Southern Flounder

Southern flounder are found in rivers and estuaries along the Atlantic Coast from North Carolina to northern Florida, and from Tampa Bay, Florida along the Gulf coast into southern Texas. Their distribution is discontinuous around the southern tip of Florida, leading some biologists to wonder if there are two genetically separate natural stocks. Southern flounder are found in a wide range of salinities; adults have been captured in a range of 0 to 36 ppt (parts per thousand) salinity, and it is not uncommon to catch them by hook and line far inland on coastal rivers.

The southern (or armless) flounders are a small family, Achiropsettidae, of flounders found in Antarctic and sub-Antarctic waters. There are four genera, each with one species.

The broad flounder, Paralichthys squamilentus, is similar but is rarely found in inshore waters. Adults prefer depths of 100-220 meters. Juveniles are found in shallower water, but seldom in estuaries or bays. As the name implies, the broad flounder's body is wider, with the body width being half the length or greater.

Another 15 species of lefteye flounders are found in the northern Gulf of Mexico, but they are unlikely to be confused with the southern, gulf, or broad flounder.

The southern flounder generally prefers sandy - muddy bottoms throughout most of the estuary, but it can occur in channel and bay mouths and also frequents areas around piers, pilings, and rock jetties. Migrations to offshore spawning grounds begin in late fall at the onset of cold weather, and spawning is completed during winter months. They will lay in the sand around any natural structure, or around any of the numerous artificial reefs and wrecks. Spear-fishermen take some huge flounder around these wrecks in the winter months. This species is the prefect predator, lying in total camouflage on the bottom until unsuspecting prey wander within reach and are capture with lightning quick movements. Foods of this species include shrimp and fishes

• Scientific Name: Paralichthys lethostigma
• Common Names: flounder, mud flounder, plie (Louisiana French)
• Order: Pleuronectiformes
• Family: Paralichthyidae
• Population trend: stable

The southern flounder and Gulf flounder and other flatfish are compressed laterally and spend most of their life lying on the bottom or swimming along the bottom on their side. They have prominent eyes and a large mouth with large, sharp, pointed teeth.

Southern flounder and Gulf flounder are known as left-eye flounders; the eyes of the adults are always on the fish's left side. The opposite is true for other species of flounders, halibut, and all the species of soles, whose eyes are on the right side.

The left or "up" side of the southern and Gulf flounders is light olive brown to dark brown or nearly black, with many blotches and spots of darker and lighter color. The eyeless "down" size side is white or dusky. Gulf flounders are distinguished by three large dark eye-like spots, arranged in a triangle with a pair of spots about midway on the length of the fish and a third closer to the tail. Southern flounders may also have scattered large spots but they are much more diffuse and gradually disappear as the fish grows older. The scales are small. As described below, flounders can modify their coloration and patterning to match the bottom.

Flounder lying in ambush and partially buried on a sandy bottom. Click for a larger version.
Southern flounders are larger and live longer than Gulf flounders. Female southern flounders typically grow to about 28", while typical female Gulf flounders reach only about 18". Males of both species are smaller, typically reaching only 10 to 14" in length. After their first year of life, males spend most of their lives offshore, seldom venturing into estuaries and bays. Thus, the majority of flounders caught by anglers in inshore waters are females.

Flounders have small body cavities and lack a swim bladder, making it easier for them to maintain their position on the bottom.

VIDEO - Southern Flounder