Gadus morhua

Cod

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Cod Cod Cod

 

Description

The cod is a relatively large and stout bodied fish with a large head and long chin barbel. It has three dorsal fins and two anal fins which are all rounded in outline. The colour can vary from greenish-grey with orange-brown or grey mottling. It has a conspicuous white lateral line. Adult fish can grow to approximately 1.7m although most are less than 1.2m. The large head, stout body, mottled coloration and distinctive white lateral line distinguish the cod from other members of the cod family.

Geography

Atlantic cod range from the north and eastern coast of North America, around the southern tip of Greenland across the north Atlantic to the waters around Iceland, the Faroes, the North Sea and the Barents Sea. It is found all around the British coast, reaching south to the Bay of Biscay.

Ecosystem

Atlantic cod are marine benthopelagic fish, living near the bottom and in the open ocean (Riede 2004). Cod also inhabit brackish waters. Cod can be found in a wide range of habitats within the ocean, from the shoreline down to the continental shelf. They can be found at depths of 500 to 600 meters in coastal waters and are also numerous in open ocean waters. These fish are located in a temperate climate with a range in temperature from 0 to 20 degrees Celsius. Geographically the majority of the population lies within a latitude of 80 to 35 degrees north (Frimodt 1995).

Conservation

Atlantic cod was listed as a vulnerable species in 1996. In the early 1990’s many cod populations collapsed in areas where commercial fishing was intense. The collapse is attributed to overfishing, and specifically to the commercial fishing of older/larger cod which resulted in a smaller population of fertile females and the harvesting of young fish before they have had a chance to mature and reproduce. The prosperity that fishermen enjoyed prior to the collapse lured many into the commercial fisheries and as a result the cod population was negatively affected.

Some efforts have been made to help certain cod populations rebound. Moratoriums and fishing regulations were placed in regions of Canada but were unsuccessful in maintaining or increasing population size. The main deterrent in properly managing cod stocks relates to the geographic range which the cod occupy. Cod are found throughout the waters of the Atlantic, and since these are international waters it makes it difficult for any one region to impose certain regulations. Research shows that populations can easily fall below the “Safe Biological Limits,” which represent the number of fish needed to maintain a proper population. Biologists argue that regulation alone will not be enough to keep the cod population at a sustainable level, but it is a start. Suggestions such as no-catch zones in areas of spawning and along migration routes may be helpful if enacted. As cod stocks move towards critically low levels, it is apparent that serious conservation efforts must be put into place to prevent the devastation of this important fish species.

 

Threats

The Atlantic cod is a fish in crisis. The fish stocks in the Irish Sea have fallen drastically within the last few years. Recent figures compiled and published by the European Environment Agency (EEA) warn that the risk of a collapse of the fish stock in the North Sea is high, and that populations are now outside safe biological limits. The spawning stock biomass (the breeding population of the fish) hit an historic low figure during 2001, and during February and April that year, much of the North Sea was closed to fishing fleets as part of an emergency plan to protect young cod. It is also thought that the spawning stock biomass for the North Sea has been below the 'biomass precautionary approach reference point' - the critical level for sustaining the population - for almost two decades, and this warning also applies to waters adjacent to the North Sea. Throughout its range, the harvesting of young fish before they have been able to reproduce successfully is a serious threat to Atlantic cod.

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