Cerastoderma

Cerastoderma is a genus of small to medium-sized marine bivalves in the family Cardiidae, commonly known as cockles. The genus includes several species, most notably Cerastoderma edule (the common cockle) and Cerastoderma glaucum (the lagoon cockle). Members of Cerastoderma have thick, rounded shells with pronounced radial ribs and a heart-shaped overall outline. Shells are usually 2 to 5 centimeters long and display variable coloration, often brown, gray, or reddish with lighter markings.

They occur in the temperate coastal waters of Europe and adjacent regions, typically in estuaries, shallow bays, and tidal flats with sandy or muddy substrates. They burrow just below the sediment surface and feed by filtering plankton and organic particles from the water.

Reproduction is sexual and external: adults release eggs and sperm into the water, where fertilization occurs. The larvae are free-swimming and pass through planktonic stages before settling to the substrate as juveniles. In favorable conditions they grow quickly and reach reproductive maturity within the first year or two.

Ecologically, Cerastoderma species contribute to sediment stabilization and water filtration and serve as prey for birds, crabs, and other predators. They are also economically important as a fishery resource, harvested for consumption in many parts of Europe and beyond, known as cockles or berberechos in some languages.

Conservation and management vary by region, but pressures from overharvesting, habitat loss, pollution, and coastal development have led to regulatory measures such as size limits, seasonal closures, and closed areas to sustain populations.