Invasive predatory lake trout Salvelinus namaycush were discovered in Yellowstone Lake in 1994 and caused a precipitous decrease in abundance of native Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri. Suppression efforts (primarily gillnetting) initiated in 1995 did not curtail lake trout population growth or lakewide expansion. An adaptive management strategy was developed in 2010 that specified desired conditions indicative of ecosystem recovery. Population modeling was used to estimate effects of suppression efforts on the lake trout and establish effort benchmarks to achieve negative population growth (λ < 1). Partnerships enhanced funding support, and a scientific review panel provided guidance to increase suppression gillnetting effort to >46,800 100-m net nights; this effort level was achieved in 2012 and led to a reduction in lake trout biomass. Total lake trout biomass declined from 432,017 kg in 2012 to 196,675 kg in 2019, primarily because of a 79% reduction in adults. Total abundance declined from 925,208 in 2012 to 673,983 in 2019 but was highly variable because of recruitment of age-2 fish. Overall, 3.35 million lake trout were killed by suppression efforts from 1995 to 2019. Cutthroat trout abundance remained below target levels, but relative condition increased, large individuals (> 400 mm) became more abundant, and individual weights doubled, probably because of reduced density. Continued actions to suppress lake trout will facilitate further recovery of the cutthroat trout population and integrity of the Yellowstone Lake ecosystem.

Brook Trout Salvelinus fontinalis have been introduced across the western USA, where the species competes with and often replaces native salmonids. Nonnative Brook Trout are difficult to eradicate; thus, new removal strategies are needed. One novel methodology couples the partial suppression of wild Brook Trout with the replacement of MYY Brook Trout (males with two Y chromosomes). If MYY fish survive to reproduce with wild female Brook Trout, their progeny will be 100% male, which eventually shifts the sex ratio and theoretically extirpates the population. However, the effectiveness of this approach depends on survival and reproduction of MYY fish relative to the surviving wild conspecifics. From 2018 to 2020, we annually removed an estimated 45.7% of wild Brook Trout from three streams in New Mexico and stocked fingerling MYY Brook Trout (mean TL = 94 mm; range = 61–123 mm) targeting 50.0% of wild annual abundance estimates. Annual survival for MYY and wild Brook Trout was similar in Leandro Creek (MYY = 0.63 and wild = 0.63) and Rito de los Piños (MYY = 0.37 and wild = 0.46) but differed in Placer Creek (MYY = 0.28 and wild = 0.75). During spawning, we evaluated the reproductive potential of MYY Brook Trout by comparing the percentage of sexually mature male Brook Trout comprised of MYY fish to the percentage of hybrid (MYY × wild) F1 progeny. By the second spawning season (2019), MYY fish comprised 59.8, 50.4, and 34.5% of milt‐producing Brook Trout, which resulted in 55.1, 33.3, and 0% hybrid progeny in Leandro Creek, Rito de los Piños, and Placer Creek, respectively. We demonstrated that MYY fish exhibit similar vital rates compared with wild conspecifics in two of three streams; however, differences among streams highlights unforeseen variables that influence MYY survival and reproduction. The study offers promising results of the MYY approach for potentially eradicating unwanted Brook Trout populations.