Fish and Aquatic Conservation



illustration of an Alligator gar fish

Alligator gar

Atractosteus spatula, (Lacepede, 1803)

Cool Facts

Alligator gar are voracious ambush predators that are primarily piscivorous. This species of gar is the largest apex predators in the Mississippi River system. The heaviest published weight for an alligator gar is 137 kg (301 lbs.)

SIZE: The common length for alligator is 200 cm (78.7in.) with the maximum reported length being 305 cm (10 ft).

RANGE: Alligator gar range from southwestern Ohio and southern Illinois to the Mississippi River drainage basin. Their range continues south to the Gulf of Mexico and the Gulf of Mexico coastal plain from the Ecofina River in Florida to Veracruz, Mexico.

HABITAT: Alligator gar inhabit sluggish pools and the back waters of large rivers, swamps, bayous and lakes. They prefer large rivers that have a large overflow flood plain. Alligator gar have even been known to enter brackish or marine waters upon occasion.

DIET: Alligator gar feed on blue crabs, turtles, waterfowl or other birds and small mammals.

Natural History

Alligator gar come together in groups near specific locations during their pre-spawning period and while overwintering. The spawning period for alligator gar varies widely depending on environmental conditions and their geographic location. There have also been reports of alligator gar gathering together during their post-spawning period. Spawning usually occurs when water temperatures reach approximately 23 degrees Celsius (73.4 degrees Fahrenheit). A female alligator gar, along with several male gar alongside her, will extrude her sticky eggs over submerged aquatic vegetation and the males will fertilize the eggs with their milt before they become attached to the underwater vegetation. Alligator gar eggs normally hatch between 48 to 72 hours after having been laid. Larval gar will remain attached to the submerged aquatic vegetation until their egg yolks are absorbed. The yolk sac absorption stage normally lasts between 5 to 10 days. After their yolks have been absorbed, young alligator gar will detach themselves from the underwater vegetation and begin to search for food. Juvenile gar feed on plankton, invertebrates, amphibians and fish before becoming almost totally piscivorous adults.

Conservation

Alligator gar are primarily a commercial species in the southern U.S., along with other gar species. Alligator gar are not normally considered a recreational species, with the exception of the state of Alabama and in the Rio Grande River where there is a recreational bow fishery for alligator gar. Alligator gar populations have substantially decreased over the past 50 years. This species has been classified as Rare in Missouri, Threatened in Illinois and Endangered in Arkansas and Kentucky.