Cod is the common name for the
genus Gadus, belonging to the
family Gadidae, and
is also used in the common name for various other fishes. Cod is a
popular
food with a mild flavor, low fat
content and a dense, flaky white flesh. Cod livers are processed to
make
cod liver oil, an important
source of
Vitamin A,
Vitamin D,
Vitamin E and
omega-3 fatty acids (
EPA and
DHA). Larger cod caught during
spawning are sometimes called
skrei. Young Atlantic cod or
haddock prepared in strips for cooking is called
scrod.
The Atlantic cod, which can change color at certain water depths,
has two distinct color phases: grey-green and reddish brown. Its
average weight is , but specimens weighing up to have been
recorded. Cod feed on
molluscs,
crabs,
starfish,
worms,
squid, and small fish. Some
migrate to warm water in winter to spawn. A large female lays up to
five million eggs in midocean, a very small number of which
survive.
Pollock, and
coalfish are often found on the same grounds as
codfish in cool Atlantic waters. Pollock have shovel-shaped tails
and pale lateral lines and grow to and . Some grow to in
length.
Cod meat is moist and flaky when cooked and is white in color.
In the
United
Kingdom
, Atlantic cod is one of
the most common ingredients in fish and
chips, along with haddock and plaice. It is also frequently consumed in Portugal
and Spain
.
Cod are currently at risk from overfishing in the UK, Canada and
most other Atlantic countries.
Taxonomy
At various times in the past, taxonomists incorrectly included many
species in Gadus. The great majority of
these are now either classified in other genera, or have been
recognized as simply forms of one of three species. Modern
taxonomy, therefore, recognizes 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.
"Cod" that is not cod
Related species
Cod forms part of the
common
name of many other fish no longer classified in the genus
Gadus. Many are members of the family
Gadidae; others are members of three related
families within the order
Gadiformes
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
placed in Gadidae.
Gadiformes include:
Some 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
Some fish commonly known as cod are unrelated to
Gadus.
Part of this name confusion is market-driven. Severely shrunken
Atlantic cod stocks have led to the marketing of cod replacements
using
names of the form "
x
cod", according to culinary rather than phyletic similarity.
The common
names for the following species have become well-established; note
that all inhabit the Southern Hemisphere
.
Perciformes
Fish of the
order Perciformes that are commonly called "cod"
include:
Rock cod, reef cod, and coral cod
Almost all
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 and as
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:
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.
Marketed as
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
Cod have three rounded
dorsal and two
anal fins. The
pelvic
fins are small with the first ray extended, and are set under
the
gill cover (i.e. the throat region), in
front of the
pectoral fins. The upper
jaw extends over the lower jaw, which has a well developed
chin barbel. The eyes are medium sized,
approximately the same as the length of the chin barbel. Cod have 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
Cod divide
into several stocks, including the Arcto-Norwegian
, North
Sea
, Faroe
, Iceland
, East Greenland
, West
Greenland
, Newfoundland, and Labrador stocks. There seems to be little
interchange between the stocks, although migrations to their
individual breeding grounds may involve distances of or more.
Spawning occurs between January to April (March and April are the
peak months), at a depth of in specific spawning grounds at water
temperatures of between .
Around the UK, the major spawning grounds are
in 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 inverts himself beneath the
female, and the pair swim in circles while spawning. The eggs are
planktonic and hatch between 8 to 23 days with larva reaching in
length. This planktonic phase lasts some ten weeks, enabling the
young cod to increase its body weight by 40-fold, and growing to
about . The young cod then move to the seabed and change their diet
to small
benthic crustaceans, such as
isopods and small crabs. They increase in size to in
the first six months, by the end of their first year, and to by the
end of the second. Growth tends to be less at higher latitudes. Cod
reach maturity at about at about 3 to 4 years of age.
Biome
Cod occupy varied habitat, favouring rough ground, especially
inshore.
Demersal in depths of between , on
average, although not uncommon to depths of .
Off the Norwegian and
New England coasts and on the Grand Banks of
Newfoundland
, cod congregate at certain seasons in water of
depth. Cod are gregarious and form schools, although
shoaling tends to be a feature of the
spawning season.
Predation
Adult cod are active hunters, feeding on
sand
eels,
whiting,
haddock, small cod,
squid,
crabs,
lobsters,
mussels,
worms,
mackerel, and
molluscs.
Young cod avoid larger prey.
Parasites
Cod and related species are plagued by parasites. One of the most
interesting is a grotesque and massively modified crustacean, known
as the
cod worm (
Lernaeocera
branchialis). This animal starts life as a small free swimming
larva that is undoubtedly a crustacean. Its
first host is the
lumpsucker which it
captures with grasping hooks at the front of its body. It
penetrates the lumpsucker with a thin
filament that it uses to suck blood. Cod worms mate
on the lumpsucker and the female takes her fertilized eggs to a cod
and clinging to its gills, metamorphoses into something that looks
scarcely animal. Her crustacean features give way to a plump,
s-shaped, worm-like body. Nestled against the rear of her body is a
coiled mass of egg strings. The worm is also grotesque in behaviour
because the front part of her body penetrates the body of the fish
and enters the rear bulb of the host's
heart.
Firmly rooted in the cod's circulatory system, the front part of
the female parasite grows like the branches of a tree, reaching
down into the main
artery. The worm extracts
nutrients from the cod's blood and remains there, safely tucked
beneath the cod's gill cover, eventually releasing her offspring
into the water.
Range
Gadus morhua cod live in the colder waters and deeper sea
regions throughout the Northern Atlantic.
The Gadus
macrocephalus is found in both eastern and western regions of
the Pacific
.
Cod Trade/History
Cod has been an important economic commodity in
international markets since the
Viking period (around 800 AD).
Norwegians traveled with dried
cod and soon a dried cod market developed in southern Europe. This market has lasted for more than
1000 years, enduring the
Black Death,
wars and other crises and is still an important Norwegian fish
trade. The
Portuguese began been
fishing cod in the 15th century.
Clipfish
is widely enjoyed in Portugal.
The Basques played an
important role in the cod trade and allegedly found the Canadian
fishing banks before Columbus' discovery of America.
The North American east coast developed in part due to the vast cod
stocks. Many cities in the New England area located near cod
fishing grounds.
Apart from the long history cod differ from most fish because the
fishing grounds are far from population centers. 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. Since the
introduction of salt, dried
salt cod
(clipfish or 'klippfisk' in Norwegian) has also been exported.
By the
end of the 14th century the Hanseatic
League dominated trade operations and sea transport, with
Bergen
the most
important port.
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,
creating trade networks and cross-cultural exchanges.
In 1733,
Britain tried to gain control over trade between New England and
the British Caribbean
by imposing the Molasses
Act, which they believed would eliminate the trade by making it
unprofitable. The cod trade grew instead because the “French
were eager to work with the New Englanders in a lucrative
contraband arrangement”. The American settlers traded cod with the
French Caribbean for rum-producing molasses. In addition to
increasing trade, the New England settlers organized into a
“codfish aristocracy”.
The colonists rose up against Britain's
“tariff on an import”, and inflamed by merchants, including John
Hancock and John Rowe, disguised themselves, boarded their own
ships and dumped their own goods into the harbor, an event known as
the Boston Tea
Party
(p. 96).
In the
20th century, Iceland re-emerged
as a fishing power and entered the Cod
Wars. In the late 20th and early 21st centuries, fishing
off the European and American coasts severely depleted stocks and
become a major political issue. The necessity of restricting
catches to allow stocks to recover upset the fishing industry and
politicians reluctant to hurt employment. The 2006 Northwest
Atlantic cod quota
is 23,000 tons representing half the available stocks, while the
Northeast Atlantic quota is 473,000 tons.
Pacific Cod is currently enjoying strong global demand.
The 2006
Total Allowable Catch (TAC)
for the Gulf of
Alaska
and Aleutian Islands
was 260,000 tons.
Endangered-species controversies in Canada and Europe
Following
the early 1990s collapse of Canadian stocks, the Canadian Department of Fisheries and
Oceans (DFO) banned Northern cod fishing in 1992, which caused
great economic hardship in Newfoundland and Labrador
. In 1995, in a controversial move,
Brian Tobin the Canadian Federal Minister of
Fisheries and Oceans, reopened the hunt on the
harp seal, which prey on cod, stating: "There is
only one major player still fishing the cod. His name is harp and
his second name is seal."
The DFO partly lifted its ban in 1997, although the
International
Council for the Exploration of the Sea noted the poor recovery
of Canadian stocks. In general, depleted populations of cod and
other gadids appear to recover poorly when fishing pressure is
reduced or stopped.
In 1998, the
Committee
on the Status of Endangered Wildlife in Canada (COSEWIC) listed
the Atlantic cod as a species of "special concern", though not as
an
endangered species.
Dr. Kim Bell, who drafted the report for
COSEWIC, subsequently stated that the original report in fact
had advised endangered status but that pressure by the DFO
had suppressed this.
In 2000, WWF placed cod on the
endangered species list. The WWF issued a
report stating that global cod catch had suffered a 70 per cent
drop over the last 30 years, and that if this trend continued, the
world’s cod stocks would disappear in 15 years.
Åsmund Bjordal,
director of the Norwegian Institute of Marine
Research
disputed the WWF's claim, noting the healthy
Barents
Sea
cod population. Cod is among Norway's
most important fishery exports and the Barents Sea is Norway's most important cod
fishery.
In 2003,
COSEWIC placed the Newfoundland and Labrador fisheries on the endangered species list and
Fisheries Minister Robert Thibault
announced an indefinite closure in the Gulf of St.
Lawrence
and off Newfoundland's northeast coast.
In a 2004
report, the WWF agreed that the Barents Sea cod fishery appeared to be healthy but that the
situation may not last due to illegal fishing, industrial
development, and high quotas.
In 2005
the WWF—Canada accused
both foreign and Canadian fishing vessels of deliberate,
large-scale violations of the restrictions on the Grand Banks
, in the form of bycatch. WWF also claimed poor enforcement by
NAFO, an intergovernmental organization with a
mandate to provide scientific fishery advice and management in the
northwestern Atlantic
.
According to
Seafood Watch, cod is
currently on the list of fish that consumers should avoid. In a
book on the subject,
Charles
Clover claims that cod is only an example of how unsustainable
fishing is destroying ocean ecosystems.
King cod
Periodically a cod with a deformed skull is found; the skull has a
distinct top or crown giving it the name "king cod" or kongetorsk
in Norwegian. In Norway this rare fish was earlier considered to be
able to forecast the weather and was commonly used for that
purpose. A woolen thread suspended the fish from the ceiling; its
nose would point in a different direction depending on the coming
weather. In reality, the thread rather than the fish that caused
the movement. The twisted thread served as a primitive
hygrometer by reacting to the air's humidity,
turning the fish as the humidity rose and fell.
Liver
Cod's soft liver can be tinned and eaten.
See also
References
- Pollack sales rise, as public gets message on cod -
Green Living, Environment - Independent.co.uk
- "Cod", Encyclopedia Britannica online 2008
- Sea Shepherd - Ocean Realm Autumn 1999
- Marine World - Will Atlantic cod ever
recover
- Collapse and recovery of marine fishes: Abstract:
Nature
- Atlantic Cod Endangered: Canadian Geographic
Magazine
- WWF - No more cod in 15 years, WWF report
warns
- Cod not endangered species - Aftenposten.no
- WWF - The Barents Sea Cod - the last of the large
cod stocks
- WWF Canada - News - Fisheries laying waste to
endangered fish stocks: WWF-Canada Report
- WWF - Cod overfished in the North-West Atlantic
despite ban
External links
Wikis
Quiz
Map
Misc
Search