What is an alligator gar and why is Illinois trying to protect them?

Prehistoric fish may not solve the Asian carp crisis, but four native gar species are gaining respect in Illinois.

This gravid female alligator gar served as broodstock at Private John Allen National Fish Hatchery in Tupelo, Miss. Photo: Dan O’Keefe | Michigan Sea Grant
This gravid female alligator gar served as broodstock at Private John Allen National Fish Hatchery in Tupelo, Miss. Photo: Dan O’Keefe | Michigan Sea Grant

On May 31, 2016, the Illinois Senate voted unanimously to adopt a resolution urging the Illinois Department of Natural Resources to expedite the reintroduction of alligator gar and develop protections for four native gar species. The Illinois House of Representatives had unanimously passed the same resolution three weeks earlier.

No one paid much attention, unfortunately.

On July 29, 2016, an Associated Press story was published entitled “Huge, once hated fish now seen as a weapon against Asian carp.”  All of a sudden gar were in the spotlight, and the press was all positive. Alligator gar were once demonized and subjected to extermination efforts, but for more than a decade state and federal agencies have been working to restore alligator gar in certain areas.

From the beginning, these efforts were seen as a way to bring a fascinating and valuable fish back to places they had disappeared from. Unregulated commercial fishing, rod-and-reel fishing, bowfishing, and targeted removal have probably taken a toll on some populations but destruction of natural large river habitat was a bigger factor in the disappearance of alligator gar from the northern part of their range in the Mississippi River basin from Tennessee north to central Illinois.

Building of dams and levees along the Mississippi River allowed for commercial navigation and protected valuable farmland from floods, but it also blocked alligator gar and other native fish from moving freely between feeding and spawning habitats. In some places, including The Nature Conservancy’s Spunky Bottoms Preserve in Illinois, alligator gar reintroduction was specifically targeted to areas where habitat restoration projects have reconnected floodplain wetlands with main channel river habitats.

As an educator with Michigan State University Extension, I have had the opportunity to talk gar a lot over the past few weeks. Answers to some of the most common questions are below, and more detail can be found in the Science Around Michigan podcast.

Will alligator gar control Asian carp?

Alligator gar are large, non-selective predators. In other words, they tend to eat whatever is most abundant. In parts of the Mississippi River, and in the Illinois River in particular, Asian carp are super-abundant. It stands to reason that alligator gar will take advantage of this and prey on troublesome silver carp, bighead carp and grass carp (the three Asian carp species found in the Illinois River).

After all, other species of gar have already been documented feeding on young-of-the-year silver carp, along with six other native predators. Unfortunately, these other native fish that are already found in the Illinois River do not control the Asian carp where carp are super-abundant, and neither do commercial fishers that currently target primarily the larger bighead carp.

The reality is that alligator gar will be one more predator taking advantage of Asian carp, but it will not be the “silver bullet” that wins the war against carp.

Do alligator gar pose a threat to people?

There has never been a confirmed case of an alligator gar attacking a person in the water. If you bring an alligator gar (or any other large toothy fish) into the boat there is always the risk of injury if you are not careful, but gar are not aggressive toward people. Their eggs are poisonous and should not be eaten.

Do alligator gar pose a threat to gamefish?

Generally no. Alligator gar typically eat whatever appropriately-sized fish (over eight inches long) are available, and in many river and reservoir habitats this means plankton-eating fish like shad. In weedy habitats where bass and panfish are most common, gar will eat them. Even so, predators like gar do not necessarily damage populations of their prey species and can even be helpful when prey species are overabundant and slow-growing (see article on stunted panfish). Alligator gar will also scavenge on dead fish and occasionally eat waterfowl.

Should alligator gar be stocked in the Great Lakes?

No. The alligator gar is not native to the Great Lakes basin. It is native to large river systems that flow into the Gulf of Mexico.

What about other gars in Michigan?

Two species are native to Michigan waters: longnose gar and spotted gar.

The longnose gar is most common and is sometimes (incorrectly) referred to as alligator gar or garpike. Longnose gar can grow to over four feet long in Michigan, but never reach the massive proportions of alligator gar, which can weigh over 300 pounds and measure over eight feet long.

Spotted gar are only found in the southwest portion of the Lower Peninsula and are listed as a Species of Greatest Conservation Need by Michigan Natural Features Inventory.

 Is there a need to protect gars in Michigan?

Unfortunately we do not know much of anything regarding the dynamics of spotted gar and longnose gar populations in Michigan. In Illinois, the Ancient Sport Fish Project (see video) is currently working to sample gar and bowfin populations and use fisheries science to gain a better understanding of whether management tools such as size limits or bag limits might be needed. In Michigan, no such effort is underway.

Michigan Sea Grant helps to foster economic growth and protect Michigan’s coastal, Great Lakes resources through education, research and outreach. A collaborative effort of the University of Michigan and Michigan State University and its MSU Extension, Michigan Sea Grant is part of the NOAA-National Sea Grant network of 33 university-based programs.

Related story: Setting the record straight on alligator gar and Asian carp

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