KALISPELL — Montana Fish, Wildlife & Parks (FWP) has confirmed the detection of a non-native brown trout in the Flathead River upstream of a fishing access site near Evergreen.
Brown trout can be devastating to native trout species in the river, such as bull trout and westslope cutthroat trout.
“If they catch a brown trout, we want to know about it as soon as possible,” said FWP spokesman Dillon Tabish.
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Tabish is asking for the public’s help after an angler caught a non-native brown trout in the Flathead River.
“This is one of the last strongholds for westslope cutthroat trout here in the Flathead and we don’t want to have another harmful impact on those fish."
Brown trout can harm native trout species, such as bull trout and westslope cutthroat, by outcompeting them for resources and preying on juvenile fish.
“So that can have impacts on those populations that are already pretty sensitive, you know, bull trout are federally protected species because they are threatened species and then westslope cutthroat trout are a species of concern,” said Tabish.
Tabish said anglers can help FWP understand how many brown trout are in the Flathead River by killing them immediately after a catch and reporting information on where and when the fish was caught.
“Keep the fish, kill the fish, bring it to Fish, Wildlife and Parks so that we can study it, we can learn a lot from that fish once we get it, find out if it was born here in the Flathead or from somewhere else and brought here,” said Tabish.
Fisherman David Aniol said it’s up to all anglers on the Flathead River to do their part to prevent the takeover of brown trout.
“By catching them and killing them right, we definitely don’t want invasive species in here, we want to keep the native population as high as we can, you know that’s the fish that have always been in here, so I want to be coming here with my kids one day, so it’s important for us to do the best we can to keep it how it is,” said Aniol.
Tabish said FWP is deploying environmental DNA sampling to help determine if brown trout DNA is present in the river. Biologists are sampling water up and down the Flathead River and its tributaries.
“So that’s one tool that we are using to see how big of a problem this may be.”
Tabish said the brown trout was likely brought to the Flathead River from a different body of water.
The illegal introduction of non-native fish can lead to a financial fine and a loss of fishing privileges.
“And we really need anglers to understand that moving live fish around is illegal and it’s illegal for a good reason because it disrupts our fisheries, it harms people’s opportunities to go fishing.”
Anglers can report a catch to the FWP Region 1 office at 406-752-5501.
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.
