Sam Bourret

Montana Fish Wildlife and Parks · Fisheries

Hybridization between native and invasive species, a major cause of biodiversity loss, can spread rapidly even when hybrids have reduced fitness. This paradox suggests that hybrids have greater dispersal rates than non-hybridized individuals, yet this mechanism has not been empirically tested in animal populations. Here, we test if non-native genet...

Significance Invasive species are a leading cause of biodiversity loss, yet the mechanisms by which invaders progressively disrupt ecosystems and native species remain unclear. Using an extensive isotope dataset across multiple ecosystems and stages of invasion, we show that an invasive fish predator (lake trout) disrupted food webs by forcing nati...

Nonnative fish eradication via the piscicide rotenone is an effective tool for fisheries management and conservation of native species. However, the long-term effects on non-target organisms, including benthic invertebrates and zooplankton in alpine lakes, are under-studied and are poorly understood. As part of a landscape-scale native fish conserv...

Early life history data are critical for conservation and management of trout species in freshwater river networks and are imperative for planning habitat restoration in degraded watersheds. In this study, we use otolith geochemical signatures to assign natal provenance and determine age of tributary outmigration for fluvial Brown Trout (Salmo trut...

The spread of non-native fish species is a common problem in lakes and streams worldwide. Species that establish viable populations in a new environment can seriously deplete populations of native species and desired sportfishes. In some instances, extirpation of a native species has occurred. In western North America, the most common avenue by whi...

On a cold December afternoon, I chased Clint Muhlfeld through his favorite powder stashes at our home mountain in northwest Montana. It had not been a particularly bountiful snowfall season thus far, but every time we arrived at an untracked hallway of thigh deep powder among old growth conifers, he said, “Go ahead first, this is a great run.” I ha...

Illegal fish introductions create some of the most challenging problems for resource managers because of their potential to harm existing recreational fisheries and their impact on species of conservation concern. Determining the origin of a suspected illegal fish introduction can aid managers in preventing the colonization and subsequent ecosystem...

Life history variability includes phenotypic variation in morphology, age, and size at key stage transitions and arises from genotypic, environmental, and genotype-by-environment effects. Life history variation contributes to population abundance, productivity, and resilience, and management units often reflect life history classes. Recent evidence...

Isotopic composition of 87Sr:86Sr and natural elemental tracers (Sr, Ba, Mg, Mn and Ca) were quantified from otoliths in juvenile and adult Chinook salmon Oncorhynchus tshawytscha to assess the ability of otolith microchemistry and microstructure to reconstruct juvenile O. tshawytscha rearing habitat and growth. Daily increments were measured to as...

Background/Question/Methods Understanding the distribution, abundance and relative performance of life history types is critical for development of passage for juvenile Chinook salmon in the Willamette Valley Basin (WVB), and an important element of the Willamette Valley Biological Opinion. Recent analyses of screw trap data suggest that juvenile...

Pacific salmon populations have suffered declines and local extirpations in the Pacific Northwest over the last century as a result of physical and functional changes to their freshwater environments, yet persist in highly altered habitats. Life history variation in Pacific salmonids has been suggested as one factor that contributes to population r...

Maximum daily consumption and specific daily metabolic demand were determined for juvenile flathead catfish (Pylodictis olivaris) in the laboratory over a temperature range of 3–32 °C. Maximum daily consumption increased with increasing water temperature, was significantly higher at 19 °C than at colder temperatures, and remained elevated up to 32...