Hard Clam, Northern Quahog, Round Clam, Chowder Clam
Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Veneridae, Genus: Mercenaria, Species: M. mercenaria · Veneridae (Venus Clam family) · Bivalve (single valve shown). Subcircular/heart-shaped thick shell.
Species
Mercenaria mercenaria
Shell Type
Bivalve (single valve shown). Subcircular/heart-shaped thick shell.
Family
Veneridae (Venus Clam family)
Size
Approximately 3.5 to 4.5 inches. This is a large adult (chowder size); the species typically ranges from 1 to 5 inches.
Color & Pattern
Dirty white to greyish exterior with prominent dark blue-grey or purple mineral staining. The fossilized or weathered appearance suggests long exposure. Natural growth rings are visible as concentric ridges.
Rarity
Very Common. This is one of the most prolific shells found on Myrtle Beach and the US East Coast.
Habitat
Found in shallow estuarine and marine waters, typically buried in sandy or muddy substrates. Common in intertidal and subtidal zones.
Geographic Range
Western Atlantic coast from Gulf of St. Lawrence, Canada, to Florida and the Gulf of Mexico. Very common in South Carolina.
Description
A heavy, thick, and durable bivalve shell with a sub-ovate to heart-shaped profile. The exterior is characterized by prominent concentric growth rings that are more crowded at the margins. This specific specimen shows significant beach wear, some minor predatory boring holes, and the classic heavy calcification of an older adult clam.
Key Features
Thick heavy weight; heart-shaped profile near the umbo (beak); concentric growth lines; often features purple staining on the interior (wampum).
Collector Value
Minimal financial value (less than $1-$2) due to extreme abundance. However, specimens with deep, vibrant purple interiors are highly sought after by jewelry makers and artisans.
Condition Notes
Fair to Good. The shell is weathered with some cracking and erosion on the lower margin. It features small pin-sized holes likely made by boring sponges (Cliona) or predatory gastropods. It has lost its shiny periostracum.
Interesting Facts
The name 'Quahog' comes from the Narragansett word 'Poquauhock'. Native Americans used the deep purple interior parts of these shells to create 'Wampum' beads, which served as a form of currency and a medium for recording history.
Ecological Role
Suspension feeders that filter phytoplankton from the water, playing a crucial role in maintaining water quality. They are a primary food source for whelks, sea stars, and humans.
Similar Species
Southern Quahog (Mercenaria campechiensis) which is usually larger, heavier, and lacks the smooth purple interior mark of the Northern Quahog.
Beach Finding Tips
Look along the wrack line or in the shallow surf after a high tide or storm. At Myrtle Beach, they are often found partially buried in the sand or among shell deposits near the piers.
Notes
Myrtle Beach SC