Freshwater mussels

Shellfish is divided into two categories: mollusks and crustacean. Mollusks are surrounded either wholly or partially by a hard shell. Common types include clams, oysters, scallops and mussels.

The phylum Mollusca includes approximately 90000 species with a wide array of body size, shapes and forms. Freshwater mussels are aquatic mollusks with edible soft tissues and hard, calcareous shells.

Freshwater mussels are a conspicuous and important element of aquatic ecosystems in much of North America and throughout the world. Mussels are bivalve mollusks and are built much like marine bivalves.

Mussels are less often consumed raw but occasionally are eaten raw in some regions. In the United States, many state regulatory agencies require that consumer health risk notices be present on restaurant menus and consumption risk warning signs be prominently displayed at retail outlets.
Freshwater mussels

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) 

Mollusks

Mollusks
There are over 130,000 species of mollusks, varying in size a few million to over 20 m. However, only rather small group of this vast phyla are commercially important.

The edible mollusks can be divided into three main groups: univalves having a single shell, bivalves which have two shells, and cephalopods.

The first group consists of snail, winkles, whelks and abalones, the second of oysters, mussels and clams and the third of squid, cuttlefish an octopus.

Mollusks form about 7% of the total world catch and play an important role in international trade.

The majority of uni- or bivalves are commonly consumed fresh, sold on the market with the shell on. However, freezing as well as canning of shelled meat, plays an increasingly important role.

Cephalopods exist practically in all waters, exhibiting considerable variety of form and eating characteristics. Texture is of particular concern.

Cephalopods are marketed in many forms mainly as fresh, canned, dried, slated, and smoked. The most important of all cephalopods are squids. Most commercially exploited squids belong to two main families: Ommastrephidae and Loliginidae.

The most important single species are Todarodes pacificus and Ommastrephes bartrami.
Mollusks