Atlantic Calico Scallop (also known as Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole individual valve, fan-shaped disc
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole individual valve, fan-shaped disc
Family
Pectinidae (Scallop family)
Size
Approximately 1.25 inches across, which is typical for a mature specimen. Adult sizes generally range from 1 to 2 inches.
Color & Pattern
Displays a mottled pattern of white overlaid with warm peach, pink, and orange patches resembling calico fabric. The coloration is natural and shows typical variance found in shallow-water populations.
Rarity
Common, frequently found washed ashore on beaches throughout its natural range.
Habitat
Shallow marine waters, typically found resting on sandy or shelly substrates in bays, sounds, and offshore marine environments down to depths of about 150 feet.
Geographic Range
Western Atlantic Ocean, from North Carolina southward through the Florida Keys, the Gulf of Mexico, and the Caribbean Sea.
Description
A classic fan-shaped bivalve with symmetrical rounded ears at the hinge. The exterior features strong, well-defined radiating ribs that span from the umbo to the outer margin, creating a scalloped edge. The surface texture is finely ridged, and the valve exhibits a gentle convexity.
Key Features
Symmetrical ears (auricles) at the hinge line, prominent radiating ribs (typically numbering around 18 to 22), and a distinctive mottled calico coloration pattern.
Collector Value
Low to moderate commercial and collector value. Commonly found in shell shops and collected by beachcombers; prized for crafts and decorative displays rather than as rare collector centerpieces.
Condition Notes
Good overall condition with intact margins, clear coloration, and no major structural fractures or boring marks. Minor natural wear along the outer lip.
Interesting Facts
Unlike many bivalves that burrow or remain stationary, calico scallops are capable of swimming short distances by rapidly clapping their valves together to expel water, allowing them to escape predators.
Ecological Role
Serves as an important prey item for various marine predators including fish, rays, crabs, and sea stars. They are filter feeders that help maintain water clarity by consuming suspended phytoplankton.
Similar Species
Rough Scallop (Argopecten irradians), which tends to be slightly more rounded with fewer ribs, and the Atlantic Bay Scallop which prefers very shallow seagrass beds.
Beach Finding Tips
Look along ocean-facing beaches after storms or high tides, particularly near inlet passes or areas with coarse shell hash where wave action deposits light bivalve shells.