Pecten / Scallop
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten irradians · Pectinidae (Scallop family) · Bivalve, whole shell, fan shape
Species
Argopecten irradians (Bay Scallop)
Shell Type
Bivalve, whole shell, fan shape
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches, which is typical for an adult bay scallop. Adults generally range from 1.5 to 3 inches.
Color & Pattern
Cream to off-white base with prominent reddish-brown and dark brown zigzag or flammule patterns radiating from the umbo. Colors appear completely natural with clear demarcation of rays.
Rarity
Common
Habitat
Shallow marine waters, typically found in seagrass beds, bays, and estuaries at depths ranging from the intertidal zone down to a few fathoms.
Geographic Range
Western Atlantic Ocean and Gulf of Mexico, ranging from Nova Scotia down to the Caribbean and South America.
Description
A classic, attractive fan-shaped bivalve shell featuring strong, prominent radial ribs and characteristic symmetrical auricles (ears) at the hinge. The exterior displays a robust grid-like texture formed by growth lines crossing the ribs.
Key Features
Symmetrical fan shape, pronounced radial ribs, unequal or distinct wing-like ears at the hinge, and vibrant contrasting brown chevron or ray patterns on a light background.
Collector Value
Low to Moderate value. While very popular for crafts and beginner collections due to their aesthetic appeal, they are abundant and generally inexpensive.
Condition Notes
Good to Fine condition. The shell is intact with sharp ribs, minimal wear on the margins, and well-preserved coloration without excessive sun-bleaching.
Interesting Facts
Bay scallops are famously capable of swimming by rapidly clapping their valves together to expel water. They also possess dozens of tiny, bright blue eyes along the edge of their mantle that can detect light and motion.
Ecological Role
Bay scallops serve as an important food source for various marine predators including crabs, rays, and sea stars. They are filter feeders that help maintain water clarity in coastal ecosystems.
Similar Species
Atlantic Calico Scallop (Argopecten gibbus), which is more convex and typically has more mottled, multi-colored patterns rather than distinct organized rays.
Beach Finding Tips
Look along shallow sandy bays, near seagrass beds, or shell-rich tidelines shortly after high tide or during storm washups.