Tennessee Wildlife Resources Agency

TWRA's Region 4 - East Tennessee

Reservoir Fisheries Management Program

Alligator Gar - Atractosteus spatula

(This page was last updated - 06/11/2007)

Scientific name: Atractosteus spatula (Atract "spindle", osteus "bony", spatula refers to the shape of the snout)

Common names: Alligator gar, gator gar, garpike, garfish, greater gar

Alligator gar by Eric Brinkman
A 160 pound Oklahoma specimen - photograph by Eric Brinkman

Species Overview

The Alligator gar is one of the largest North American freshwater fishes and is extremely rare in Tennessee. There are very few recent records of the species and they are considered to be "in need of management" by the TWRA and "of special concern" by the Heritage Program. One of the more recent reports came from the discovery of two alligator gar skulls from a trash pile at a fish camp on the lower Hatchie River in 2004. Anglers are encouraged to report sightings of any "short-nosed" gar exceeding 10 lbs. to their local TWRA officials and release the fish immediately.

The former range of alligator gar included Tennessee's Mississippi River Basin. It is assumed that their abundance has decreased since the mid 1900's as a result of river channelization and the drainage of swamps along the Mississippi River lowlands.

They inhabit large, slow moving rivers, reservoirs, and oxbow lakes. They prefer large rivers that have overflowing floodplains, but these rivers have all but disappeared in Tennessee due to human activities such as dredging and the building of dams and levees.

TWRA and the U.S. Fish and Wildlife Service have begun to restore this species into suitable habitat within their historical range. There was an initial stocking of 200 fingerlings into the South Fork of the Obion River, 25 fingerlings into the Middle Fork of the Forked Deer River, and 50 fingerlings into both Clear Creek and Crooked Creek in 1999. A total of 3,685 have been stocked into Tennessee waters. The most recent stocking of Cold Creek and the Hatchie River occurred in 2006.

Identification

All gars have a torpedo-shaped body with the dorsal and anal fins located far back towards the tail. They are covered by thick ganoid scales that create a very hard protective covering.

The snout of an alligator gar is similar to that of a shortnose or spotted gar, but very dissimilar to the long, thin snout of a longnose gar. The minimum width of an alligator gar's snout will be contained 4.5 or fewer times in the snout length while that of other gars will be 5 or more times. In other words, their snouts are proportionally wider than in other gars.

Alligator gar have two rows of "canine like" teeth on the upper jaw while other gars usually have only one row. Some shortnose gar will have a second row of short, prickly teeth on the upper jaw.

It has been suggested that the length from the tip of the snout to the corner of the mouth will be shorter than the remainder of the head on an alligator gar. Importantly, any "shortnosed" gar weighing over 10 pounds is most likely going to be an alligator gar.

 

alligator gar
Photo of a Moon Lake Mississippi alligator gar from the 1930's
From the American Museum of Natural History (www.magikglasses.com)

Habits

Alligator gars are voracious predators. They are ambush predators and lie still in the water until an unsuspecting fish swims by. They lunge forward and lash their heads from side to side in order to capture prey. All four of Tennessee's gar spend much of the time lying still or swimming slowly near the surface.

Alligator gar consume primarily fish, but are also known to prey on birds, small mammals, turtles, and dead animals. They have reportedly attacked duck decoys and eaten injured waterfowl shot by hunters.

Life Cycle

Spawning is assumed to occur in late spring in the United States. Alligator gars are thought to congregate in large numbers while spawning, with one or more males swimming on either side of a female to fertilize the eggs she releases.

Females generally carry an average of 140,000 eggs. After being fertilized, the adhesive eggs sink to the bottom and stick to the substrate. The eggs are bright red and poisonous to humans. Alligator gars are thought to spawn near vegetation in the floodplain of large rivers which gives the young protection from predators.

Newly hatched gars have an adhesive disc on the underside of the snout which they use to attach to objects on the bottom until the yolk sac is absorbed. A dorsal caudal filament at the posterior end of their upturned vertebral column disappears when they mature.

Gars are slow growing, with females reaching sexual maturity around age 11 and may live to age 50. Male alligator gars mature around age 6 and live at least 26 years. Alligator gars commonly grow to 6.5 ft. and can exceed 100 lbs. The largest alligator gar on record weighed 350 lbs. and came from the St. Francis River, Arkansas in the 1930's.

 

Alligator gar

Stocking

 

Year Location Number
     
1999    Clear Creek
50
1999 Crooked Creek
50
1999 Middle Fork of Fork Deer River
25
1999 South Fork of Obion River
200
2006 Obion River
1,145
2006 Cold Creek
1,044
2006 Hatchie River
1,161

 

 

Recent alligator Gar sightings - stockings in Tennessee
West Tennessee's Miss. River Drainage - from TWRA's 2005 Alligator Gar Management Plan

References

Etnier, D. and W. Starnes. 1993. The Fishes of Tennessee. The University of Tennessee Press.

TWRA. 2005. Tennessee Alligator Gar Management Plan pdf. Fisheries Management Division of the Tennessee Wildlife Resources Agency. Nashville, TN.

Ichthyology at the Florida Museum of Natural History pdf

 

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