Christopher Guy, PhD (Former Employee)

The decomposition of vertebrates in lake ecosystems has been largely understudied despite being a vital part of ecosystem processes. Invasive lake trout (Salvelinus namaycush) invaded Yellowstone Lake and caused a decline in the native Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) population. To restore Yellowstone cutthroat trout, lake trout were suppressed by gillnetting...

Conservation propagation of pallid sturgeon (Scaphirhynchus albus) upstream of Fort Peck Reservoir, Montana, USA has successfully recruited a new generation of spawning-capable pallid sturgeon where there would otherwise be fewer than 30 remaining wild reproductively mature pallid sturgeon. Successful recovery of pallid sturgeon will now rely on the behavior of pallid sturgeon (e.g...

Diet plasticity is a common behavior exhibited by piscivores to sustain predator biomass when preferred prey biomass is reduced. Invasive piscivore diet plasticity could complicate suppression success; thus, understanding invasive predator consumption is insightful to meeting conservation targets. Here, we determine if diet plasticity exists in an invasive apex piscivore and whether...

Invasive Lake Trout Salvelinus namaycush in the Yellowstone Lake ecosystem have been gillnetted since 1995 to suppress the population and allow for recovery of native Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri. Although gillnetting is effective (Lake Trout population growth rate λ ≤ 0.6 during 2012–2022), the effort only targets free-swimming, age-2 and older Lake Trout...

Body condition indices are commonly used in the management of fish populations and are a surrogate to physiological attributes such as tissue-energy reserves. Relative condition factor (Kn) describes the condition of species relative to populations in a geographic area. We developed models to allow for the calculation of Kn in Montana, USA by using the weight–length data collected by...

Skipped spawning, or variation in spawning periodicity, occurs in many annual spawning fish species and is an important consideration for population management. We assessed plasma sex steroid concentrations and measured gonad size and ovarian follicle diameter as metrics to nonlethally identify mass ovarian follicular atresia, which may contribute to skipped spawning in Burbot Lota lota...