''Boreogadus saida'', known as the polar cod or as the Arctic cod, is a fish of the cod

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Gadidae The Gadidae are a family of marine fish, included in the order Gadiformes, known as the cods, codfishes, or true cods. It contains several commercially important fishes, including the cod, haddock, whiting, and pollock. Most gadid species ...

, related to the true cod (genus ''Gadus''). Another fish species for which both the common names Arctic cod and polar cod are used is ''

Arctogadus glacialis ''Arctogadus glacialis'', known also with ambiguous common names Arctic cod and polar cod, is an Arctic species of fish in the cod family Gadidae, related to the true cod (genus ''Gadus''). ''Arctogadus glacialis'' is found in icy water. They g ...

''. ''B. saida'' has a slender body, a deeply forked tail, a projecting mouth, and a small whisker on its chin. It is plainly coloured with brownish spots and a silvery body. It grows to a length of . This species is found further north than any other fishChristiansen JS (2012): TUNU Programme: Euro-Arctic marine fishes - Adaptation and evolution. pp 35-50. In: Adaptation and Evolution in Marine Environments, Vol. 1: The Impacts of Global Change on Biodiversity. Springer-Verlag, Berlin Heidelberg. (beyond 84°N) with a distribution spanning the Arctic seas off northern

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

, and

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland ...

. This fish is most commonly found at the water's surface, but is also known to travel at depths greater than . The polar cod is known to frequent river mouths. It is a hardy fish that survives best at temperatures of , but may tolerate colder temperatures owing to the presence of

antifreeze protein Antifreeze proteins (AFPs) or ice structuring proteins refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water. AFPs bind to small ...

compounds in its blood. They group in large schools in ice-free waters. ''B. saida'' feeds on

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cruc ...

and

krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...

. It is in turn the primary food source for

narwhal The narwhal, also known as a narwhale (''Monodon monoceros''), is a medium-sized toothed whale that possesses a large " tusk" from a protruding canine tooth. It lives year-round in the Arctic waters around Greenland, Canada and Russia. It is ...

s, belugas,

ringed seal The ringed seal (''Pusa hispida'') is an earless seal inhabiting the Arctic and sub-Arctic regions. The ringed seal is a relatively small seal, rarely greater than 1.5 m in length, with a distinctive patterning of dark spots surrounded by light ...

s, and

seabird Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same envir ...

s. They are

fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...

ed commercially in Russia. Although very populous throughout the

Arctic ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

s, it still can be a victim to population threats through human actions. Global warming has increased steadily over the past years, and it has caused an increase in ocean temperatures of the Arctic Ocean. ''Boreogadus saida'' live in extremely cold water temperatures, and therefore they have adapted to the cold. Their larvae must be in 3°C to hatch normally, and a rise in ocean temperatures can easily lead to phenotypic changes of this cod species. Possible alterations of the species due to increasing ocean temperatures include, smaller size, reduced fecundity, earlier maturation, and increased investment in reproduction at an early age for some.

References

Pepijn De Vries, Jacqueline Tamis, Jasmine Nahrgang, Marianne Frantzen, Robbert Jak, Martine Van Den Heuvel‐Greve, Chris Klok, Lia Hemerik (2021). Quantifying the consequence of applying conservative assumptions in the assessment of oil spill effects on polar cod (Boreogadus saida) populations.

External links

Arctic cod, ''Boreogadus saida''
University of Guelph {{Taxonbar, from=Q829980 Gadidae Fish of the Arctic Ocean Fish of Europe Monotypic fish genera Taxa named by Ivan Lepyokhin Fish described in 1774