Calico Scallop (also known as the Atlantic Calico Scallop)
Phylum Mollusca, Class Bivalvia, Order Pectinida, Family Pectinidae, Genus Argopecten, Species Argopecten gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell valve, fan-shaped disc
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole shell valve, fan-shaped disc
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch in width, which is slightly smaller than average. Adult Calico Scallops typically range from 1 to 2.5 inches.
Color & Pattern
The exterior features a creamy white base color adorned with distinctive reddish-brown zig-zag and chevron markings radiating from the umbo, along with scattered darker brown spots near the margins. Colors are entirely natural and vibrant.
Rarity
Common, frequently found washed ashore along southeastern US and Gulf Coast beaches, especially after storms.
Habitat
Found in shallow marine waters, typically in depths ranging from a few feet to over 150 feet. They prefer clean sandy or shelly substrates, often inhabiting offshore continental shelf waters and occasionally shallow bays.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through Florida, the Gulf of Mexico, the Caribbean, and south to Bermuda and northern South America.
Description
A charming, solid, fan-shaped bivalve with roughly 18 to 21 strong, rounded radial ribs extending from the beak to the scalloped margin. The exterior texture is finely ribbed and grooved, presenting a classic symmetrical scallop profile with unequal 'ears' (auricles) near the hinge.
Key Features
Distinguished by its plump, convex valves, strong radial ribs, and the distinct chevron or zig-zag reddish-brown color patterns against a pale background. Unlike some other scallops, both valves are quite convex.
Collector Value
Low to moderate commercial value due to their abundance, but always popular among beachcombers and beginner-to-intermediate shell collectors for their bright, cheerful patterns. Typically valued at under a dollar individually, though pristine sets command modest souvenir appeal.
Condition Notes
The shell is in excellent, near-Gem condition with intact margins, bright natural coloration, no major chips, and well-preserved structural ribs. A very desirable collectible specimen.
Interesting Facts
Unlike many bivalves that burrow or stay permanently attached, Calico Scallops are capable of swimming actively by rapidly snapping their valves together to expel water, allowing them to escape predators like starfish.
Ecological Role
Calico Scallops act as important filter feeders in benthic marine ecosystems, clearing suspended particles from the water column. They serve as a vital food source for numerous marine predators, including sea stars, octopuses, fish, and gulls.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which tends to be slightly larger, flatter, and often has more compressed ribs and a more northern range.
Beach Finding Tips
Look along high-tide wrack lines on Gulf Coast and Florida Atlantic beaches, particularly following strong offshore winds or winter storms. Scallop shells wash ashore frequently in shell-rich drift zones.