars. The winter beach is narrower and lower. While this phenomenon is more extreme on the Atlantic and Pacific coasts, nevertheless our Panhandle beaches also go through this cycle.

Because sand is pulled off the beach in winter, shells that were buried all year are now exposed. Both tourists and residents can be seen carrying buckets or bags of shells to take home. The most commonly collected shells are the giant cockles and white angelwings, with the occasional empty shell of a large left-handed whelk.

The giant cockle or heart cockle (Dinocardium robustum) is familiar to most residents. It is that big – up to five inches long - tan or cream colored bivalve with parallel ribs with brown patches. It occurs around Florida wherever one finds their preferred habitat - sandy shallows off beaches. Therefore, the big bend area, with its lack of wave energy, and therefore lack of beaches, does not offer suitable habitat for the giant cockle. The giant cockles found on our Gulf beaches is a more colorful variety than their Atlantic cousin and is classified as a subspecies, Dinocardium robustum vanhyningi, often called Van Hyning’s cockle.

These bivalves are filter feeders that use their long muscular foot to dig down into the sand and extend their siphons into the water column to pump in suspended food particles. The cardium part of their genus name, Dinocardium, may remind you of heart. To see why they are sometimes called heart cockles, find two shells of about equal size and place their edges together. Now turn them to the side and look at the shells with their edge facing you. The profile from the side resembles a Valentine heart. The fully grown shells are also about the size of a human heart.

You probably remember the old song about Molly Malone singing, “cockles and mussels, alive, alive oh!”  As Molly was pushing her wheelbarrow, the cockles she was selling were not our Van Hyning’s cockle, but the common European cockle, Cerastoderma edule, or any of several small cockle-like clam species that are harvested using rakes at low tide. Cockles are still available at seaside stalls in the United Kingdom. Our own giant cockles are edible also and the reddish flesh makes fine chowder. However, few people go to the trouble to harvest our giant cockles. For a bit of trivia, cockles are even mentioned in the Magna Carta. That historic document granted English subjects the right to collect up to eight pounds of cockles from the shore without hindrance or confiscation.

Our beaches have several other smaller shells that are classified in the same family as the giant cockle. One can easily find shells of the Atlantic strawberry cockle (Americardia media), spiny papercockle (Papyridea soleniformis), Florida pricklycockle (Trachycardium egmontianum), and even the smooth-shelled common egg cockle (Laevicardium laevigatum).



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