Otter complained that wolves are rapidly killing elk and other animals essential to Idaho's multimillion-dollar hunting industry. The 100 surviving wolves would be the minimum before they could once again be considered endangered.
Wolves were reintroduced to the northern Rocky Mountains a decade ago after being hunted to near-extinction. More than 1,200 now live in the region.
The U.S. Fish and Wildlife Service plans to start removing federal protections for gray wolves in Montana and Idaho in the next few weeks.