Cod fisheries are fisheries for cod. Cod is the common name for fish of the genus Gadus, belonging to the family Gadidae, and this article is confined to three species that belong to this genus: the Atlantic cod, the Pacific cod and the Greenland cod. Although there is a fourth species of the cod genus Gadus, Alaska pollock, it is commonly not called cod and therefore currently not covered here.
Cod are demersal fish found in huge schools confined to temperate waters in the northern hemisphere. Atlantic cod are found in the colder waters and deeper sea regions throughout the Northern Atlantic. The Pacific cod is found in both eastern and western regions of the Pacific. Atlantic cod can grow to in length. Its average weight is , but specimens weighing up to have been recorded. Pacific cod are smaller, and may grow up to and weigh up to . Cod 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 mid-ocean, a very small number of which survive.
Cod has been an important economic commodity in international markets since the Viking period (around A.D. 800). Cod are popular as a food fish with a mild flavour, low fat content and a dense white flesh. When cooked, cod is moist and flaky. Cod livers are processed to make cod liver oil. Cod are currently at risk from overfishing.
Species 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 widely consumed in Portugal and the Basque Country, where it is considered a treasure of the nation's cuisine.
Cod are highly prolific, producing several million eggs at each spawning. This contributes to their high population numbers, which, in turn, makes commercial fishing relatively easy. Adult cod are active hunters, feeding on sand eels, whiting, haddock, small cod, squid, crabs, lobsters, mussels, worms, mackerel, and molluscs, supplementing their diets. Young cod eat the same but avoid larger prey.
Atlantic cod
Atlantic cod is a well-known demersal food fish belonging to the family Gadidae. 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 and Norwegian Sea, areas around Iceland and the Barents Sea.
It can grow to in length. Its average weight is , but specimens weighing up to have been recorded. Sexual maturity is generally attained between 2 and 4 years, but can be as late as 8 years in the northeast Arctic.ICES (2007), Arctic Fisheries Working Group Report, Section 03, Table 3.5, (accessed 2008/12/11) The Atlantic cod can change colour at certain water depths, and has two distinct colour phases: grey-green and reddish brown. Colouring is brown to green with spots on the dorsal side, shading to silver ventrally. A lateral line is clearly visible. Its habitat ranges from the shoreline down to the continental shelf.
Several cod stocks collapsed in the 1990s (declined by >95% of maximum historical biomass) and have failed to recover even with the cessation of fishing. This absence of the apex predator has led to a trophic cascade in many areas. While the north west Atlantic cod stocks have not yet recovered fully from overfishing in the past, most stocks in the East Atlantic are currently in good condition and well managed, such as those at North Norway and Svalbard.
In the early 2000s the European Union introduced a Cod Recovery Plan which covers the North Sea (incl. the Eastern English Channel and the Kattegat), the Irish Sea and waters to the West of Scotland where cod has continued to decline. It is broadly accepted that the plan has been a failure and has not delivered its objective of recovering the cod stocks in these areas because of the plan's over reliance on effort (days-at-sea) that created an indiscriminate ‘race to fish’ which in fact increased fishing mortality on the biomass for cod, on other demersal species and had a destructive impact on the benthic zone of the seabed where it is intensely fished. On the other hand, conservation initiatives undertaken by fishermen working in cooperation with government, such catch-quota management, have made a very meaningful contribution to the recovery of cod in the central and northern North Sea. The biomass of cod in the Irish Sea and West of Scotland remains depleted. A temporary cod plan that excludes a days-at-sea regime will apply from 1 January 2017 before this is superseded by new multi-species plans for individual sea basins; e.g. the North Sea multi-annual plan which was proposed by the European Commission in August 2016.
Pacific cod The Pacific cod is an important commercial food species. It has three separate dorsal fins, and the catfish-like whiskers on its lower jaw. In appearance, it is similar to the Atlantic Cod. A bottom dweller, it is found mainly along the continental shelf and upper slopes with a range around the rim of the North Pacific Ocean, from the Yellow Sea to the Bering Strait, along the Aleutian Islands, and south to about Los Angeles, down to the depths of . They may grow up to 78–79 cm and weigh up to . It is found in huge schools. In Northwest Pacific catches of Pacific cod by the United States trawl fishery and joint-venture fisheries increased from less than in 1979 to nearly in 1984 and reached in 1995. Today, catches are tightly regulated, and the Pacific cod quota is split among fisheries that use hook and line gear, pots, and bottom trawls.
Greenland cod Greenland cod is generally sombre-coloured, ranging from tan to brown to silvery. Its appearance is similar to that of other cod species; generally heavy-bodied, elongate, usually with a stout caudal peduncle. They can grow to a length of .
They are bottom fishes inhabiting inshore waters and continental shelves, up to depths of . Their range covers the Arctic Ocean and Northwest Atlantic Ocean from Alaska to West Greenland, then south along the Canadian coast to the Gulf of St. Lawrence and Cape Breton Island generally from 45 to 75 degrees north. Their flesh is whitish and flaky but firmer and tougher and less desirable than that of the Atlantic cod. The stock of Greenland cod has been strongly reduced in recent years.
Distribution
Northeast Atlantic cod
The Northeast Atlantic is the world's largest population of cod. By far the largest part of this population is the North-East Arctic Cod, as it is labelled by the ICES, or the Arcto-Norwegian cod stock, also referred to as skrei, a Norwegian name meaning something like "the wanderer", distinguishing it from coastal cod. The North-East Arctic Cod is found in the Barents Sea area. 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. In 2012 the biomass of the Northeast Atlantic cod stock was estimated to be at an all-time high since scientists started observing stock status some 100 years ago.
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%). In the 1970s, the annual catch rose to between 200,000 - 300,000 tons. Due to concerns about overfishing, 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 moratorium on catching 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.
Baltic Sea cod are divided into two stocks: Western Baltic cod and Eastern Baltic cod. In 2013 the main catches of Western Baltic cod were by Denmark (55%), Germany (25%) and Sweden (13%), and the main catches of Eastern Baltic cod were by Poland (38%), Denmark (19%) and Sweden (17% ). The Eastern Baltic cod stock had quite low abundance until the 1970s, but then grew rapidly due to low fishing pressure and favourable environmental conditions for egg and larvae survival (high salinity, oxygen amount and abundance of prey copepods). In the late 1980s, stock size declined as a result of overfishing and degradation of spawning areas (decreased oxygen amount in the deeper zones of the Eastern Baltic). The stock recovered somewhat in 2010, but concentrated mainly in Bornholm Basin.
Spawning The spawning stock of North-East Arctic cod was more than a million tons following World War II, but declined to a historic minimum of 118,000 tons in 1987. The North-East Arctic cod 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.
Newfoundland's northern cod fishery can be traced back to the 16th century. "On average, about of cod was landed annually until the 1960s, when advances in technology enabled factory trawlers, many of them foreign, to take larger catches. By 1968, landings for the fish peaked at before a gradual decline set in. With the reopening of the limited cod fisheries last year, nearly of cod were hauled in. Today, it's estimated that offshore cod stocks are at one per cent of what they were in 1977,"
Technologies that contributed to the collapse of Atlantic Cod include engine-powered vessels and frozen food compartments aboard ships. Engine power vessels had larger nets, larger engines, and better navigation. The capacity to catch fish became limitless. In addition, sonar technology gave an edge to catching and detecting fish. Sonar was originally developed during World War II to locate enemy submarines, but was later applied to locating schools of fish. These new technologies, as well as bottom-trawlers that destroyed entire ecosystems, contributed to the collapse of Atlantic Cod. They were vastly different from old techniques used, such as hand lines and long lines.
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.
Population tracking