The haddock (Melanogrammus aeglefinus) is a marine fish distributed on both sides of the North Atlantic. Haddock is a popular food fish and is widely fished commercially. The haddock is easily recognized by a black lateral line running along its white side and a distinctive dark blotch above the pectoral fin, often described as a “thumbprint”. Haddock is most commonly found at depths of 40 to 133 m (130 to 436 ft), but has a range as deep as 300 m (980 ft). It thrives in temperatures of 2 to 10°C (36 to 50°F). Generally, adult haddock do not engage in long migratory behaviour. Reaching sizes up to 1.1 m (3 ft 7 in), haddock is fished for year-round. The commercial catch of haddock in North America had declined sharply in recent years, but is now recovering, with recruitment rates running around where they historically were from the 1930s to 1960s. Haddock populations on the offshore grounds of Georges Bank off New England and Nova Scotia have made a remarkable comeback with the adoption of catch shares management program, and are currently harvested at only a fraction of sustainable yields.