Pollock (alternatively spelled pollack; pronounced //) is the common name used for either of the two species of North Atlantic marine fish in the genus Pollachius ("P."). 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 at times known as Boston blues (distinct from bluefish), coalfish (or coley), silver bills or saithe.
There are currently two recognised species in this genus:
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 colour is a greenish black. The belly is white, while P. pollachius has a distinctly crocked lateral line, greyish to golden belly and a dark brown back. P. pollachius additionally has a strong under-bite. 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".
Other fish called pollock
One member of the genus Gadus is additionally commonly referred to as pollock. This is the Alaska pollock or walleye pollock (Gadus chalcogrammus) including the form known as the Norwegian pollock. While related (they are additionally members of the family Gadidae) to the above pollock species, they aren't 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 additional 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 fertilised 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 flavoured one. Traditionally a popular source of food in a few countries, such as Norway, in the United Kingdom it has previously been largely consumed as a cheaper and versatile alternative to cod and haddock. Notwithstanding 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 grey 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 additionally be salted and smoked and achieve a salmon-like orange colour (although it isn't 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 might 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 renamed pollock 'Colin' in a bid to boost 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."
In the U.S. and worldwide, Alaska pollock is the primary fish used by the McDonald's chain in their Filet-O-Fish sandwich.