In Illinois, wildlife officials believe that alligator gar may help fight the spread of invasive Asian carp, which are on the invading the Great Lakes. Gator gar commonly feed on carp but pose little or no threat to game-fish populations, biologists believe. Also, despite the gator gar’s fearsome appearance, there has never been a confirmed gator gar attack on a human.

Jennifer Walling, the executive director of the Illinois Environmental Council, told the Belleville News-Democrat that alligator gar could be a potential solution to the Asian carp problem, in addition to being a trophy quarry. “The more we learn about alligator gar,” Walling said, “the more intrigued we are that they could help in the fight against Asian carp, drive revenue as a target of anglers, and become a popular niche food fish.”

There is a bit of a disagreement on how much they target game fish, especially in New York in places where Asian carp aren't established.

http://www.timesunion.com/local/article/DEC-searching-Schenectady-pond-for-alligator-gar-8463420.php

"The alligator gar in Iroquois Lake [in Schenectady, NY] is just over 1-foot long, DeLugo estimated after seeing pictures of the fish. He said a gar that size could eat plenty of fish, but does not pose any danger to humans. DeLugo said he has taken many large fish off the hands of customers who move or can no longer manage to feed and house the fish. "Then I get on the phone and start calling crazy guys who have hot tubs for a tank — giant things they can put them in," he said.