Great Scallop (also known as King Scallop or St. James Shell)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Pecten, Species: maximus · Pectinidae (Scallop family) · Bivalve (specifically the flat upper valve); Fan-shaped
Species
Pecten maximus
Shell Type
Bivalve (specifically the flat upper valve); Fan-shaped
Family
Pectinidae (Scallop family)
Size
Estimated 4-6 inches (10-15 cm) in width. This specimen is mid-range for an adult; they can reach up to 8 inches.
Color & Pattern
Creamy white to light beige base with reddish-brown to orange-brown radiating streaks and mottling. The pattern follows the radial ribs, with heavier pigment concentration in the troughs and along the margin.
Rarity
Common (frequently found as beach wash-up in Western Europe and via commercial fishing).
Habitat
Subtidal marine environments, typically on clean firm sand, fine gravel, or sandy mud. They are found at depths from 5 meters down to over 150 meters.
Geographic Range
Northeast Atlantic Ocean, from northern Norway and the British Isles south to the Iberian Peninsula and North Africa.
Description
A classic, elegant fan-shaped shell featuring approximately 15 to 17 wide, rounded radiating ribs. This specimen represents the upper (left) valve, which is naturally flatter than the deeply recessed lower (right) valve. It possesses two roughly equal wings (auricles) at the hinge. The texture is slightly rough with visible concentric growth lines crossing the ribs.
Key Features
Symmetrical ears (auricles) flanking the hinge; 15-17 prominent rounded ribs; flat profile (indicative of the upper valve); large overall size compared to most beach-found scallops.
Collector Value
Low to Moderate ($2 - $15 USD). While beautiful and iconic, they are widely harvested for food, making specimens easily available. Large, perfectly articulated (both valves) or uniquely colored specimens hold higher value.
Condition Notes
Good / Collector Grade. The shell appears intact with a sharp margin and well-defined ribs. Some minor surface erosion and sun-bleaching are evident, but the primary pigment remains visible. No obvious predator drill holes.
Interesting Facts
Pecten maximus has dozens of tiny, bright blue eyes along the edge of its mantle that can detect movement. In history, this shell is the 'Pilgrim's Shell' associated with St. James and the Camino de Santiago. It is also the inspiration for the Shell Oil corporate logo.
Ecological Role
Active filter feeders that help clear the water of phytoplankton and organic detritus. They are a major food source for sea stars, crabs, and humans. They are unique among bivalves for their ability to 'swim' by rapidly clapping their valves.
Similar Species
Pecten jacobaeus (Mediterranean Scallop), which has more angular/square ribs; and Aequipecten opercularis (Queen Scallop), which is much smaller and has both valves rounded.
Beach Finding Tips
Look along the high-tide line after strong Atlantic storms, especially on the coasts of France, Ireland, and the UK. Divers and snorkelers often find them settled in sandy depressions.