BOISE — Idaho could be losing as much as $24 million annually in hunting-related revenue due to wolves killing deer and elk, according to the Idaho Department of Fish and Game.

The report relies heavily on a 1994 environmental impact statement related to the introduction of wolves to Yellowstone National Park, and then extrapolates those numbers.

"This is a projection," said Lance Hebdon, intergovernmental policy coordinator with Fish and Game. "Is it realistic to think we would have more elk hunters if we had more elk in some units? I think that is a reasonable assumption."

The report released earlier this week was requested by Sen. Gary Schroeder, R-Moscow, who earlier this month sponsored a bill — approved 31-1 in the Senate — to give the state's wolves to the rest of the country.

"I think this at least gives us some data with some science behind it," Schroeder, chairman of the Senate Resources and Environment Committee, told the Lewiston Tribune about the report. "The question is, as wolf numbers increase, are we going to have to curtail hunting opportunities? Overall, I like seeing economic activity, because it drives tax revenue. Anytime I see something that drives business away, that's important to me."

The Hailey-based Western Watersheds Project, a conservation group, blasted the report.

"They're cooking the books on it," said Brian Ertz, the group's media director. "It seems to me what Gary Schroeder is doing is political grandstanding. If he's really concerned about wildlife in Idaho, why is he not concerned about public lands ranching?"

The report said hunters are less likely to hunt if they don't think game is available, and assigns a value of $127.40 for each day a hunter spends pursuing game. It's called a hunter day. Hebdon said the dollar amount came from a 2002 report from the Wildlife Society, a professional organization of wildlife scientists.

The report estimates there could be more than 180,000 hunter days lost because of wolves, adding up to as much as $24 million. The report puts the low end of lost hunter days at 120,000, adding up to about $15 million.

The state sold 93,000 elk tags in 1998, a number that dropped to 80,000 in 2008. Sales of deer tags have increased in the last decade, going from 122,000 in 1998 to 127,000 last year. Nonresident tags are capped.

Officials said they have no way of determining whether big game tag sales would have increased if wolves were not in the state.

"This is a very simple analysis," Hebdon said. "It's simply providing the public and the Legislature with information that there are economic costs to these foregone hunter opportunities."

The Fish and Game report also used a second method to estimate the state's economic loss due to wolves. With that method, the report put an economic value on elk killed by wolves. The report estimated that 824 wolves in Idaho kill 9,517 elk a year.

The report estimated that 20 percent of those elk — 1,903 — would likely have instead been killed by hunters. The value of a harvested elk, the report said, was $8,000, giving an economic loss to the state of more than $15 million.

The state also assesses damages for elk that are poached or wasted at $750 per animal. The report considered the remaining estimated elk killed by wolves to be in that category, upping the economic loss another roughly $6 million.

The 1994 study estimated wolf kills would be 70 percent deer and 30 percent elk. But Fish and Game, in the report, said a more recent study estimates wolf kills are about 70 percent elk.

Hebdon said the agency didn't feel pressured to put out a report to reflect any particular view about wolves.

"We were asked to do an analysis of wolves on hunting," he said. "We completed that given the information we had."