Boreogadus saida (Lepechin 1774)

A pelagic cod adapted to close association with ice (cryopelagic)

Dark bluish head and back with violet sheen; Protruding lower jaw; Deeply indented caudal fin with rounded tips; Lateral line with curves; Greatest body depth behind the head

A main consumer of plankton offshore in the Arctic; The main food of many marine mammals, seabirds, and some fishes

Panarctic, endemic (only found in Arctic); One of the most northerly distributed fishes, collected near the North Pole; Cryopelagic or demersal; Brackish lagoons and river mouths to oceanic waters over deep central basins; Occasionally in large schools

Spawns once per lifetime, averaging 11,900 eggs per female; Migrate to nearshore waters to spawn; Eggs and larvae are pelagic; Mature at 2-6 years depending on region and sex; Maximum age is 6-7 years

The Arctic cod is circumpolar and occurs in coastal habitats during both summer and winter. In the Beaufort Sea, it is also found in brackish lagoons and in almost fresh water in river mouths. Although associated with the occurrence of ice (White Sea), the Arctic cod is present in ice-free nearshore waters (Alaska);also found at 50-175 km offshore in the Beaufort and Chulkchi Seas, at depths of 40 to 400 m. This fish is tolerant of widely fluctuating temperatures, salinities, and turbidities. Migration patterns are unknown, except for a prespawning migration to nearshore waters in late summer in the Beaufort Sea. The Barents Sea stock also under-takes winter mass migrations into the White Sea for spawning. In the Beaufort Sea, most mature males are 2 to 3 years old, whereas most mature females are 3 years old. These ages at first maturity are similar to those reported for the northwest Atlantic and Soviet stocks. In Cheshskaya Bay (White Sea), sexual maturity occurs in the 4th to 5th year of life. A predominance of females among older fish is reported in most populations of Arctic cod (74% females in populations of 3 to 6 years old fish). Arctic cod spawns once in its lifetime . Its fecundity is 9 000 to 21 000 eggs, on average 11 900 eggs per females. The spawning season extends from late November to early February in the Beaufort Sea, from end of December to February in Soviet waters, and from January to February (sometimes April) in the White Sea. Although spawning occurs in the coastal areas of the Beaufort Sea and under the shore ice of the White and Barents Seas, the relative importance of nearshore sites compared with regions farther offshore for spawning remains unknown. Because of the unpredictable conditions of its environment, Arctic cod is an r-selected species with early maturity, rapid growth, production of larger numbers of offspring at a given parental size, small body size, high rates of mortality, and shorter life span. Lagoon and coastal fish are larger at each age than those from deep offshore waters, since warmer coastal waters provide more favorable growth conditions. In Simpson lagoon (Beaufort Sea), a 1 year individual may attain 60 mm total length (usually 21 mm), and older fish vary from 45-257 mm (usually 60-170 mm) while the largest fish offshore usually vary from 60-110 mm; the maximum age is 6-7 years.Arctic cod feed mostly on epibenthic mysids and also on amphipods and copepods. For those that are under the ice surface in offshore waters, fish is the principal food item during the winter. Although they prefer to eat mysids, the dietary importance and proportions of the major groups of prey are based on prey availability. For example, the food of some of the specimens examined in the White Sea consisted exclusively of young shrimp.It is an important food-fish for many of the larger mammals and birds of the Arctic seas.

Reaches 40 cm total length; common to 25 cm.

Found throughout the entire north polar basin, around Greenland and Iceland, into Hudson Bay and in the north and northwest Bering Sea.

Jaws of about equal length or lower jaw slightly longer. Chin barbel very small. Palatine teeth always absent. Three dorsal fins, two anal fins, all separate from each other; first anal fin base short, less than one-half of preanal distance; caudal fin deeply concave. Pectoral fin reaching beyond end of first dorsal fin; pelvic fin with a slightly elongated ray. Lateral line interrupted along its entire length, variable in position. No lateral line pores on head. Scales small and embedded, not overlapping. Colour: along back brownish, with many fine dark points; sides and belly silvery; fins dusky, with pale margins.

Arctic cod used to be intensively fished by former USSR, Norway, Danish and German Dm Rp vessels using bottom trawl and mid-water trawl. The fishing grounds are the European part of former USSR, Barents and White Seas, and the northwest Atlantic. The fish is pursued from January through May producing massive catches during February. In 1984, world catches totalled 23 709 t, and after that year they declined steadily, although the stocks are little affected by fishing because r-selected species can support higher levels of fishing mortality and have a quicker recovery time. The total catch reported for 1987 in the FAO Yearbook for Fishery Statistics is 11 713 t, all taken by former USSR. In Canadian waters, Arctic cod has a limited commercial value because it is small and apparently not abundant. The flesh is said to be of low quality. It is exploited in a minor way as an industrial fish, but has great potential for increased catches. Its major utilization by Norwegians is for fish meal and oil.The total catch reported for this species to FAO for 1999 was 22 005 t. The countries with the largest catches were Russian Federation (22 005 t).

Occurs in coastal habitats during summer and winter (Ref. 1371). In the Beaufort Sea, it may also be found in brackish lagoons and in almost fresh water in river mouths (Ref. 1371). Although associated with the occurrence of ice (White Sea), it is present in ice-free near-shore waters (Alaska) (Ref. 1371). Onshore-offshore movements are associated with spawning and movements of the ice (Ref. 27547). Feeds mostly on epibenthic mysids, also amphipods, copepods and fishes (Ref. 1371). Preyed upon by marine mammals, seabirds (murres and black guillemots), fishes (Atlantic salmon, Arctic char, Atlantic cod, Greenland halibut and Greenland cod), harp seals, bearded seals, ringed seals, white whales and narwhals. Parasites of the species include Clavella adunca, Haemobaphes cyclopterina and Sphyrion lumpi (copepods) (Ref. 5951). Also caught with mid-water trawls (Ref. 1371).

Dorsal spines (total): 0; Dorsal soft rays (total): 42 - 57; Analspines: 0; Analsoft rays: 33 - 44; Vertebrae: 49 - 57

Oceanodromous. Migrating within oceans typically between spawning and different feeding areas, as tunas do. Migrations should be cyclical and predictable and cover more than 100 km.

Oviparous, sexes are separate (Ref. 101194). Fish move close inshore, often in large numbers to spawn (Ref. 27547).

Caudal fin deeply concave. Lower jaw slightly longer than upper jaw. Chin barbel very small. No lateral line pores on head. Scales small and embedded, not overlapping. Brownish along the back with many fine points; the sides and belly silvery; the fins dusky with pale margins (Ref. 1371).

Occurs in coastal habitats during summer and winter (Ref. 1371). Cryopelagic or epontic, from surface down to 1383 m (Ref. 58426). In the Beaufort Sea, it may also be found in brackish lagoons and in almost fresh water in river mouths (Ref. 1371). Although associated with the occurrence of ice (White Sea), it is present in ice-free near-shore waters (Alaska) (Ref. 1371). Onshore-offshore movements are associated with spawning and movements of the ice (Ref. 27547). Feeds mostly on epibenthic mysids, also amphipods, copepods and fishes (Ref. 1371). Also caught with mid-water trawls (Ref. 1371). Utilized as fishmeal and source of oil (Ref. 1371). Euryhaline and eurythermic.

fisheries: highly commercial; price category: high; price reliability: reliable: based on ex-vessel price for this species

Boreogadus saida, known as the polar cod or as the Arctic cod, is a fish of the cod family Gadidae, 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.

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 40 cm (16 in). This species is found further north than any other fish (beyond 84°N) with a distribution spanning the Arctic seas off northern Russia, Alaska, Canada, and Greenland.

This fish is most commonly found at the water's surface, but is also known to travel at depths greater than 900 metres (3,000 ft). The polar cod is known to frequent river mouths. It is a hardy fish that survives best at temperatures of 0–4 °C (32–39 °F), but may tolerate colder temperatures owing to the presence of antifreeze protein compounds in its blood. They group in large schools in ice-free waters.

B. saida feeds on plankton and krill. It is in turn the primary food source for narwhals, belugas, ringed seals, and seabirds. They are fished commercially in Russia.

Although very populous throughout the Arctic oceans, 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.

Feeds mostly on epibenthic mysids, also amphipods, copepods and fishes

North Atlantic: White Sea, Iceland, and southern Greenland into the Miramichi River, New Brunswick in Canada

Occurs in coastal habitats during summer and winter.

benthic

Under-ice