Once abundant, gator gar are struggling

Hal Schramm
August 31, 2009 at 10:16 am  | Mobile Reader | Pring this storyPrint 

This is one of three female alligator gar spawned this spring at the Pvt. John Allen National Fish Hatchery.
This is one of three female alligator gar spawned this spring at the Pvt. John Allen National Fish Hatchery.
Iíve heard they attack people. Any fish that grows to more than 7 feet and 150 pounds, has a tooth-lined snout big enough to grab and hold a grown manís leg, and lurks in shallow backwaters is bound to generate some scary stories.

Someone somewhere may have been bitten by an alligator gar, but they actually are pretty docile.

The once-abundant alligator gar historically inhabited rivers and tributaries throughout the Mississippi River Valley from Ohio to Illinois and downstream into the estuaries of the Gulf of Mexico. They may have even existed as far north as Iowa and as far west as Kansas and Nebraska.

Currently known populations exist only in the lower Mississippi River Valley from Oklahoma to the west, Arkansas to the north, Texas and portions of Mexico to the south, and east along the coast to Florida.

Alligator gar are distinguished from other gars by the broad and relatively short snout. Close inspection reveals that the alligator gar has two rows of teeth on the upper jaw; one row is outside the jaws when the mouth is closed. At a distance, ígator gar can be distinguished by a snout that is just about as wide as the head. And if itís more than 6 feet long, itís a ígator gar.

Alligator gar biology

This species is most commonly found in slower-moving rivers, floodplain lakes and freshwater marshes and brackish estuaries along the Gulf of Mexico, but they occasionally have been found farther out in salt water. They have thrived in a few impoundments like Toledo Bend, an impoundment of the Sabine River on the Louisiana-Texas border.

Most of the year, the fish are solitary. Congregations occasionally occur during the pre-spawn.

ďItís hard to figure where the fish will congregate, or even areas that will hold a lot of gator gar,Ē explained Ricky Campbell, manager of the U.S. Fish and Wildlife Service fish hatchery in Tupelo.

Campbell collects mature alligator gar in the spring to spawn at the hatchery, so he is always looking for areas with abundant gar.

ďAreas where gar are abundant seem to be consistently so,Ē he said. ďYet other locations that look just like these donít have any gator gar. Obviously we have a lot to learn.Ē

Spawning occurs in shallow, vegetated water with little or no current, and begins when water temperatures climb to 73 degrees. Single females accompanied usually by multiple (often up to five) males release eggs into the water column that are fertilized by the trailing males. The fertilized, adhesive eggs attach to the vegetation where incubation occurs. The eggs hatch in 48 to 72 hours, depending on temperature.

Larval gar remain attached to the vegetation by a suctorial disk while development continues. After 10-15 days, the yolk sac has been absorbed. The tiny fish releases its hold on the vegetation and begins feeding. Initially the small fish are limited to zooplankton, but they grow quickly. By the time they reach 2 to 3 inches, they begin feeding on fish. Commonly, the fish grow to lengths exceeding 12 inches in their first year.

Though man-eating gator gar are fable, claims of toxic eggs and yolk sacs are true. Do not eat or even handle gar eggs.

There are many gaps in biologistsí knowledge about gator gar, but the biology of the juveniles ó fish from age 1 to sexual maturity at about 4 feet long ó is truly a black box. Those fish are rarely collected or seen.

One manís trash is anotherís treasure

Although gator gar are still moderately abundant in a few areas, such as east-Texas reservoirs and coastal marshes, they are relatively rare in their inland, river-related historic homes. The cause of the apparent decline is probably a combination of habitat alteration and harvest. While many gar have been, and continue to be, killed as trash fish, they are a valued target of sport anglers, bowfishers and commercial fishermen in Louisiana and Texas, where populations still remain relatively strong.

Gator gar conservation

Campbell and other alligator gar researchers developed an alligator gar consortium ó the Alligator Gar Technical Committee ó that works cooperatively with the International Network for Lepisosteid Research. This international organization coordinates the gathering and sharing of critical information used to promote the conservation of alligator gar.

In an effort to restore their numbers, Campbell and his staff at the hatchery spawn and rear alligator gar for stocking in Alabama, Kentucky, Missouri and Tennessee. Alligator gar are also cultured in Mexico and Thailand to support food and sport fisheries.

As an apex predator with moderately specific habitat requirements, the alligator gar may be an indicator of the health of our river-floodplain ecosystems. Through the efforts of Campbell and the other fisheries scientists involved with alligator gar research and management, we may conserve this giant icon of southern fisheries and the riverine habitats that support them.






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