Calico Scallop
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole individual valve, fan shape
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole individual valve, fan shape
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 inches in width and height, which is typical for an adult Calico Scallop. Adults generally range from 1 to 2 inches.
Color & Pattern
The exterior features a creamy off-white base with distinct, broken reddish-brown or purplish-brown rectangular spots and dashes aligned along the prominent radial ribs. The coloration is entirely natural and well-preserved, showing crisp contrast without excessive bleaching.
Rarity
Common, frequently found by beachcombers along the southeastern coast of the United States and the Gulf of Mexico.
Habitat
Found in shallow marine waters, typically ranging from the intertidal zone down to depths of about 150 feet. They inhabit sandy bottoms, seagrass beds, and shell rubble areas.
Geographic Range
Western Atlantic Ocean, extending from North Carolina down through Florida, the Gulf of Mexico, Bermuda, and the Caribbean Sea.
Description
A classic, symmetrical fan-shaped bivalve featuring approximately 18 to 21 strong, rounded radial ribs. The valve exhibits equal ears (auricles) at the hinge line. The margins are scalloped to interlock tightly, and the surface displays fine, concentric growth lines crossing the strong ribs.
Key Features
Symmetrical fan shape with roughly 18-21 prominent radial ribs, equal-sized auricles (ears) flanking the straight hinge line, and characteristic broken reddish-brown dashes marking the ribs.
Collector Value
Low to moderate commercial and collector value. While highly popular among casual beachcombers and crafters, their abundance keeps individual specimen prices low (typically under a dollar individually, though valued in collections for pristine color forms).
Condition Notes
Fine to Gem condition. The single valve is fully intact with sharp marginal edges, minimal wear, strong structural integrity, and vibrant natural color patterns with no significant fading or boring holes.
Interesting Facts
Unlike many bivalves that burrow or remain sessile, calico scallops are capable of swimming short distances by rapidly clapping their valves together to expel water. They also possess dozens of simple blue eyes along the mantle edge that can detect light and movement.
Ecological Role
As suspension feeders, calico scallops help filter phytoplankton from the water column, improving water clarity. They serve as an important food source for numerous marine predators including fish, rays, sea stars, and octopuses.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which tends to be slightly larger with fewer, broader ribs and a more rounded, less inflated profile compared to the Calico Scallop.
Beach Finding Tips
Look along high-tide wrack lines on sandy beaches in Florida and the Carolinas, particularly after storms or heavy winds. Calm mornings following incoming tides often yield the best unbroken specimens.