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, fan-shaped whole shell)
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled, fan-shaped whole shell)
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches in width, which is typical for an adult of this species. Adults generally range from 1 to 2.5 inches.
Color & Pattern
A creamy off-white or yellowish base heavily splashed with striking reddish-pink to brownish-maroon blotches and broken bands radiating from the umbo to the ventral margin. The coloration is completely natural and vibrant, showing typical 'calico' patterning.
Rarity
Common to Very Common, frequently washed up on beaches throughout its native range, especially following storms.
Habitat
Shallow marine waters, typically found on sandy bottoms, shell hash, and seagrass beds from the low intertidal zone down to depths of about 160 feet (50 meters).
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through the Florida keys, the Gulf of Mexico, and the Caribbean Sea.
Description
An attractive, roughly symmetrical fan-shaped bivalve with roughly 18 to 22 prominent, rounded radial ribs extending outward from the hinge. The margins are scalloped to interlock tightly, and the auricles (ears) at the hinge line are somewhat unequal in size. The exterior texture is finely striated across the sturdy ribs.
Key Features
Rounded radial ribs numbering around 20, distinct unequal ears at the hinge, and the characteristic mottled reddish 'calico' color pattern over a pale background.
Collector Value
Low to moderate commercial value. While very popular among casual beachcombers and crafters due to their bright colors, they are too common for high-end specialist collections, typically selling for mere cents or included in bulk shell lots.
Condition Notes
Good to Fine condition. The valve is intact with well-preserved natural coloration and minimal edge wear, though slight fading or minor chipping may be present along the delicate ventral margin.
Interesting Facts
Unlike most bivalves that burrow or attach permanently, Calico Scallops are capable of active swimming by rapidly clapping their valves together to expel water, allowing them to escape predators like starfish.
Ecological Role
Calico scallops serve as important filter feeders, improving water clarity, and act as a vital food source for numerous marine predators including fish, rays, sea turtles, and carnivorous snails.
Similar Species
Bay Scallop (Argopecten irradians) - can be distinguished by having fewer ribs (usually 17 or fewer) and a slightly flatter, more rounded profile with equal-sized ears.
Beach Finding Tips
Look along high-tide wrack lines on sandy ocean-facing beaches, particularly in Florida and the southeastern United States, right after strong onshore winds or tropical storms.