YELLOWSTONE NATIONAL PARK, Wyo. (AP) — Yellowstone National Park officials are about to deliberately poison off nonnative fish species in one of the park's major river drainages.

The operation along the upper Gibbon River begins Monday and will include lakes in the river drainage.

Park officials are targeting lake-dwelling grayling as well as rainbow trout and brook trout. They plan to reintroduce native species after the operation is finished.

Trails and campsites in the area will be closed.