March brings spring weather, the renewal of fishing licenses and sadly, this year another step backwards for native trout in the Flathead!
The story is well known. The accidental introduction of nonnative Mysis shrimp to Flathead Lake in the 1980s led to a surge in predatory lake trout populations, resulting in the demise of highly valued kokanee and a systemwide decline of native westslope cutthroat and bull trout.
In 1992, Montana Fish, Wildlife and Parks (FWP) and the Confederated Salish and Kootenai Tribes (CSKT) implemented a “slot limit” for lake trout, requiring anglers to release fish between 30 and 36 inches to preserve trophy lake trout fishing opportunity. But, by the early 2000s, agency management strategies diverged. Beginning in 2014, CSKT prioritized saving native trout by aggressively reducing lake trout numbers through Mack Days tournaments and commercial-scale gillnetting and they removed the slot limit on lake trout in the southern half of Flathead Lake. Stubbornly, FWP retained the trophy lake trout slot limit on the north half of the lake, leading to inconsistent and biologically nonsensical regulations in two halves of the same lake. In essence, FWP protected large lake trout spawners that the Tribes were trying to remove.
Flathead Valley Trout Unlimited consistently advocated for a unified fisheries management approach of the Flathead Lake and River system, focused on native trout recovery. We supported the Tribes approach. But we were recently stunned to learn that after 12 years of attempting to maximize lake trout removal, CSKT as of March 1 is reinstating the lake trout slot limit on the Tribal half of Flathead Lake. Why? They acknowledged their recent monitoring indicates that after two decades they are finally making the desired impact and are seeing a shift in lake trout population structure, with considerably fewer large individuals. So, why back off now, potentially snatching defeat from the jaws of victory?
Large lake trout can consume even adult native trout. They live up to 40 years and accumulate significant bio-toxins. Due to mercury and PCB contamination Montana FWP and CSKT both publish warnings to limit lake trout consumption, especially for children and women of childbearing age. Yet, in 2026 the new fishing regulations once again favor nonnative, potentially toxic lake trout over threatened native bull trout and cutthroat. This has raised concerns among both conservation and human health advocates. The return of the lake trout slot limit certainly does not benefit native trout and is exasperating and toxic in more ways than one.
Wade Fredenberg, president
Flathead Valley Trout Unlimited