The winter flounder (Pseudopleuronectes americanus), also known as the black back, is a right-eyed ("dextral") flatfish of the family Pleuronectidae. It is native to coastal waters of the western north Atlantic coast, from Labrador, Canada to Georgia, United States, although it is less common south of Delaware Bay. It is the most common near-shore (shallow-water) flounder in the waters from Newfoundland down through Massachusetts Bay, reaching a maximum size around 61 cm in length and 2.25 kg in weight. The species grows larger on Georges Bank, where they can reach a length of 70 cm and weight of 3.6 kg. Although winter flounder historically supported large commercial and recreational fisheries, biomass and landings have decreased since the 1980s.