DALS WILDLIFE SITE { WILDLIFE OF NORTHERN ENGLAND}

WILDLIFE OF NORTHERN ENGLAND

Sea fish -Cod

 

 

Image courtesy of Hans Petter Field"   CC BY-SA 2.5 license.

Introduction.

Cod belong to the genus Gadus belonging to the family Gadidae. Three species in the genus Gadus are called Cod, these are the Atlantic Cod, Gadus moruha. The Pacific Cod, Gadus macrocephalus. The Greenland Cod,Gadus ogac.  Here we review the Atlantic Cod found in the waters of the UK.

Atlantic cod juvenille.

Image courtesy of Hans Hilliwaert  CC BY-SA 4.0 License.

Description 

They are distinct by the hair-like barbel that hangs from the chin, they have three dorsal fins and two anal fins and a broom-like tail. Atlantic cod are larger and live longer than thier Pacific counterparts. They may attain the age of twenty five years.

Atlantic cod are brown to green or grey on the doral sides { Uppersides } and flanks with a pale ventral {undersides} and they have small smooth scales.

Cod caught in Norway.

Image courtesy of Arstein Ronning.   CC BY-SA 3.0 License.Gadus.JPG

Lifestyle and general behaviour 

The Atlantic cod feed at dawn or dusk and the diet is very varied including invertebrates and fish. Prior to their recent population declines {see conservation issues below}, they were the top tier predators in the north west Atlantic  along with species such as Haddock and Flounder, feeding opon smaller prey such as Herring and capelin ,shrimp and small crabs. However, now that cod stocks have markedly decreased the prey they fed upon has had a population explosion and now many of those animals have become the top predators in the food chain of the ocean.

Reproduction.

This species is a rather fecund fish with the female capable of laying  3 and 9 million eggs depending on their size, in a single spawning. They breed in the winter and again in spring via external fertilization. Spawning takes place near the sea floor where the temperature suits their requirements.

They reach sexual maturity at the age of between two and four years although some fish do not spawn until they are seven years old. 

Atlantic cod at fishmongers.

Public domain wikicommons.Atlantic cod live.jpg

Conservation Issues. 

Cod was the most sought after fish in the western world for food. As a result of overfishing  the population declined by 84% between 1970-2006. Now after decades of declining stocks North Sea cod have been declared sustainable by the Marine Stewardship Council which is welcome news. 

The recovery has been acheived by a variety of reasons including the decommissioning  of  fishing boats,  altering the mesh size of trawler nets and the banning of fishing in nursery grounds. Also helped was the responsible sourcing by supermarkets support for the MSC label.

In other parts of the north Atlantic ocean the  stocks are still recovering and fishing exemptions are still in place.

Resuse of images.

The images on this page may be reused. However, the name of the relevant author must be attributed along with any accompanying license.

Thank you for visiting