Theses and Dissertations at Montana State University (MSU)
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Item Fish assemblage response to habitat restoration in Elk Springs Creek, Montana: implications for arctic grayling (Thymallus arcticus) restoration(Montana State University - Bozeman, College of Letters & Science, 2021) Marsh, Jason William; Chairperson, Graduate Committee: Alexander V. ZaleThe abundance and distribution of Arctic Grayling Thymallus arcticus in Montana have declined substantially during the past century as a result of habitat degradation and loss. Biologists tasked with conserving Arctic Grayling populations in the Centennial Valley of southwestern Montana implemented two habitat restoration projects to reclaim historical Arctic Grayling migration corridors and spawning habitats in Elk Springs Creek. I used before-after and before-after control-impact (BACI) study designs to evaluate the effects of these habitat restoration projects on physical habitat, water quality, and Arctic Grayling in Elk Springs and Picnic creeks. Because Arctic Grayling were rare in Elk Springs and Picnic creeks, I also examined the effects of restoration on two additional species (Brook Trout Salvelinus fontinalis and White Suckers Catostomus commersonii) with habitat requirements and life history characteristics similar to those of Arctic Grayling. I used electrofishing to monitor the abundance, biomass, and size distribution of each species before the restoration in 2016, and after the restoration during 2017 and 2018. A PIT-tag detection network monitored the seasonal movements of Arctic Grayling, Brook Trout, and White Suckers from spring 2016 through autumn 2018. In situ data loggers measured summer stream temperatures and dissolved oxygen concentration in expected fish migration corridors both before and after restoration. The abundances and biomasses of Arctic Grayling and White Suckers were similar before and after restoration. However, Brook Trout abundance and biomass increased significantly in the restored (impacted) reaches relative to the unrestored (control) reaches two years after habitat restoration. The size-class distributions of Arctic Grayling and Brook Trout broadened after restoration. Movements of Arctic Grayling, Brook Trout, and White Suckers among unique habitat segments in Elk Springs and Picnic creeks increased after restoration, but pre-restoration movement data was sparse and limited inference. Following channel restoration, summer stream temperatures decreased, and dissolved oxygen concentration increased and equilibrated. Physical habitat improved (i.e., fine sediments decreased, and depth, percentage of pools, and gravels increased) in restored historical Arctic Grayling spawning areas. I thereby showed that channel reconnection and spawning habitat restoration can substantially improve water quality and physical habitat. However, the restoration measures implemented in Elk Springs Creek affected my target species disproportionately.Item Attraction, entrance, and passage efficiency of arctic grayling, trout, and suckers at Denil fishways in the Big Hole River Basin, Montana(Montana State University - Bozeman, College of Letters & Science, 2020) Triano, Benjamin Louis; Chairperson, Graduate Committee: Thomas E. McMahonThe Big Hole River in southwest Montana supports the only indigenous, self-sustaining fluvial population of Arctic Grayling (Thymallus arcticus) in the conterminous United States. Denil fishways have been installed at 63 low-head irrigation diversion dams throughout the basin to provide grayling and other fishes year-round access to critical habitats; however, their efficiency has not been evaluated comprehensively. We quantified attraction, entrance, and passage efficiency of grayling, trout (Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta), and suckers (White Sucker Catostomus commersonii and Longnose Sucker C. catostomus) at six Denil fishways during 14 trials conducted over a range of fishway slopes and hydraulic conditions. Tagged hatchery-reared grayling and wild fish of several taxa were released downstream of diversions in each trial, and upstream passage was monitored for 72 hours using passive integrated transponder telemetry. Attraction (60.4-84.3%) and entrance (44.3-78.6%) efficiencies limited overall fishway efficiencies (19.1-55.8%), but passage efficiencies (96.2-97.0%) were high for all taxa over all conditions tested. Attraction of hatchery-reared grayling was limited at fishways with shallow upstream depths (low fishway discharges) and low attraction flows, but wild trout and suckers were less limited by these effects. Entrance of grayling and trout was limited at high fishway discharges and fishways with steep slopes, but both species groups were more likely to enter fishways with deep downstream depths than those with shallow downstream depths. Entrance appeared to be limited by turbulent plunging conditions associated with shallow downstream depths. Denil fishways demonstrated great promise for improving habitat connectivity for grayling and other fishes in the Big Hole River basin; however, attraction and entrance were key bottlenecks that limited overall fishway efficiency. Maintaining high attraction flows and deep downstream depths should be the focus of adaptive management strategies and design criteria to improve overall efficiency of Denil fishways in the Big Hole basin.Item Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana(Montana State University - Bozeman, College of Letters & Science, 2017) McCullough, Austin Robert; Chairperson, Graduate Committee: Christopher S. GuyArctic Grayling Thymallus arcticus in Montana have experienced declines in abundance and distribution over the last century, which contributed to the species being designated as a Species of Concern and petitioned for protection under the Endangered Species Act. Conservation of Arctic Grayling in the Big Hole River watershed was based on presumed environmental influences. Interactions with nonnative species, increasing stream water temperatures, drought, and habitat alterations are suggested to influence Arctic Grayling abundances, although sparse quantitative information exists to support these hypotheses. My objective was to evaluate the influence of these biotic and abiotic factors on Arctic Grayling abundances using data collected in the Big Hole River drainage from 1983 through 2015. Arctic Grayling and nonnative salmonids were sampled at 32 sites, stream temperature data were collected at 33 sites, stream discharge data were collected at 21 sites, and habitat data were collected at 441 sites. Ordinary least squares and quantile (Tau = 0.90) regression analyses were used to evaluate the relationships among Arctic Grayling catch per unit effort (CPUE), nonnative salmonids CPUE, stream temperature, stream discharge, and habitat condition. The strongest univariate relationship was a positive correlation between the CPUE of Arctic Grayling > or = age 1 and Brook Trout Salvelinus fontinalis CPUE (r = 0.55, N = 77), which was contrary to the a priori predicted relationship. Multivariate analyses suggested that high water temperatures and low discharges during drought conditions have the greatest limiting influences on the CPUE of Arctic Grayling > or = age 1; Brown Trout CPUE, low water temperatures, and high maximum discharges were suggested as having the greatest limiting influences on age-0 Arctic Grayling CPUE. My findings support current management to increase discharge during drought conditions and further explore relationships between Arctic Grayling CPUE, habitat conditions, and Brown Trout CPUE.Item Winter survival and habitat as limiting factors for Arctic grayling at Red Rock Lakes National Wildlife Refuge(Montana State University - Bozeman, College of Letters & Science, 2016) Davis, Michael Nordstrom; Chairperson, Graduate Committee: Thomas E. McMahon; Thomas McMahon was a co-author of the article, 'Factors affecting winter hypoxia in a large boreal lake: evidence for a hypoxia refuge and for reoxygenation prior to spring ice loss' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.; Thomas McMahon and Molly Webb were co-authors of the article, 'Winter survival, habitat use and hypoxia tolerance of Arctic grayling in an ice-covered boreal lake prone to winterkill' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.Arctic grayling (Thymallus arcticus) are a now rare, glacial relict species occupying only a fraction of their historic range in Montana. The population in Upper Red Rock Lake is the only significant remaining native, adfluvial population and has undergone significant declines in abundance and distribution. Previous studies have documented instances of very low winter DO in the lake and low overwinter survival due to winter hypoxia has been hypothesized as a potential limiting factor for this population. We tested this hypothesis using a combined laboratory and telemetry study to document extent of hypoxia in Upper Red Rock Lake over two winters and assess the physiological tolerance, behavioral response and winter survival rate to hypoxia. In the laboratory study we observed a significant behavioral and physiological response to DO < 4 mg/L and determined 24-hr LD 50 values of 0.75 mg/L for adults and 1.50 - 1.96 for juveniles at temperatures of 1 - 3°C. In the field study we recorded a period of significantly lower lakewide average DO as well as high spatial variability in DO concentration (< 1 - 10 mg/L) during ice cover. However, we found that 69 - 100% of the lake epilimnion had DO > 4 mg/L during the ice cover period of both winters. Results of the telemetry study indicated adult winter survival rate was high (0.97 in 2014, 0.95 in 2015) and that telemetered fish selected deeper, more oxygenated habitat during ice cover. Our study demonstrates that Arctic grayling have a very high tolerance to acute hypoxia exposure and exhibit a physiological and behavioral stress response to DO < 4 mg/L. Although hypoxia was present in Upper Red Rock Lake, ample suitable habitat was available in the epilimnion in both study winters. Despite the potential for a hypoxia threat to develop in more severe winters, we conclude that low winter survival due to winter hypoxia is likely not a limiting factor for this population.Item Comparative genetics of Montana and arctic grayling, Thymallus arcticus(Montana State University - Bozeman, College of Agriculture, 1977) Lynch, Jeremiah C.Item Population viability of Arctic grayling (Thymallus arcticus) in the Gibbon River, Yellowstone National Park(Montana State University - Bozeman, College of Letters & Science, 2007) Steed, Amber Christine; Chairperson, Graduate Committee: Alexander V. Zale; Todd Koel (co-chair)The fluvial Arctic grayling Thymallus arcticus is restricted to less than 5% of its native range in the contiguous United States and was listed as Category 3 under the Endangered Species Act (ESA) until a 2007 ruling removed its protection. Fluvial grayling were thought to be restricted to the Big Hole River, Montana, where abundances were declining. Although fluvial grayling of the lower Gibbon River, Yellowstone National Park (YNP) were considered extirpated by 1935, anglers frequently reported catching grayling throughout the river since 1980. My goal was to determine if a viable population of fluvial grayling persisted in the Gibbon River, or if fish caught in the river were downstream emigrants from lacustrine populations in headwater lakes. I developed three objectives to address this goal: 1) determine grayling abundances in the Gibbon River, 2) determine the source of grayling in the Gibbon River detected downstream of headwater lakes (occupied by lacustrine populations), and 3) determine if grayling are successfully spawning in the Gibbon River.