Hard clam

The hard clam (Mercenaria mercenaria), also known as a quahog (/ˈk(w)oʊhɒɡ/; or quahaug), round clam or hard-shell (or hard-shelled) clam, is an edible marine bivalve mollusc that is native to the eastern shores of North America and Central America from Prince Edward Island to the Yucatán Peninsula. It is one of many unrelated edible bivalves that in the United States are frequently referred to simply as clams, as in the expression 'clam digging'. Older literature sources may use the systematic name Venus mercenaria; this species is in the family Veneridae, the venus clams. Confusingly, the 'ocean quahog' is a different species, Arctica islandica, which, although superficially similar in shape, is in a different family of bivalves: it is rounder than the hard clam, usually has black periostracum, and there is no pallial sinus in the interior of the shell. The hard clam has many alternative common names. It is also known as the Northern quahog, round clam, or chowder clam. In fish markets, there are specialist names for different sizes of this species of clam. The smallest legally harvestable clams are called countnecks or peanuts, next size up are littlenecks, then topnecks. Above that are the cherrystones, and the largest are called quahogs or chowder clams. The most distinctive of these names is quahog (/ˈkoʊhɒɡ/ KOH-hog, /ˈkwɔːhɒɡ/ KWAW-hog, or /kwəˈhɒɡ/ kwə-HOG). The word comes from the Narragansett word 'poquauhock', which is similar in Wampanoag and some other Algonquian languages; it is first attested in North American English in 1794. New England tribes made valuable beads called wampum from the shells, especially those colored purple; the species name mercenaria is related to the Latin word for commerce. Today people living in coastal New England still use the Native American word for the clam as they have done for hundreds of years. In many areas where aquaculture is important, clam farmers have bred specialized versions of these clams with distinctions needed for them to be distinguished in the marketplace. These are quite similar to common 'wild type' Mercenaria clams, except that their shells bear distinctive markings. These are known as the notata strain of quahogs, which occur naturally in low numbers wherever quahogs are found. Hard clams are quite common throughout New England, north into Canada, and all down the Eastern seaboard of the United States to Florida; but they are particularly abundant between Cape Cod and New Jersey, where seeding and harvesting them is an important commercial form of aquaculture. For example, the species is an important member of the suspension-feeding, benthic fauna of the lower Chesapeake Bay. Rhode Island is situated right in the middle of 'quahog country' and has supplied a quarter of the U.S.'s total annual commercial quahog catch. The quahog is the official shellfish of the U.S. state of Rhode Island. The species has also been introduced and is farmed on the Pacific coast of North America and in Great Britain and continental Europe. It reproduces sexually by females and males shedding gametes into the water.