Atlantic Bay Scallop (also known as Bay Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: A. irradians · Pectinidae (Scallop family) · Bivalve (two-shelled), whole individual valve, fan-shaped
Species
Argopecten irradians
Shell Type
Bivalve (two-shelled), whole individual valve, fan-shaped
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch in length and width, which is small to medium for this species. Adult Atlantic Bay Scallops typically range from 1.5 to 3 inches.
Color & Pattern
Pale whitish base with subtle hints of cream and pinkish-purple along the margin and ear areas. The colors are somewhat faded, indicating mild sun-bleaching or wear from wave action.
Rarity
Common, frequently found washed ashore on beaches within its geographic range, especially near seagrass meadows.
Habitat
Shallow marine waters, typically found in seagrass beds, estuaries, and sandy or muddy substrates from the low intertidal zone down to depths of about 15 feet.
Geographic Range
Western Atlantic Ocean and Gulf of Mexico, ranging from Nova Scotia down through the eastern coast of the United States to the Gulf coast of Texas.
Description
A delicate, fan-shaped bivalve shell featuring prominent symmetrical radial ribs extending from the hinge (umbo) to the outer margin. The auricles (ears) on either side of the umbo are relatively even. The margin is scalloped, matching the external ribs.
Key Features
Symmetrical fan shape, distinctive radial ribs, and the presence of two distinct lateral auricles (ears) at the hinge line characteristic of the Pectinidae family.
Collector Value
Low to moderate commercial value. While widely collected by beachcombers and used in shell crafts, standard beach-worn specimens are common and typically hold sentimental rather than high monetary value.
Condition Notes
Fair to Good condition. The shell is intact with a well-preserved outline and hinge area, though it shows signs of surface wear and fading from exposure.
Interesting Facts
Scallops are among the few bivalves that can actively swim. By rapidly clapping their valves together, they expel water and propel themselves through the water column to escape predators.
Ecological Role
Bay scallops are filter feeders that help maintain water clarity in estuarine ecosystems. They serve as an important food source for various marine predators including crabs, rays, and sea stars.
Similar Species
Rough Scallop (Aequipecten gibbus) and Calico Scallop (Argopecten gibbus), which often feature more pronounced coloration and slightly different rib counts or asymmetrical ear structures.
Beach Finding Tips
Look along sandy beaches adjacent to salt marshes and seagrass beds, particularly at low tide following storms or rough wave action.