Atlantic Deep-Sea Scallop (also known as Giant Scallop or Deep-Water Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Placopecten, Species: Placopecten magellanicus · Pectinidae (Scallop family) · Bivalve (two-shelled), whole valve, fan-shaped disc
Species
Placopecten magellanicus
Shell Type
Bivalve (two-shelled), whole valve, fan-shaped disc
Family
Pectinidae (Scallop family)
Size
Approximately 4 inches in width and length, which is a medium-to-large size for this species. Adults typically range from 3 to over 6 inches.
Color & Pattern
The exterior exhibits a weathered, dark grey to charcoal coloration, likely due to mineral staining or deep-water fossilization/sediment exposure. Underlying lighter tan or cream shell material peeks through worn areas and boring holes. The interior is not visible.
Rarity
Common in commercial fisheries, but whole, well-preserved dark or mineral-stained beach- or dredge-recovered specimens can be an interesting local find depending on the exact coastal area.
Habitat
Found on hard or sandy substrates in cold, deep marine waters, typically ranging from shallow subtidal zones down to depths of over 100 meters.
Geographic Range
Northwest Atlantic Ocean, ranging from the coast of Newfoundland down to North Carolina.
Description
A sturdy, fan-shaped bivalve featuring numerous well-defined radial ribs radiating from the umbo to the scalloped margin. The surface shows distinct signs of wear, texture variation, and minor boring damage, giving it a weathered, antique appearance characteristic of specimens exposed to marine sediments or long-term burial.
Key Features
Symmetrical fan shape, numerous fine radial ribs, pronounced auricles (ears) at the hinge line, and a slightly inequivalve structure typical of pectinids.
Collector Value
Low to Moderate commercial value, primarily prized by local beachcombers or culinary markets rather than high-end conchology collectors, though uniquely stained specimens can make interesting display pieces.
Condition Notes
Fair to Good condition. The valve is structurally intact with some surface erosion, chipping along the margin, and characteristic bio-erosion/predator boring holes near the center. Coloration is heavily altered by dark environmental staining.
Interesting Facts
Unlike many bivalves that burrow, Atlantic scallops are capable of swimming short distances 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 shadow.
Ecological Role
Important benthic filter feeder, removing suspended particles from the water column. They serve as a vital food source for sea stars, crabs, fish, and marine mammals, and support a major commercial fishery.
Similar Species
Atlantic Bay Scallop (Argopecten irradians), which is generally smaller, more globose, and typically found in much shallower seagrass beds.
Beach Finding Tips
Look along northern Atlantic coastlines after severe storms or dredging operations. Scallop valves wash ashore along sandy and shell-hash beaches, especially near deep-water inlets.