On Saturday, Oct. 26 the Kenai National Wildlife Refuge closed the brown bear hunting season after managers noted the combination of hunting, poaching, accidental deaths, and the harvest of problem bears led to a mortality rate that’s above the norm.

“Total mortalities now represent more than 10 percent of the best available estimate of a total Kenai Peninsula brown bear population, numbering 624 bears,” a press release from the refuge said. The release quoted refuge manager Andy Loranger, who said, “this level of mortality is not scientifically sustainable.”

The Alaska Dispatch says that at least 66 brown bears (Alaska grizzlies), many of them adult females, were known to be killed on the 16,000 square mile peninsula this year–23 of those were shot illegally, hit by cars, killed by agency personnel because of threats to public safety, or killed in defense of life or property.