American Plaice

American Plaice is a cold-water flatfish native to the North Atlantic, ranging from Greenland and Labrador south to the mid-Atlantic United States. A member of the righteye flounder family, it has historically supported major commercial fisheries in Atlantic Canada and New England, where it is often sold under the market name 'dab.' The species has a rounded body, rough skin, and a distinctive strongly arched lateral line near the head. Once abundant, American Plaice populations declined sharply in the late twentieth century due to overfishing and remain closely monitored, with some stocks still recovering under management measures. It is a slow-growing, long-lived species adapted to cold continental shelf waters.

Key field marks:

• Eyes on the right side of a rounded, moderately deep body
• Reddish-brown to grayish upper surface, often with faint orange or rust tinges
• Strongly curved (arched) lateral line above the pectoral fin, more pronounced than in similar flounders
• Rough, ctenoid (spiny-edged) scales giving the skin a slightly sandpapery feel
• Small mouth relative to body size, positioned low

Look-alikes: Can be confused with winter flounder, which has a smoother texture and less arched lateral line, and with witch flounder, which is more elongated and slimmer-bodied.

American Plaice inhabits cold waters of the North Atlantic continental shelf, from the eastern coast of Greenland and the Grand Banks south to about the Gulf of Maine and southern New England. It lives on soft sand, mud, or gravel bottoms at depths ranging from roughly 30 to over 1,300 feet (10-400 m), with adults typically favoring deeper, colder water than juveniles, which often settle in shallower nursery grounds. The species tolerates near-freezing bottom temperatures characteristic of high-latitude shelf seas. It is strictly marine, requiring full oceanic salinity, and is not found in estuarine or freshwater habitats.

American Plaice is a bottom-dwelling predator that feeds primarily on benthic invertebrates such as marine worms, brittle stars, mollusks, and small crustaceans, occasionally taking small fish. It is a slow-moving, solitary species that relies on camouflage against the seafloor rather than speed to avoid predators. Spawning occurs in spring, with females releasing large numbers of buoyant eggs that drift and hatch in the water column before larvae undergo flatfish metamorphosis and settle as juveniles in shallower nursery areas. The species is notably slow-growing and long-lived, with individuals capable of reaching ages beyond 15-20 years, a trait that made populations especially vulnerable to historical overfishing.