European plaice
Overview
 
The European plaice, Pleuronectes platessa, is a commercially important flatfish
Flatfish
The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development...

.
The geographical range of the European plaice is off all coasts from the Barents Sea
Barents Sea
The Barents Sea is a marginal sea of the Arctic Ocean, located north of Norway and Russia. Known in the Middle Ages as the Murman Sea, the sea takes its current name from the Dutch navigator Willem Barents...

 to the Mediterranean, also in the Northeast Atlantic and along Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

. In some locales such as the Irish Sea
Irish Sea
The Irish Sea separates the islands of Ireland and Great Britain. It is connected to the Celtic Sea in the south by St George's Channel, and to the Atlantic Ocean in the north by the North Channel. Anglesey is the largest island within the Irish Sea, followed by the Isle of Man...

 this species is considered fully exploited by commercial fishing.

It is a common flatfish, occurring on the sandy and muddy bottoms of the European shelf, usually at depths between 10 and 50 m, where they tend to burrow in sediment during day time and remain stationary for long periods.
Encyclopedia
The European plaice, Pleuronectes platessa, is a commercially important flatfish
Flatfish
The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development...

.

Distribution and habitat

The geographical range of the European plaice is off all coasts from the Barents Sea
Barents Sea
The Barents Sea is a marginal sea of the Arctic Ocean, located north of Norway and Russia. Known in the Middle Ages as the Murman Sea, the sea takes its current name from the Dutch navigator Willem Barents...

 to the Mediterranean, also in the Northeast Atlantic and along Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

. In some locales such as the Irish Sea
Irish Sea
The Irish Sea separates the islands of Ireland and Great Britain. It is connected to the Celtic Sea in the south by St George's Channel, and to the Atlantic Ocean in the north by the North Channel. Anglesey is the largest island within the Irish Sea, followed by the Isle of Man...

 this species is considered fully exploited by commercial fishing.

It is a common flatfish, occurring on the sandy and muddy bottoms of the European shelf, usually at depths between 10 and 50 m, where they tend to burrow in sediment during day time and remain stationary for long periods. They can be found at depths up to approximately 200 m. Young fish in particular come right inshore in very shallow water.

They are able to survive low salt concentrations and may occur in some cases in brackish water or even in freshwater.

Description

The European plaice is characterised above by their darkgreen to darkbrown skin, blotched with conspicuous, but irregularly distributed, orange spots. The underside is pearly white. The skin is smooth with small scales. They are able to adapt their colour somewhat to match that of their surroundings but the orange spots always remain visible The skin lacks any prickles.

Its maximum length is about 1 m but the plaice, but adults, caught in fishing nets, are usually between 50 and 60 cm in length. Its maximum published weight is 7 kg and its maximum recorded age is 50 years

The outline of adults is oval. The head is rather small and is less than 25 % of the total length. The pointed mouth is terminal and fairly small with its maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

 reaching just below the right eye. Both eyes are located at the right hand side of the body. The bony ridge behind the eyes is another characteristic for this species. The lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...

 curves slightly above the pectoral fin. The dorsal fin reaches the eye. The dorsal and anal fin are distant from the caudal fin. The anal fin contains 48 to 59 soft rays and is preceded by a spine. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 has 65-79 soft rays, the pectoral fin 10 to 11 and the ventral fin 6.

Food

It is active at night and feeds on polychaetes, crustaceans and bivalves. Young plaices (between 1 and 2 years old) tend to consume mainly shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...

s.

Life cycle

The main spawning grounds in the North Sea are located in the Southern Bight
Southern Bight
Southern Bight is the southern bight of the North Sea bounded by the coasts of the Netherlands, Belgium, France and Great Britain. The Southern Bight is south west of the German Bight and the Wadden Sea...

 and in the eastern English Channel. Plaice are determinate spawners in which fecundity
Fecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...

 is determined before the onset of spawning. Females mature, i.e. are able to spawn, at ages from 3 to 7 years old. However, in the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

, most females mature at 3 years. Ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...

 development begins around late August to September with the spawning being from December to May. Each female releases eggs in batches every 3 to 5 days for approximately 1 month.

The eggs hatch after approximately two weeks and drift passively in the plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

. The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e drift in the plankton and metamorphose
Métamorphose
"Métamorphose" - a song by French singer Amanda Lear released in 1989 by Carrere Records.- Song information :"Métamorphose" was the first single from Amanda's French-Italian album Tant qu'il y aura des hommes. The album was actually a re-release of Uomini più uomini, and consisted mostly of down-...

 after about 8 to 10 weeks, dependent on temperature, at which time they settle in the intertidal zone of sandy beaches. The larvae exhibit what is sometimes called semi-active tidal transport. As the larvae cannot swim against the prevailing currents, they make use of their ability to alter their vertical position in the water column to ensure they are transported to suitable habitat. On incoming or flood tides (water level is rising) the larvae move up into the water column and are thus transported towards land. On the outgoing or ebb tides (water level is falling), the larvae move down the water column and are not transported away from the intertidal by the tidal currents.

When the larvae have reached a suitable site for settlement, the metamorphosis to the asymmetric body shape takes place. This can take up to 10 days.

Recently transformed juveniles settle onto shallow intertidal beaches. The very youngest juveniles will, for a period of up to a week, strand themselves in very shallow pools on the intertidal once the tide has receded. The reasons for this behaviour are not clear. During the first year of life (when the fish are called 0+ group), the juveniles will stay in these shallow intertidal habitats for up to 7 months (depending on latitude and/or temperature), before migrating to deeper waters. Some of these fish will return the next year (when they are I+ group) and even fewer when they are II+ group, however, the majority of juveniles do not return after they have migrated during their first year.

Plaice as a food

Plaice is sometimes used as the fish in fish and chips
Fish and chips
Fish and chips is a popular take-away food in the United Kingdom, Australia, New Zealand and Canada...

, in countries where the dish is popular.

In North German and Danish cuisine
Cuisine of Denmark
Danish cuisine is shaped by the practice of fishing and farming, including the cultivation of the soil for raising crops and the raising of domesticated animals, and the history of Denmark. Danish cuisine is known for its open sandwiches , meat balls and sweet pastry...

 plaice is one of the most commonly eaten fishes. Filleted, battered and pan-fried plaice is popular hot or cold as an open sandwich
Open sandwich
An open sandwich, also known as an open face/faced sandwich, Ulrich Sandwich, bread baser, or tartine, consists of a single slice of bread with one or more food items on top.- In various countries :...

 topping together with remoulade
Remoulade
Remoulade or rémoulade, invented in France, is a popular condiment in many countries. Very much like the tartar sauce of some English-speaking cultures, remoulade is often aioli- or mayonnaise-based. Although similar to tartar sauce, it is often more yellowish , often flavored with curry, and...

 sauce and lemon slices. Battered plaice can also be served hot with french fries
French fries
French fries , chips, fries, or French-fried potatoes are strips of deep-fried potato. North Americans tend to refer to any pieces of deep-fried potatoes as fries or French fries, while in the United Kingdom, Australia, Ireland and New Zealand, long, thinly cut slices of deep-fried potatoes are...

 and remoulade sauce as a main dish; this fish and chips
Fish and chips
Fish and chips is a popular take-away food in the United Kingdom, Australia, New Zealand and Canada...

 variant is commonly available as a children's special in Danish restaurants. Breaded frozen plaice, ready to be baked or fried at home, are readily available in supermarkets. Fresh plaice is also oven-baked.

Threats

Plaice, along with the other major demersal fish in the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 such as cod
Cod
Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...

, monkfish
Monkfish
Monkfish is the English name of a number of types of fish in the northwest Atlantic, most notably the species of the anglerfish genus Lophius and the angelshark genus Squatina...

 and sole
Sole (fish)
Sole is a group of flatfish belonging to several families. Generally speaking, they are members of the family Soleidae, but, outside Europe, the name sole is also applied to various other similar flatfish, especially other members of the sole suborder Soleoidei as well as members of the flounder...

, is listed by the ICES
International Council for the Exploration of the Sea
The International Council for the Exploration of the Sea is the world’s oldest intergovernmental science organization. ICES is headquartered in Copenhagen, Denmark, where its multinational Secretariat staff of 51 provide scientific, administrative and secretarial support to the ICES community...

 as "outside safe biological limits." Moreover, they are growing less quickly now and are rarely older than six years, whereas they can reach forty. The World Wildlife Fund says that in 2006 that "of the eight plaice stocks recognised by ICES, only one is considered to be harvested sustainably while three are overexploited. Data is insufficient to assess the remaining stocks; however, landings for all stocks are at or near historical lows."

In 2010, Greenpeace International has added the European plaice to its seafood red list. "The Greenpeace International seafood red list is a list of fish that are commonly sold in supermarkets around the world, and which have a very high risk of being sourced from unsustainable fisheries."

External links

  • Guide to Responsible Sourcing of Plaice - produced by Seafish http://www.seafish.org/upload/file/fisheries_management/Plaice%20Factsheet2%20%20final.pdf
  • Information about plaice
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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