Hard clam

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Hard clam
LittleNeck clams USDA96c1862.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Subclass: Heterodonta
Order: Venerida
Superfamily: Veneroidea
Family: Veneridae
Genus: Mercenaria
M. mercenaria
Binomial name
Mercenaria mercenaria

The hard clam ( Mercenaria mercenaria), also known as a quahog ( /ˈk(w)hɒɡ/ ; or quahaug), round clam or hard-shell (or hard-shelled) clam, is an edible marine bivalve mollusk 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.

Alternative names

Left valve interior of Mercenaria mercenaria. Mercenaria081111.jpg
Left valve interior of Mercenaria mercenaria.

The hard clam has many alternative common names. It is also known as the Northern quahog, round clam, or chowder clam. [1]

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. [2]

The most distinctive of these names is quahog ( /ˈkhɒɡ/ 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. [3] [4] 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. [5]


An old quahog shell that has been bored (producing Entobia) and encrusted after the death of the clam BoredEncrustedShell.JPG
An old quahog shell that has been bored (producing Entobia ) and encrusted after the death of the clam

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. [2]


Quahog parasite unknown (QPX) [6] is a parasite that affects Mercenaria mercenaria. While little is known about the disease, research is currently under way in several laboratories. [7] This research is fueled by the need to inform aquaculturists, who suffer financially because of the mortality rates in clams that QPX inflicts and the ensuing years in which runs must be left fallow to clear the disease. It was discovered along the coast of Cape Cod, Massachusetts in 1995.

Human use

Steamed clams Sandiego 11 bg 010706.jpg
Steamed clams
Raw top neck clams in New Jersey. Top neck clams.JPG
Raw top neck clams in New Jersey.

In coastal areas of New England, New York, and New Jersey, restaurants known as raw bars or clam bars specialize in serving littlenecks and topnecks raw on an opened half-shell, usually with a cocktail sauce with horseradish, and often with lemon. Sometimes littlenecks are steamed and dipped in butter, though not as commonly as their soft-shelled clam cousin the "steamer". Littlenecks are often found in-the-shell in sauces, soups, stews, and clams casino, or substituted for European varieties such as the cockle in southern European seafood dishes. The largest clams are quahogs or chowders and cherrystones; they have the toughest meat and are used in such dishes as clam chowder, clam cakes, and stuffed clams, or are minced and mixed into dishes that use the smaller, more tender clams.

Historically, American Indians used the quahog as a component in wampum, the shell beads exchanged in the North American fur trade. [8] The Narragansetts used the hard clam for food and ornaments. [9]

A population of hard clams exists in Southampton Water in Hampshire, England. Originally bred in the warm water outflows at Southampton Power Station for use as eel bait, the population became self-sustaining and can now be found in Southampton Water and has also spread to Portsmouth Harbour and Langstone Harbour.

Clams and red tide

The term "red tide" refers to an accumulation of a toxin produced by marine algae. Filter-feeding shellfish are affected, such as clams, oysters, and mussels. The toxin affects the human central nervous system. Eating contaminated shellfish, raw or cooked, can be fatal. Some other kinds of algal blooms make the seawater appear red, but red tide blooms do not always discolor the water, nor are they related to tides.

Clam harvesters who violate the sanitary laws in New York face potential jail terms.

Related Research Articles

Shellfish culinary and fisheries term for exoskeleton-bearing aquatic invertebrates

Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some are found in freshwater. In addition, a few species of land crabs are eaten, for example Cardisoma guanhumi in the Caribbean. Shellfish are among the most common food allergens.

Clam common name for several kinds of bivalve molluscs

Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two shells of equal size connected by two adductor muscles and have a powerful burrowing foot. They live in both freshwater and marine environments; in salt water they prefer to burrow down into the mud and the turbidity of the water required varies with species and location; the greatest diversity of these is in North America.

Wampum A traditional shell bead of the Eastern Woodlands tribes of American Indians

Wampum is a traditional shell bead of the Eastern Woodlands tribes of Native Americans. It includes white shell beads hand fashioned from the North Atlantic channeled whelk shell and white and purple beads made from the quahog or Western North Atlantic hard-shelled clam. Before European contact, strings of wampum were used for storytelling, ceremonial gifts, and recording important treaties and historical events, such as the Two Row Wampum Treaty or The Hiawatha Belt. Wampum was also used by the northeastern Indian tribes as a means of exchange, strung together in lengths for convenience. The first Colonists adopted it as a currency in trading with them. Eventually, the Colonists applied their technologies to more efficiently produce wampum, which caused inflation and ultimately its obsolescence as currency.

Clam chowder chowders containing clams and broth

Clam chowder is any of several chowder soups containing clams and broth. In addition to clams, common ingredients include diced potatoes, onions, and celery. Other vegetables are not typically used, but small carrot strips or a garnish of parsley might occasionally be added primarily for color. A garnish of bay leaves adds both color and flavor. It is believed that clams were used in chowder because of the relative ease of harvesting them. Clam chowder is usually served with saltine crackers or small, hexagonal oyster crackers.

Soft-shell clam species of mollusc

Soft-shell clams or sand gaper, scientific name Mya arenaria, popularly called "steamers", "softshells", "piss clams", "Ipswich clams", or "Essex clams" are a species of edible saltwater clam, a marine bivalve mollusk in the family Myidae.

Raw bar

A raw bar is a small restaurant or a bar within a restaurant where live raw shellfish are shucked and served. Raw bars typically offer a variety of raw and cooked seafood and shellfish that is served cold. Seafood-based dishes may also be offered, and additional, non-seafood foods may also be part of the fare. Raw bars may offer alcoholic beverages such as oyster shooters, as well as wine and sake that is paired with various foods. Additional accompaniments may include condiments, sauces and foods such as lemon and lime. Several restaurants in the United States offer raw bars, some of which are seasonal.

Clam cakes are a New England food, most commonly found in Rhode Island although they can also be found in Connecticut, Maine, and Massachusetts. Each clam cake is a deep fried ball-shaped mixture containing chopped clam combined with various other ingredients to give it a firm consistency once fried. The batter is made from flour, milk, clam juice, eggs and a leavening agent, typically baking powder. Hank Shaw once described it as, "think clam beignet, or donut hole. Only savory. Crispy, golden brown on the outside, pillowy and light on the inside. Steam rises from the first bite. The slightest aroma of brine surrounds you. Tiny chunks of clam nestle themselves in the folds of the pillow, offering surprising bites of chewy meatiness as you down one of these little glories after another."

Veneridae family of molluscs

The Veneridae or venerids, common name: venus clams, are a very large family of minute to large, saltwater clams, marine bivalve molluscs. Over 500 living species of venerid bivalves are known, most of which are edible, and many of which are exploited as food sources.

<i>Mercenaria</i> genus of molluscs

Mercenaria is a genus of edible saltwater clams, marine bivalve molluscs in the family Veneridae, the Venus clams.

<i>Chione cancellata</i> species of mollusc

Chione cancellata, is a species of medium-sized saltwater clam, a marine bivalve mollusc in the family Veneridae, the venus clams.

Stuffed clam American seafood dish

Stuffed clams are popular in New England, especially in Rhode Island, and consist of a breadcrumb and minced clam mixture that is baked on the half shell of a quahog hard shell clam. Other ingredients typically found in the basic breadcrumb mixture are: meat such as sausage, bacon or chouriço, chili pepper, lemon juice, bell peppers, celery, onion, garlic, spices and herbs. There are many different recipes for stuffed clams; many restaurants in New England have their own variety, as do many home cooks.

Venerupis philippinarum species of mollusc

Ruditapes philippinarum is an edible species of saltwater clam in the family Veneridae, the Venus clams.

<i>Leukoma staminea</i> species of mollusc

Leukoma staminea, commonly known as the Pacific littleneck clam, the littleneck clam, the rock cockle, the hardshell clam, the Tomales Bay cockle, the rock clam or the ribbed carpet shell, is a species of bivalve mollusc in the family Veneridae. This species of mollusc was exploited by early humans in North America; for example, the Chumash peoples of Central California harvested these clams in Morro Bay approximately 1,000 years ago, and the distinctive shells form middens near their settlements.

Quahog is a common name for the hard clam and may also refer to:

Michael A. Rice American politician

Michael Alan Rice, is an American professor of fisheries and aquaculture at the University of Rhode Island and former state representative from South Kingstown, Rhode Island. A Democrat, he served in the Rhode Island House of Representatives, representing the 35th district, encompassing the village of Kingston and West Kingston, and parts of the neighborhoods of Tuckertown, Wakefield and Peace Dale. Rice was first elected in November 4, 2008 and served from January 6, 2009 to January 4, 2011.

Clams casino clam dish

Clams casino is a clam 'on the halfshell' dish with breadcrumbs and bacon. Green peppers are also a common ingredient.

Steamed clams

Steamed clams is a seafood dish consisting of various types and preparations of clam which are cooked by steaming according to local custom in various countries.

M. mercenaria may refer to:

<i>Saxidomus gigantea</i> species of mollusc

Saxidomus gigantea is a large, edible saltwater clam, a marine bivalve mollusk in the family Veneridae, the venus clams. It can be found along the western coast of North America, ranging from the Aleutian Islands to San Francisco Bay. Common names for this clam include butter clam, Washington clam, smooth Washington clam and money shell.

Quahog parasite unknown protist parasite of hard clams

The quahog parasite unknown, or QPX, is a single-celled protist parasite in the class Labyrinthulomycota. It affects hard clams, or quahogs, both cultured and wild.


  1. Harte, M. E. 2001. "Systematics and taxonomy, Chapter 1", pp. 3–51, in Kraeuter, J. N. and M. Castagna (eds.) "Biology of the Hard Clam", Developments in Aquaculture and Fisheries Science, Vol. 31. Elsevier Science B.V.: New York.
  2. 1 2 Rice, M.A. (1992). The Northern Quahog: Biology of Mercenaria mercenaria. Rhode Island Sea Grant Publication No. RIU-B-92-001, University of Rhode Island, Narragansett. 60 pp. ISBN   0-938412-33-7 web link.
  3. "Quahaug, quahog", in Shorter Oxford English Dictionary, 3rd ed (Oxford: Clarendon Press, 1973)
  4. Roger Williams, A Key Into the Language of America. London: Gregory Dexter, 1643.
  5. Eldridge, P.J., W. Waltz, and H. Mills. 1975. Relative abundance of Mercenaria mercenaria notata in estuaries of South Carolina. Veliger 18:396-397.
  6. "QPX". Marine Symbiosis.
  7. Calvo, LMR; Ford, S. E.; Kraeuter, J. N.; Leavitt, D. F.; Smolowitz, R.; Burreson, E. M. (1 January 2007). "Influence Of Host Genetic Origin And Geographic Location On Qpx Disease In Northern Quahogs (=Hard Clams), Mercenaria Mercenaria". Journal of Shellfish Research. 26: 109–119. doi:10.2983/0730-8000(2007)26[109:IOHGOA]2.0.CO;2.
  8. White, Richard (1991). The Middle Ground: Indians, Empires, and Republics in the Great Lakes Region, 1650–1815 (2nd ed.). New York: Cambridge University Press. p. 97. ISBN   9781139495684. OCLC   772696326.
  9. Feeney, Kathy (2003). Rhode Island Facts and Symbols. Albert T. Klyberg (consultant) (Revised and Updated ed.). Mankato, Minn.: Capstone Press. pp. 18–19. ISBN   9780736822701. OCLC   51204649.

Further reading