Hard clams (Mercenaria mercenaria)

The hard clam, Mercenaria mercenaria, is known by a variety of common names, including hard shell clam, round clam, quahog, mud clam, and northern quahog. Formerly hard clam was known as the common round clam or simply the round clam.

Quahog is probably the oldest one still used and is derived from its use by native Americans.

The name ‘mercenaria’ from the Latin term for money, was given to the clam by a famous biologists, Carl Linnaeus.

Hard clams is found in the northern United States and as far as the Gulf of St. Lawrence, it also is found along the entire Atlantic coast of the United States and its distribution is reported to extend through the Gulf of Mexico.

The hard calm occurs in groups ranging from small patches to extensive beds at intertidal and subtidal depths, from sand to muddy sand sediments.

The hard clam industry is the largest of all the clam species and represents more than 50% of the dockside value of all clams harvested.

These clams are sold in the shell by size. They are graded for increasing size as littleneck, cherrystone, and chowder. There is a large variability in the growth rate of hard clams, they reach commercial size sometime between 2 and 5 years; clams in southern waters grow more quickly.
Hard clams (Mercenaria mercenaria) 

Processing of Hard Shell Clam

Processing of Hard Shell Clam
In preparing hard shell clam for the market, they are washed with sea water graded for size, and cooled. Some clams may be taken from semi polluted waters provided they are depurated.

In the shell, hard shell clams are marketed according to size. The different sizes are “chowders” (large size), which are used to prepare chowders, fritters, or stuffed clams; “cherrystones” (medium size), which are used for baking; and:”little necks” (small size), which are used as steamed clams or for eating raw on the half shell. Hard shell clams are neither canned nor frozen in significant quantities.

Hard Shell clams may be cultured. In such instances, the bottom is first prepared by removing thick grass, stones and other debris. Predators, such as starfish, cockles, conchs and welks, are removed by raking and by towing floor mops over the bottom (to entangle starfish). The young clams, raised in tanks, are then spread over the area by scattering them from the side of the boat, using a shovel. Once seeded, the area is left undisturbed to permit the clams to grow to harvesting size. Predators may be removed from times to time. After seeding, the area may seed itself naturally.
Processing of Hard Shell Clam

The Hard Shell Clam

The Hard Shell Clam
The hard shell clam is similar to the oyster in its intestinal structure, the shell is rounded symmetrically and relatively smooth on the outside, coming to a gradual peak near the hinge.

The shell is quite hard and thick. Once the larvae have developed into clams that are 1/8 – ¼ in. (0.3 – 0.6 cm) in diameter, they burrow into the mud and remain just below the surface of the ocean bottom.

The hard shell clam is found from the Maine coast to the Gulf of Mexico, but is most abundant off the Atlantic Coast from southern Massachusetts up to and including Virginia.

Hard shell clams may be harvested by hand (feeling of them with hands or feet and removing them by hand). They may also be removed from shallow water with clam rakes.

The largest quantities of this clam are harvested with scratch rakes, with tongs similar to those used to remove oysters, or with dredges. Dredges are used in comparatively deep water and may be of the basket or water jet type.
The Hard Shell Clam