Alligator Gar Reintroduction Program

IDNR Fish Species Management Plan for Alligator Gar (Atractosteus spatula) in Illinois
(Download PDF)

Alligator Gar (Atractosteus spatula) populations have been declining within their historic range for at least the past 50 years, and are considered to be extirpated from much of the northern reaches (Nature Serve 2015). Declines have been attributed to several factors, most notably over-exploitation and loss of important backwater spawning habitats from the construction of levees and lock-and-dams beginning in the early 1900s. While no single factor can be identified as the definitive cause for the decline, it is likely that a combination of these factors over time resulted in the extirpation of the Alligator Gar from Illinois.

The Alligator Gar was not regulated or protected in Illinois prior to 1977.  From 1977 to 1994, the species was listed as a state-threatened fish under the Illinois Threatened and Endangered Species Act.  In 1994, the Alligator Gar was delisted and considered to be extirpated.

This plan proposes efforts and activities necessary to successfully re-establish and extensively manage Alligator Gar populations in Illinois.  The success of the plan will be documented through annual progress and achievement reports for each management objective.  The plan is considered to be an evolving document and will be used as an adaptive management tool by Illinois Department of Natural Resources, Division of Fisheries.

Download the PDF here that describes the management plan in detail for Alligator Gar.

Return of the Dinosaurs

GarAlligator Gar is the largest fish native to Illinois. With records dating back to prehistoric years, this species had not been seen in the state since the last documented Alligator Gar catch in the Cache River cutoff channel in southern Illinois in 1966. Alligator Gar were officially declared extinct in Illinois in the 1990s.

In 2010, the IDNR's Division of Fisheries began an Alligator Gar reintroduction program. During that time, Alligator Gar were stocked in a few waterways, including the lower Kaskaskia River.

“We only stocked a few thousand in total at those sites and many of those were small, so survivability was questionable,” said Dan Stephenson, the IDNR’s Former Chief of Fisheries.

The program had a brief hiatus in 2014 – 2015, but times are changing, and this program is once again becoming active with more research backing up this stocking initiative to help ensure success of survivability.

According to Stephenson:
“We now raise the fish to at least 12 inches before stocking so that their survival is vastly improved.” However, he cautions, more research still needs to be done to evaluate the survivability of this species and what needs to be done for successful reestablishment, which he predicts will be a challenge and take some time to net results. For instance, we know that female Gar do not become sexually mature until the age of 11, and even then they may not necessarily spawn every year.

The reasons for reintroducing the Alligator Gar are twofold: Bringing back an extirpated species to Illinois waters is one of the goals. In addition, the Alligator Gar is becoming a popular trophy quarry for sportsmen in the southern part of their range, Louisiana and Texas. Bowfishing enthusiasts in particular enjoy pursuing the huge fish.

For those of you worried that Alligator Gar would be detrimental to popular sportfish species, biologists say the Alligator Gar is an opportunistic predator that mostly targets shad and rough fish, such as carp. However, IDNR biologists warn that controlling Asian carp is not the reason for this reintroduction. According to Stephenson, though Alligator Gar are an apex predator that will take Asian carp, nothing can control the their population right now. In the long-term, creating commercial markets for Asian carp will be the best hope of reducing their numbers.

To answer another note of concern to some, there is no documented evidence suggesting that Alligator Gar will bite a swimmer. That has been a concern posed to the Department in the past few weeks. Swimmers simply don’t look like a prey species to an Alligator Gar.

babygar Alligator Gar stocking will begin in Southern Illinois waters, which have the correct habitat for this species and would therefore be conducive to their survival. They are being stocked initially in very small numbers in certain places to see if they can be established. Our neighboring states, Kentucky and Missouri, are also taking part in this reintroduction program with the small fish (fry) initially coming from the US Fish and Wildlife Service hatchery, then raised in the state hatcheries to stocking size.

Currently there are four types of Gar found in Illinois: Spotted, Shortnose, Longnose and now the Alligator. Alligator Gar were not traditionally found in large numbers in Illinois, and though they do grow quickly, it awaits to be seen this program’s success as females mature and reproduce in 11+ years. We will monitor this program closely and will implement creel and size limits if necessary as this population becomes established.

To effectively manage these prehistoric fish, the IDNR is working closely with University of Illinois researchers to study how Alligator Gar, in addition to the three other Gar species, grow, mature, reproduce and migrate to make certain these species continue to troll Illinois' waterways.

Fun Fact:

Alligator Gar can grow very quickly early in life, meaning that the stocked Gar will quickly become accessible to anglers. For example, in August of 2015, a bow fisherwoman harvested an Alligator Gar in the lower Kaskaskia River that had been tagged fish during the 2013 IDNR Alligator Gar stocking into the lower Kaskaskia River. When it was stocked in 2013 as a 6-month-old fish, it was 18.9 inches long and 1.14 pounds. A mere 21 months later, that fish grew 7 inches and added almost 3 pounds to its weight (26.5 inches long and 4 pounds).


Historical Perspective

This historic photo is reported to be the last alligator gar captured in Illinois. The fish was caught on hook and line from the Cache-Mississippi Diversion Channel in Alexander County in 1966. It was approximately seven feet in length and weighed in at around 130 pounds!

Additional Fun Facts:

  • Alligator Gar can exceed 300 pounds and reach 10 feet in length, making them the largest fish in the Mississippi River Valley, including Illinois.
  • Alligator Gar are long lived, with some captured individuals estimated to be nearly 100 years old.
  • Alligator Gar eggs are reported to be toxic to some animals, presumably as a defense mechanism.

Source: Poly, W.J. 2001. Distribution of the alligator gar, Atractosteus spatula (Lacepede, 1803), in Illinois. Transactions of the Illinois Academy of Science 94(3): 185-190.
Photo: courtesy of Brooks Burr