Pollock (alternatively and more commonly among anglers spelled as pollack; pronounced /ˈpɒlək/) is the common name used for either of the two species of North Atlantic marine fish in the genus Pollachius. Pollachius pollachius is referred to as pollock in both North America and the United Kingdom, while Pollachius virens today is usually known as coley in the British Isles (derived from the older name coalfish). Other names for P. pollachius include the Atlantic pollock, European pollock, lieu jaune, and lythe; while P. virens is also known as Boston blue (distinct from bluefish), silver bill, or saithe.
The currently recognized species in this genus are:P. pollachius (Linnaeus, 1758) (pollack)
P. virens (Linnaeus, 1758) (coalfish)
Both species can grow to 3 ft 6 in (1.07 m) and can weigh up to 46 lb (21 kg). P. virens has a strongly defined, silvery lateral line running down the sides. Above the lateral line, the color is a greenish black. The belly is white, while P. pollachius has a distinctly crooked lateral line, grayish to golden belly, and a dark brown back. P. pollachius also has a strong underbite. It can be found in water up to 100 fathoms (600 ft; 180 m) deep over rocks, and anywhere in the water column. Pollock are a "whitefish".
One member of the genus Gadus is also commonly referred to as Pollock, the Alaska pollock or walleye pollock (Gadus chalcogrammus) including the form known as the Norwegian pollock. While related (they are also members of the family Gadidae) to the above pollock species, they are not members of the genus Pollachius. Alaska pollock generally spawn in late winter and early spring in the southeastern Bering Sea. The Alaska pollock is a significant part of the commercial fishery in the Gulf of Alaska.
Pollock and other species of gadids are plagued by parasites, one of which is the cod worm, Lernaeocera branchialis, a copepod crustacean. At its final stage, the female parasite, with fertilized eggs, clings to the gills of the fish and metamorphoses into a plump, sinusoidal, wormlike body, with a coiled mass of egg strings at the rear.
Atlantic pollock is largely considered to be a whitefish, although it is a fairly strongly flavored one. Traditionally a popular source of food in some countries, such as Norway, in the United Kingdom it has previously been largely consumed as a cheaper and versatile alternative to cod and haddock. However, in recent years, pollock has become more popular due to overfishing of cod and haddock. It can now be found in most supermarkets as fresh fillets or prepared freezer items. For example, it is used minced in fish fingers or as an ingredient in imitation crab meat.
Because of its slightly gray color, pollock is often prepared, as in Norway, as fried fish balls, or if juvenile sized, breaded with oatmeal and fried, as in Shetland. Year-old fish are traditionally split, salted, and dried over a peat hearth in Orkney, where their texture becomes wooden. The fish can also be salted and smoked and achieve a salmon-like orange color (although it is not closely related to the salmon), as is the case in Germany, where the fish is commonly sold as Seelachs or sea salmon. In Korea, pollock may be repeatedly frozen and defrosted to create hwangtae, half-dried to create ko-da-ri, or fully dried and eaten as book-o.
In 2009, U.K. supermarket Sainsbury's briefly renamed pollock 'colin' in a bid to boost ecofriendly sales of the fish as an alternative to cod. Sainsbury's, which said the new name was derived from the French for cooked pollock (colin), launched the product under the banner "Colin and chips can save British cod."