Population Assessment of Alligator Gar Atractosteus spatula in Alabama


Alabama Department of Conservation and Natural Resources

Alabama Cooperative Fish & Wildlife Research Unit

Auburn University
Department of Fisheries

United States Geological Survey
Biological Resources Division

Alligator gar are "charismatic megafauna" (i.e., really cool and big).  There is a high level of interest in management and conservation of alligator gar.  Concerns over increased commercial harvest of alligator gar Atractosteus spatula in the Mobile Delta, Alabama during the late 1980's and early 1990's resulted in alligator gar being designated a sport fish with a two fish per day creel limit in July 1992.  The purpose of this study is to provide Alabama Wildlife and Freshwater Fisheries biologists (Alabama Department of Conservation and Natural Resources) with basic life history data and population statistics needed to manage alligator gar.  Because alligator gar are managed as a sport fish in Alabama, an assessment of their population status is warranted.  The overall goal of the project is to identify basic population parameters of alligator gar.

Specific objectives are as follows:
1) Quantify distribution, abundance, size and age structure of the population
2) Identify sex ratio, spawning period, fecundity and age at maturity
3) Use population models to determine sustainable harvest regimes
4) Document movement patterns using telemetry

Various capture techniques including gill nets, jug lines, and angling are being utilized. We are also collaborating with local and out-of-state bow anglers for fish collection and to determine appropriate habitats for future sampling.  In addition, specimens have been collected in MS, LA, and TX through cooperation with MS Parks and Wildlife, LA Wildlife and Fisheries, LA commercial fishermen, Sabine National Wildlife Refuge (LA) and TX Parks and Wildlife.  To determine movement patterns, five alligator gar were fitted with externally mounted radio tags and ten gar were fitted with ultrasonic tags.  Tracking of tagged fish will be used to examine spawning movements and to identify potential nursery habitats for juveniles (fish up to approximately 1 m total length).  Telemetry data collection is difficult in the Mobile Delta.  Factors such as dense aquatic vegetation, complex channel morphology, and complex bathymetry of shallow areas may obscure ultrasonic signals.  In addition, salinity interferes with the reception of radio transmitter signals.

Gonadosomatic index (GSI) will be used to determine spawning periods by comparing the size of the ovaries to the total body weight.  Fecundity (number of eggs) is also being determined.  Steroid analysis to determine spawning periodicity and percent spawners in the population is underway.  Techniques for determination of sex (internally) have been developed, and will be useful to managers.  Branchiostegal rays and otoliths are being examined for age determination.  Longnose gar Lepisosteus osseus and spotted gar L. oculatus have also been collected for surrogates to refine techniques used on alligator gar.

Related publications:
Alabama Agricultural Experiment Station Highlights of Agricultural Research:
"Fish Tales: Study Seeking to Tell Story of Alabama's Alligator Gar"

Field and Stream, April 2001, Vol. CV No. 12:
"Slaying Dragons"


If you like really big gar, then click here!

Funding provided by:
Alabama Department of Conservation and Natural Resources,Division of Wildlife and Freshwater Fisheries

Special thanks to:
Sabine NWR
Private John Allen NFH
LA Wildlife and Fisheries
TX Parks and Wildlife
MS Wildlife, Fisheries and Parks
American Sport Fish Hatchery
Mr. Joseph Landry Kelone (Mr. Landry)
John Ferrara (Cuyahoga Community College, Cleveland, Ohio)
Numerous recreational anglers


Other links of interest:

Gar Anglers' Sporting Society

International Bowfishing Association, Inc.

To view some really neat gar art, visit the Ray Troll web site
OR, just click on the pic below...