Home / Environment / Idaho Lake's Predator Problem Solved!
Idaho Lake's Predator Problem Solved!
20 Aug
Summary
- Invasive lake trout numbers dropped 64% in ten years.
- Native kokanee salmon and rainbow trout populations recovered.
- Angler bounties and commercial nets were key to success.
A decade-long campaign successfully curbed invasive lake trout in northern Idaho's Lake Pend Oreille. By 2016, the Idaho Department of Fish and Game reported a 64% decrease in adult lake trout, enabling native rainbow trout and kokanee salmon to recover. The lake, once known for trophy trout, faced ecological crisis due to introduced lake trout preying on kokanee, a vital food source.
Launched in 2006, a multi-faceted suppression plan combined angler bounties, paying $15 per lake trout, with targeted commercial netting. Anglers removed tens of thousands of fish annually, while commercial fishermen used deep-water nets to catch spawning lake trout. This dual approach proved effective, targeting different fish sizes and locations.
This suppression effort led to remarkable ecological changes. Kokanee densities reached levels unseen since the 1970s, increasing biomass more than tenfold and benefiting other predatory fish. Rainbow trout grew faster, and bull trout, a threatened species, also saw improved conditions. Limited kokanee fishing reopened in 2013.
Despite success, complete eradication is unlikely in the lake's deep, complex waters. Ongoing efforts, including a smaller netting program and continued bounties, are necessary to maintain low lake trout numbers. The Lake Pend Oreille project now serves as a model for invasive fish management across western North America.
