The polar cod also known as the Arctic cod, is a fish of the cod family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Gadidae

Gadidae

Gadidae is a family of marine fish, included in the order Gadiformes. It includes the cod, haddock, whiting, and pollock.Most species of gadid are found in temperate waters of the northern hemisphere, although there are some exceptions. They are generally medium sized fish, and are distinguished...

, related to the true cod

Cod

Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...

 (genus Gadus). Note that there is another fish with the common name Arctic cod

Arctic cod

The Arctic cod is an Arctic deepwater fish related to the true cod .-Names:The fish has several common names, including polar cod and Greenland cod...

, Arctogadus glacialis.

The polar cod has a slender body, deeply forked tail, 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 30 cm. The polar cod is found further north than any other fish species (beyond 84°N) with a distribution spanning the Arctic seas off northern Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

, Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, and Greenland

Greenland

Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

.

This fish is most commonly found at the water's surface, but is also known to travel at depths greater than 900 m. The polar cod is known to frequent river mouths. It is a hardy fish that survives best at temperatures of 0–4 °C but may tolerate colder temperatures owing to the presence of antifreeze protein

Antifreeze protein

Antifreeze proteins or ice structuring proteins refer to a class of polypeptides produced by certain vertebrates, plants, fungi and bacteria that permit their survival in subzero environments. AFPs bind to small ice crystals to inhibit growth and recrystallization of ice that would otherwise be...

 compounds in its blood. They group in large schools in ice-free waters.

The polar cod feeds on plankton

Plankton

Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

 and krill

Krill

Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...

. It is in turn the primary food source for narwhal

Narwhal

The narwhal, Monodon monoceros, is a medium-sized toothed whale that lives year-round in the Arctic. One of two living species of whale in the Monodontidae family, along with the beluga whale, the narwhal males are distinguished by a characteristic long, straight, helical tusk extending from their...

s, belugas, ringed seal

Ringed Seal

The ringed seal , also known as the jar seal and as netsik or nattiq by the Inuit, is an earless seal inhabiting the Arctic and sub-Arctic regions...

s and seabird

Seabird

Seabirds are birds that have 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 environmental problems and feeding niches have resulted in similar adaptations...

s. They are fish

Fishing

Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

ed commercially in Russia.

External links

• [ftp://ftp.fao.org/docrep/fao/009/t0243e/t0243e00.pdf Gadiform fishes of the World (Order Gadiformes) An annotated and illustrated catalogue of Cods, Hakes, Grenadiers and other gadiform fishes known to date.] FAO Fisheries Synopsis No. 125, Volume 10. 1990.
• Arctic cod, Boreogadus saida University of Guelph
• Arctic Cod Aquatic species. Fisheries and Oceans Canada.