Flounder

Winter flounder, Pseudopleuronectes americanus

Flowery flounder, Bothus mancus,
Bahía de la Chiva, at Hawaii

Flounders are a group of flatfish species. They are demersal fish found at the bottom of oceans around the world; some species will also enter estuaries.

Taxonomy

The name flounder is used for several only distantly related species, though all are in the suborder Pleuronectoidei (families Achiropsettidae, Bothidae, 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
• Northwestern Pacific
  • Olive flounder - Paralichthys olivaceus

Eye migration

In its life cycle, an adult flounder has two eyes situated on one side of its head, while at hatching one eye is located on each side of its brain. One eye migrates to the other side of the body as a process of metamorphosis as it grows from larval to juvenile stage. As an adult, a flounder changes its habits and camouflages itself by lying on the bottom of the ocean floor as protection against predators. As a result, the eyes are then on the side which faces up. The side to which the eyes migrate is dependent on the species type.

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, crustaceans, polychaetes and small fish. Flounder typically grow to a length of 22–60 centimeters (8.7–23.6 in), and as large as 95 centimeters (37 in). Their width is about half their length. Male Platichthys are known to display a pioneering spirit, and have been found up to 80 miles off the coast of northern Sardinia, sometimes with heavy encrustations of various species of barnacle.

Threats

A flounder blending into its environment

World stocks of large predatory fish and large ground fish, such as 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, along the coast of Texas, research indicates the flounder population could be as low as 15 million due to heavy overfishing and industrial pollution.

According to Seafood Watch, Atlantic flounders and soles are currently on the list of seafood that sustainability-minded consumers should avoid.

External links

• Common names containing "flounder" at FishBase
• Video of a Fresh Water Flounder on YouTube