Atlantic Bay Scallop
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten irradians · Pectinidae (Scallop family) · Bivalve (fan-shaped single valve)
Species
Argopecten irradians
Shell Type
Bivalve (fan-shaped single valve)
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch; typical for a juvenile specimen. Adults usually range between 2 to 3 inches in diameter.
Color & Pattern
Base color of cream-beige with distinct reddish-pink or mauve radiating bands. The coloration is more intense near the scalloped edge and appears naturally preserved rather than sun-bleached. The interior (not fully visible) is likely white with a purple stain near the hinge.
Rarity
Common (frequently found on beaches along the North Carolina coast)
Habitat
Shallow marine waters, specifically seagrass beds (eelgrass), sandy bottoms, and salt marshes. Found in depths ranging from the low-tide line to 60 feet.
Geographic Range
Western Atlantic coast, specifically from Cape Cod to the Gulf of Mexico. This specimen from Holden Beach, NC, is within its primary range.
Description
An attractive, ribbed fan-shaped shell with approximately 17 to 20 radiating ribs. The auricles (ears) at the hinge are nearly equal in size. The exterior texture is slightly rough due to growth lines, and the overall shape is nearly circular except for the hinge line.
Key Features
Symmetrical 'ears' (auricles) at the hinge, 17-21 smooth radiating ribs, and the characteristic rounded fan shape which distinguishes it from the more elongated Calico Scallop.
Collector Value
Minimal monetary value ($0.50 - $2.00) due to high abundance. However, they are highly desirable for craft enthusiasts and beginner collectors due to their iconic shape and varied color patterns.
Condition Notes
Good; the valve is intact with no major chips, visible predator boreholes, or heavy erosion. Some minor edge wear is present. Collectibility Grade: Fine (standard beach specimen).
Interesting Facts
Living Atlantic Bay Scallops have up to 100 bright blue eyes located along the edge of their mantle that can detect movement and shadows. They are also unique among bivalves because they can swim over short distances by rapidly clapping their valves together.
Ecological Role
Filter feeders that improve water clarity by consuming plankton and organic detritus. They are a vital food source for crabs, sea stars, and various shorebirds. They are also a commercially important species for the seafood industry.
Similar Species
Calico Scallop (Argopecten gibbus) which usually has more mottled, spotted color patterns and more convex shells. Lion's Paw (Nodipecten nodosus) which is much larger and has distinct heavy knobs on the ribs.
Beach Finding Tips
Look in the 'wrack line' (debris left by high tide) after a storm or during extreme low tides. Holden Beach is excellent for finding these after dredging projects or heavy surf.
Notes
Holden Beach, NC