Atlantic Calico Scallop (also known simply as Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve, whole shell, fan-shaped
Species
Argopecten gibbus
Shell Type
Bivalve, whole shell, fan-shaped
Family
Pectinidae (Scallop family)
Size
Approximately 1 to 1.5 inches in diameter, which is typical for an adult of this species. Full-grown specimens rarely exceed 2 inches.
Color & Pattern
Mottled pattern featuring patches and splashes of reddish-brown, orange, purple, and cream against a lighter background. The colors appear natural and fairly fresh, showcasing the characteristic 'calico' print on the exterior ribs.
Rarity
Common; frequently washed up on beaches throughout its range, particularly after storms.
Habitat
Shallow marine waters, typically found living on sandy or shelly substrates in offshore beds, ranging from shallow subtidal zones down to depths of about 150 feet.
Geographic Range
Western Atlantic Ocean, extending from North Carolina down through the Florida coasts, the Gulf of Mexico, and into the Caribbean.
Description
A charming, fan-shaped bivalve with symmetrical, slightly rounded ears at the hinge. The exterior features strong, well-defined radial ribs that radiate from the umbo to the scalloped outer margin. The texture is slightly rough due to the ribbing and growth lines, and the coloration displays a vibrant, speckled calico motif.
Key Features
Nearly equilateral and equivalve fan shape, prominent and equal-sized auricles (ears) at the hinge line, numerous well-rounded radial ribs (typically around 18 to 21), and the distinctive multi-colored speckled or mottled pattern.
Collector Value
Low to moderate commercial or monetary value because they are common, but highly prized by casual beachcombers for crafts and decorative collections due to their cheerful patterns.
Condition Notes
The specimen appears to be in Good to Fine condition, largely intact with good retention of its natural coloration and pattern, though showing minor natural wear along the delicate margin and hinge.
Interesting Facts
Unlike many bivalves that burrow or cement themselves, Calico Scallops are capable of swimming. By rapidly clapping their valves together, they can jet-propel themselves through the water column to escape predators.
Ecological Role
Serves as an important prey item for various marine predators including fish, rays, and sea stars. They are filter feeders that help maintain water clarity and quality in marine ecosystems.
Similar Species
Bay Scallop (Argopecten irradians), which tends to be slightly larger, has fewer ribs (usually 17 or fewer), and prefers shallower seagrass bed habitats.
Beach Finding Tips
Look along high tide wrack lines on southeastern US and Gulf Coast beaches, especially following strong offshore winds or storms that churn up offshore seabeds.