Diagnostic features
Total gill rakers on first arch 26 to 34.  Colour: blue-grey on the back, paler on the sides, shading to white on the belly. Sometimes a small dark blotch at base of pectoral fin. 

Geographical distribution
North Atlantic from the Barents Sea south through the eastern Norwegian Sea, around Iceland, through the eastern Atlantic, in the western Mediterranean, and south along the African coast to Cape Bojador. Also taken around southern Greenland and occasionally off southeast Canada and the northeastern coast of the USA.


Blue whiting - Geographical distribution
 

Habitat and biology
Oceanic and benthopelagic over the continental slope and shelffrom 150 to more than 1000 m, but more common at 300-400 m.  Migrates in summer, after spawning, to the North (Faeroes, E. Iceland and Norway) and back to the spawning areas in January-February. Also makes daily vertical migrations: surface waters at night and near the bottom during the day. Reaches its first maturity at 3 years of age.

From February to June, 6 000 to 150 000 eggs are laid, the major spawning grounds being the western.  UK Islands, but also off Portugal, Bay of Biscay, Faeroes, Norway and Iceland, above the continental shelf. Growth is fast: 1 year = 16 cm; 5 years = 27 to 29 cm; 10 years = 29 to 34 cm. Females are usually larger than males. Maximum age is 20 years (45 cm).

Feeds mostly on small crustaceans, but large individuals also prey on small fish and cephalopods.

Size
Reaching 50 cm total length; common from 15 to 30 cm.

Fisheries
The Blue whiting is caught mainly with trawls, longlines, trammel nets, gillnets, seines, lamparas and handlines, mostly beyond the edge of the continental shelf.  It is marketed fresh and frozen, but a large part of the catch is processed industrially as oil and fishmeal, due to difficulties encountered in the conservation of the flesh, and to the high demand for fishmeal in the eastern European countries. However, considerable research is being conducted, especially in the UK, on new conservation technologies (fish blocks).

Source: FAO