Seafood of the Week - Clams

Edible clams in the family Veneridae

A clam is a generic term for many kinds of bivalve molluscs, some of which are edible.
Clams, like most molluscs, also have open circulatory systems, which means that their organs are surrounded by watery blood that contains nutrients and oxygen. They feed on plankton by filter feeding. Clams filter feed by drawing in water containing food using an incurrent siphon. The food is then filtered out of the water by the gills and swept toward the mouth on a layer of mucus. The water is then expelled from the animal by an ex-current siphon.






In the United States, the word "clam" has several different meanings. First, it can generally cover all molluscs. It can also be used in a more limited sense as cave sediment bivalves, rather than those attached to the substrate (like oysters and mussels) or those that swim (like scallops). It can also refer to one or more kinds of commonly consumed marine bivalves, such as in the phrase clam chowder, which refers to shellfish soup. Many edible bivalves are roughly oval-shaped; however, the Pacific razor clam has an elongated, parallel-sided shell, the shape of the show, an old-fashioned straight razor.
In the United Kingdom, "clam" is one of the common names of various species of marine bivalve mollusc, but it is not used as a term covering either edible clams that burrow or bivalves in general.
Numerous edible marine bivalve species live buried in sand or mud and respire by means of siphons, which reach to the surface. In the United States, these clams are collected by "digging for clams" or clam digging.
In October 2007 an Arctica islandica clam, caught off the coast of Iceland, was found to be at least 405 years old and declared the world's oldest living animal by researchers from Bangor University. It was later named Ming.
Some species of bivalves are too small to be useful for food, and not all species are considered palatable.
The word "clam" is used in the metaphor "to clam up," meaning to refuse to talk or answer, based on the clam behavior of quickly closing the shell when threatened. A "clamshell" is the name given to a container or mobile phone consisting of two hinged halves that lock together. Clams have also inspired the phrase "happy as a clam," short for "happy as a clam at high tide" (when it can't easily be dug up and eaten).

Littleneck clams, small hard clams, species Mercenaria mercenaria

A clam's shell consists of two (usually equal) halves, which are connected by a hinge joint and a ligament which can be external or internal.
In clams, two adductor muscles contract to close the shells. The clam has no head or eyes, though scallops are an exception of this rule. Clams do have kidneys, a heart, a mouth, and an anus.
Clams begin as a shellfish the size of a grain of sand when born. It has a natural glue on it that causes it to connect to other shells or things at the bottom of the river. Once a clam is secure, it feeds on the plankton, as stated, and moves with the tide. It takes a clam 24-30 months to become harvestable.

Yummy bowl of steamed clams in broth

In culinary use, within the eastern coast of the United States, the term "clam" most often refers to the hard clam Mercenaria mercenaria. It may also refer to a few other common edible species, such as the soft-shell clam, Mya arenaria, and the ocean quahog, Arctica islandica. Another species which is commercially exploited on the Atlantic Coast of the United States is the surf clam Spisula solidissima.
Clams can be eaten raw, steamed, boiled, baked or fried. They can also be made into clam chowder or they can be cooked using hot rocks and seaweed in a New England clam bake.