About the Species
The Gulf sturgeon is a sub-species of the Atlantic sturgeon that can be found from Lake Pontchartrain and the Pearl River system in Louisiana and Mississippi to the Suwannee River in Florida. Hatched in the freshwater of rivers, Gulf sturgeon head out to sea as juveniles, and return to the rivers to over summer or spawn (lay eggs) when they reach adulthood.
The Gulf sturgeon has five rows of bony plates known as scutes that run along its body and a snout with four barbels (slender, whisker-like, soft tissue projections) in front of its mouth. Similar to sharks, Gulf sturgeon have tails where one side, or lobe, is larger than the other. All of these features give the fish its unique look.
In 1991, Gulf sturgeon were listed as threatened under the Endangered Species Act after their population was greatly reduced or eliminated throughout much of their range because of overfishing, dam construction, and habitat degradation. NOAA Fisheries and the U.S. Fish and Wildlife Service jointly manage and protect Gulf sturgeon.
Population Status
A variety of survey methods and gear have been used to estimate Gulf Sturgeon abundance both within and across rivers. Some surveys regularly target only particular geographic areas within a river (e.g., a summer holding area) or specific age-classes making it difficult to assess Gulf sturgeon abundance at both riverine and species scales.. Therefore, surveys over time within and across rivers are not easily comparable.
Learn more about Gulf sturgeon population estimates
Appearance
Gulf sturgeon can grow to be 9 feet in length and weigh over 300 pounds. Females grow larger than males. They are bluish-black or olive brown on their dorsal side (or back), with paler sides and a white belly. They have five major rows of dermal "scutes,” or thorny plates along the length of their body.
Behavior and Diet
Gulf sturgeon spawn in rivers in the spring and fall and spend the summer months in the riverine habitat between the upstream spawning areas (where they lay their eggs) and the estuary (mixed-salinity area where a river meets the sea). Subadults and adults do not feed when they are in the river. In the fall, both subadults and adults move into estuarine waters and feed extensively. Adults will move into marine waters in the winter, but younger size classes remain in the estuarine and freshwater habitats until about age 2 or 3.
Gulf sturgeon are described as opportunistic and indiscriminate benthivores (bottom-feeders) that change their diets and foraging areas during different life stages. Gulf sturgeon use specialized snout parts that look like whiskers, called barbels, to feel around on the bottom for food that includes invertebrates such as crustaceans, worms, and mollusks.
Where They Live
Historically, Gulf sturgeon occurred from the Mississippi River east to Tampa Bay. Sporadic occurrences were recorded as far west as the Rio Grande River in Texas and Mexico, and to Florida Bay in the east. Their present range extends from Lake Pontchartrain and the Pearl River system in Louisiana and Mississippi respectively, east to the Suwannee River in Florida. Based on current data, populations continue to reproduce in seven river systems (Pearl, Pascagoula, Escambia, Yellow/Blackwater, Choctawhatchee, Apalachicola, and Suwannee rivers). In addition to the seven spawning riverine populations, Gulf sturgeon are also known to inhabit the Mobile, and Ochlocknee rivers.
World map providing approximate representation of the marine portion of the Gulf sturgeon's range
Lifespan & Reproduction
Gulf sturgeon live 20 to 25 years on average, but they may live up to 50 years.
Gulf sturgeon move from the Gulf of Mexico into coastal rivers in early spring (March to May). Spawning occurs in the upper reaches of rivers in the spring when the water temperature is around 59°F to 68°F. Fertilization is external. Females deposit their eggs on the river bottom and males fertilize them. Gulf sturgeon eggs sink and adhere to the bottom, and they vary in color from gray to brown to black. After hatching, juvenile Gulf sturgeon generally disperse downstream of spawning sites, though some may travel upstream as well, and move into estuarine feeding areas for the winter months.
In the fall, movement from rivers into estuaries and associated bays begins in September and continues through November. Most subadult and adult Gulf sturgeon spend the cool winter months (October/November to March/ April) in bays, estuaries, and the nearshore Gulf of Mexico. Tagged fish have been found in well-oxygenated shallow water areas that support burrowing macro invertebrates. These areas may include shallow shoals (5 to 7 feet), deep holes near passes, unvegetated sand habitats such as sandbars, and intertidal and subtidal energy zones.
Threats
Contaminants
Pollution and contamination from industrial, agricultural, and municipal activities is believed to cause a variety of physical, behavioral, and physiological impacts to sturgeon worldwide. Specific impacts include muscle atrophy; abnormal gonad, sperm, egg, and larval development; organ mutations; tumors; and disruption of hormone production. Chemicals and metals often settle to the river bottom and are later incorporated into the food web as they are consumed by benthic feeders, such as sturgeon or macroinvertebrates.
Dredging
Dredging activities can significantly impact aquatic ecosystems by directly removing or burying organisms, causing turbidity/siltation effects, resuspending contaminants, making noise and causing disturbance, altering the hydrodynamic regime and physical habitat, and destroying riparian habitat. Dredging operations may also destroy benthic feeding areas, disrupt spawning migrations, inadvertently injure or kill individual fish by suction into the draghead, and resuspend fine sediments causing siltation over required substrate in spawning habitat. Because Gulf sturgeon are benthic omnivores, the modification of the benthos affects the quality, quantity, and availability of prey.
Dams
Dams significantly impact Gulf sturgeon by blocking passage to historical spawning habitats, which reduces the amount of available spawning habitat, where reproduction occurs, or entirely impedes access to it. The ongoing operations of these dams also affect downstream habitat, by altering flow and water quality.
Climate Change
Global climate change may lead to accelerated changes in Gulf sturgeon habitat through saltwater intrusion, changes in water temperature, increased frequency and intensity of hurricanes and red tides (and associated fish kills), exacerbation of the world’s largest dead zone where the Mississippi river meets the Gulf of Mexico, and extreme weather periods that could increase both the frequency and intensity of droughts and floods.
Scientific Classification
| Animalia |
Chordata |
Osteichthyes |
Acipenseriformes |
Acipenseridae |
Acipenser |
oxyrinchus |
Last updated by NOAA Fisheries on 11/21/2024
