Atlantic Bay Scallop (also known as the Common Bay Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten irradians · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell, fan-shaped
Species
Argopecten irradians
Shell Type
Bivalve (two-shelled), whole shell, fan-shaped
Family
Pectinidae (Scallop family)
Size
Approximately 2 to 2.5 inches in width, which is typical for an adult Atlantic Bay Scallop. Adults generally range from 2 to 3 inches.
Color & Pattern
Predominantly off-white or cream-colored base with faint brownish-orange wash near the center. The coloration appears natural and slightly weathered with typical beach wear.
Rarity
Common, frequently found washed ashore on beaches within its natural range, especially near seagrass beds.
Habitat
Found in shallow marine waters, typically in bays, estuaries, and protected coastal areas associated with seagrass beds (especially eelgrass) at depths ranging from intertidal down to about 60 feet.
Geographic Range
Western Atlantic Ocean, ranging from Nova Scotia down the coast of the United States to the Gulf of Mexico, Texas, and parts of the Caribbean.
Description
A classic fan-shaped bivalve featuring pronounced radial ribs radiating from a symmetrical auricled hinge. The margins are subtly scalloped, and the exterior surface exhibits fine concentric growth lines crossing the prominent rounded ribs.
Key Features
Nearly equilateral, rounded fan shape with prominent, rounded radial ribs (usually around 17 to 22) and asymmetrical "ears" (auricles) flanking the hinge area.
Collector Value
Low to moderate commercial and collector value. While highly appreciated by casual beachcombers and used extensively in crafts, specimens are common and typically inexpensive unless they exhibit rare color morphs.
Condition Notes
Good condition. It is a whole single valve showing minor natural weathering, some fading of coloration, and slight wear around the hinge and edges, grading as a Good to Fine collector specimen.
Interesting Facts
Bay scallops possess up to 60 bright blue, simple eyes along the mantle edge that can detect light, shadow, and movement. They are also capable of swimming by rapidly clapping their valves together to eject water.
Ecological Role
Bay scallops are filter feeders that help maintain water clarity in estuarine ecosystems. They serve as an important food source for various fish, crabs, and sea birds, and support a culturally and economically significant commercial fishery.
Similar Species
Calico Scallop (Argopecten gibbus), which is more convex and has more rounded valves, and the Lion's Paw Scallop (Nodipecten nodosus), which features prominent knobs on the ribs and is much larger.
Beach Finding Tips
Look along sandy or shelly beaches adjacent to seagrass flats, especially after storms or during extreme low tides. Single valves are very common drift items.