Minnesota's black bear population — which now numbers 10,000 to 15,000 after peaking around 25,000 — appears to have stabilized after state officials deliberately reduced the population by boosting hunter numbers.

Bruin numbers topped out in the late 1990s and early 2000s, then fell dramatically as the Department of Natural Resources issued more permits to hunters.

"Our bear population was increasing quite fast during the 1980s and '90s, and the only way to control it was to increase the number of hunters,'' said Karen Noyce, DNR bear research biologist in Grand Rapids.

To do that, the DNR made more hunting permits available, and the number of bear hunters increased from 3,700 in 1985 to nearly 17,000 in 2000.

"The goal was to level off the bear population growth,'' she said.

It worked. Maybe too well.

In 1985, those 3,700 hunters killed 1,340 bears, but in 1995, the number of hunters had jumped to 11,600, and they harvested nearly 5,000 bears. Over the next 10 years, hunters averaged 3,500 bears yearly.

The bear population dropped.

By 2008, the DNR estimated bear numbers had fallen about 30 percent to 15,000 to 20,000.

"We accomplished what we wanted to do,'' Noyce said. But it appeared the population continued to fall even though the number of bear permits available to hunters was slashed.

"It was a trend we didn't like,'' Noyce said. "We decreased hunter numbers dramatically because we wanted to be sure to stop the population from declining further.''

Last year and this fall, the DNR offered just 3,750 permits, the fewest in 30 years. (Hunters don't need those permits in some areas.) Hunters killed just 1,618 bears this fall, the lowest in 26 years. About 6,200 people hunted bears, the lowest since 1989. The season ended Oct. 12.

Fewer bear hunters in the woods is OK, officials say. When hunter numbers were at a peak, Noyce said, hunters complained the woods were too crowded and the quality of the hunt fell. Though bear hunter numbers have fallen because of the reduced availability of permits, interest remains high: More than 18,000 people applied for permits last year.

These days officials believe the bear population is between 10,000 and 15,000.

"We'd like to see it come back up a ways,'' Noyce said. The DNR has no population target.

"We'd be pretty happy with 15,000 to 20,000 bears,'' Noyce said.

Estimating the population of bears — and managing that population — is tricky business. The DNR puts out baits laced with tetracycline, an antibiotic. The chemical is deposited in the teeth and bones, and can be detected later in bears killed by hunters.

Successful bear hunters are required to submit two teeth from their animals to the DNR. The percentage of those bears with tetracycline allows researchers to estimate the population. The DNR also uses the teeth to age bears, which also provides a way to estimate the population.

The amount of natural food in the woods can vary dramatically, and that has a big impact on whether bears will be lured to hunters' baits and killed.

"The harvest fluctuates a lot each year for reasons other than how many bears there are and how many hunters are out there,'' Noyce said.

"In 1995, we shot nearly 5,000 bears. The very next year we shot less than 2,000 bears with similar number of hunters.'' The difference was the availability of food. Lack of natural food in the woods also triggers more nuisance bear complaints as bruins seek out food at bird feeders or garbage cans.

Noyce said neither hunters nor wildlife watchers need to be concerned about the bear population.

"With the level of harvest, we'll be coming back up very soon, if we're not already,'' she said. "We have a good, robust population. With any [wildlife] population, there are going to be ebbs and flows.

"I don't have any concerns about the bear population.''

Doug Smith doug.smith@startribune.com

Twitter: @dougsmithstrib