Atlantic Calico Scallop (Calico Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. gibbus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell, fan-shaped disc
Species
Argopecten gibbus
Shell Type
Bivalve (two-shelled), whole shell, fan-shaped disc
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches in width and length, which is average for this species. Adults typically range from 1.5 to 2.5 inches.
Color & Pattern
The exterior exhibits a mottled pattern of purplish-brown and white typical of the calico scallop, though it is slightly sun-bleached with muted tones. The pattern consists of irregular splashes and zig-zags of reddish-brown over a lighter whitish or cream base.
Rarity
Very Common
Habitat
Found in shallow marine waters, typically subtidal zones down to about 150 feet. Prefers sandy or shelly substrates, often inhabiting offshore grass flats and sandy bottoms.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down to the Caribbean and Brazil, with dense populations commonly found off the coast of North Carolina and Florida.
Description
A classic fan-shaped bivalve with roughly 18 to 21 rounded, prominent radial ribs. The shell is nearly equivalve with slightly unequal auricles (ears) at the hinge. The margin is scalloped, matching the external ribs.
Key Features
Distinguished by its rounded radial ribs (usually 18-21), somewhat inflated valves, and the characteristic mottled reddish-brown or purplish 'calico' pattern.
Collector Value
Low to moderate commercial and collector value due to abundance, but highly prized by casual beachcombers. Typically valued at a few cents to a dollar per specimen.
Condition Notes
Good condition with minor wear on the umbo and some slight sun-bleaching. The margin is mostly intact with minor chips. Collectibility grade is Good.
Interesting Facts
Unlike many bivalves, calico scallops are capable of swimming short distances by rapidly clapping their valves together to expel water, allowing them to escape predators like starfish.
Ecological Role
Serves as an important prey species for fish, rays, sea turtles, and marine mammals. Filter feeders that help maintain water quality in marine ecosystems.
Similar Species
Bay Scallop (Argopecten irradians) which tends to have flatter ribs and a more rounded, less inflated shape, and is often found in shallower estuarine waters.
Beach Finding Tips
Look along North Carolina beaches after storms or rough surf, particularly at low tide along the surf line where shell deposits accumulate in shell lines.
Notes
NC beaches