Theses and Dissertations at Montana State University (MSU)
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Item Use of eDNA to estimate abundances of spawning Yellowstone cutthroat trout in Yellowstone National Part, Wyoming, USA(Montana State University - Bozeman, College of Letters & Science, 2020) Detjens, Colleen Rachel; Chairperson, Graduate Committee: Alexander V. ZaleInvasive Lake Trout Salvelinus namaycush and whirling disease have reduced the abundance of native Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri (YCT) in Yellowstone Lake, Yellowstone National Park, thereby disrupting the Yellowstone Lake ecosystem. One indication of the YCT population decline is the decrease in the number of adults returning to tributaries to spawn each spring. Yellowstone National Park implemented a gillnetting program to remove Lake Trout starting in 1995 to restore YCT abundance and size structure and thereby conserve the Yellowstone Lake ecosystem. An important metric for evaluating the success of the program is the number of YCT ascending spawning tributaries each year. Annually, 9 to 11 of these tributaries are visually surveyed on a weekly basis from May through July for the presence of spawners, but these surveys are time consuming. The use of environmental DNA (eDNA) has become increasingly common for determining presence of aquatic species and may provide managers with a more efficient tool for estimating abundances of YCT spawners. The primary objective of my study was to evaluate the efficacy and accuracy of using eDNA to detect the presence and estimate abundance of YCT spawners by collecting eDNA samples from spawning tributaries to Yellowstone Lake in conjunction with visual surveys of YCT spawners. A secondary objective was to evaluate whether terrestrial or semi-terrestrial species such as grizzly bear Ursus arctos horribilis and North American river otter Lontra canadensis could be detected in a water sample from YCT spawning tributaries. Environmental DNA quantities were more effective for determining presence of YCT spawners than for predicting their abundances, but eDNA quantities were positively related to spawner abundances. The difference between eDNA rates when spawners are present versus absent may provide managers with an efficient method for monitoring YCT in tributaries throughout Yellowstone Lake basin. I also demonstrated that DNA from a terrestrial species, grizzly bear, can be detected in water samples. Incorporation of eDNA sampling with existing methods for monitoring YCT spawners in Yellowstone Lake tributaries would facilitate an increased scale of assessment and allow for detection and quantification of multiple species of current and future interest from single samples.Item Feasibility of walleye population suppression in Buffalo Bill Reservoir, Wyoming(Montana State University - Bozeman, College of Letters & Science, 2019) Kaus, Daniel Joseph; Chairperson, Graduate Committee: Christopher S. GuyBuffalo Bill Reservoir, Wyoming is managed as a wild Rainbow Trout Oncorhynchus mykiss and Cutthroat Trout Oncorhynchus clarkii fishery. Nonnative Walleyes Sander vitreus were discovered in 2008, and spring sampling of Walleye indicate natural recruitment and a rapidly expanding population. Walleyes pose a predation threat to the wild trout populations in Buffalo Bill Reservoir. The Wyoming Game and Fish Department (WGFD) is interested in suppressing the Walleye population using mechanical removal with electrofishing and gillnetting during the Walleye spawning period. The purpose of this study was to evaluate the population demographics of Walleyes in Buffalo Bill Reservoir. Age-structured population models were used to estimate the Walleye population growth rate for scenarios with and without Walleye removal. To inform the population models, age-specific fecundity, probability of maturity, natural mortality, and fishing mortality were estimated. Mean asymptotic population growth rate for the five scenarios were estimated as 1.22 (95% CI of 1.05 to 1.37) for no suppression, 1.18 (95% CI of 1.04 to 1.32) for electrofish exploitation, 1.04 (95% CI of 0.88 to 1.19) for gill-net exploitation, 0.91 (95% CI of 0.61 to 1.36) for angler exploitation, and 0.81 (95% CI of 0.66 to 0.96) for angler and gill-net exploitation combined. Results from the age-structured population models suggest that long-term population suppression is a viable goal, and additional gill-net effort and angler harvest incentives should be pursued. During this study the density of mature Walleyes was low, indicating that the population had not yet reached carrying capacity. Analysis of population inertia indicates that the projected abundance of the initial population vector results in a lower population size compared to projected abundance of a population with stable-age distribution. Results from this study will be used to inform cost-effective management decisions regarding the future of the recreational fishery in Buffalo Bill Reservoir. The cost per mature female removed in 2017 was $490.91 and $80.08 for electrofish and gill net removal, respectively. Future suppression efforts should be monitored using population indices of age diversity for female Walleyes.Item Influence of reach and watershed characteristics on fish distributions in small streams of eastern Montana(Montana State University - Bozeman, College of Letters & Science, 2007) Wuellner, Melissa Renee; Chairperson, Graduate Committee: Christopher S. GuyThe prairie biome is arguably the most endangered ecoregion in North America, and the chance of extinction for many fishes is greater than in other ecoregions. Fisheries scientists and managers must understand the ecology of fishes at multiple spatial scales for effective conservation. Statistical models designed to explain distributions of fishes using environmental characteristics measured at multiple scales have provided this critical information. The objectives of this study were to: i) identify the reach- (i.e., physicochemical and biotic) and watershed-scale characteristics that affect the distribution (i.e., presence or absence) of fishes in prairie streams of Montana; and ii) identify which scale best explains the distribution of fishes in Montana prairie streams: reach, watershed, or a combination of variables measured at either scale (i.e., combined models). Reach and watershed information from 120 sites sampled between 1999 and 2004 was used to model the presence or absence of 20 species using tree classifiers. Models were evaluated by strict criteria in this study as compared to similar studies of prairie fishes. In this study, variables used in models had to reduce a significant amount of the deviance in species distributions before they could be evaluated for their predictive ability; other studies have only examined whether reach- or watershed-scale variables could be used to predict the occurrence of species.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.Item An assessment of losses of native fish to irrigation diversions on selected tributaries of the Bitterroot River, Montana(Montana State University - Bozeman, College of Letters & Science, 2007) Bahn, Leslie; Chairperson, Graduate Committee: Alexander V. ZaleWithdrawals of surface water for irrigation and stock water leave the Bitterroot River and its tributaries chronically dewatered during the irrigation season. These water withdrawals affect local trout populations by entraining migratory trout into irrigation diversion canals at multiple life stages, and through the loss and degradation of available habitat for aquatic species. Irrigation losses may be responsible in part for the low abundances and restricted distributions of migratory native westslope cutthroat trout Onchorhyncus clarkii lewisi and bull trout Salvelinus confluentus in this system. My objectives were to quantify entrainment of fish into irrigation diversions on Lost Horse and Tin Cup Creeks, two tributaries of the Bitterroot River used by migratory adult westslope cutthroat trout for spawning, and to identify characteristics of these diversions that correlate with entrainment. I sampled fish species by snorkeling, electrofishing, fry trapping, and reconnaissance at 60 sites in 2005 and 54 sites in 2006. Annual entrainment estimates for age-0 salmonids were 18,061 and 8,972 in 2005 and 2006 in Lost Horse Creek diversions. Concurrent entrainment estimates for Tin Cup Creek were 2,995 and 2,312. Annual entrainment estimates for juvenile and adult trout (>40 mm TL) were 7,947 and 7,877 in 2005 and 2006 in Lost Horse Creek diversions.Item Spatiotemporal variation of fish assemblages in Montana prairie streams(Montana State University - Bozeman, College of Letters & Science, 2007) Mullen, Jason Alan; Chairperson, Graduate Committee: Christopher S. GuyFisheries biologists must be certain that their samples represent true parameters to make sound management decisions. A large-scale effort was conducted in the past decade to sample Montana prairie stream fish assemblages. This effort focused on sampling as many streams as possible, mostly during summer. Longitudinal sampling within drainages and replication of sites across time was minimal. Consequently, the spatiotemporal variation of prairie stream fish assemblages in Montana is not well understood. The objectives of this study were to 1) determine the influence of spatial, temporal, and abiotic variables in structuring prairie stream fish assemblages and 2) determine the survey design that best characterizes prairie stream fish assemblages. To assess spatiotemporal variation, lower, middle, and upper sites were sampled on five tributaries of the Yellowstone River during each season over a two-year period. Spatial position explained the greatest amount of variation (18.5%), followed by proportion of fine substrates (13.9%). Season (i.e., temporal variation) was not significant in explaining the overall variation in the fish assemblage. Fish species were associated with lower, middle, and upper spatial positions and along the fine substrates gradient based on abundance by species.Item Limiting factors for trout populations in the upper Clark Fork River superfund site, Montana(Montana State University - Bozeman, College of Letters & Science, 2013) Mayfield, Mariah Pine; Chairperson, Graduate Committee: Thomas E. McMahonLarge-scale heavy metal contamination of the upper Clark Fork River from mining deposits has created significant damage to aquatic habitat in the drainage. Trout are present in the system, although with abundances lower than expected. The objectives of this study were to identify critical habitat areas and to identify conditions that continue to limit both native and nonnative trout populations, with the focus of the study on the lingering environmental effects caused by high heavy metal concentrations. A radiotelemetry study, with 256 tagged brown trout Salmo trutta, westslope cutthroat trout Oncorhynchus clarkii lewisi, and cutthroat/rainbow hybrid trout, was conducted from 2009 to 2011. The radiotelemetry relocation data was used to determine temporal and spatial patterns in movement and survival rates in relation to heavy metals and other environmental factors, and to identify critical habitat areas (e.g., spawning locations and overwintering areas). Brown trout spawning occurred in numerous tributaries throughout the basin and in the upper reaches of the mainstem. Cutthroat trout spawned only in tributaries, and these tributaries were often smaller and more degraded by land use practices than brown trout spawning tributaries. Multistate mark-recapture survival analysis estimated that survival is lowest in the stream segment with the greatest amount of heavy metal contamination; the weekly likelihood of survival was estimated at 0.97 (95% confidence interval 0.97 - 0.98) for brown trout and 0.90 (95% confidence interval 0.84 - 0.97) for cutthroat trout. Additionally, weekly survival estimates for cutthroat trout in tributaries was also low (0.92; 95% confidence interval 0.87 - 0.94), likely because of anthropogenic land use pressures. Very limited movement was observed, except in relation to spawning migrations. Cutthroat trout moved greater distances and at a higher rate than brown trout. The results from this study indicate that the remaining mining contamination continues to reduce trout survival rates throughout the basin and should be removed in order to increase trout densities. Additionally, restoration priority should be placed on tributaries that are negatively affected by land use pressures.Item Distribution and population characteristics of lake trout in Lake McDonald, Glacier National Park : implications for suppression(Montana State University - Bozeman, College of Letters & Science, 2005) Dux, Andrew Martin; Chairperson, Graduate Committee: Christopher S. GuyBull trout Salvelinus confluentus have declined since the establishment of nonnative lake trout Salvelinus namaycush in Lake McDonald, Glacier National Park (GNP). In an attempt to prevent further decline of this population, GNP is considering implementing a lake trout suppression program. I used ultrasonic telemetry to examine the spatial and temporal distribution of lake trout and gill nets to evaluate population characteristics and diet. Model simulations were used to predict lake trout responses to varying levels of suppression. I relocated 36 lake trout (508-859 mm total length) 1,137 times from June through November 2003 and March through November 2004. Lake trout had a narrow vertical distribution during all seasons in both 2003 and 2004, rarely occupying depths >30 m. During thermal stratification, lake trout occupied depths in the upper hypolimnion where mean temperature varied from 8-9°C and dissolved oxygen was highest. Lake trout typically were suspended in the water column during all seasons except autumn. When spawning commenced in late-October, lake trout were associated with littoral habitats containing clean cobble and boulder substrates. The lake trout population had a broad age structure and a maximum age of 37 years. Males reached maturity earlier (12 years) than females (15 years), and total annual mortality rate for lake trout ages 8-27 was 13.2%. Growth rates were slow and relative weight values were among the lowest observed for lake trout throughout their range. Food habits were sampled from 254 lake trout, and 95% of the diet by weight consisted of fish prey. Model simulations indicated that substantial population reduction could be achieved with moderate exploitation (20-50%); however, this was more easily achieved as the size at which lake trout could effectively be captured was reduced. Simulations suggested that recruitment could be reduced to a level where adults are not being replaced at low exploitation (10-30%). These data will allow suppression efforts to be focused at times and places that will maximize efficiency, and population simulations suggest that substantial reduction of the lake trout population is feasible. Ultimately, results from this study should promote recovery of bull trout in Lake McDonald.Item Evaluation of distribution and fish passage in relation to road culverts in two eastern Montana prairie streams(Montana State University - Bozeman, College of Letters & Science, 2007) Rosenthal, Leo Richard; Chairperson, Graduate Committee: Thomas E. McMahonRoad culverts can restrict passage of fish migrating between seasonal habitats. The development of new roads, as well as the repair and upgrade of existing roads, has led to research addressing the effects culverts have on fish populations. The majority of this research has focused on salmonid species, and the effect of culverts on movements of small-bodied, weak swimming species is largely unknown. Fish passage within a assemblage of prairie fishes was examined in two tributaries of the lower Yellowstone River having a variety of culvert types. Passage restriction at culverts was determined using a combination of existing fish passage models, downstream displacement experiments, and patterns of longitudinal fish distribution above and below culverts. Fish movement during experiments was not significantly different through culvert versus natural reaches for most species (P > 0.05), however longnose dace passage was significantly restricted.Item Assessment of culvert passage of Yellowstone cutthroat trout in a Yellowstone River spawning tributary using a passive integrated transponder system(Montana State University - Bozeman, College of Letters & Science, 2007) Solcz, Andrew Anthony; Chairperson, Graduate Committee: Thomas E. McMahonRoad crossing culverts can pose passage barriers during salmonid migration. However, existing models to predict passage have not been sufficiently tested, particularly for non-anadromous species. In addition, most existing tools for evaluating culvert passage status categorize culverts as passable or impassable whereas an estimate of the probability of passage under a range of flows and hydraulic conditions would be more useful for assessing barrier status. This study used Half-duplex (HDX) Passive Integrated Transponder (PIT) tags and PIT tag reading antennas to examine the ability of migrating fluvial-adfluvial Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri to pass through three distinct culvert types over a variety of hydraulic conditions. PIT tag detecting antennas were installed on the upper and lower ends of each culvert and below the plunge pool downstream of the culvert. This design allowed determination of (1) passage success or failure; (2) the number of passage attempts made at each culvert; and (3) the time required for passage through each culvert; and (4) the number of tagged individuals that attempted passage at a particular culvert.