Pacific Giant Cockle (also known as the Nuttall's Cockle)
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Cardiidae, Genus: Clinocardium, Species: Clinocardium nuttallii · Cardiidae (Cockle family) · Bivalve (two-shelled), whole shell, fan/heart-shaped morphology
Species
Clinocardium nuttallii
Shell Type
Bivalve (two-shelled), whole shell, fan/heart-shaped morphology
Family
Cardiidae (Cockle family)
Size
Approximately 3 to 4 inches in width and height, which is typical for an adult specimen. Full-grown adults can reach up to 5 inches.
Color & Pattern
Cream to light yellowish-tan base color with subtle concentric growth lines and darker brownish or yellowish undertones. The interior is typically polished white with a purple or dark brown blotch near the hinge.
Rarity
Common, frequently discovered by beachcombers and clam diggers along the Pacific Northwest coast.
Habitat
Found intertidally to shallow subtidal depths, typically buried just beneath the surface in sandy, muddy, or fine gravel substrates in protected bays and estuaries.
Geographic Range
Northeast Pacific Ocean, ranging from the Aleutian Islands in Alaska down to southern California.
Description
A robust, inflated bivalve shell featuring prominent, rounded radial ribs (usually around 35) that extend from the umbo to the margin, creating a strongly scalloped edge. The surface exhibits fine concentric growth lines crossing the ribs.
Key Features
Distinguished by its heart-shaped profile when viewed from the side, prominent inflated beaks (umbones), and numerous rounded radial ribs that interlock tightly at the margin.
Collector Value
Low to moderate value. While widely available and popular among casual beachcombers, perfect double-valve specimens with pristine ribs are appreciated in regional collections.
Condition Notes
The specimen appears to be in good to fine condition, retaining its natural coloration and structural integrity with minimal weathering or erosion.
Interesting Facts
Clinocardium nuttallii uses its remarkably strong, muscular, hatchet-shaped foot not only for burrowing into the sediment but also for executing powerful leaps to escape predators like starfish.
Ecological Role
Serves as an important prey species for sea otters, diving ducks, crabs, and starfish, while filtering organic particles from the water column to help maintain water clarity.
Similar Species
Puede be confused with other cockle species such as the Basket Cockle, but Clinocardium nuttallii is generally larger and possesses more numerous and prominent radial ribs.
Beach Finding Tips
Look along Pacific Northwest beaches after winter storms or low spring tides, particularly in sandy tidal flats and areas near eelgrass beds where they burrow.