Flounders are a group of

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish order (biology), order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the ...

species. They are

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They occ ...

, found at the bottom of oceans around the world; some species will also enter

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

Taxonomy

The name "flounder" is used for several only distantly related species, though all are in the suborder

Pleuronectoidei A flatfish is a member of the ray-finned demersal fish order Pleuronectiformes, 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 migrati ...

(families Achiropsettidae, Bothidae,

Pleuronectidae Pleuronectidae, also known as righteye flounders, are a family of flounders. They are called "righteye flounders" because most species lie on the sea bottom on their left sides, with both eyes on their right sides. The Paralichthyidae are the op ...

Paralichthyidae Large-tooth flounders or sand flounders are a family, Paralichthyidae, of flounders. The family contains 14 genera with a total of about 110 species. They lie on the sea bed on their right side; both eyes are always on the left side of the head, ...

, and

Samaridae Samaridae (''Samariscus corallines'') is a family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to mainta ...

). Some of the better known species that are important in fisheries are: * Western Atlantic **

Gulf flounder The Gulf flounder (''Paralichthys albigutta'') is a species of saltwater flounder. Description The Gulf flounder is a flatfish that swims on its side. Their two eyes look upward when swimming. They have sharp teeth, two eyes on one side, and hav ...

– ''Paralichthys albigutta'' **

Southern flounder The southern (or armless) flounders are a small family, Achiropsettidae, of flounders found in Antarctic and sub-Antarctic waters. There are four genera, each with one species. The bodies of southern flounders are greatly compressed, with both ...

– ''Paralichthys lethostigma'' **

Summer flounder The summer flounder or fluke (''Paralichthys dentatus'') is a marine flatfish that is found in the Atlantic Ocean off the East Coast of the United States and Canada. It is especially abundant in waters from North Carolina to Massachusetts. De ...

(also known as ''fluke'') – ''Paralichthys dentatus'' **

Winter flounder 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 ...

– ''Pseudopleuronectes americanus'' * European waters **

European flounder The European flounder (''Platichthys flesus'') is a flatfish of European coastal waters from the White Sea in the north to the Mediterranean and the Black Sea in the south. It has been introduced into the United States and Canada accidentally th ...

– ''Platichthys flesus'' ** Witch flounder – ''Glyptocephalus cynoglossus'' * North Pacific **

Halibut Halibut is the common name for three flatfish in the genera '' Hippoglossus'' and ''Reinhardtius'' from the family of right-eye flounders and, in some regions, and less commonly, other species of large flatfish. The word is derived from ''h ...

– ''Hippoglossus stenolepis'' **

Olive flounder The olive flounder (''Paralichthys olivaceus''), bastard halibut or Japanese halibut, is a temperate marine species of large-tooth flounder native to the North-western Pacific Ocean. It is often referred to as the Japanese flatfish or Korean fla ...

– ''Paralichthys olivaceus''

Eye migration

Larval flounder are born with one eye on each side of their head, but as they grow from the larval to juvenile stage through

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

, one eye migrates to the other side of the body. As a result, both eyes are then on the side which faces up. The side to which the eyes migrate is dependent on the species type. As an adult, a flounder changes its habits and

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...

s itself by lying on the bottom of the ocean floor as protection against predators.

Habitat

Flounders ambush their prey, feeding at soft muddy areas of the sea bottom, near bridge piles, docks, and coral reefs. A flounder's diet consists mainly of fish spawn,

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

polychaete Polychaeta () is a paraphyletic class (biology), class of generally marine invertebrate, marine annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that ...

s and small fish. Flounder typically grow to a length of , and as large as . Their width is about half their length. Male ''Platichthys'' have been found up to off the coast of northern Sardinia, sometimes with heavy encrustations of various species of

barnacle A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...

. Fluke, a type of flounder, are being farm raised in open water by Mariculture Technologies in Greenport, New York.

Threats

World stocks of large

predatory fish Predatory fish are hypercarnivorous fish that actively prey upon other fish or aquatic animals, with examples including shark, billfish, barracuda, pike/muskellunge, walleye, perch and salmon. Some omnivorous fish, such as the red-bellied piranha ...

and large ground fish, including sole and flounder, were estimated in 2003 to be only about 10% of pre-industrial levels, largely due to

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...

. Most overfishing is due to the extensive activities of the fishing industry. Current estimates suggest that approximately 30 million flounder (excluding sole) are alive in the world today. In the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

, along the coast of

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, research indicates the flounder population could be as low as 15 million due to heavy overfishing and industrial pollution.

References

External links

Common names containing "flounder"
at

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

* {{commercial fish topics Commercial fish Pleuronectiformes Fish of Hawaii Fish common names Cuisine of the Southern United States Hawaiian cuisine