Long a popular species on both sides of the Atlantic, this member of the cod family ranges in North American waters from the Strait of Belle Isle to Cape Cod. Haddock generally resemble cod, although smaller on average, being from 38 to 63 centimetres in length, with an average weight of .9 to 1.8 kilograms. The head and back are a dark purple-grey with a black lateral line, and the underside is silver-grey with a slight pink cast. It is harvested inshore, nearshore, and offshore by otter trawls, traps, longliners and gillnets. Haddock stocks have suffered with other groundfish stocks in recent years and availability is less than it has been in the past. Highest concentrations occur on Georges Bank.

The raw meat is white and cooks up even whiter. Flesh is firm and resilient. Haddock is often sold skin-on so buyers can use the distinguishing black mark (the "devil's thumbprint" or "St. Peter's mark") to differentiate it from cod. Haddock has a delicate flake, finer than cod, and a slightly sweet taste. Cold-smoked haddock (the famous finnan haddie invented by the Scots) is one of the real treats of the sea.