Atractosteus spatula
Alligator gar
(Also: Gemfish)

Atractosteus spatula is found in the Ohio River in southwestern Ohio and the Mississippi river south to the Gulf of Mexico. They are found in drainages throughout the southeastern coastal United States (Alligator Gar, 2005). They are found in parts of Florida, Georgia, Alabama, Tennessee, Arkansas, Oklahoma, and Texas (Knopf, 2002; Shultz, 2004). Their range is from 44° to 20° north latitude and 101° to 82° west longitude (Agbayani, 2005). ("Alligator Gar", 2005; Agbayani, 2005; Knopf, 2002; Schultz, 2004)

Alligator gar are found in large lakes, rivers, and bayous. Typically they are found in backwaters and bottomland swamps. They are found in both freshwater and brackish waters, they rarely enter marine waters (Etnier, 1993; Knopf, 2002). (Etnier and Starnes, 1993; Knopf, 2002)

Alligator gar are grayish green to brown color on their dorsal surface and yellowish or white colored ventrally (Page and Burr, 1991). They may also have brownish spots on their dorsal surface. They are alligator-like in appearance, with their long, slender body, jaws armed with many teeth, and their habit of floating at the water surface (Goddard 2005). Their eyes are small. They have a heterocercal tail. Their swim bladder can function as a lung. The snout is short and broad with two rows of teeth on the upper jaw (Etnier 1993, Knopf, 2002). They are protected by a thick set of ganoid scales (Knopf 2002). This species is the largest of the gars and one of the largest freshwater fishes in North America, growing to nearly 3 meters long and up to 137 kg. Lateral line scales number 58 to 62 (Etnier, 1993). (Etnier and Starnes, 1993; Goddard, 2005; Knopf, 2002; Page and Burr, 1991)

Young alligator gars develop from eggs and then float to the water's surface, resembling sticks (Shultz, 2004). They have a disc on the bottom of their snouth that allows them to attach to rocks and other objects until their yolk is absorbed (Goddard, 2005). Shortly afterwards, the young begin searching for food. (Goddard, 2005; Schultz, 2004)

Mating behaviors in this species are not known. (Goddard, 2005)

Female alligator gars lay eggs that are dark green or red and stick to rocks and vegetation. The eggs are poisonous if eaten. Alligator gar may take many years to reach sexual maturity, although little is known about reproduction in this species. (Goddard, 2005; Schultz, 2004)

Alligator gars are oviparous. Once the eggs are laid, the young are left to survive on their own (Shultz, 2004). (Schultz, 2004)

Females generally live longer than males and are larger, they may live from 26 to 50 years in the wild (Etnier and Starnes, 1993). (Etnier and Starnes, 1993; Goddard, 2005)

Little is known about alligator gar behavior. They are not known to be extensively social or to migrate.

Home ranges of alligator gar are unknown.

Not much information is known about communication in alligator gars. Their lateral line system is used to detect motion in the water. They are also likely to use chemical cues and vision to some extent.

Alligator gars are opportunistic carnivores and sit-and-wait predators. They appear to be sluggish, but can ambush prey with short bursts of speed (Goddard, 2005). They feed on almost anything, including fish, ducks, turtles, small mammals, and carrion (Schultz, 2004). (Goddard, 2005; Schultz, 2004)

Alligator gars have few predators. They may be eaten by larger fish as eggs, fry, and juveniles . Because of their large size, their only natural predators as adults are American alligators (Alligator mississippiensis). Humans also prey on adult alligator gars. (Goddard, 2005)

Alligator gars are generalist predators and eat anything they can find. They are especially important as top predators in aquatic systems (Goddard, 2005). (Goddard, 2005)

Alligator gars have been fished commercially (Knopf, 2002). In Lousiana, they are fished for food, acting as a substitute for lobster (Etnier and Starnes, 1993). Like many other fish, they are also collected for aquaria. (Etnier and Starnes, 1993; Knopf, 2002)

Because these fish are predators, they consume gamefish, (Shultz, 2004). In turn, they cause a problem for humans in terms of sport fishing and consumption. There are several undocumented reports of injuries to humans. Their eggs are poinsonous if consumed (Goddard, 2005). (Goddard, 2005; Schultz, 2004)

Alligator gar are not currently listed as endangered, threatened, or of special concern. There are some concerns about overfishing and indications that populations have declined in areas where their preferred habitat, bottomland swamps, has been destroyed through channelization and and the building of levees. (Goddard, 2005)