David Schmetterling

• Project Manager at Montana Fish, Wildlife and Parks

Objective Long‐term standardized monitoring programs are fundamental to assessing how fish populations respond to anthropogenic stressors. Standardized monitoring programs may need to adopt new methods to adapt to rapid environmental changes that are associated with a changing climate. In the upper Yellowstone River, Montana, biologists have used a...

During a statewide crayfish survey of Montana, we documented the southern plains crayfish Procambarus simulans for the first time in the state. Procambarus simulans is native to, and commonly found in, southern and central US states, including Arkansas, Colorado, Kansas, Louisiana, New Mexico, Oklahoma, and Texas. We found this species in a single...

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...

Heterogeneity is a central feature of ecosystem resilience, but how this translates to socioeconomic resilience depends on people's ability to track shifting resources in space and time. Here, we quantify how climatic extremes have influenced how people (fishers) track economically valuable ecosystem services (fishing opportunities) across a range...

Climate change and anthropogenic activities are altering the body sizes of fishes, yet our understanding of factors influencing body size for many taxa remains incomplete. We evaluated the relationships between climate, environmental, and landscape attributes and the body size of different taxa of freshwater trout (Salmonidae) in the USA. Hierarchi...

Climate change and invasive species are major threats to native biodiversity, but few empirical studies have examined their combined effects at large spatial and temporal scales. Using 21,917 surveys collected over 30 years, we quantified the impacts of climate change on the past and future distributions of five interacting native and invasive trou...

Excessive fishing pressure can induce population declines or complete collapse of fisheries. Unless commercial and recreational fisheries for K-selected fishes, or those with slow growth and late maturation, are carefully managed, declines in abundance or fishery collapse is probable. Paddlefish Polyodon spathula, are a K-selected species that expe...

We used redd count data from 88 bull trout (Salvelinus confluentus) populations in the upper Columbia River basin to quantify local and regional patterns in population dynamics, including adult abundance, long-term trend, and population synchrony. We further used this information to assess conservation risk of metapopulations using eight population...

We appreciate the comments of Young et al. (2017) on our recent paper (Muhlfeld et al., 2017) concerning spatiotemporal dynamics of hybridization between native westslope cutthroat trout (Oncoryhnchus clarkii lewisi; WCT) and introduced coastal rainbow trout (O. mykiss irideus; RBT). Nevertheless, we believe there is no evidence for “ecological seg...

Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large, mul...

Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold‐water fishes. Research addressing the consequences of climate change on cold‐water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences population...

Understanding how climate change may facilitate species turnover is an important step in identifying potential conservation strategies. We used data from 33 sites in western Montana to quantify climate associations with native bull trout (Salvelinus confluentus) and non-native brown trout (Salmo trutta) abundance and population growth rates (λ). We...

The upper Clark Fork River basin of western Montana supports a poorly understood sculpin (Uranidea spp.) fauna that has perplexed ichthyologists and fish ecologists since the late 1800s. During our study, the basin contained three sculpin taxa whose taxonomy was under revision. All three taxa were formerly referred to the genus Cottus but are now t...

Electrofishing‐based estimates of fish abundance are common. Most population models assume that samples are drawn from a closed population, but population closure is sometimes difficult to achieve. Consequently, we individually electrofished 103 radio‐tagged trout of two species, westslope cutthroat trout Oncorhynchus clarkii lewisi and brook trout...

Using data collected from three river reaches in Montana, we evaluated our ability to detect population trends and predict fish future fish abundance. Data were collected as part of a long-term monitoring program conducted by Montana Fish, Wildlife and Parks to primarily estimate rainbow (Oncorhynchus mykiss) and brown trout (Salmo trutta) abundanc...

Like many species of amphibians, Boreal Toads (Bufo boreas boreas, Bufonidae) are declining throughout portions of their range. Recent efforts have focused on describing the ecology of this species, yet few studies have evaluated demographic characteristics that may influence the persistence of Boreal Toad populations. Because Boreal Toads often co...

The Boreal Toad (Bufo boreas boreas) is widely distributed in the western United States but has declined in portions of its range. Research directed at conserving Boreal Toads has indicated that their movements are largely terrestrial and often limited after the breeding season. We used a combination of stream-based netting, PIT tagging, and radio...

Freshwater sculpins (Cottidae) are a diverse and ecologically important component of cool- and coldwater ecosystems throughout the northern hemisphere. More than 60 sculpin species occur in a variety of habitats, and sculpin distributions range from highly localized to widespread. Despite the frequently high biomass of sculpins and their numerous e...

Despite the abundance of largescale suckers (Catostomus macrocheilus) in western North America, little is known about their biology and ecology. Tens of thousands of largescale suckers annually congregate in the spring in the tailrace of Milltown Dam, Montana, apparently impeded on upstream migrations. To determine the destination of migrants and a...

We studied movements by fishes in Chamberlain Creek, Montana, from 24 July to 16 August 2001. We operated six weirs with two-way traps and one additional upstream trap, separated by 14–1,596 m, to quantify the timing, direction, and distance of movements and to estimate fish populations in the study reaches. We trapped and marked 567 fish of seven...

The effects of electrofishing on salmonid movement and of salmonid movement on electrofishing‐derived abundance estimates were studied in two streams in western Montana, U.S.A. Electrofishing increased emigration of salmonids from study reaches for 1 day, but not for succeeding days, whereas immigration to study reaches was unaffected. Movement of...

Milltown Dam annually impedes the migration of 11 fish species, and data suggest that fish that migrate to the dam do not spawn once their migration is impeded. Densities of westslope cutthroat trout Oncorhynchus clarki lewisi and bull trout Salvelinus confluentus are low near Milltown Dam, but their annual presence at the dam suggests the potentia...

In order to enhance the understanding and conservation of native fish in the West, we developed an educational program (Adopt-A-Trout) to introduce fisheries research to students in rural Montana schools. This innovative project provides data on fish migrations to schools in the Blackfoot watershed through teacher training, a website, and field tri...

We evaluated the efficacy of three Denil fish ladders retrofitted to three irrigation diversions in two tributaries to the Blackfoot River, Montana. Fish ladders were 2.4–6.1 m long, with slopes of 9.6–15.8% and mean velocities of 18–140 cm/s. We captured westslope cutthroat trout Oncorhynchus clarki lewisi, brown trout Salmo trutta, bull trout Sal...

I studied the seasonal movements and habitat use of fluvial westslope cutthroat trout Oncorhynchus clarki lewisi from 1997 to 1999 in the Blackfoot River drainage in western Montana to help guide restoration efforts and lead to a better understanding of this subspecies. Of 22 radio-tagged fish, 16 migrated during the spawning period (mean length, 3...

Angular rock riprap is used to reduce riverbank erosion in developed riparian corridors. We reviewed peer reviewed as well as non-refereed literature to determine the effects of riprap on salmonid habitat and populations and to identify areas for future (applied) research. Although commonly used to armor banks, riprap affects salmonid populations a...

Westslope cutthroat trout Oncorhynchus clarki lewisi spawned in May 1998 as flows subsided after peak discharges in four tributaries to the Blackfoot River in western Montana. For 32 redds, water depths averaged 12.9 cm and velocities averaged 56 cm/s. Spawning occurred in substrate sizes ranging from 6 to 110 mm. Redd pits averaged 0.61 m long, an...

Although many potamodromous fishes make extensive migrations, dams that block their upstream movements are not often mitigated with passage facilities. Over several months in 1998 and 1999 we studied the numbers of all fish species attempting to migrate beyond Milltown Dam, a hydroelectric dam on the Clark Fork River, Montana. Using a radial-gate r...

Gold Creek, in western Montana, lost complexity and diversity of fish habitat following riparian logging activities, removal of instream wood, and subsequent scouring. In the 4.8-km study area, the stream was almost totally void of large woody debris (4.2 pieces/km) and associated pools (1.3 pools/km). We constructed 66 structures made of natural m...

The efficacy of fishing regulations relies on anglers knowing and understanding regulations as well as their ability to identify fish correctly. While the legal harvest of both bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisi) has been restricted or eliminated in west central Montana to restore these nat...

The effects of surgical staples on incision healing and long-term fish growth are largely unknown. To determine these effects, we implanted 50 rainbow trout Oncorhynchus mykiss with dummy radio transmitters, closed incisions with either silk sutures or steel staples, and monitored these fish for 6 months. Surgeries with staples were performed twice...