- This article is about the fish. For other uses, see Cod
(disambiguation).
Cod is the common name for the genus Gadus of fish,
belonging to the family Gadidae, and is also used in
the common name of a variety of other fishes. Cod is a popular food fish with a mild flavor, low
fat content and a dense white flesh that flakes easily. Cod livers are processed to make cod
liver oil, an important source of Vitamin A, Vitamin
D and omega-3 fatty acids (EPA
and DHA). The Atlantic cod fish, which can change colors at certain depths of
water, has two distinct color phases: gray-green and reddish brown. Its average weight is 10 to 25 lb (4.5—11.3 kg), but
specimens weighing up to 200 lb (90 kg) have been recorded. Young Atlantic cod or haddock prepared in strips for cooking is
called scrod. Cods feed on mollusks, crabs, starfish, worms, squid, and small fish. Some migrate south in winter to spawn. A
large female lays up to five million eggs in midocean, a very small number of which survive. The Pacific cod is found North of
Oregon. The tomcod resembles a young Atlantic cod with long, tapering ventral fins. It rarely exceeds 15 inches (37.5 cm) in
length and lives close to shore. The pollock, also called coalfish or green cod, is a plump
olive-green cod found in cool waters of the Atlantic. Pollacks have forked tails and pale lateral lines and grow to 3 ft (90 cm)
and 30 lb (13.6 kg). Some grow to 6 feet in length.
In the United Kingdom, Atlantic cod is one of
the most common kinds of fish to be found in fish and chips, along with haddock and plaice.
It is also well known for being largely consumed in Portugal, where it is considered a
treasure of the nation's cuisine.
It is an important link in the food chain.
Species in genus Gadus
Cod caught by a fisherman
At various times in the past, a very considerable number of species have been classified in
this genus. However the great majority of them are now either classified in other genera, or have been recognised as simply forms
of one of three species. Modern taxonomy, therefore, recognises only three species in this genus:
All these species have a profusion of common names, most of them including the word
"cod". Many common names have been used of more than one species, in different places or at different times.
Related species called cod
Cod forms part of the common name of many other fish no longer classified in the
genus Gadus. Many of these are members of the family Gadidae, and several were formerly classified in genus Gadus;
others are members of three related families whose names include the word "cod": the morid cods,
Moridae (100 or so species); the eel cods, Muraenolepididae (4 species); and the Eucla cod,
Euclichthyidae (1 species). The tadpole cod family (Ranicipitidae) has now been absorbed within Gadidae.
Species within the order Gadiformes that are
commonly called cod include:
Some other related fish have common names derived from "cod", such as codling,
codlet or tomcod. ("Codling" is also used as a name for a young
cod.)
Unrelated species called cod
However there are also fish commonly known as cod that are quite unrelated to the genus Gadus. Part of this confusion
of names is market-driven. Since the decline in cod stocks has made the Atlantic cod harder to catch, cod replacements
are marketed under names of the form "x cod", and culinary rather than phyletic
similarity has governed the emergence of these names. A very large number of fish have thus been named as some kind of cod at
some time. The following species, however, seem to have well established common names including the word "cod"; note that all are
Southern Hemisphere species.
Perciformes
Norwegian fisher with cod
Fish of the order Perciformes that are commonly
called "cod" include:
Rock cod, reef cod, and coral cod
Almost all the fish known as coral cod, reef cod or rock cod are also in order Perciformes. Most are better known as
groupers, and belong to the family Serranidae. Others belong
to the Nototheniidiae. Two exceptions are the Australasian red rock cod, which belongs to a
different order (see below), and the fish known simply as the rock cod also by soft cod in New Zealand, Lotella rhacina,
which as noted above actually is related to the true cod (it is a morid cod).
Scorpaeniformes
From the order Scorpaeniformes:
- Ling cod Ophiodon elongatus
- Red rock cod Scorpaena papillosa
Ophidiiformes
The tadpole cod family, Ranicipitidae, and the Eucla cod
family, Euclichthyidae, were formerly classified in the order Ophidiiformes, but are now grouped with the Gadiformes.
Species marketed as cod
Some fish that do not have "cod" in their names are sometimes sold as cod. Haddock and whiting belong in the same family, the
Gadidae, as cod.
Identification
Classic codfish shape, with three rounded dorsal and two anal fins. The pelvic fins are small with the first ray extended, and
are set under the gill cover (ie the throat region), in front of the pectorals. The upper jaw extends over the lower jaw, which
has a well developed chin barbel. Medium sized eyes, approximately the same as the length of the chin barbel. It has a distinct
white lateral line running from the gill slit above the pectoral fin, to the base of the caudal or tail fin. The back tends to be
a greenish to sandy brown, and showing extensive mottling especially towards the lighter sides and white belly. Dark brown
colouration of the back and sides is not uncommon especially for individuals who have resided in rocky inshore regions.
Breeding
The Cod population comprises a number of reasonably distinct stocks over its range. These include the Arcto-Norwegian, North
Sea, Faroe, Iceland, East Greenland, West Greenland, Newfoundland, and Labrador stocks. There would seem to be little interchange
between the stocks, although migrations to their individual breeding grounds may involve distances of 200 miles or more. Spawning
occurs between January to April (March and April are the peak months), at a depth of 200m in specific spawning grounds at water
temperatures of between 4-6oC. Around the UK, the major ones are associated with the Middle to Southern North Sea, the start of
the Bristol Channel (north of Newquay), the Irish Channel (both east and west of the Isle of Man), around Stornoway, and east of
Helmsdale.
Pre-spawning courtship involves fin displays, and male grunting, which leads to pairing. The male is inverted underneath the
female, whilst the pair swim in circles during the spawning process. The eggs are planktonic and hatch between 8 to 23 days with
the larva being some 4mm in length. This planktonic phase lasts some ten weeks, during which the young cod will increase it's
body weight by 40 times, and be about 2cm in length. The young cod move to the seabed and their diet changes to small benthic
crustaceans, such as isopods and small crabs. They increase in size to 8cm in the first six months, 14 to 18cm by the end of
their first year, and some 25 to 35cm by the end of the second. This rate of growth tends to be less in individuals occupying
northerly grounds. Cod reach maturity at about 50cm in length at about 3 to 4 years of age.
Habitat
Varied, although often favouring rough ground especially inshore. Demersal in depths of between 20 to 200m (80m Av.), although
not uncommon to depths of 600m. Gregarious and forms schools, although shoaling tends to be a feature of the spawning season.
Food
Adult cod are active hunters, feeding on sandeels, whiting, haddock, small cod, and squid, crabs, lobsters, mussels, worms,
mackerel, and molluscs supplementing their diets. While young cod eat the same they may not eat food sources that are too
large.
Range
Throughout most of the UK waters, although generally seen as a winter fish in the south. They are found in the Northern
Atlantic. These are the areas with the greatest amount of cod fishing: Newfoundland Labrador New England Nova Scotia Iceland
Alaska Indian Ocean Mediterrainian sea Gulf of valdez Florida
Cod trade
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Cod has been an important economic commodity in an international market since the
Viking period (around 800 AD). Norwegians used
dried cod during their travels and soon a dried cod market developed in southern
Europe. This market has lasted for more than 1000 years, passing through periods of
Black Death, wars and other crises and still is an important Norwegian fish trade.[1] The Portuguese since
the 15th century have been fishing cod in the North Atlantic and clipfish is widely eaten and appreciated in Portugal. The
Basques also played an important role in the cod trade and are believed to have found the
Canadian fishing banks before the Colombus' discovery of America. The North American east coast developed in part due to the vast
amount of cod, and many cities in the New England area spawned near cod fishing grounds.
Apart from the long history this particular trade also differs from most other trade of fish by the location of the fishing
grounds, far from large populations and without any domestic market. The large cod
fisheries along the coast of North Norway (and in particular close to the Lofoten islands) have been developed almost uniquely for export, depending on
sea transport of stockfish over large distances.[2] Since the introduction of salt, dried salt cod
('klippfisk' in Norwegian) has also been exported. The trade operations and the sea transport were by the end of the 14th century
taken over by the Hanseatic League, Bergen
being the most important port of trade.[3]
William Pitt the Elder, criticizing the Treaty of Paris in Parliament, claimed that cod
was British gold; and that it was folly to restore Newfoundland fishing rights to
the French.
In the 17th and 18th centuries, the New World, especially in Massachusetts and
Newfoundland, cod became a major commodity, forming trade networks and cross-cultural exchanges. In the 20th century,
Iceland re-emerged as a fishing power and entered the Cod Wars
to gain control over the north Atlantic seas. In the late 20th and early 21st centuries, cod fishing off the coast of Europe and
America severely depleted cod stocks there which has since become a major political issue as the necessity of restricting catches
to allow fish populations to recover has run up against opposition from the fishing industry and politicians reluctant to approve
any measures that will result in job losses. The 2006 Northwest Atlantic cod
quota is set at 23,000 tons representing half the available stocks, while it is
set to 473,000 tons for the Northeast Atlantic cod.
Trivia
A Norwegian "king cod" commonly used for weather forecast in the old days.
- The Norwegian municipality Vågan has a cod in its coat-of-arms.
- A "Sacred Cod" hangs in the Massachusetts House of Representatives.
- In Sweden, a person who solicit prostitutes is known as a "torsk", meaning cod in
Swedish.
- Cod was the fish originally used in McDonald's Filet-O-Fish.
- Every now and then cod with deformed skull is found, the skull has a top or crown giving it the name "king cod" or kongetorsk
in Norwegian. This rare fish was earlier considered to have the ability of forecasting the weather and in Norway it was commonly
used. A woollen thread was used to hang the fish in the ceiling and the fish nose will point in different directions depending on
the weather to come the few next days. Actually it was not the fish, but rather the thread giving reason for the movement. By
absorbing humidity from the air, the twisted thread served as a primitive hygrometer, turning
the fish to slightly different positions depending on air humidity.
- Barnstable County in Massachusetts is commonly known as Cape Cod since the area of which it's
located is abundant in the cod fish.
References
- Clover, Charles (2004). The End of the Line: How
Overfishing Is Changing the World and What We Eat. London: Ebury Press. ISBN 0-09-189780-7.
- Kurlansky,
Mark (1997). Cod: A Biography of the Fish That Changed the World. New York: Walker. ISBN
0-8027-1326-2.
- ^ James Barrett, Roelf Beukens, Ian Simpson,
Patrick Ashmore, Sandra Poaps and Jacqui Huntley (2000). "What Was the Viking Age and When did it Happen? A View from Orkney.".
Norwegian Archaeological Review 33(1).
- ^ G. Rolfsen (1966). "Norwegian fisheries
Research.". FiskDir. Skr. Ser. HavUnders. 14(1): 36.
- ^ A. Holt-Jensen (1985). "Norway and sea the
shifting importance of marine resources through Norwegian history.". GeoJournal
10(4).
See also
External links
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