The Montana Fish and Wildlife Commission has issued a kill order on all brown trout caught on the Kootenai River between Libby Dam and Kootenai Falls.

On March 1, Montana Fish, Wildlife and Parks documented the first brown trout in this stretch of the Kootenai, also home to kokanee salmon, rainbow trout and bull trout. In a release, the agency warned that “risks from an expanding brown trout population include growth to trophy sizes due to abundant forage, by-catch of bull trout from angler species misidentification, and predation of naturally reproduced rainbow and bull trout.”

The agency aims to keep brown trout from becoming established in the area, and to research and document the extent of the problem. Under a rule adopted by the Fish and Wildlife Commission at its April 19 meeting, those who catch a brown trout in the area will have to kill it and report it to Fish, Wildlife and Parks staff within 24 hours.

Fisheries Division Administrator Eileen Ryce told the Commissioners that anglers will be allowed to take the trout home once its otolith, a bone that contains chemical clues to a fish’s life history, has been removed.