- Scientific Name: Acipenser oxyrinchus desotoi
- Common name: Gulf Sturgeon, Gulf of Mexico Sturgeon
- Order: Acipenseriformes
- Family: Acipenseridae
- Management Category: Threatened
Occurrence and Description
The Gulf sturgeon, Acipenser oxyrinchus desotoi, is a large, primitive fish that has bony plates, or "scutes," rather than scales and a hard, extended snout. Gulf sturgeon have a toothless, vacuum-like mouth that projects from the lower surface of the head and four whisker-like barbels. The backbone is cartilaginous, like those of sharks, as are the five rows of external scutes that protect the head and top portion of the body. Sturgeon typically range in color from a light neutral color to dark brown and have a white under belly. Their caudal fin is heterocercal, meaning that their tail is distinctly asymmetrical with the upper lobe longer than the lower.
Adult Gulf sturgeon range from 4 feet (1-2.5 m) in length and weight up to 200 pounds. Females attain larger sizes than males. Gulf sturgeon can live for as long as 60 years, but their average lifespan is about 20-25 years.
Sturgeons are an ancient group of fish dating back about 200 million years to the age of dinosaurs. Gulf sturgeon are a subspecies of Atlantic sturgeon, Acipenser oxyrinchus. It is very difficult to visually distinguish between the two. Worldwide there are 27 sturgeon species and two closely related species of paddlefish.
The Gulf sturgeon is a federally-listed threatened species (Federal Register 1991) and much of the river, bay and nearshore areas throughout its range are considered critical habitat in support of spawning,in-river holding, or feeding activities. (Critical habitat is a term used in the Endangered Species Act (ESA) to refer to specific geographic areas that are essential for the conservation of a threatened or endangered species and that may require special management and protection.) Catching, harming, or disturbing Gulf sturgeon is prohibited by federal and Mississippi regulations.
Gulf sturgeon occur in drainages from the Suwannee River in Florida to the Pearl River on the boundary of Louisiana and Mississippi. They spawn in up river reaches during the early spring and young-of-the-year (YOY) spend 6–10 months feeding in the river as they migrate down stream. They appear in the estuaries in December through February. Juveniles (< 6 years; except YOY) are believed to overwinter in the estuary. In Mississippi, large sub-adult and adult Gulf sturgeon have been shown to overwinter in the Mississippi Sound, congregating near the passes between barrier islands. The estuaries provide a essential link in the life history of Gulf sturgeon, ranging from a travel corridor connecting vital spawning and summer in-river holding areas, to nearshore and offshore marine feeding areas.
Feeding and Diet
Gulf sturgeon are bottom feeders (supra-benthic cruisers), consuming primarily macro-invertebrates, including brachiopods, mollusks, amphipods, polychaete worms, and other crustaceans. They rely on their barbels to detect prey items.
Adult Gulf sturgeon feed almost exclusively in brackish or marine waters of the Gulf of Mexico and its estuaries. Recently, it has been determined that Gulf sturgeon do very little feeding while in riverine habitats during the summer. The adults feed heavily in the winter when they are in the Gulf of Mexico and experience a substantial weight gain, followed by a weight loss during the summer.
Life Cycle & Reproduction
Gulf sturgeon are anadromous as adults (>1250 mm or four feet fork length), meaning that they spend time in both saltwater and freshwater, like salmon. Adults migrate upriver from the Gulf of Mexico in the springtime to spawn, returning to their natal streams to spawn, again similar to salmon.
Female Gulf sturgeon reach sexual maturity at 8-17 years of age. Males mature slightly earlier, at 7-12 years of age. Gulf sturgeon eggs are sticky and sink to the bottom, where they adhere in clumps to snags, or outcroppings.
They spawn in freshwater and migrate into marine waters in the fall to forage and overwinter. Juvenile Gulf sturgeon (304-890 mm FL) stay in the river for about the first two to three years and then move to the estuary where they forage until they reach sub-adult sized (891-1250 mm FL or three to four feet). Then they move to the barrier islands to forage, generally between December and March.
Interesting Facts About Gulf SturgeonJumping - All species of sturgeon will jump at times. Gulf sturgeon can jump six feet out of the water. The Gulf sturgeon is known to jump at two times during the year: in the rivers during July and August and early in the offshore feeding period. It is thought that they jump in order to communicate and maintain group cohesion. Read more in this National Geographic News article.
Sounds - During spawning, sturgeon make a noise similar to a creaky door hinge.
Name - The subspecies name of desotoi honors Hernando de Soto, the Spaniard who explored what is now the southeastern U.S. in the 16th century.
The total number of adult Gulf sturgeon is unknown. However, the population in the seven coastal rivers of the Gulf of Mexico inhabited by Gulf sturgeon is estimated at more than 15,000 adults. Of those rivers, the Suwannee River in Georgia and Florida supports the most viable subpopulation, estimated at more than 9,000 adults in the mid-2000s. The subpopulation estimate for mature Gulf sturgeon in the Choctawhatchee River in Alabama and Florida is about 3,000 fish. However, estimates for other rivers (Pearl, Pascagoula, Escambia, Yellow, and Apalachicola) average around 400.
Historic populations of Gulf sturgeon were greatly reduced by overfishing, for meat and roe, throughout most of the 20th century.
Current threats include the following.
- construction of water control structures, such as dams and sills, mostly after 1950, exacerbated habitat loss
- groundwater extraction
- irrigation and runoff
- flow alterations
- poor water quality
- contaminants, primarily from industrial sources
Conservation and Recovery Efforts
On September 30, 1991, the Gulf sturgeon was listed as a threatened species under the Endangered Species Act. In 2003, the National Marine Fisheries Service and the U.S. Fish and Wildlife Service jointly designated Gulf Sturgeon critical habitat in 14 geographic areas from Florida to Louisiana, encompassing spawning rivers and adjacent estuarine areas. In 1995, a Recovery/Management Plan was published for the Gulf Sturgeon. All U.S. fisheries for the Gulf sturgeon have been closed. This species is also included on the International Union for Conservation of Nature Red List of Threatened Species.
Since 2007, faculty and staff of GCRL's Fisheries Ecology Lab have worked closely with colleagues at the U.S. Army Corps of Engineers Engineer Research and Development Center (USACE-ERDC) in Vicksburg to study Gulf Sturgeon ecology and movements. Currently, there are three joint projects: the Pascagoula River, the Gulfport Harbor Expansion Project, and Ship Island Restoration. Dr. Mark Peterson is principal investigator for all three projects. Todd Slack, from the USACE-ERDC, is co-PI on the Gulfport Harbor and Ship Island projects.
Pascagoula River Project
The Pascagoula River is the only large river in the lower 48 States that is not dammed or has sills on the main stream. Our longest running project is conducted on this beautiful and wild river. Our research has provided considerable data on Gulf Sturgeon movements and ecology. We tag Gulf Sturgeon in the Pascagoula River as well as in the Pearl River system.
The project focuses on movements of juvenile and sub-adult Gulf sturgeon relative to spatial and temporal benthic resource density (food items) and seasonal changes in that benthic component. Early results strongly suggest minimal use of the east river zone of the Pascagoula River which has been strongly altered by urbanization, dredging, and other human activities. The more natural west river zone shows much higher Gulf Sturgeon activity.
Ship Island, Year Two
GCRL and other research groups track the movements of sturgeon in our area with the aid of acoustic tags implanted in the fish and listening buoys anchored in coastal waters. Each fish's acoustic tags emit a uniquely coded signal at regular time intervals. When a tagged fish passes within range of a buoy (roughly 1000 feet), a datalogger records the time and the tag identification code unique to that fish. One array of listening buoys is located at Ship Island and in the pass eastward to the tip of Horn Island. In 2012, a total of 21 Gulf sturgeon were tagged with acoustic tags in nearby rivers.
- Pearl River (6 tagged fish) (Forms boundary between Louisiana and Mississippi)
- Pascagoula River (n=4) (Drains into Mississippi Sound at Pascagoula, Mississippi)
- Escambia River (n=1) (drains into Pensacola Bay, Florida)
- Blackwater River (n=3) (drains into Pensacola Bay, Florida)
- Yellow River (n=2) (Drains into Blackwater Bay near Milton, Florida)
- Choctawhatchee River (n=1) (Drains into Choctawhatchee Bay, between Destin and Panama City, Florida)
- Brothers River (n=4) (north of Apalachicola, Florida)
During the second year of our study, we recorded a total of 94,244 detections. (Not corrected for simultaneous detections from multiple buoys.)
Gulfport Harbor Project, 2012-2013
GCRL researchers and others have been able to quantify movement and occupancy of all size classes of Gulf Sturgeon in these areas. This information increases our understanding of the western population of Gulf Sturgeon and provides valuable data to local and federal agencies. The information is particularly valuable to the NOAA-NMFS Office of Species Protection and USFWS, who manage the conservation plan for this threatened species.
Resources and References
More photos from gulf sturgeon research at GCRL
- "Gulf Sturgeon: A Canary in the Coal Mine"
A presentation by Dr. Mark Peterson at the Gulf Coast Research Laboratory's 2011 Earth Day Celebration, April 16, 2011
Youtube: part 1 Part 2 Part 3
- Youtube, USFWS tagging Gulf Sturgeon on the Escambia River of Alabama and Florida
- Youtube, underwater video of sturgeon at Weeki Wachee Springs, Florida
- Youtube, USFWS tagging Gulf sturgeon on the Yellow River in the Florida panhandle
- Atlantic sturgeon (very similar to Gulf sturgeon) in an aquarium, shows close-up details
- Youtube, Sturgeon Jumping on the Suwannee River
- Wikipedia article on Gulf sturgeon
- National Geographic News, Mystery of Florida's Giant Jumping Sturgeon Solved?
- Florida Fish and Wildlife Commission sturgeon page
- The Nature Conservancy Gulf sturgeon in Mississippi
- Anonymous (2010) Sturgeon more critically endangered than any other group of species. Mar Poll Bulletin 60:640-641.
- Dynesius M, and Nilsson C (1994) Fragmentation and flow regulation of river systems in the northern third of the world. Science 266:753–762.
- Federal Register (1991) Endangered and threatened wildlife and plants: Threatened status for the Gulf sturgeon. Code of Federal Regulations, 50 CFR Part 17. 56(189):49653-49658.
- Federal Register (2003) Endangered and threatened wildlife and plants: Designation of critical habitat for the Gulf sturgeon. Code of Federal Regulations, 50 CFR Parts 17 and 226. 68(53):13370-13495.
- Gulf Sturgeon (Acipenser oxyrinchus desotoi). 5-Year Review: Summary and Evaluation. 2009. U.S. Fish and Wildlife Service, Southeast Region, Panama City Ecological Services Field Office, Panama City, Florida and National Marine Fisheries Service, Southeast Region, Office of Protected Resources, St. Petersburg, Florida.
- Heise RJ, Slack WT, Ross ST, and Dugo MA (2004) Spawning and associated movement patterns of Gulf sturgeon in the Pascagoula River drainage, Mississippi. Trans Amer Fish Soc 133:221–230.
- Jackson, DC (2012). Mississippi's Pascagoula River designated as a model river in America's Great Outdoor Rivers Program. Fisheries 37(7):294.
- Rogillio HE, Ruth RT, Behrens EH, Doolittle CN, Granger WJ, and Kirk JP (2007) Gulf sturgeon movements in the Pearl River drainage and the Mississippi Sound. N Amer J Fish Manag 27:89–95.
- Ross ST, Slack WT, Heise RJ, Dugo MA, Rogillio H, Bowen BR, Mickle and P, Heard RW (2009) Estuarine and coastal habitat use of Gulf sturgeon (Acipenser oxyrinchus desotoi) in the North-Central Gulf of Mexico. Est Coasts 32:360–374.
- United States Fish and Wildlife Service and Gulf States Marine Fisheries Commission. 1995. Gulf sturgeon recovery plan. Atlanta, Georgia.