Are Brown Trout Now in Montana Waters Where They Don’t Belong?

Lake trout. Smallmouth and largemouth bass. Northern pike.

Some of the usual suspects you think of when discussing species that could pose a threat to Montana lakes and streams in which they don't belong. But how often do brown trout come up in the conversation?

Well, they do now. From the Kalispell area, Montana Fish, Wildlife and Parks tells us that they have confirmed the detection of a non-native brown trout in the Flathead River upstream of Pressentine Fishing Access Site near Evergreen, and anglers are encouraged to submit any additional brown trout caught within the drainage.

To assess the extent of the issue, FWP is deploying environmental DNA sampling technology to detect any additional presence of brown trout in the Flathead River and tributaries This method will help identify areas where brown trout may be present, guiding future management actions.

FWP strongly urges anglers who catch a brown trout in the Flathead River or its tributaries to kill the fish immediately and report the catch to the FWP Region 1 office at 406-752-5501. Anglers are asked to provide the fish as well as the location and date of the catch to assist in monitoring efforts.

Brown trout can harm native trout species, such as bull trout and westslope cutthroat trout, by out-competing them for resources and preying on juvenile fish. In a press release, Montana FWP Regional Fisheries Manager Mike Hensler stated, “Protecting our native trout populations is a priority. Brown trout pose a threat to native species in the Flathead drainage, and we need the public’s help to manage this invasive species.”

Moving live fish from one water body to another is illegal. The illegal introduction of non-native fish and other invasive species can have devastating ecological, recreational and economic impacts.

Brown trout are identified by their golden brown to yellow-brown color, with dark spots often surrounded by lighter halos, and sometimes with red or orange spots.