AUGUSTA — The two groups fighting over a contentious ballot measure in Maine that would ban the use of dogs, bait and traps for bear hunting have spent $1.6 million so far to run television advertisements, according to information the Center for Public Integrity released on Thursday.

The pro-ban group Mainers for Fair Bear Hunting has spent $860,500 to run nearly 2,200 ads, according to the group’s analysis of Kantar Media/CMAG research, which tracks political advertising. The Maine Wildlife Conservation Council, which opposes the ballot question, has shelled out $712,700 to run about 1,800 ads.

Overall, the groups have spent about $1.50 on the ads for every one Maine voter.

The Center for Public Integrity’s analysis details spending through Oct. 20 for ads on national cable and broadcast television in each of the country’s 210 media markets. The numbers don’t include money spent to make the ads. They also don’t include radio, online and direct mail or ads that aired on local cable systems.

Maine ranks 13th in the country for money being spent on ballot questions, according to the Washington, D.C.-based organization. TV ad spending nationally came in around $119 million through Oct. 20. Spending was highest in California, where voters have gotten bombarded by more than 41,000 ballot question ads worth $58 million.

Michael Franz, an associate professor of government at Bowdoin College who specializes in campaign advertising, said the amount of money being spent on the question shows that the issue is polarizing and competitive. Spending likely will accelerate between now and Election Day, Nov. 4, he said.

“It could be the case that this becomes a $3 million campaign,” Franz said.

Recent campaign finance reports showed that Mainers For Fair Bear Hunting had raised $1.36 million this year while Maine Wildlife Conservation Council has raised $1.87 million.

In one of its ads, Mainers for Fair Bear Hunting shows images of bears caught in traps, “suffering for hours,” some “even trying to chew off their own limbs to escape.” Eventually, they’re “shot at a point-blank range,” it says.

“Do you want to end this cruelty?” it asks.

In a Maine Wildlife Conservation Council ad, some of the state’s bear biologists accuse a “Washington, D.C., special interest group” of trying to take away the “most effective methods to control bears and prevent attacks.” It calls the ban a “serious threat to public safety.”

The vast majority of Mainers for Fair Bear Hunting’s money has come from the Washington, D.C-based Humane Society of the United States and its legislative fund.

The Maine Wildlife Conservation Council is being funded from a variety of groups, including the Ohio-based U.S. Sportsmen’s Alliance, Arizona-based Safari Club International and numerous out-of-state hunting groups.