Geology topics

Research about Michigan

Source-linked reports with geographic coverage including Michigan.

At least 37 records · Page 2Linked to original sources

USGS2025

Differential population responses to white-nose syndrome between two Michigan bat hibernacula are not due to differences in host susceptibility

Disease outcomes result from the interaction between host, pathogen, and environmental factors. Understanding how these components interact to influence spatial and temporal variations in disease severity can enhance our insights into the drivers of disease outbreaks, ultimately improving our ability to mitigate the impact of disease through better forecasts and management actions. White-nose syndrome (WNS) in bats, caused by the fungal pathogen Pseudogymnoascus destructans (Pd), has been detected in hibernating bats across much of the United States and Canada. This pathogen has led to widespread population declines in some bat species, for example, Myotis lucifugus ; however, not all infected populations exhibit similar decreases in numbers. Despite long-term detection and high infection levels, the population of M. lucifugus that uses Tippy Dam, in northern Michigan, as a hibernaculum has not experienced a decline compared to other populations in the state. To assess local population effects that may contribute to reduced disease severity at Tippy Dam, we brought 30 hibernating M. lucifugus from Tippy Dam and 30 from a geographically similar hibernaculum with a history of declines from WNS into captivity at the U.S. Geological Survey, National Wildlife Health Center. We challenged the bats with a Pd inoculum and monitored survival, pathology, and Pd loads for up to 120 days. This allowed us to remove local environmental effects that could influence WNS disease severity. We observed no effect of source population on either survival or wing damage from Pd infection. Our results suggest that population persistence and lowered disease severity in Tippy Dam are likely driven by local environmental factors found within the dam. As Pd continues to spread westward, understanding environmental factors that influence the severity of Pd infection in hibernating bats has the potential to guide management decisions and help predict the survival of susceptible bat species in the western United States.

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USGS2025

Day versus night relations between larval lake whitefish, cisco, and zooplankton onshore in Lakes Michigan, Huron, and Superior

Lake whitefish ( Coregonus clupeaformis ) populations in the upper Great Lakes have undergone declines in the past two decades, particularly in Lakes Michigan and Huron. However, cisco ( Coregonus artedi ) are recovering in parts of the Great Lakes. Population declines are hypothesized to be due, in part, to reduced zooplankton prey in areas that serve as critical habitat for larval coregonines. Larval lake whitefish, cisco, and zooplankton are commonly sampled only during daylight hours. Habitat use, community composition, catch rates, and abundance estimates of larval fish and zooplankton can change drastically at night versus day, necessitating diel comparisons for a more comprehensive understanding of the early life history of coregonines and their prey. We collected paired day and night onshore (≤ 1 m depth) zooplankton and larval coregonine samples from Lakes Michigan, Huron, and Superior in March–June 2021 to test if there were diel differences in lake whitefish and cisco abundance and zooplankton density and biomass. We also tested if relationships exist between larval coregonine abundance and zooplankton density and biomass and environmental variables (water temperature, dissolved oxygen concentration, pH, specific conductivity, substrate type). We observed consistently higher zooplankton density and biomass and larval lake whitefish and cisco abundance at night. Larval coregonine abundance was positively related to higher zooplankton population estimates but was not related to the environmental variables measured. Our results provide insight into sampling practices for larval lake whitefish, cisco, and zooplankton onshore in the Great Lakes to better understand factors influencing larval lake whitefish and cisco recruitment.

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USGS2025

Environmental DNA metabarcoding for monitoring fish biodiversity in remote lakes

Objective Environmental DNA (eDNA) metabarcoding provides an attractive option for monitoring biodiversity in remote freshwater ecosystems, where the deployment of conventional gears encounters major logistical constraints. We evaluated eDNA metabarcoding for monitoring fish communities and early detection of nonnative species in three remote lakes on Isle Royale, Michigan, USA. Methods At each of the three lakes, we collected surface, midwater, and lake bottom samples from 10 sites during spring and fall sampling events. We performed metabarcoding on all the water samples, targeting the 12S region of all fish species. Results Despite a relatively small sample size ( N = 60 samples per lake across two visits; 10 locations with three depths per location), we recovered 70% of all the species that were previously observed using conventional methods. We recovered several detections of putative Cisco Coregonus artedi , a vulnerable coldwater species, providing evidence that Cisco have persisted in these lakes. However, we found disentangling likely false positives from rare species challenging, which we overcame by employing multiple types of detection thresholds and a species-specific quantitative PCR assay. Conclusions Although we were able to successfully characterize the fish communities using eDNA metabarcoding, more attention needs to be given to the detection thresholds and communication protocols that provide guidance in interpretating new eDNA detections and using eDNA detections to inform management decisions. Although eDNA metabarcoding has limitations that should be accounted for at the outset of the project, the ease of sample collection makes eDNA metabarcoding an option for monitoring freshwater biodiversity in remote systems.

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USGS2025

Metaproteomics and metagenomics reveal microbial pathways of organic matter degradation and methanogenesis in a marginally producing natural gas well

The expansion of natural gas production and utilization worldwide has led to the decline of many once-productive wells, eventually resulting in costly well-plugging and unused infrastructure. However, in areas like the Michigan basin, MI, where the majority of natural gas is biogenically produced, microbial communities could potentially be stimulated to generate additional methane, increasing gas supply and reducing the need to drill new wells. In this study, we performed metaproteomic, metagenomic, and geochemical analyses of Antrim Shale formation water from a marginally producing natural gas well to evaluate resident microbial community functions in the context of potential bioenergy production. Functional proteins involved in methanogenesis, degradation/catabolism (including organic matter degradation), biosynthesis, energy utilization, transmembrane transport, and stress response were among the most commonly identified groups. Three metagenome-assembled genomes (MAGs) were characterized, including Methanomicrobiaceae, Methanothrix , and Smithella . For each, the identified proteins involved in methanogenesis and the degradation of diverse organic compounds, strongly suggest their role in utilizing shale-derived organic matter. These findings provide an increased understanding of the microorganisms and their metabolisms generating natural gas in the Antrim Shale and establish a foundation for future stimulation efforts aimed at enhancing biogenic methane production in marginal gas wells.

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USGS2025

Movements and survival of hatchery reared juvenile cisco (Coregonus artedi) in Saginaw Bay, Lake Huron

Background Cisco ( Coregonus artedi ) were historically abundant throughout Lake Huron, including Saginaw Bay, but only a few remnant populations remain in northern Lake Huron today. Reestablishment of cisco is an important component of management plans to restore sustainable fisheries in Lake Huron. Cisco restoration efforts have focused on the release of hatchery-reared fish, but the fate and behavior of stocked fish after release is unknown. Mortality due to predation and behavior of hatchery-reared fish after release may influence success of restoration stocking programs. Acoustic telemetry tags with predation sensors show promise for tracking movements and survival of juvenile fish; however, guidelines for designing receiver arrays to capture movements and determine the fate of juvenile fish are not well-established. Results We examined whether an acoustic receiver array with approximately 20 km 2 of coverage was sufficient to determine movements and fate of cisco during the first month after release. We implanted 26 juvenile cisco (mean total length = 161 mm) with acoustic tags equipped with a sensor to detect predation. Thirteen fish (50%) moved more than 4 km from the release location and out of the array, seven fish (27%) were consumed by predators while in the array within 17 days of release, and the fates of six fish (23%) were unknown. Of fish that left the array, 50% left between 4 and 7 days after release. No fish were detected after 17 days after release. Cisco moved with water currents during the first day after release, but this was not observed in subsequent days. Concurrent with fish release, detection range was estimated from stationary tags at three locations within the receiver array. Daily estimates of detection range were greater than 50% at 250 m during October 2021. Conclusions This study provides evidence that hatchery-reared juvenile cisco can move more than 4 km within 17 days of release but are vulnerable to predation. To fully quantify sources of mortality and spatial extent of movements by hatchery-reared cisco, future acoustic telemetry studies will require a receiver array designed to track movements of tagged fish and their predators over larger distances than monitored in this study.

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USGS2025

Wetlands, groundwater and seasonality influence the spatial distribution of stream chemistry in a low-relief catchment

Evaluating stream water chemistry patterns provides insight into catchment ecosystem and hydrologic processes. Spatially distributed patterns and controls of stream solutes are well-established for high-relief catchments where solute flow paths align with surface topography. However, the controls on solute patterns are poorly constrained for low-relief catchments where hydrogeologic heterogeneities and river corridor features, like wetlands, may influence water and solute transport. Here, we provide a data set of solute patterns from 58 synoptic surveys across 28 sites and over 32 months in a low-relief wetland-rich catchment to determine the major surface and subsurface controls along with wetland influence across the catchment. In this low-relief catchment, the expected wetland storage, processing, and transport of solutes is only apparent in solute patterns of the smallest subcatchments. Meanwhile, downstream seasonal and wetland influence on observed chemistry can be masked by large groundwater contributions to the main stream channel. These findings highlight the importance of incorporating variable groundwater contributions into catchment-scale studies for low-relief catchments, and that understanding the overall influence of wetlands on stream chemistry requires sampling across various spatial and temporal scales. Therefore, in low-relief wetland-rich catchments, given the mosaic of above and below ground controls on stream solutes, modeling efforts may need to include both surface and subsurface hydrological data and processes.

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USGS2025

Observability of eastern massasauga (Sistrurus catenatus) during visual encounter surveys in Michigan, USA

Visual encounter surveys are commonly used to document site occupancy for the eastern massasauga ( Sistrurus catenatus ; EMR). Efficacy of surveys depends on visual and auditory cues, with basking behavior and burrow use strongly affecting detection. Our goal was to predict body exposure and probability of burrow use from telemetered EMR to better inform implementation of visual encounter surveys. We collected body exposure and burrow use from 23 EMR (14 females [12 gravid], 9 males) from April through September (i.e., active season) at 2 sites in south central Michigan, USA, 2020–2022. Average body exposure for observed snakes was 42% (SE = 3%) and ranged from 0–100%. Percent body exposure during the active season was positively influenced by air temperature, where body exposure increased from ~25% at ~15°C to ~50% at ~35°C. We did not find an effect of cloud cover, hour of day, humidity, or sex on EMR body exposure. Of 176 observations of EMR during the active season, we found EMR using burrows 20 times (~11% of observations). Julian date and air temperature affected the probability of EMR burrow use early in the active season. Probability of EMR burrow use was <0.10 from the end of May through the end of October and was almost 0.00 after mid-July. The probability of using a burrow was generally low (i.e., <0.25) across the range of air temperatures measured in our study, but approached 0.00 as temperatures exceeded 30°C. We did not find an effect of cloud cover, time of day, humidity, or sex on probability of EMR burrow use. Our results indicated that EMR observability in southern Michigan was greatest when air temperatures were 30°C to 35°C, corresponding to when EMR were visible and aboveground.

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USGS2025

New constraints on location and timing of the Great Lakes tectonic zone, central Upper Peninsula, Michigan, USA

The Great Lakes tectonic zone (GLTZ) forms the boundary between the Wawa–Abitibi and Minnesota River Valley subprovinces within the Archean Superior Province. The GLTZ is concealed for all of its 1100 km length, except for a segment in the central Upper Peninsula of Michigan. There, it is exposed as a northwest-striking mylonite zone along a 11 km segment, extending to the onlap of Paleozoic rocks to the east. Farther east, its location has been unknown. Here, we use aeromagnetic and gravity data to develop interpretations of the expression of the GLTZ and to define its extent under cover. Aeromagnetic gradients over the mylonite zone are interpreted to be produced by structurally juxtaposed rocks with varying magnetizations. Gravity data show a regional gradient along the GLTZ, produced by the juxtaposition of a dense greenstone belt on the north against lower-density gneisses and granites on the south. The GLTZ is interpreted to extend ∼55 km under cover to the east. The GLTZ is terminated on the east by the buried eastern arm of the ca. 1100 Ma Midcontinent Rift. An undeformed granitic dike that cuts the mylonitic foliation produces a U–Pb apatite age of 2523 ± 33 Ma, implying no major post-Archean shearing occurred, and is at odds with previous interpretations of major Proterozoic reactivation. A granite intrusion in the Minnesota River Valley subprovince produces a Pb–Pb zircon age of 2606.9 ± 3.6/7.4 Ma. This suggests that magmatism related to the Sacred Heart orogeny, previously known in Minnesota, extended to Michigan.

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USGS2025

Movement patterns of invasive red swamp crayfish vary with sex and environmental factors

Invasive species disproportionately invade freshwater ecosystems, threatening biodiversity. Defining when, where, and why aquatic invasive species move can help inform management strategies, yet the movement ecology of some of the most pervasive invasive species remains unknown. Red swamp crayfish ( Procambarus clarkii ; RSC) are the most widespread invasive crayfish and negatively affect ecosystems worldwide. We employed high-dimensional acoustic telemetry to investigate the movement patterns of 24 individual RSC across three months in an invaded water body. We assessed the effects of various extrinsic factors, such as time of day, temperature, precipitation, and proximity to the water’s edge, along with intrinsic factors, such as sex, reproductive form, and size, at different scales, including movement steps, range distribution, and behavioral states. We found that movement patterns across all scales were overwhelmingly driven by sex and reproductive form. Furthermore, RSC showed increased overall activity at night and near the water’s edge. By establishing baseline movement patterns and identifying key contributing factors, these findings provide a foundation for the development of adaptive management strategies for controlling invasive RSC populations.

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USGS2025

Effect of copper mill waste material on benthic invertebrates and zooplankton diversity and abundance

Copper (Cu) stamp mill mining in North America from the early 1900s produced a pulverized ore by-product now known as stamp sands (SS). In a mining operation near the city of Gay (Michigan, USA), SS were originally deposited near a Lake Superior beach, but erosion and wave action have moved many SS into beaches and reefs that are critical spawning and nursery areas for native fish (e.g., Lake Whitefish). Larval and juvenile native fish consume zooplankton and benthic invertebrates during their development, and many of these invertebrate taxa may be sensitive to metal contamination from the SS. Here, we sampled the invertebrate community from beaches with high SS, moderate SS and low SS, as well as a control beach 58 km from the source of the SS. The high SS site was characterized by fewer benthic taxa, and less density of several taxa than the low SS site, especially benthic copepods. All beaches had comparable zooplankton diversity, but the abundance was ~ 2 orders of magnitude lower at the high SS site. Cu and several other metals were elevated at beaches with more SS. We found support for associations between benthic density and diversity with depth (positive effect) and Cu concentration (negative effect). Cu concentration was a better predictor of declines in benthic invertebrate abundance and diversity than SS although sensitivity to Cu varied among taxa. We also observed that the relationship between Cu concentration and SS was non-linear, and highly variable. For example, 149 mg Cu/kg dry weight sediment is a consensus threshold used in the literature to identify Cu toxicity, but the prediction interval for estimating that concentration of Cu from measurements of SS is 26-851 mg Cu/kg dry weight. A better predictive model of this relationship would be beneficial to develop an understanding of what level of SS reduction would prevent Cu impacts on invertebrates.

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USGS2025

Not all who meander are lost: Migrating sea lamprey follow river thalwegs to facilitate safe and efficient passage upstream

Efficient navigation is crucial for the reproductive success of many migratory species, often driven by competing pressures to conserve energy and reduce predation risk. Little is known about how non-homing species achieve this balance. We show that sea lamprey ( Petromyzon marinus ), an ancient extant vertebrate, uses persistent patterns in hydro-geomorphology to quickly and efficiently navigate through complex ecosystems. Hydrodynamic flow models coupled with bathymetric mapping and fine-scale acoustic telemetry revealed movement paths that tracked thalweg scour channels, which are often the deepest and fastest-flowing sections of a river. These paths allow rapid and efficient upstream migration and suggest the existence of a bathymetric highway system. Near-substrate swimming along this path resulted in a median of 5.8% energy savings while also promoting improved safety from nocturnally active predators. We hypothesize sea lampreys use hydrostatic pressure-guided rheotaxis to achieve this navigation. It is likely this tactic relies on sensory information from the animal's primitive lateral line and perhaps the inner ear. Insights from this study can be used to redesign conservation practices to achieve improved control where the animal is invasive and improved fish passage within its native range.

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USGS2025

A real-time fish detection system for partially dewatered fish to support selective fish passage

Recent advances in fish transportation technologies and deep machine learning-based fish classification have created an opportunity for real-time, autonomous fish sorting through a selective passage mechanism. This research presents a case study of a novel application that utilizes deep machine learning to detect partially dewatered fish exiting an Archimedes Screw Fish Lift (ASFL). A MobileNet SSD model was trained on images of partially dewatered fish volitionally passing through an ASFL. Then, this model was integrated with a network video recorder to monitor video from the ASFL. Additional models were also trained using images from a similar fish scanning device to test the feasibility of this approach for fish classification. Open source software and edge computing design principles were employed to ensure that the system is capable of fast data processing. The findings from this research demonstrate that such a system integrated with an ASFL can support real-time fish detection. This research contributes to the goal of automated data collection in a selective fish passage system and presents a viable path towards realizing optical fish sorting.

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USGS2025

Burbot population dynamics in northern Lake Michigan, 2001–2023, and predation on newly stocked lake trout by burbot

Although the worldwide status of burbot ( Lota lota ) across its Holarctic distribution has recently been assessed, adverse effects of dreissenid mussels on burbot abundance in waters invaded by mussels have not been investigated. We analyzed data from an annual spring gillnet survey to characterize burbot population dynamics in northern Lake Michigan during 2001–2023. Adult burbot abundance in northern Lake Michigan trended neither significantly upward nor downward during 2001–2023. Thus, expansion of the quagga mussel ( Dreissena rostriformis bugensis ) population into deeper waters of Lake Michigan during 2003–2008 had no detectable negative effects on burbot abundance. Burbot continued to feed on lake trout ( Salvelinus namaycush ) stocked in the Northern Refuge of Lake Michigan through 2023, which supported a hypothesis that the burbot population potentially impeded lake trout restoration in the refuge.

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USGS2025

Metal-rich lacustrine sediments from legacy mining perpetuate copper exposure to aquatic-riparian food webs

Historic copper mining left a legacy of metal-rich tailings resulting in ecological impacts along and within Torch Lake, an area of concern in the Keweenaw Peninsula, Michigan, USA. Given the toxicity of copper to invertebrates, this study assessed the influence of this legacy on present day nearshore aquatic and terrestrial ecosystems. We measured the metal (Co, Cu, Ni, Zn, Cd) and metalloid (As) concentrations in sediment, pore water, surface water, larval and adult insects, and two riparian spider taxa collected from Torch Lake and a nearby reference lake. Overall, elevated metal and metalloid concentrations, particularly Cu, were measured in all sediment samples and some surface and pore water samples collected from Torch Lake. For instance, Cu concentrations in the Torch Lake sediment were ∼200% higher than the reference lake and all measured concentrations exceeded predicted effects concentrations by at least ninefold. Within larval insect tissues, we observed 160% higher Cu concentrations than measured in the reference lake, and Cu was the only measured element above predicted effects concentrations in Torch Lake. Adult insects collected at both lakes had similar metal concentrations irrespective of exposure levels. Yet we found 100% higher copper concentrations in Torch Lake riparian spiders, demonstrating elevated exposure risk to insectivores across the aquatic-terrestrial boundary. Our results highlight that other metals in the mixture may not be as concerning to adjacent riparian ecosystems, but copper remains a contaminant of concern in Torch Lake 60 years after mining ceased.

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USGS2025

Effects of chronic metal exposure and metamorphosis on the microbiomes of larval and adult insects and riparian spiders through the aquatic-riparian food web

The macroinvertebrate microbiome controls various aspects of the host's physiology, from regulation of environmental contaminants to reproductive output. Aquatic insects provide critical nutritional subsidies linking aquatic and riparian food webs while simultaneously serving as a contaminant pathway for riparian insectivores in polluted ecosystems. Previous studies have characterized the transport and transfer of contaminants from aquatic to riparian ecosystems through insect metamorphosis, but both contaminant exposure and metamorphosis are energetically intensive processes that may cause host microbiomes to undergo radical transformation in structure and function, potentially affecting the host's physiology. We collected arthropods from three sites within Torch Lake, a historical copper mine in the Keweenaw Peninsula, Michigan, USA, and three sites within a nearby reference lake. Our objectives were to: 1) characterize the variation in microbiome communities and predicted metagenomic functions with legacy copper mining activity across space, among host types and family-level host taxonomy, 2) characterize how insect metamorphosis alters the microbiome community, including the degree of endosymbiotic infection, and predicted metagenomic function. We field-collected organisms, extracted their DNA, and sequenced the 16S region of the rRNA gene to characterize microbiome communities, then predicted metagenomic function. Site, lake, and host taxonomy affected the host microbiome community composition. Copper exposure increased the abundance of xenobiotic and lipid metabolism pathways in the Araneidae spider microbiome. Insect metamorphosis reduced the alpha diversity, altered the community composition, and predicted metagenomic function. We observed a bioconcentration of endosymbiotic bacteria in adult insects, especially holometabolous insects. Through metamorphosis, we observed a transition in function from xenobiotic degradation pathways to carbohydrate metabolism. Overall, contaminant exposure alters the microbiome composition in aquatic insects and riparian spiders and alters the function of the microbiome across the aquatic-riparian interface. Furthermore, metamorphosis is a critical element in shaping the aquatic insect microbiome across its life history.

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USGS2025

Larger larval sea lamprey (Petromyzon marinus) have longer survival times when exposed to the lampricide 3-trifluoromethyl-4-nitrophenol

Invasive sea lamprey ( Petromyzon marinus ) in the Laurentian Great Lakes have negatively impacted ecologically and economically important fishes for nearly a century. To mitigate these effects, the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is applied annually on a rotating basis to selected Great Lakes tributaries to kill larval lamprey before they become juveniles, out-migrate to the lakes, and parasitize other fishes. It has been hypothesized that larval size (e.g., mass, length) may affect survival time in response to TFM. To test this hypothesis, we conducted an experiment with 8611 larvae across four temporal replicates, in which TFM concentrations equivalent to those used in present-day stream treatments were applied for up to 18 h. When examining the survival times of larval lamprey exposed to TFM, we found a significant, positive relationship between length, mass, toxicity, and their interactions. For every 1 mm increase in total length, a corresponding increase by 1 g of mass reduced survival time by 0.4315 min [95 % CI: 0.5283–0.2992] and vice versa (i.e., the significant interaction between length and mass revealed that as larvae increase in mass, the survival benefit to being longer decreases, and vice versa). The changes in total length and mass of larval sea lamprey stored in ethanol for 4 months was also quantified. The observation that five larvae survived well past the 12-hour time window of a typical TFM field treatment highlights the need for continuous monitoring and the development of new control strategies to ensure the continued effective management of this invasive species.

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USGS2025

Water temperature analysis of the North Branch Au Sable River, Michigan, and implications to salmonid populations

Ambient stream water temperatures affect salmonid movement and survival with fish actively seeking thermal refugia from warming waters. This study sought to investigate the potential role of water temperature in the perceived decline in native Brook Trout Salvelinus fontinalis and non-native Brown Trout Salmo trutta populations in the North Branch Au Sable River by fishers and reported to resource managers in 2018 and 2019. Water temperature was analyzed at nine stations within the North Branch Au Sable River in 2021 and 2022. A total of 61,390 temperature observations were collected with 58.0% exceeding the optimal growth threshold for Brook Trout of 16°C; 37.9% exceeding the movement threshold for Brook Trout of 18°C; 3.4% exceeding the upper limit for positive growth for Brook Trout of 23.4°C; and 28.6% exceeding the optimal growth threshold for Brown Trout of 19°C. The maximum daily water temperatures recorded for each year were 27.58°C in 2021 and 26.89°C in 2022. The availability of cold water thermal refugia is critical to the viability of native Brook Trout populations in the North Branch Au Sable River and its tributaries. Efforts should be taken to increase ambient stream water temperature monitoring year-round and to determine the size, frequency, and availability of thermal refugia within the watershed to increase the likelihood of a system resilient to the impacts of a warming climate.

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USGS2024

Predicting the response of fish populations to changes in river connectivity using individual-based models

Barrier removal restores physical stream processes and improves accessibility of critical habitats to migratory fishes. Although increasing connectivity benefits stream systems and migratory fishes, barrier removals may also lead to increased production of undesirable or invasive migratory species, as well as myriad other concerns (e.g., reduced recreational opportunities). Few studies have predicted how migratory fish populations will respond to enhanced fish passage, despite being a critical step in the decision-making process. We developed an individual-based model framework to forecast the response of migratory fishes to changes in connectivity and applied the framework to six species under multiple fish passage scenarios for the FishPass project on the Boardman River, MI, which outlets into Lake Michigan. Population response to barrier removal was species-specific and varied based on initial population size and distribution within the watershed, number of fish passed upstream, and species life history traits. Species restricted to below the barrier prior to removal benefitted most; non-native species were found to have greater production potential under full passage scenarios than native Great Lakes species. With increasing passage of non-native Pacific salmonids, steelhead Oncorhynchus mykiss surpassed brook trout Salvelinus fontinalis as the system’s dominant species. Our results will inform decision-makers on management alternatives for fish passage on the Boardman River and our model framework can be modified, updated, and applied to additional river systems as more barrier removal projects are conducted in the future.

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