Atlantic cod

Atlantic cod
Conservation status
Vulnerable  (IUCN 2.3)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Gadiformes
Family:	Gadidae
Genus:	Gadus
Species:	G. morhua
Binomial name
Gadus morhua Linnaeus, 1758

The Atlantic cod, Gadus morhua, is a well-known food fish belonging to the family Gadidae. It grows to two metres (6 1/2 feet) in length. Coloring is brown to green on the dorsal side, shading to silver ventrally. Its habitat ranges from the shoreline down to the continental shelf.

In the western Atlantic Ocean cod has a distribution north of Cape Hatteras, North Carolina, and round both coasts of Greenland; in the eastern Atlantic it is found from the Bay of Biscay north to the Arctic Ocean, including the North Sea, areas around Iceland and the Barents Sea, which is the most important feeding area.

Distribution

Northeast Atlantic cod

Estimated biomasses of North-East Arctic Cod 1946-2004 in mill. tonnes. The estimation are performed by the Arctic Fisheries Working Group of ICES, published in the ICES Report AFWG 2005, ACFM:20. Estimation method: Standard VPA.

The northeast Arctic or Arcto-Norwegian stock is at present the world's largest population of Atlantic cod distributed in the Barents Sea area. This stock is sometimes referred to as skrei, a Norwegian name meaning something like "the wanderer", distinguishing it from non-migrating coastal cod. This stock spawns in March and April along the Norwegian coast, about 40% around the Lofoten archipelago. Newly hatched larvae drift northwards with the coastal current while feeding on larval copepods. By summer the young cod reach the Barents Sea where they stay for the rest of their life, until their spawning migration. As the cod grow, they feed on krill and other small crustaceans and fish. Adult cod primarily feed on fish such as capelin and herring. The northeast Arctic cod also shows cannibalistic behaviour. Estimated stock size was in 2004 1.6 million tonnes.

The North Sea cod stock is primarily fished by European Union member states and Norway. In 1999 the catch was divided among Denmark (31%), Scotland (25%), the rest of the United Kingdom (12%), the Netherlands (10%), Belgium, Germany and Norway (17%). Briefly in the 1970s, the annual catch rose to between 200,000 - 300,000 tons, however catch quotas were repeatedly reduced in the 1980s and 1990s. In 2003, ICES stated that there is a high risk of stock collapse if current exploitation levels continue, and recommended a zero catch of Atlantic cod in the North Sea during 2004. However Agriculture and Fisheries ministers from the Council of the European Union endorsed the EU/Norway Agreement and set the Total Allowable Catch (TAC) 27,300 tons.

Population state and development

Atlantic cod catch 1950-2002. Northeast Atlantic (blue), northwest Atlantic (green) and total (red)

The spawning stock of cod (those over 7 years of age) was more than a million tons following World War II, but declined to a historic minimum of 118,000 tons in 1987. The catch reached a historic maximum of 1,343,000 tons in 1956, and bottomed out at 212,000 tons in 1990. Since 2000, the spawning stock has increased quite quickly, helped by low fishing pressure. However, there are worries about a decreased age at first spawning (often an early sign of stock collapse), combined with the level of discards and unreported catches. The total catch in 2003 was 521,949 tons, the major fishers being Norway (191,976 tons) and Russia (182,160 tons).

Northwest Atlantic cod

The northwest Atlantic cod has been regarded as heavily overfished throughout its range, resulting in a crash in the fishery in the United States and Canada during the early 1990s. The fishery has yet to recover, and may not recover at all because of a possibly stable change in the food chain. Atlantic cod was a top-tier predator, along with haddock, flounder and hake, feeding upon smaller prey such as herring, capelin, shrimp and snow crab. With the large predatory fish removed, their prey has had a population explosion and have become the top predators. Young Atlantic Cod have become the prey in the northwest Atlantic, making recovery extremely slow as they do not spawn until about 7 years of age. The northwest Atlantic populations spawn in the winter and spring at Georges Bank in the Cape Cod region.

Alternative explanations and solutions

Unofficial and at odds with science and economics is Debbie MacKenzie's homespun common sense account of the collapse of the cod stocks of the Grand Banks and beyond [1]. Sustained massive overfishing by drag-trawlers has depleted the nutrient cycle of a closed ecosystem (surface plankton, schools of fish, bottom-feeders and dwellers). The depletion of growing biomass leaves the ocean starving, and leaves unfixed carbon dioxide in the atmosphere. The ocean of evidence is in plankton depletion at the base of the food chain, a dearth of filter-feeders in favour of seaweed fed on nitrogen-loaded water, to the loss of cod and pelagic fish which were at the top. The solution is: i) to stop strip-mining the ocean floor with destructive dragnets, ii) to feed the fish with food, not the suffocating waste from sewage-polluted estuaries that causes pseudo-eutrophication, and most importantly iii) to enforce the regulation of commercial fishing very effectively. The economic alternative is to suffer the Tragedy of the Commons, where all potential resource rent is lost and normal profit obtained - where cost is public and shared, but gain is private and individual until the resource is gone.

Population tracking

Cod populations or stocks can differ significantly both in appearance and biology. For instance, the cod stocks of the Baltic Sea are adapted to low-salinity water. Organizations such as the Northwest Atlantic Fishery Organization (NAFO) and ICES divide the cod into management units or stocks; however these units are not always biologically distinguishable stocks. Some major stocks/management units on the Canadian/US shelf are (see map of NAFO areas) are the Southern Labrador-Eastern Newfoundland stock (NAFO divisions 2J3KL), the Northern Gulf of St. Lawrence stock (NAFO divisions 3Pn4RS), the Northern Scotian Shelf stock (NAFO divisions 4VsW), which all lie in Canadian waters, and the Georges Bank and Gulf of Maine stocks in USA waters. In the European Atlantic, there are numerous separate stocks, e.g. on the shelves of Iceland, the coast of Norway, the Barents Sea, the Faroes, and Western Scotland, in the North Sea, Irish Sea and Celtic Sea and in the Baltic Sea.

See also

• Cod
• Cod War
• Cod Trade

> Star Wars fish will take over the world..... along with their queen, lisa riley.

External links

• FishBase
• Codtrace
• The Centre for Environment Fisheries and Aquaculture Science
• Skrei - the miraculous cod
• The history of the northern cod fishery in Canada
• ICES recommendation for the North Sea Cod stock (2003)
• ICES recommendation for the North East Arctic Cod stock (2004)
• Reports on the status of Canadian fishing stocks, including cod
• Explains the collapse of the cod stocks of the grand banks, at odds with DFO accounts