The plaice (Pleuronectes platessa) is one of the most commercially significant flatfish species found across European waters. It belongs to the family Pleuronectidae, often referred to as the right-eye flounders, which describes the placement of its eyes in adulthood. The plaice is a demersal species, living on or near the seabed, and is common in the shallow, sandy, and muddy bottoms of the North Atlantic. Its importance extends beyond its biology, making it a familiar name in the culinary world as a popular food fish.
Defining Physical Characteristics
The European plaice has a distinctive, laterally compressed, oval or diamond-shaped body. Both eyes are situated on the right side of its head, a trait that emerges during its larval transformation. The dorsal side is typically dark green to brown, marked by conspicuous, irregularly distributed, bright orange or reddish spots.
The most reliable distinguishing feature is a bony ridge, a row of four to seven bony knobs, that runs along the head toward the lateral line. This ridge differentiates it from related flatfish, such as the common flounder or dab. The underside is a clean, pearly white.
The skin is smooth, covered with small scales, and lacks the prickles found on other flatfish species. While the fish can slightly alter its base color to camouflage with the substrate, the vivid orange spots remain visible. Adult plaice commonly reach 40 to 50 centimeters in length, though individuals have been recorded to grow up to one meter and weigh as much as 7 kilograms.
Distribution and Behavior
The European plaice ranges across the northeastern Atlantic Ocean, extending from the Barents Sea down to the Iberian Peninsula. It is particularly abundant around the European continental shelf, including the North Sea, the Irish Sea, and the English Channel. It is a benthic organism, preferring flat, mixed bottoms of sand, mud, or gravel, typically at depths between a few meters and 100 meters.
Plaice are generally active at night, foraging for food along the seabed. During the day, they often conceal themselves by partially burying in the soft sediment to hide from predators. Their diet consists primarily of bottom-dwelling invertebrates, with a strong preference for thin-shelled mollusks, bivalves, and polychaete worms.
The species undergoes seasonal movements, with adults engaging in significant migrations for spawning purposes. Spawning typically occurs in the colder months between January and March, usually in well-defined areas of relatively shallow water. Juveniles initially inhabit very shallow coastal waters and estuaries.
Culinary and Commercial Importance
Plaice is a highly valued species, ranking as the most important flatfish for European fishing fleets, especially those operating in the North Sea. Its substantial economic significance provides a major source of income for fishing communities across countries like the Netherlands, Denmark, and the United Kingdom. The fish is primarily harvested using demersal fishing gear, such as beam trawls, otter trawls, and Danish seines, though it is also caught with gillnets and longlines.
The flesh of the plaice is appreciated for its delicate, mild, and slightly sweet flavor, complemented by a fine, firm texture. This flavor profile makes it suitable for various culinary preparations, including steaming, frying, baking, and grilling. It is a traditional choice in many European dishes and is a popular option for classic fish and chips.
In the consumer market, plaice is sometimes confused with or marketed interchangeably with other flatfish, particularly flounder and sole, due to the similar appearance of filleted products. However, the European plaice is a distinct species. Many plaice stocks, particularly in the North Sea, have shown significant recovery from past overfishing, with current management practices often resulting in a healthy biomass status. Consumers can often look for certifications from organizations like the Marine Stewardship Council to ensure they are purchasing plaice from well-managed fisheries.