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 individual valve with a circular, slightly asymmetrical fan-like shape
Species
Placopecten magellanicus
Shell Type
Bivalve (two-shelled), whole individual valve with a circular, slightly asymmetrical fan-like shape
Family
Pectinidae (Scallop family)
Size
Approximately 3.5 to 4 inches in diameter, which is a medium-sized specimen for this species. Adults typically range from 3 to 8 inches.
Color & Pattern
Dull grayish-brown to cream exterior with concentric growth rings. The natural vibrant red-brown tones are heavily faded due to weathering and sun exposure. The interior (not fully visible) is typically white or translucent with a glossy finish.
Rarity
Common in deep waters and commercial fisheries, but whole, intact mature beach-worn valves can be uncommon depending on the specific coastline and storm activity.
Habitat
Found on hard surfaces, gravel, sand, or shell rubble in deep offshore waters, typically ranging from shallow subtidal zones down to depths of over 100 meters.
Geographic Range
Northwest Atlantic Ocean, ranging from Labrador and Newfoundland down along the eastern coast of the United States to Cape Hatteras, North Carolina.
Description
A sturdy, nearly circular bivalve shell featuring prominent, fine concentric growth lines and subtly radiating ribs. The auricles (ears) near the hinge are relatively even. The exterior shows signs of weathering and pitting from marine elements, giving it a rustic, antique appeal.
Key Features
Nearly circular, compressed valve profile; smooth, non-prominent radial ribbing compared to other scallops; relatively equal-sized auricles at the straight hinge line.
Collector Value
Low to moderate commercial value; widely harvested for food rather than as a rare collector's specimen. Pristine, brightly colored live-taken specimens command higher attention, while weathered beach finds are common novelties.
Condition Notes
Fair to Good collectibility grade. The shell is structurally intact as a single valve, but it shows heavy weathering, surface pitting, and loss of original bright coloration due to prolonged exposure in the marine environment or on the beach.
Interesting Facts
Unlike many bivalves that burrow or remain sessile, Atlantic scallops can swim short distances by rapidly clapping their valves together to jet water. They also possess up to 100 simple blue eyes along the edge of their mantle.
Ecological Role
Acts as an important benthic filter feeder, removing suspended organic matter from the water column. It serves as a vital food source for sea stars, crabs, and bottom-feeding fish.
Similar Species
Calico Scallop (Argopecten gibbus) and Bay Scallop (Argopecten irradians), both of which are significantly smaller and possess much deeper, more pronounced radial ribs.
Beach Finding Tips
Look along northern Atlantic beaches following major storms or nor'easters that churn up offshore marine sediments and deposit heavy shells near the high tide line.