Flounders are a group of flatfish 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 oc ...

, 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 environme ...

Taxonomy

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

Bothidae Bothidae or lefteye flounders are a family of flounders. They are called "lefteye flounders" because most species lie on the sea bottom on their right sides, with both eyes on their left sides. The family is also distinguished by the presence of ...

, Pleuronectidae, Paralichthyidae, and Samaridae). Some of the better known species that are important in fisheries are: * Western Atlantic ** Gulf flounder – ''Paralichthys albigutta'' ** Southern flounder – ''Paralichthys lethostigma'' ** Summer flounder (also known as ''fluke'') – ''Paralichthys dentatus'' ** Winter flounder – ''Pseudopleuronectes americanus'' * European waters ** European flounder – ''Platichthys flesus'' ** Witch flounder – ''Glyptocephalus cynoglossus'' * North Pacific ** Halibut – ''Hippoglossus stenolepis'' ** Olive flounder – ''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, 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 b ...

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 decapoda, decapods, ostracoda, seed shrimp, branchiopoda, branchiopods, argulidae, fish lice, krill, remipedes, isopoda, isopods, barnacles, copepods, ...

s, polychaetes 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. 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-bellie ...

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. 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 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 the United ...

, along the coast of

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

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