Southern Flounder (Paralichthys lethostigma)


The southern flounder is thought to be the largest Gulf of Mexico flatfish. A member of the Bothidae family of left-eyed flounder, it is a highly desired food fish, and considerable numbers are harvested by trawlers.

Identification

The southern flounder resembles the summer flounder in appearance. Its coloring is light to dark olive-brown, and it is marked with diffused dark blotches and spots, instead of distinct ocelli (spots ringed with distinct lighter areas). These spots often disappear in large fish.

The underside is white, the simple fins make an even fringe around the body, and its beady eyes are located extremely close together. It can be distinguished from the summer flounder by having fewer gill rakers and by the presence of distinct spots. It is also similar to the gulf flounder, which has no distinct ocelli.


Size/Age

Mature individuals grow to 36 inches and more than 12 pounds. The average size is 12 to 24 inches and 2 to 3 pounds. The all-tackle record is 20 pounds, 9 ounces. Southern flounder can live up to 20 years in the Gulf of Mexico.

Spawning behavior

Southern flounder spawn in offshore waters. In the northern Gulf of Mexico, they move out of bays and estuaries in the fall; this occurs quickly if there is an abrupt cold snap, but it happens more slowly if there is gradual cooling. Spawning occurs afterward, in the late fall and the early winter. A female typically releases several hundred thousand eggs, which hatch and migrate into the estuaries and change from upright swimmers into left-eyed bottom dwellers.

Food and feeding habits

The southern flounder feeds partly by burying itself in the sand and waiting to ambush its prey. Small flounder consume shrimp and other small crustaceans, whereas larger flounder eat blue crabs, shrimp, and fish such as anchovies, mullet, menhaden, Atlantic croaker, and pinfish.

Other Names

flatfish, flounder, halibut, mud flounder, plie, southern fluke; Spanish: lenguado de Floride.

Distribution

The southern flounder can be found from North Carolina to northern Mexico, although it is not present in southern Florida.

Habitat

As an estuarine-dependent bottom fish, the southern flounder commonly inhabits inshore channels, bay mouths, estuaries, and sometimes freshwater. It is tolerant of a wide range of temperatures (50° to 90°F) and is often found in waters where salinities fluctuate from 0 to 20 parts per thousand. No other flounder of the eastern United States is regularly encountered in this type of environment. Anglers regularly catch this fish inshore from bridges and jetties.
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