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Morphology & Biology

Atlantic cod is a pelagic saltwater fish, living in the open ocean, within the cod family (Gadidae). In the past atlantic cod up to 2 meters in length, with a weight of 96 kg, has been reported. They reach maturity when they are between 0.31 – 0.71 meter long and can live up to max 25 years old. The colour depends on the habitat in which they live. Arranging from reddish or greenish in waters populated with algae, and pale grey in deep water or near a sandy bottom. They have a clear stripe at both sides used to detect vibrations. The type of food they feed on varies in different stages of their live. At adult age they are carnivores eating sand eels, mackerels, haddocks, molluscs, squids and crabs. The adult cod are on top of the food web, being top predators for species such as haddocks, and therefore almost do not have natural enemies. The biggest natural enemy for the adult cod are the humans.

When they reach sexual maturity depend on the territory. The more oceanic stocks reach sexual maturity around 6-9 years, whereas the more coastal cod may reach sexual maturity already around 2-4 years. They spawn once a year for 2 a 3 month period in very big groups. They spawn mostly in spring in shallow warmer coast waters between December and June, mostly between 10-15 meters but sometimes also at 4 meters. Female lies up to 5 million eggs if they are very big in size. However, different types of fish and other sea creatures will eat most eggs. The males compete to fertilise the surviving eggs. After fertilisation depending on the temperatures they will hatch after two a four weeks. Larvae are transparent and only 0.16 inches long. Their size will increase 40 times after just 10 weeks. The larvae diet consists of plankton. Later (when they become larger) the young cod will enrich their diet with small crustaceans.

Atlantic cod (Gadus morhua), Norway (Photo: Peter Prokosch)

Distribution

The atlantic cod is widely distributed. It is found on both side of the Atlantic Ocean, from Cape Hatteras to around Greenland and Iceland. Furthermore, they are found at the coasts of Europe, from the Bay of Biscay to the Barents Sea.

They are slow swimmers travelling together in big shoals/aggregations. The larger fishesact as scout, leading the shoal’s direction. Atlantic cod, individual or in big schools, can perform very long migration, some individuals even do not return to the birthplace. They perform migration up to 5 km per day.

Threats

The Atlantic cod is suffering from overfishing, already since the moment man began to fish. Together with Salmon and Tuna is one of the most consumed and commercially known fish in Europe. Therefore, is also known as “The beef of the sea”. Several wild cods stocks collapsed already in 1990 such as the Canadian stock, with >95% of the stock gone which have never really recovered even when fishing limitations were implemented.

Fisheries & Aquaculture

The largest fishery can be found in the Northeast Arctic and Iceland. The overall wild stocks are overexploited and therefore the worldwide wild stock is in a vulnerable status. Even more, with the current fish catches is becoming an endangered species in the very near future. This is very dangerous as they are very important for the balance of the ecosystem as a top predator species.

Cod sold from aquaculture are more and more popular and often obtain a higher price than the wild cod. The farming of cod also started already a long time ago. In 1880 the Norwegian sea-captain G.M. Dannevig started to experimented with farming cod, which was succesful but not profitable enough yet.

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