A premium whitefish, haddock is a member of the cod family, though smaller than Atlantic cod, generally weighing 2 to 5 pounds. The haddock bears a distinguishing black mark, often referred to as the “devil’s thumbprint” or “St. Peter’s mark,” in the “shoulder” area, and its skin is less mottled than the cod’s. The term “scrod” is used to describe head-on, gutted haddock between 1 1/2 and 2 pounds. Haddock under 1 1/2 pounds are referred to as “snapper haddock,” and 2 1/2 pounds and up are “large.” Haddock is found on both sides of the North Atlantic. Highest concentrations on the U.S./Canada coast occur on Georges Bank and in the Gulf of Maine. Haddock is also found throughout northern Europe, where it is revered for fish and chips and as a cold-smoked product — the famous finnan haddie invented in Scotland over a century ago. Haddock are taken by longlines and trawl nets.