Cue the theme to “Jaws”: the alligator gar may be coming to a river or stream nearby.
The fish may look fearsome, but there is little reason for alarm.
The alligator gar is believed to have been extinct in Illinois since about 1966. Small numbers of the fish, which regularly reach six feet in length and weighs more than 125 pounds, have been stocked in Illinois waters on a hit-and-miss basis since 2010.
The fish’s range in Illinois is limited. The alligator gar was never here in large numbers. And, the anatomy of the fish’s mouth make it nearly impossible for the gar to attack large prey.
Some alligator gar have been stocked into Powerton, Hopper and Hennepin lakes in northern Illinois. A total of 279 have been stocked into the Kaskaskia River.
“I’d like to keep them further south,” said Dan Stephenson, chief of fisheries for the Illinois Department of Natural Resources. “I’m assuming some will go back into the Kaskaskia, that’s more their historic range. It wouldn’t surprise me if we don’t get fish from Missouri and Kentucky because they move during high water.”
Historically, the alligator gar was found in the Kaskaskia, Mississippi and Ohio rivers. Stephenson said none were ever officially spotted in the Cache River, but there were reports the fish lived in the Post Creek Cutoff which links the Cache to the Ohio River.
“They were never here in great numbers, at least historically what we can tell in the data,” Stephenson said. “We are at the northern edge of their range.”
Loss of habitat is the likely cause for the alligator gar’s demise in Illinois.
“It’s probably several things,” Stephenson said. “They need to have backwaters and clear water to spawn. We were always at the north end of their range. You get to some point where they cross a threshold where they can’t come back — a male can’t find a female.”
The restocking program will likely be an ongoing issue. Ideally, 12-to-18-inch fish are used for stocking. The fish grow rapidly, but females don’t reach sexual maturity until they are 11 years old. Establishing a breeding population will take time.
“The process is going to take a while,” Stephenson said. “We’re talking about 20 years. A female has to be 11 years old before they spawn. They had reports of (living) up to 100 years. I don’t know how accurate that is. It certainly wouldn’t surprise me if they live up to 30, 40, 50 years old.
“Establishing a breeding population, that would be nice. I would think that would be our long-range goal. I don’t know if we’ll be successful. It’s an extirpated species. It’s a top of the line predator. Missouri and Kentucky are doing the same thing.”
Stephenson added there have been some misconceptions regarding the re-introduction of the alligator gar. He said worries about the large fish attacking swimmers or having a detrimental effect on the game fish population are unfounded.
Despite its large body, the alligator gar has a small mouth. It feeds primarily on shad, not larger fish.
Likewise, Stephenson said suggestions that re-introduction of the fish will help control Asian carp are also untrue.
On the other hand, if the alligator gar becomes established, it could be a boon to fishing.
“Places in Louisiana and Texas, you have guide services because they get so big,” Stephenson said. “They are quite a trophy. Bow fishermen in particular appreciate them.”
And, in the final analysis, there is no compelling reason not to continue the stocking program.
“I can’t think of anything that would be detrimental to the habitat,” Stephenson said. “They will have no impact on the sports fishery.”