Common Cockle, Heart Cockle
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Cardiidae, Genus: Cerastoderma, Species: C. edule · Cardiidae (Cockle family) · Bivalve (Two-shelled); this specimen is a single valve. Shape is oval to roughly square/heart-shaped.
Species
Cerastoderma edule
Shell Type
Bivalve (Two-shelled); this specimen is a single valve. Shape is oval to roughly square/heart-shaped.
Family
Cardiidae (Cockle family)
Size
Approximately 1.25 inches (3.2 cm). This is a mature specimen; typical adult range is 1 to 2 inches.
Color & Pattern
Uniform creamy white to pale off-white. The shell appears sun-bleached or naturally light-colored, lacking the darker brown or yellow concentric bands often seen in live specimens. The interior appears pure white.
Rarity
Very Common. These are among the most frequently found shells on European and North Atlantic beaches.
Habitat
Intertidal and shallow subtidal zones. Prefers soft substrates like sand, mud, or fine gravel in estuaries and coastal lagoons.
Geographic Range
Commonly found in the North Atlantic, ranging from Iceland and Norway down to Western Africa and throughout the Mediterranean Sea.
Description
A robust, thick-walled bivalve valve with a convex, slightly inflated profile. The exterior is characterized by 22-28 prominent radiating ribs that are crossed by fine concentric growth lines, giving the ribs a slightly scaly or notched texture upon close inspection. The margin is distinctly crenulated, matching the ends of the exterior ribs.
Key Features
Rounded-quadrate shape with a prominent umbo (beak); approximately 24 strong radial ribs; crenulated (scalloped) edge; sturdy hinge structure.
Collector Value
Minimal monetary value (under $1 USD) due to its abundance. It is primarily a sentimental or decorative find for beachcombers rather than a high-end investment piece.
Condition Notes
Good condition. The valve is intact without major chips or cracks. It shows signs of beach-wear (slight smoothing of the rib scales) and has been bleached white by the sun. Resulting collectibility grade: Fine.
Interesting Facts
Cockles are capable of 'jumping' by using their strong, L-shaped muscular foot to push off the sandy seabed to escape predators like starfish. They have been a significant human food source for thousands of years and are still commercially harvested today.
Ecological Role
Suspension feeder that filters plankton and organic detritus from the water column. They are a vital food source for shorebirds (like Oystercatchers), crabs, and flatfish.
Similar Species
Cerastoderma glaucum (Lagoon Cockle), which prefers lower salinity and has a more elongated posterior. Acanthocardia echinata (Prickly Cockle) has sharp spines along the ribs.
Beach Finding Tips
Best found after a retreating tide on sandy flats or in the wrack line (debris piles) after a storm. They often accumulate in large numbers in sheltered bays.