Clams are a diverse group of bivalve mollusks found in coastal salt waters worldwide. Species and nomenclature vary, but generally speaking, clams are classified as either hard-shell or soft-shell.

The habitat of hard-shell clams is intertidal or subtidal bays from Canada to the Gulf of Mexico; most of the U.S. harvest takes place between Cape Cod and New Jersey. Hard-shells are also farm-raised from Massachusetts to Florida.

The smallest hard-shells are known as littlenecks, measuring 1-2 in. across and graded 450-600 live clams per 60-lb. bushel.

Cherrystones measure 2-3 in. across, with 300-400 units per bushel. Next are top-necks (3 to 3-1⁄2 in.; 200 units) and chowder clams, a.k.a. quahogs (wider than 3-1⁄2 in.; under 200 but averaging 125 clams per bushel). Spec hard-shell clams according to intended usage. Smaller clams are more tender, making them ideal for half-shell and baked applications, as well as fried or steamed.

Yields of both meat and juice increase as the size of the clam increases. Large hard-shells are stuffed, or used in chowders, stews, and clam cakes.

In addition to their live form, hard-shells are also available fresh or frozen (either whole or chopped), in clam juice, and smoked.

Surf clams—also known as skimmer, hen, sea, giant, or bar clams—are this country’s most important commercial clam species by volume, accounting for about 50% of annual landings. Al-though not offered live, they are available fresh-shucked, frozen, and canned. The foot, or tongue, which makes up about half the shucked meat, is often frozen for clam strips, breaded or unbreaded. The remaining mantle, adductor muscle, and siphon are available chopped or minced, for use in chowders, soups, and pasta sauces.

Soft-shell clams have a brittle, oval-shaped white shell. Known as “steamers” on the East Coast, they are taken on both sides of the Atlantic, with North American populations found from North Carolina to Eastern Canada. They are also available fresh or frozen in whole or chopped form. The most famous West Coast soft-shell clam is the razor clam, so-named because it resembles an old-fashioned straight razor.

Other important species of clams include ocean quahog, geoduck, and manila. Ocean quahogs, also known as mahogany clams, look like hard-shell quahogs, with a dark- brown or blackish covering on their shells. Geoducks (pronounced “gooey-duck”) are large West Coast soft-shell clams with a rectangular, grayish-white shell and a huge siphon that can be four to seven times longer than the shell. The increasingly popular species known as Manilla clams are small, round clams with thin, somewhat brittle light to dark-brown shells.

• Hard-shell clams should be tightly closed, heavy, and moist, with a faint, briny odor. Discard clams with open or broken shells.
• To remove sand, brush with a stiff brush and soak for several 30-minute sessions in cold, salted water, changing the water frequently; do not rinse, store, or transport in fresh water.
• Because of their protruding siphons, soft-shells do not close completely and are slightly agape. To purge gritty soft-shell clams of sand and debris, place clams in salted water (1⁄3 cup salt per gal. of water) along with a cup of cornmeal.
• The shelf life for live, refrigerated clams—hard-shell or soft-shell—is 5-7 days in an open box or sack that breathes. Never store clams in fresh water.