Soft Shell Clam

Mya arenaria

The soft shell clam is a bivalve mollusk with thin, oval, elongated shells, also called valves.

• The shells are chalky white with a thin, parchment-like covering that varies in color from brownish to yellowish to gray.
• When closed, the shells gape at both ends and a foot and two siphons protrude from either end.
• Both siphons are enclosed in a leathery membrane.
• The left valve has a spoon-like depression at the hinge.
• Soft shell clams grow to about 3 to 4 inches.

Where does the soft shell clam live?

Soft shell clams bury themselves in soft sediments from the Bay's shoreline to depths of about 30 feet. They generally range from Eastern Bay to Pocomoke Sound on the Eastern Shore and from Maryland's Severn River to Virginia's Rappahannock River on the western shore.

What does the soft shell clam eat?

Soft shell clams are filter feeders. They draw water in through their incurrent siphon and filter out microscopic algae. Unused particles are ejected through the exhalent siphon.

How does the soft shell clam reproduce?

Soft shell clams usually spawn twice per year: once in late spring and once in mid- to late autumn.

• Both eggs and sperm are released into the water column. The number of eggs a female releases depends on the clam's size.
• Eggs develop into larvae within one day of being fertilized.
• Larvae swim freely for about one to three weeks, during which they develop their foot and shells.
• When the larvae are ready to metamorphose into juvenile clams, they swim near and crawl on the bottom for several hours before settling. Newly settled clams, called spat, usually attach themselves to any available surface with thin threads secreted from a gland on the foot.
• Small juvenile soft shell clams can be very active, crawling about with their foot. Eventually the clam burrows permanently, and, unless disturbed, spends the rest of its life in one place.

Other facts about the soft shell clam:

• Unlike most other clams, the soft shell clam's siphons cannot completely retract into the clam's shells.
• Soft shell clams are preyed upon by diving ducks, cownose rays and many other Bay creatures.