Pollock

Pollock (alternatively spelled pollack; pronounced ) is the common name used for either of the two species of marine fish in the Pollachius ("P.") genus. Both P. pollachius and P. virens are commonly referred to as pollock. Other names for P. pollachius include the Atlantic pollock, European pollock, lieu jaune, and lythe; while P. virens is sometimes known as Boston blues (distinct from bluefish), coalfish (or coley), silver bills or saithe.

Species
There are currently two recognized species in this genus:
 * Pollachius pollachius (Linnaeus, 1758) (Pollack)
 * Pollachius virens (Linnaeus, 1758) (Saithe)

Description
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 crocked lateral line, gray-ish to golden belly and a dark brown back. P. pollachius also has a strong under-bite. It can be found in water up to 100 fathoms (180 m) deep over rocks, and anywhere in the water column. Pollock are a "whitefish".

Other fish called pollock
One member of the genus Gadus is also commonly referred to as pollock. This is the Alaska pollock or walleye pollock (Theragra chalcogramma) 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 Pollachius genus. 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.

Parasites
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.

As food
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 over-fishing 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 melted 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 renamed pollock 'Colin' in a bid to boost ecofriendly sales of the fish as an alternative to cod. The supermarket also suggested some shoppers may be too embarrassed to ask for the species under its proper title, due to its reputation as an inferior fish, and its similarity to a popular English swear word (bollocks). 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."

In the U.S. and worldwide, it is the primary fish used by the McDonald's chain in their Filet-O-Fish sandwich.