Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Nonnative Walleye Detected In Thompson Chain Of Lakes

An illegally introduced walleye found in Montana's Swan Lake in 2015.
Courtesy Montana Fish, Wildlife and Parks
An illegally introduced walleye found in Montana's Swan Lake in 2015.

Two nonnative walleyes were detected during a routine fishery survey west of Kalispell last week. The species could prove detrimental for a number of lakes in the area, and fishery managers are still deciding how to respond.

During Montana Fish, Wildlife and Parks’ routine fishery survey at Upper Thompson Lake, two female walleyes were found in separate nets. Walleye are considered invasive throughout Montana, but most established populations are in lakes and rivers east of the continental divide.

FWP Spokesperson Dillon Tabish said walleye can wreak havoc on native populations.

"Folks who like to fish for perch in the Thompson Chain of Lakes should be worried about this news," he said. "We stock rainbows in those lakes, kokanee; All those fish populations now could be completely altered and reduced if a walleye population gets established.”

Tabish said the agency believes the fish were intentionally introduced. The nearest established population of walleye is in Noxon Reservoir about 25 miles west, but there’s a dam and other infrastructure preventing those fish from leaving and entering the Thompson River.

“So now our staff will begin further investigation that will have follow-up surveys to better understand the potential distribution of population size of walleye in the Thompson Chain of Lakes area.”

Officials are waiting to determine whether the species is established before it rolls out any management actions. FWP is asking anyone with information on the illegal introduction of the walleye to call their wildlife crime hotline at 1 (800) TIP-MONT, or 1 (800) 847-6668.

Copyright 2020 Montana Public Radio. To see more, visit Montana Public Radio.

Aaron is Montana Public Radio's Flathead reporter.