Atlantic Bay Scallop (also known as Common Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. irradians · Pectinidae (Scallop family) · Bivalve (two-shelled), whole individual valve with a fan or disc shape
Species
Argopecten irradians
Shell Type
Bivalve (two-shelled), whole individual valve with a fan or disc shape
Family
Pectinidae (Scallop family)
Size
Approximately 2.5 inches in width and length, which is a very typical and average size for an adult specimen of this species. Adults generally range from 2 to 3.5 inches.
Color & Pattern
Warm golden-tan and brown base coloration featuring distinct radial ribbing with darker charcoal or greyish undertones between the elevated ribs. The colors appear completely natural and well-preserved with minor signs of gentle weathering.
Rarity
Common, frequently discovered by beachcombers along the eastern United States and Gulf coasts, especially near seagrass meadows.
Habitat
Found in shallow marine waters, typically ranging from the intertidal zone down to about 60 feet. They prefer soft sandy or muddy substrates and are frequently associated with dense eelgrass and seagrass beds.
Geographic Range
Western Atlantic Ocean and the Gulf of Mexico, ranging from Nova Scotia and Cape Cod down to Texas and the Caribbean, commonly found along the eastern seaboard of the United States.
Description
A classic fan-shaped bivalve featuring strong, prominent radial ribs that radiate outwards from the umbo to the scalloped margin. The surface exhibits a pleasing rough texture with growth lines crossing the ribs. The symmetry is characteristic of scallops, and the margins form an undulating edge.
Key Features
Distinguished by its approximately 17 to 22 rounded radial ribs, nearly symmetrical ears (auricles) flanking the beak, and a distinct fan shape that clearly separates it from other bivalves.
Collector Value
Low to moderate commercial and collector value. While extremely popular for crafts and general shell collections, common specimens are widely abundant and typically valued as inexpensive souvenirs.
Condition Notes
Good to Fine condition. The single valve is structurally intact with clear, vibrant coloration and well-preserved ribs, displaying minimal edge wear and no major fractures.
Interesting Facts
Scallops are unique among bivalves because they are capable of swimming by rapidly clapping their valves together to expel water, and they possess dozens of tiny, bright blue eyes along the mantle edge that can detect light and motion.
Ecological Role
Bay scallops are important filter feeders that help maintain water clarity and quality in coastal ecosystems. They serve as a crucial food source for various marine predators including fish, crabs, and sea birds, and their populations are often monitored closely for environmental health.
Similar Species
Calico Scallop (Argopecten gibbus) and Rough Scallop (Aequipecten opercularis). The Atlantic Bay Scallop differs by having fewer, broader ribs and a more compressed, rounded profile.
Beach Finding Tips
Look along sandy beaches adjacent to bays, estuaries, and salt marshes with seagrass beds, particularly following heavy storm activity or at low tide when shells wash ashore.