Paralichthys lethostigma

southern flounder




Type Locality

Indian River, Florida (Jordan and Gilbert 1884 in Jordan and Meek 1884).


Etymology/Derivation of Scientific Name

Paralichthys: parallel fish (Jordan and Evermann 1898); lethostigma: forgetting spots, in reference to the absence of conspicuous spots on the body.



Same name since type locale (Ross 2001).



Maximum size:  915 mm TL (Shipp 1986).


Coloration: The eyed side may be variable, depending somewhat on background coloration, but is often brown with darker mottling and sometimes has four to five rows of diffuse spots on the sides, none of which are oscillated. The blind side is usually white, although it is sometimes dusky (Ross 2001).


Teeth count: The slender, pointed teeth are in a single series, are about equally developed on the eyed and blind sides of the jaw, and become caninelike anteriorly (Ross 2001).


Counts: 78-100 SC, 10-14 long and slender gillrakers, 80-95 dorsal rays, 63-74 anal rays, and 11-13 pectoral rays (Ross 2001; adapted in part from Ginsburg 1952).


Body shape: Large, left-eyed flounder with symmetrical pelvic bases (Ross 2001).


Mouth position: Large, terminal mouth (Ross 2001).


External morphology: Lateral line highly arched over the pectoral fin on the ocular side (Hubbs et al 1991). The eyes are separated by a distance equal or greater than eye diameter. The lateral line is strongly arched over the pectoral fin on both the eyed and blind sides (Ross 2001).


Distribution (Native and Introduced)

U.S. distribution: Ranges in coastal habitats from North Carolina south through Florida and west along the Gulf Coast to northern Mexico (Hubbs et al 1991).


Texas distribution: Probably inhabit most bays and estuaries in the state, also occurring in the lower reaches of coastal streams (Hubbs et al 1991).


Abundance/Conservation status (Federal, State, NGO)

However, rapid coastal development, resulting in the loss of shallow, marsh-edge habitat, is reducing nursery areas and may lead to a decline of this estuarine-dependent species (Ross 2001).


Habitat Associations

Macrohabitat: Typically occur in estuaries, but may also enter brackish or even fresh water, especially in winter and spring (Guntherz 1967). Adult flounder can survive indefinitely in freshwater reservoirs if water temperatures remain above 9°C (Prentice 1989). Estuarine-dependant species: spawn in higher salinity Gulf waters, with the young fish then moving into estuaries to grow (Enge and Mulholland 1985).


Mesohabitat: In coastal, estuarine, or river-mouth habitats, southern flounder occur more over fine, organic substrata (i.e. mud, silt, and clay) rather than over sand (Powell and Schwartz 1977). Young southern flounder require low salinity areas of coastal rivers and sounds as nursery areas (Deubler 1958).



Spawning season: Late fall to February (Enge and Mulholland 1985) at water temperatures of 16-18°C (Arnold et al. 1977).


Spawning location:


Reproductive strategy: A male closely follows behind a female, placing his head within 2-3 cm of her vent whenever she stops. If the female is receptive, both fish swim to the surface, where the eggs are released and quickly fertilized. Spawning occurs during the day (Arnold et al. 1977).




Age at maturation: Usually two years (Stokes 1977; Etxold and Christmas 1979) at about 300 ml TL (Enge and Mulholland 1985), however, some females are not mature until their sixth year (Nall 1979).


Migration:Show limited travel between or within estuaries (Stokes 1977).


Longevity: Normally, fish reach ages of three to six years, with a maximum of ten (Nall 1979).


Food habits: Fishes, and to a lesser extent, crustaceans make up most of the diet of the southern flounder. Major fish prey includes anchovies (Anchoa spp.), juvenile striped mullet, menhadens, Atlantic croaker (Micropogonias undulatus), spot (Leiostomus xanthurus), pinfish (Lagodon rhombides), and fat sleeper (Dormitator maculatus; Darnell 1958; Fox and White 1969; Powell and Schwartz 1979; Wright et al. 1993). Common crustaceans in the diet are mysids, isopods, amphipods (Gammarus spp.), penaeid shrimp (Penaeus), and portunid crabs (Stokes 1977; Powell and Schwartz 1979l Wright et al. 1993).


Growth: Average SL of southern flounder ay the end of years 1-9 are: 63 mm, 102 mm, 145 mm, 191 mm, 231 mm, 272 mm, 320 mm, 351 mm, and 382 mm, respectively (Nall 1979).


Phylogeny and morphologically similar fishes



Host Records



Commercial or Environmental Importance




Arnold, C. R., W. H. Bailey, T. D. Williams, A. Johnson, and J. L. Lasswell. 1977. Laboratory spawning and larval rearing of red drum and southern flounder. Proc. S.E. Assoc. Fish and Wildl. Agencies 31:437-440.

Darnell, R. M. 1958. Food habits of fishes and larger invertebrates of Lake Pontchartrain, Louisiana, an estuarine community. Univ. Texas, Publ. Inst. Mar. Sci. 5:353-416.

Deubler, E. E., Jr. 1958. A comparative study of the postlarvae of three flounders (Paralichthys) in North Carolina. Copeia 1958(2):112-116.

Enge, K. M. and R. Mulholland. 1985. Habitat suitability index models: southern and gulf flounders. U.S. Fish and Wildlife Service, National Coastal Ecosystems Team, Biological Rept. 82(10.92).

Etzold, D. J., and J. Y. Christmas, eds. 1979. A Mississippi marine finfish management plan, pp. 1-36. MAGSP-78-046, Mississippi-Alabama Sea Grant Consortium, Ocean Springs, Miss.

Fox, L. S., and C. J. White. 1969. Feeding habits of the southern flounder, Paralichthys lethostigma, in Barataria Bay, La. Proc. La. Acad. Sci. 32:31-38.

Ginsburg, I. 1952. Flounders of the genus Paralichthys and related genera in American waters. Fish. Bull. (U.S.) 52(71):267-351.

Guntherz, E. L. 1967. Field guide to the flatfishes of the family Bothidae in the western North Atlantic, pp. 1-47. Circ., no. 263, U.S. Fish and Wildlife Service, Washington, D.C.

Hubbs, C., R. J. Edwards, and G. P. Garrett. 1991. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. Texas Journal of Science, Supplement 43(4):1-56.

Jordan, D. S., and S. E. Meek. 1884. List of fishes observed in the St. John's River at Jacksonville, Florida. Proc. U.S. Nat. Mus. 1884(1885)7:235-237.

Nall, L. E. 1979. Age and growth of the southern flounder (Paralichthys lethostigma) in the northern Gulf of Mexico with nores on Paralichthys albigutta. Master's thesis, Florida State Univ., Tallahassee.

Powell, A. D., and F. J. Schwartz. 1977. Distribution of paralichthid flounders (Bothidae: Paralichthys) in North Carolina estuaries. Chesapeake Sci. 18(4):334-339.

Powell, A. D., and F. J. Schwartz. 1979. Food of Paralichthys dentatus and P. lethostigma (Pisces: Bothidae) in North Carolina estuaries. Estuaries 2(4):276-279.

Prentice, J. A. 1989. Low-temperature tolerance of southern flounder in Texas. Trans. Amer. Fish. Soc. 118:30-35.

Ross, S. T. 2001. The Inland Fishes of Mississippi. University Press of Mississippi 624 pp.

Shipp, R. L. 1986. Guide to fishes of the Gulf of Mexico. Albama Marine Environmental Science Consortium, Dauphin Island Sea Laboratory, Dauphin Island, Alabama.

Simmons, E. G. and H. D. Hoese. Studies on the hydrographay and fish migrations of Cedar Bayou, a natural tidal inlet on the central Texas coast. Publ. Inst. Mar. Sci. Univ. Texas 6:56-80.

Stokes, G. M. 1977. Life history studies of southern flounder (Paralichthys lethostigma) and gulf flounder (P. albigutta) in the Aransas Bay area of Texas, pp. 1-37. Tech. Ser. no. 25, Texas Parks and Wildlife Department, Austin.

Wright, R. A., L. B. Crowder, and T. H. Martin. 1993. The effects of predation on the survival and size-distribution of estuarine fishes: an experimental approach. Env. Biol. Fish. 36:291-300.