''Paralichthys lethostigma'', the southern flounder, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

large-tooth flounder 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, ...

native to the

East Coast of the United States The East Coast of the United States, also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard, is the coastline along which the Eastern United States meets the North Atlantic Ocean. The eastern seaboard contains the coa ...

and the northern

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 ...

. It is a popular

sport fish Game fish, sport fish or quarry refer to popular fish pursued by recreational anglers, and can be freshwater or saltwater fish. Game fish can be eaten after being caught, or released after capture. Some game fish are also targeted commercial ...

and is the largest and most commercially valuable

flounder 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, thou ...

in the western

North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...

Ocean and Gulf of Mexico. It is a "left-eyed flounder", meaning the left side is pigmented and is the "up side".

Description

The body color is brown with diffuse, unocellated spots and blotches. This species typically grows to around in length.

Diet

Larval and postlarval southern flounder feed on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. As a juvenile, the southern flounder's diet consists of small invertebrates, shifting to larger invertebrates and fish as the flounder reaches adult size. Southern flounder feed on the bottom of the ocean and in the water column, and are considered to be near-

top predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...

s in their benthic environment.

Habitat

Adult fish breed and spend the warmer season in coastal embayments and nearshore shelf waters, where the eggs develop until they are late stage larvae, which are then pushed by currents into the estuaries where the fish settle into the sediment and grow into juveniles. The juveniles stay in the estuaries until they reach sexual maturity and leave to spawn. The southern flounder can survive in low salinity and has even been found in freshwater habitats both as a juvenile and as an adult.

Reproduction and life cycle

Juvenile southern flounder stay in estuaries, and most leave to spawn offshore during the fall and winter as adults. Young fish are eventually pushed into the estuaries by ocean currents to mature. Southern flounder reach sexual maturity around two years of age. Older, larger fish tend to begin the spawning migration earlier. Female fish both grow faster and live longer than males. The annual growth cycle of the southern flounder starts in the spring and ends in the fall as the water temperature decreases. Males live for around 5 years, and females live for around 7–8 years.

Distribution

The southern flounder is distributed along the East Coast of the United States, north to

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

, and along the northern Gulf of Mexico, south to

Tuxpan Tuxpan (or Túxpam, fully Túxpam de Rodríguez Cano) is both a municipality and city located in the Mexican state of Veracruz. The population of the city was 78,523 and of the municipality was 134,394 inhabitants, according to the INEGI census o ...

, but is not found in far southern

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

or the

Florida Keys The Florida Keys are a coral cay archipelago located off the southern coast of Florida, forming the southernmost part of the continental United States. They begin at the southeastern coast of the Florida peninsula, about south of Miami, and e ...

. A single specimen was reported in 2015 in the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

off Israel, a likely escapee from mariculture. This species is listed by the IUCN as near threatened due to both commercial and recreational overfishing, and mortality from the shrimp trawl industry. This species is also affected by habitat destruction from human causes.

Importance to humans

Southern flounders are a major and valuable species in the highly important commercial and recreational flounder fishery in the Gulf of Mexico. Most of the commercial catch in the Gulf of Mexico is incidental to the catch by shrimp trawlers. Recreationally, they can easily be caught by anglers on a line with either a lure or live bait. Another, riskier way of collecting flounders is night

gigging Gigging is the practice of hunting fish or small game with a gig or similar multi-pronged spear. Commonly harvested wildlife include freshwater suckers, saltwater flounder, and small game, such as frogs. A gig can refer to any long pole which ...

. Waders use a gig, or a multi-pronged spear, to impale fish after using a flashlight to spot them in the water at night. This practice is very hazardous due to the possibility of stepping on submerged sharp objects or of impaling dangerous

stingray Stingrays are a group of sea rays, which are cartilaginous fish related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae ( ...

s, which also frequent shallow waters and may be mistaken for flounder.

Southern flounder are also considered valuable as an aquaculture species because of their ability to live in water of varying salinities. Research has been conducted on using soy based protein sources rather than fish meal to grow the fish to reduce environmental impact.

Etymology

The genus name, ''Paralichthys'', is usually interpreted as "parallel fish" in reference to the deeply compressed body shape. However, some interpret it as "close to the sea", from the Greek word, ''para'', meaning beside or near. This can be in reference to the way it buries itself in the sand and lies flat as if it is a part of the sea floor itself. The species name, ''lethostigma'', comes from the Latin word, ''letho'', meaning death, and the Greek word, ''stigma'', meaning spots. The meaning "forgotten spots" or "death of spots" refers to the absence of conspicuous large

ocelli A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-l ...

(pigmented scaled areas that look like eyes) that are common in other species 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 ...

References

External links

FishBase entry for Southern Flounder
{{Taxonbar, from=Q7134909 Paralichthyidae Commercial fish Fauna of the Southeastern United States Fish of the Gulf of Mexico Fish described in 1884 Taxa named by David Starr Jordan Taxa named by Charles Henry Gilbert