SEATTLE - Wildlife managers are calling it an ecological success story. Conservation advocates say it threatens to undermine years of work to recover a once-endangered species.

The debate: A total of 553 wolves that have been killed by hunters and trappers in the Northern Rockies this season, the second since hunting of the furtive predators was made legal.

An additional 216 wolves were killed by federal Wildlife Services agents, largely to prevent ongoing conflicts with livestock.

Figures are trickling in as hunting seasons wind down in Montana, Idaho and Wyoming, where wolves were hunted to extinction in the last century but, in the wake of a controversial reintroduction program, are now ensconced in all three states and busting out toward Washington, Oregon and California.

State wildlife officials, fearing the recovery has been too robust, have been encouraging hunters and trappers to shave the numbers back, and the latest figures show that effort has worked, with 225 wolves killed in Montana, 69 in Wyoming and 259 in Idaho.

"Is that a healthy number? No, that's persecution at an incredible level," said Marc Cooke, spokesman for an advocacy group, Wolves of the Rockies, in Stevensville, Mont.

But state wildlife officials say they are maintaining healthy wolf populations in all three states and cannot ask citizens to put up with more.

"We need to achieve a reduction. Montana has made room for wolves, we are long past the period of recovering wolves, and we are committed to managing for a recovered population," said Jeff Hagener, director of the Montana Department of Fish, Wildlife & Parks. "The best news is that hunters and trappers, the core of Montana's wildlife conservation program, are helping us manage Montana's most recently recovered native species."

A coalition of conservation groups has filed suit in federal court challenging Wyoming's relatively lax hunting restrictions, seeking to have wolves returned to federal Endangered Species Act protections.

"This allows wolves in 85 percent of the state to be shot on sight as predators," said Michael Garrity, executive director of the Alliance for the Wild Rockies, a plaintiff in the suit.

Overall, he said, the number of wolves being shot and trapped across all three states threatens the ability to maintain a viable, connected population - a goal that many biologists believe would require 2,000 to 5,000 wolves spread across about 500 packs.

At its last official count in December 2011, the U.S. Fish and Wildlife Service said the Northern Rockies was home to at least 1,774 wolves in about 287 packs, up 3 percent from the previous year.