The hard clam (''
Mercenaria
''Mercenaria'' is a genus of edible saltwater clams, marine bivalve molluscs in the family Veneridae, the Venus clams.
The genus ''Mercenaria'' includes the quahogs, consisting of ''Mercenaria mercenaria'', the northern quahog or hard clam, an ...
mercenaria''), also known as the round clam, hard-shell (or hard-shelled) clam, or the quahog, is an edible
marine
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
* Marine habitats
* Marine life
* Marine pollution
Military
* ...
bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
that is native to the eastern shores of
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
and
Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
from
Prince Edward Island
Prince Edward Island (PEI; ) is one of the thirteen Provinces and territories of Canada, provinces and territories of Canada. It is the smallest province in terms of land area and population, but the most densely populated. The island has seve ...
to the
Yucatán Peninsula
The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...
. It is one of many unrelated edible bivalves that in the United States are frequently referred to simply as
clam
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 she ...
s, as in the expression "
clam digging
Clam digging is a North American term for a common way to harvest clams (edible infaunal bivalve mollusks) from below the surface of the tidal sand flats or mud flats where they live. It is done both recreationally (for enjoyment or as a sou ...
". Older literature sources may use the systematic name ''Venus mercenaria''; this species is in the family
Veneridae
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 e ...
, the venus clams.
Confusingly, the "ocean quahog" is a different species, ''
Arctica islandica
The ocean quahog (''Arctica islandica'') is a species of edible clam, a marine bivalve mollusk in the family Arcticidae. This species is native to the North Atlantic Ocean, and it is harvested commercially as a food source. This species is ...
'', which, although superficially similar in shape, is in a different family of bivalves: it is rounder than the hard clam, usually has black
periostracum
The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods and ...
, and there is no
pallial sinus
The pallial sinus is an indentation or inward bending in the pallial line on the interior of a bivalve mollusk shell's valves that corresponds to the position of the siphons in those types of clams which have siphons (i.e. siphonate). The posit ...
in the interior of the shell.
Alternative names
![Mercenaria081111](https://upload.wikimedia.org/wikipedia/commons/3/37/Mercenaria081111.jpg)
The hard clam has many alternative
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...
s. 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.
[ 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.]
web link
The most distinctive of these names is ''quahog'' ( , , or , also spelt ''quahaug'', ''quohog'' or ''cohog''). The word comes from the
Narragansett word "poquauhock", which is similar in
Wampanoag
The Wampanoag , also rendered Wôpanâak, are an Indigenous people of the Northeastern Woodlands based in southeastern Massachusetts and historically parts of eastern Rhode Island,Salwen, "Indians of Southern New England and Long Island," p. 17 ...
and some other
Algonquian languages
The Algonquian languages ( or ; also Algonkian) are a subfamily of Indigenous languages of the Americas, indigenous American languages that include most languages in the Algic languages, Algic language family. The name of the Algonquian language f ...
; it is first attested in North American English in 1794. Native polities on the eastern Atlantic seaboard made valuable beads called
wampum
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 Nort ...
from the shells, especially those colored purple; the species name ''mercenaria'' is related to the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
word for commerce. Today people living in coastal New England still use Algonquian words for the clam, as they have done for thousands of years.
In many areas where
aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
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.
Distribution
![BoredEncrustedShell](https://upload.wikimedia.org/wikipedia/commons/1/10/BoredEncrustedShell.JPG)
Hard clams are quite common throughout
New England
New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
, north into
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
, and all down the
Eastern seaboard of the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
to
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
; but they are particularly abundant between
Cape Cod
Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of mainland Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer mont ...
and
New Jersey
New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...
, where seeding and harvesting them is an important commercial form of
aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
. For example, the species is an important member of the suspension-feeding,
benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
fauna of the lower
Chesapeake Bay
The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the ...
.
Rhode Island
Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...
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
Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...
. The species has also been
introduced and is farmed on the
Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
coast of North America and in
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
and continental
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
. It reproduces sexually by females and males shedding
gametes
A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce t ...
into the water.
Parasite
Quahog parasite unknown (QPX) is a
parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
that affects the hard shell clam ''Mercenaria mercenaria''. While little is known about the disease, research is currently under way in several laboratories. This research is fueled by the need to inform
aquaculturist
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lotus ...
s, who suffer financially because of the mortality rates in clams that QPX inflicts and the ensuing years in which runs must be left
fallow
Fallow is a farming technique in which arable land is left without sowing for one or more vegetative cycles. The goal of fallowing is to allow the land to recover and store organic matter while retaining moisture and disrupting pest life cycles ...
to clear the disease. It was discovered along the coast of
Cape Cod
Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of mainland Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer mont ...
, Massachusetts in 1995.
Quahog parasite X (or quahog parasite unknown
PX disease of the hard clam ''Mercenaria mercenaria'' is caused by a poorly known protistan parasite. Its DNA sequence analysis places the QPX parasite among the
thraustochytrid
Thraustochytrids are single-celled saprotrophic eukaryotes (decomposers) that are widely distributed in marine ecosystems, and which secrete enzymes including, but not limited to amylases, proteases, phosphatases. They are most abundant in regio ...
stramenopile
Stramenopile is a clade of organisms distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, and in some they have be ...
s. Thraustochytrids are common protists in marine sediments and the water column, but only a few thraustochytrids are known as parasites of marine animals. Although QPX disease was first recorded on the Atlantic coast of Canada in the early 1960s, it did not become a major economic problem until its appearance in cultured clams at Prince Edward Island, Massachusetts in 1992, and Virginia in 1997. Infected clams are characterized by the presence of blisters or pustules in the mantle and later by gaping and death.
Human use
![Top neck clams](https://upload.wikimedia.org/wikipedia/commons/5/56/Top_neck_clams.JPG)
In coastal areas of the New England states, Long Island, 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
Cocktail sauce, also known as seafood sauce, is one of several types of cold or room temperature sauces often served as part of a dish referred to as a seafood cocktail or as a condiment with other seafoods. The sauce, and the dish for which it ...
with
horseradish
Horseradish (''Armoracia rusticana'', syn. ''Cochlearia armoracia'') is a perennial plant of the family Brassicaceae (which also includes mustard, wasabi, broccoli, cabbage, and radish). It is a root vegetable, cultivated and used worldwide ...
, and often with
lemon
The lemon (''Citrus limon'') is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China.
The tree's ellipsoidal yellow fruit is used for culin ...
. 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 chowder is any of several chowder soups in American cuisine containing clams. In addition to clams, common ingredients include diced potatoes, salt pork, and onions. Other vegetables are not typically used. It is believed that clams were us ...
,
clam cakes
Clam cakes (also known as clam fritters) are a part of New England cuisine, most commonly found in Rhode Island although they can also be found in Connecticut, Maine, and Massachusetts. They are balls of battered clams which have been deep-fried ...
, and
stuffed clam
Stuffed clams (or stuffies) 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 bre ...
s, or are minced and mixed into dishes that use the smaller, more tender clams.
Historically,
Native Americans used the quahog as a component in
wampum
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 Nort ...
, the shell beads exchanged in the
North American fur trade
The North American fur trade is the commercial trade in furs in North America. Various Indigenous peoples of the Americas traded furs with other tribes during the pre-Columbian era. Europeans started their participation in the North American fur ...
. The
Narragansetts
The Narragansett people are an Algonquian American Indian tribe from Rhode Island. Today, Narragansett people are enrolled in the federally recognized Narragansett Indian Tribe. They gained federal recognition in 1983.
The tribe was nearly lan ...
used the hard clam for food and ornaments.
A population of hard clams exists in
Southampton Water
Southampton Water is a tidal estuary north of the Solent and the Isle of Wight in England. The city of Southampton lies at its most northerly point, where the estuaries of the River Test and River Itchen meet. Along its salt marsh-fringed wes ...
in
Hampshire
Hampshire (, ; abbreviated to Hants) is a ceremonial county, ceremonial and non-metropolitan county, non-metropolitan counties of England, county in western South East England on the coast of the English Channel. Home to two major English citi ...
,
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
. 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
Portsmouth Harbour is a biological Site of Special Scientific Interest between Portsmouth and Gosport in Hampshire. It is a Ramsar site and a Special Protection Area.
It is a large natural harbour in Hampshire, England. Geographically it i ...
and
Langstone Harbour
Langstone Harbour is a biological Site of Special Scientific Interest in Hampshire. It is an inlet of the English Channel in Hampshire, sandwiched between Portsea Island to the south and west, Hayling Island to the south and east, and Langs ...
.
Clams and red tide
The term "
red tide
A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural phycotoxin, algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are ...
" refers to an accumulation of a toxin, such as
saxitoxin
Saxitoxin (STX) is a potent neurotoxin and the best-known paralytic shellfish toxin (PST). Ingestion of saxitoxin by humans, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the illness known as paralytic ...
, produced by marine algae.
Filter-feeding shellfish are affected, such as clams, oysters, and mussels.
[ The toxin affects the human ]central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
.[ 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.][
]
Notes
References
{{DEFAULTSORT:Hard Clam
Clams
Veneridae
Marine molluscs of North America
Molluscs of the Atlantic Ocean
Molluscs of the United States
Molluscs of Mexico
Fauna of the Northeastern United States
Fauna of the Southeastern United States
Molluscs described in 1758
Taxa named by Carl Linnaeus
Symbols of Rhode Island
Rhode Island cuisine
Native American culture
Seafood in Native American cuisine