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Flounder, Southern (Paralichthys lethostigma)
Also known as: Doormat, Flounder, Fluke, Mud flounder
Source: Wild-caught in Gulf state waters, mostly from Alabama to Texas

Southern flounder are found in coastal waters of the western Atlantic Ocean, from North Carolina to the mouth of the Rio Grande River and southward into Mexico. In the Gulf, they’re usually found west of the Mississippi River. Southern flounder is mainly an inshore species but lives in a variety of habitats, depending on gender, life stage, and environmental factors. Larvae hatch offshore in the water column; currents transport them inshore to shallow estuaries and tidal rivers. Juveniles settle in shallow, grassy areas of estuaries where food is abundant. Adults spend the warmer months over muddy bottoms in upper estuaries and the fall and winter offshore (for spawning).

Small flounder grow rapidly and can reach one foot in length by the end of their first year. Males seldom exceed this size, but females can grow up to nearly three feet long and 20 pounds. Most flounder harvested in the fishery are one to five pounds. Southern flounder can reproduce at two years of age. When waters start to cool in the fall, they migrate out to offshore Gulf waters to spawn. Between November and January, females spawn every three to seven days, producing thousands of eggs each time. Male southern flounder rarely live past age three; females can live up to about seven years.

With flat bodies and camouflage coloration, adult southern flounder are able to lie on the bottom and ambush their prey. They primarily feed on other fish (striped mullet, spot, and mummichog) but also eat crustaceans, including shrimp and blue crabs. Larvae feed on microorganisms in the water column; juveniles prey on various invertebrates.

Southern flounder are a flat, oval-shaped fish. They spend most of their life lying and swimming along the bottom on their side. Their right side (underbelly) is white, and their left, or top, side is brown with dark and light spots. The coloration on their left side can change to match their habitat, making them nearly invisible. Both eyes are on the left side of its body—when flounder larvae hatch, they have an eye on each side like other fish, but when they develop into juveniles, their right eye moves across the top of the head to the left side. Juvenile southern flounder have large spots that gradually disappear as they grow older, giving them their scientific name Paralichthys lethostigma, meaning parallel fish with forgotten spots.

Most common in the northwestern Gulf from Mobile Bay, Alabama, to Brownsville, Texas, southern flounder is a valued by both commercial and recreational fishermen alike for its excellent taste. Although flounder are not harvested in the same quantity as other popular commercial and recreational species, they’re still an important component of Gulf fisheries and the main flatfish harvested in the Gulf.

Since the mid-1990s, flounder harvests have declined due to regulations restricting the use of entangling nets and requiring bycatch reduction devices in shrimp trawls (much of the flounder harvest is taken incidentally in shrimp trawls). However, due to the demand for this delicious fish, the price per pound for flounder has increased significantly.

Individual Gulf State fisheries management agencies are responsible for monitoring and managing the flounder resource in the Gulf. The Gulf States Marine Fisheries Commission helps coordinate monitoring and management among the states to ensure they’re consistent through the species’ range. The Commission developed a regional management plan for flounder to provide an understanding of the biological, social, and economic characteristics of flounder fisheries as well as efforts regarding science and management of flounder in the Gulf. Although specific management measures vary among the states, their general goal is to ensure the viability of flounder fisheries for the long-term through size and possession limits, gear restrictions, and license requirements.

Methods Seasons Landings
Commercial Recreational

Since 2000, flounder landings in the Gulf have been highly variable and averaged about 433,000 pounds per year. In 2013, total flounder landings for the Gulf were more than 245,000 pounds with revenues of nearly $596,000. Most states do not differentiate between flounder species in their catch data; although the majority of landings are southern flounder, they may also include Gulf and ocellated flounder.

Source: NOAA Fisheries Annual Commercial Landings Statistics

Landings Summary Data :  

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Overview Current Abundance Additional Reasearch

Individual Gulf states assess the status of the southern flounder resource using data from biological sampling and survey programs. They monitor commercial southern flounder harvests through trip ticket programs—docks purchasing flounder directly from commercial fishermen submit information pertaining to the catch, including who caught it, where and when it was caught, how much was caught, etc. Commercial fishermen who sell their catch directly to the public are also required to submit trip tickets. They collect data on recreational harvests through the federal Marine Recreational Information Program survey or state-run data collection programs (in Louisiana and Texas).

Current Abundance

There is no comprehensive Gulf-wide stock assessment for southern flounder. According to available state assessments, estimates of current abundance are uncertain due to insufficient data; fishing mortality has been declining, and the fisheries for this resource are operating at appropriate levels.

Additional Research


Who's Responsible Management Program
Who's Responsible

Each Gulf state is responsible for managing southern flounder fisheries in their state waters. The Gulf States Marine Fisheries Commission helps coordinate monitoring and management among the states, gathering scientific data and organizing management measures to ensure they’re consistent through the species’ range.

Flounder are most abundant and almost exclusively harvested in state waters so federal agencies do not directly manage flounder fisheries in the Gulf.

Management Program

The Gulf States Marine Fisheries Commission’s 2000 Regional Management Plan for the Flounder Fishery of the Gulf of Mexico provides an understanding of the biological, social, and economic characteristics of flounder fisheries as well as efforts regarding science and management of flounder in the Gulf. The plan sets goals and recommends management measures for ensuring the viability of flounder fisheries for the long term. Specific management measures vary among the states but generally include size and possession limits, gear restrictions, and licensing requirements.