Alligator Gar

Header Image Public Domain by Duane Raver, Jr. Commissioned by USFWS.

Appearance

Close up of hard diamond scales of alligator gar — Hard, diamond-shaped ganoid scales of alligator gar.

USFWS Photo by Ryan Hagerty.

The alligator gar is the largest member of the Family Lepisosteidae, reaching 8 feet (2.44 m) in length and over 300 pounds (136 kg). Having long torpedo-shaped bodies, broad snouts, and hard, diamond-shaped (ganoid) scales, they are easily distinguished from other freshwater fish species. Their broad snouts resemble that of an alligator, giving this fish its name and is a unique feature when compared to other gar species. They have 2 rows of sharp teeth as well as the unique ganoid scales that act as heavy armor. Their relatively small fins are positioned further back on their body, towards their round tail (caudal) fin. This species ranges from brown to olive in color with counter shading featured on their underside. The contrasting light and dark colors help them camouflage when viewed from either below or above.

Habitat

Florida range map of Alligator Gar limited to the Perdido, Escambia, Blackwater, Choctawhatchee, and Econfina Creeks in the western Panhandle.

Alligator gar primarily live in freshwater. They prefer large, slow-moving rivers, lakes, swamps, and bays. This species of gar is the most tolerant to salt water, allowing them to spend time in marine habitats. In Florida, they are restricted to six rivers in the western Panhandle and the bays these rivers are connected to.

Behavior

Close up of Alligator Gar head with mouth open being held by two fwc researchers in the river.

Alligator gars reproduce in late spring, but regional differences can occur between populations. Spawning involves an individual female joined by multiple males in shallow areas. The males compete to fertilize the eggs as the female releases them over submerged vegetation. The eggs are toxic to crayfish and small rodents, which may prevent predators that are attracted to the splashing that occurs during spawning. Juveniles grow at fast rates. This growth slows as they get older and sexual maturity is reached at around 10 years old. Fish are part of the diet throughout the entirety of the alligator gar’s life cycle. During their early life stages, young alligator gar also feed on larvae and insects, shifting to larger vertebrates like birds and small mammals as adults. Adult alligator gar have few natural predators, but American alligators are known to eat them.

Threats

Many regional populations of this species are declining from human impacts. The major threats for the alligator gar include overfishing, habitat modifications, and domestic, urban, industrial, and agricultural pollution. Habitat loss is the primary threat for this species. Changes to the movement and distribution of water can reduce the natural seasonal water flow in the systems where these fish occur. Due to the species’ reproductive behavior, many males remain in spawning areas for extended periods, making them particularly susceptible to harvesting.

Conservation and Management

FWC staff kneeling while holding an alligator gar at the rivers edge.

The FWC ended take and possession of the alligator gar in 2006 without a special permit. Currently, no take of alligator gar within Florida is allowed without a permit. If you are interested in aquaculture of alligator gar, contact the Florida Department of Agriculture and Consumer Sciences.

The FWC received a species evaluation request for the alligator gar in 2022 to determine if it might be eligible for listing as a State-designated Threatened species. In December 2023, the FWC Commissioners approved the convening of a Biological Review Group to review the species' status against state-listing criteria. The findings of the Biological Review Group will be presented at an upcoming Commission Meeting. The alligator gar is also listed as one of Florida’s Species of Greatest Conservation Need. Current information on listing can be found at MyFWC.com/Listing.

Researchers at the FWC have been studying alligator gar in the Escambia River since 2010. They hope to learn more about their population size, movement and habitat use.

Further conservation approaches could include the proper planning and regulation of hydrology channels, impoundments, barge traffic, and commercial fishing that take place in habitats inhabited by alligator gar. Additionally, the mitigation and management of pollution runoff along rivers and coasts may be beneficial in the conservation of this species.

Alligator Gar Sampling on the Escambia River

How You Can Help

You can help Florida’s alligator gar and other native fish and wildlife by never releasing aquarium species into the wild. Releasing aquarium fish or invertebrates can introduce nonnative species and novel diseases to our ecosystems, which can have a negative impact on our native fish and wildlife.

Enjoying your time in Florida’s waters? Another way to help is to ‘stash your trash’ to protect our ecosystems and wildlife from aquatic debris. You can also learn more about other ways you can help by visiting our freshwater and marine ecosystem webpages.

References

Aguilera,C., R. Mendoza, G. Rodriguez, and G. Marquez. 2002. Morphological description of alligator gar and tropical gar larvae, with an emphasis on growth indicators. Transactions of the American Fisheries Society 131:899-909

Alligator Gar (Atractosteus spatula). tpwd.texas.gov/huntwild/wild/species/alg

“Atractosteus spatula.” Discover Fishes, www.floridamuseum.ufl.edu/discover-fish/species-profiles/atractosteus-spatula.

Boschung, H.T., and R.L. Mayden. 2004. Fishes of Alabama. Smithsonian Institution Press, Washington, D.C. 960 pp

Echelle, A.A., and C.D. Riggs. 1972. Aspects of the early history of gars (Lepisosteus) in Lake Texoma. Transactions of the American Fisheries Society 101:106-112.

Etnier, D.A., and W.C. Starnes. 1993. The Fishes of Tennessee. University of Tennessee Press, Knoxville, Tennessee. xiv + 681 pp.

Garcia de Leon, F.J., L. Gonzalez-Garcia, J.M. Herrera-Castillo, K.O. Winemiller, and A. Banda-Valdes. 2001. Ecology of the alligator gar, Atractosteus spatula, in the Vicente Guerrero Reservoir, Tamaulipas, Mexico. Southwestern Naturalist 46(2):151-157.

O'Connell, M.T., T.D. Shepherd, A.M.U. O'Connell, and R.A. Myers. 2007. Long-term Declines in Two Apex Predators, Bull Sharks (Carcharhinus leucas) and Alligator Gar (Atractosteus spatula), in Lake Pontchartrain, an Oligohaline Estuary in Southeastern Louisiana. Estuaries and Coasts 30: 567-574.

Smith, N. G., D.J. Daughtery, J.W. Schlechte, and D.L. Buckmeier. 2018. Modeling the responses of alligator gar populations to harvest under various length-based regulations: Implications for conservation and management. Transactions of the American Fisheries Society 147:665-673.