BILLINGS — Montana’s gray wolf population declined slightly for the first time in almost a decade in 2012, amid stepped-up efforts to curb the predator’s numbers through increased hunting and trapping, state officials said Thursday.

At least 625 wolves from 147 packs roamed Montana at the end of last year. That’s down about 4 percent from the 653 animals tallied in 2011, Montana Fish, Wildlife and Parks said.

The decline came after trapping was introduced and hunting quotas were lifted across most of the state last year in an attempt to reduce wolf attacks on livestock and wildlife. A new state law means even fewer restrictions for next winter’s wolf season, when hunters will be allowed to use electronic calls and take up to three wolves apiece.

State officials say roughly 400 to 500 wolves are needed to maintain a stable population, However, that’s considered a rough target and not a definitive goal.

“We’ve taken a more aggressive approach, and this combined with hunting pressure is lowering livestock conflicts in some areas,” Fish, Wildlife and Parks director Jeff Hagener said in a statement released by the agency.

Hunters and trappers killed 175 wolves in 2012. Another 108 were killed in response to livestock attacks.

The 2012 population estimate is considered a minimum number. It does not account for 95 wolves killed by hunters and trappers since Jan. 1, said Fish, Wildlife and Parks spokesman Ron Aasheim.

The state’s wolf population last recorded a decline in 2004.

The reintroduction of wolves to the Northern Rockies by the federal government in the 1990s stirred widespread opposition from elected officials and the livestock industry. Some of those sentiments still linger as ranchers and hunters prod for the state to be even more aggressive against the animals.

“We’re not advocating an annihilation of predators of any sort, but we certainly are on the high end of the scale in terms of numbers,” said David Allen, president of the Rocky Mountain Elk Foundation, a Missoula-based hunting and conservation group.

But wildlife advocates warn killing too many of the animals will drive away wildlife-seeking tourists. They also say it could put the population’s long-term survival at risk — just two years after Congress stripped the animals of protections under the Endangered Species Act.

Marc Cooke with the advocacy group Wolves of the Rockies said provisions in the new wolf law signed last month by Gov. Steve Bullock set the stage for “persecution of wolves on a huge level.”

He said the potential intensity of future hunting and trapping seasons will disrupt the social structure within wolf packs, possibly leading to increased livestock conflicts.

“Overall they’re making it too easy to kill wolves,” he said.

Eventually, Cooke added, the state’s actions could trigger a federal government review of whether endangered species protections should be restored.

State officials have pledged repeatedly in recent years to maintain wolves at levels sufficient to keep the population healthy and viable.

Total livestock attacks by wolves were up in 2012, with 67 cattle, 37 sheep, one dog, two horses and one llama confirmed killed, according to the state. The combined total of 108 animals killed compares with 88 killed in 2011.

However, the number of cattle killed last year marked the fewest since 2006.

Wildlife officials said livestock attacks have seen a general downward trend since 2009, when more than 300 domestic animals were confirmed killed.

Montana’s wolves are part of a broader Northern Rockies population that includes animals in Idaho, Washington, Wyoming and Oregon. A population count covering that entire region is expected to be released in coming weeks.