Watersheds are often managed without direct knowledge of how salmonid species use spatially-distinct spawning habitats within their watersheds, and rarely take into account the relationship between fish movement and potential population structure when making management decisions. The population of native Bonneville cutthroat trout (Oncorhynchus clarki utah) within the Logan River is the largest documented population remaining for this imperiled species, and still maintains extremely high densities of native fish in the upper river. Currently, fishing is not allowed in the upper 20 kilometers of the Logan River watershed during spawning, based on the assumption that cutthroat trout migrate to and spawn primarily in this section. I redetected cutthroat trout tagged (2,271) during years 2008-2012 in seven mainstem and tributary reaches of the Logan River during spawning months (April-June) of 2013 using a combination of stationary detection systems and mobile scanning techniques. Cutthroat trout in both mainstem and tributary reaches exhibit a leptokurtic movement distribution, indicating most fish spawn near to their original tagging site; however, small percentages of trout moved long distances to seek out spawning sites throughout the watershed. Growth, length, and condition estimates between mobile and non-mobile tagged fish demonstrate that while mobile fish tend to growth faster, be slightly larger, and in some cases be in relatively poorer condition, these differences are often biologically insignificant and dependent on site location within the watershed. A genetic microsatellite DNA analysis conducted on trout sampled from each study site confirms the assumption of panmixia, and I observed very little evidence of sub-population structure. Using River Styles® to assess geomorphically distinct reaches, I created a large-scale population estimate of spawning individuals, which found approximately 61% of spawning cutthroat trout are not subject to angling during the spawning season, while 39% could be susceptible to harvest in the lower basin and its tributaries. Most trout within the Logan River likely spawned very close to initial tagging locations and microsatellite analyses confirmed the population is genetically well-mixed, indicating conservation efforts should promote risk-averse management throughout the watershed, rather than focus heavily on any one section of the river.

Users of the Instream Flow Incremental Methodology CTFIM) commonly assume that there is a positive linear relationship between available habitat (WUA) and stream fish biomass. However, several studies have shown a lack cf correlation between WUA and biomass. Such poor relationships may occur if other factors limit fish abundance. Food availability is a potentially important factor limiting abundance of stream fishes and can affect blomass by influencing fish condition (individual weight). I collected rainbow trout (Oncorhynchus mykiss) exposed to different levels of invertebrate-drift density to determine if condition was greater where food was more abundant. I also examined whether size-selective predation and gut fullness varied with drift density. Size-selective predation was not related to drift density. However, condition and gut fullness were both significantly correlated with drift density. Furthermore, changes in drift density appeared to have a stronger influence on small-trout condition than large-trout condition. The results of this study and others support the contention that the reliability of the IFIM might be improved if food availability were incorporated into models.

The study of the cutthroat trout in the Logan River drainage was initiated in cooperation with the Utah Cooperative Wildlife Research Unit and the Utah Fish and Game Department during May of 1948. The first field work began that month. The taking of fish was terminated in November, 1949, although several trips were made into the study area as late as January, 1950.

Comprehensive population studies in the field of fisheries are in great demand. Many of our fishable waters are being changed, and we need to be able to predict the results of these habitat alterations. We must know how to include beneficial modifications in readjustments of habitat in order to create a fishery or prevent destruction of an existing one. The acceptable situations for good fish production in large mountain streams are not well-knowno A fishery can be properly managed only if the manager has sufficient knowledge of the carrying capacity of the habitat, the survival and mortality of the population, and the movements of the fish within the population. My study is an attempt to answer some of these questions about the self-sustaining populations of brown trout (Salmo trutta fario Linnaeus) and mountain whitefish (Prosopium williamsoni Girard) in a 5-mile section of Logan River, Utah.

Nine hemoglobins have been isolated from the blood of cutthroat trout. All nine hemoglobins bind oxygen cooperatively and appear to be tetramers with molecular weights of -64,000. The oxygen equilibria and subunit structures of the purified hemoglobins were studied. In addition, the red blood cells of cutthroat trout were examined for the presence of ATP and GTP, which are known to be physiological modulators of hemoglobins in fishes. Five hemoglobins with isoelectric points from 9.1 to 7.0 are classified as cathodal hemoglobins. These five hemoglobins have identical oxygen binding properties by the criteria tested. All have oxygen equilibria which are unaffected by protons and ATP and essentially independent of temperature, with overall enthalpies of oxygenation ~0. Two hemoglobins with isoelectric points near 6.5, classified as a nodal hemoglobins, have oxygen binding properties distinctly different from those of the cathodal hemoglobins. Both are characterized by a Root effect, displaying non-cooperative oxygen binding and low oxygen affinity at pH 6.2. ATP causes a large reduction in the oxygen affinity without affecting the cooperativity of oxygen binding. GTP has a similar but slightly larger effect on both hemoglobins. The oxygen equilibria of the anodal hemoglobins are temperature dependent, with the oxygen affinity being reduced as temperature increases. The overall enthalpy of oxygenation is -14 kcal/mol for both hemoglobins. The two remaining hemoglobins represent only a small percentage of the total hemoglobin. These hemoglobins are tentatively designated as embryonic hemoglobins based primarily on a comparison of their properties to those observed for hemoglobins from newly-hatched rainbow trout (Iuchi, I. (1973) Comp. Biochem. Physiol. 44B, 1087-1101). These two hemoglobins have isoelectric points near 5.9 and oxygen binding properties similar to those of the cathodal hemoglobins. With the possible exception of one of the embryonic hemoglobins (for which globins were not obtained), all the hemoglobins are composed of two different types of globin chains. Six are ∝_2 β_2 tetramers, while two of the cathodal hemoglobins are hybrid tetramers of the type 〖∝∝'β〗_2 and ∝∝'ββ. Red blood cells of cutthroat trout contain both ATP and GTP, suggesting that, in contrast to rainbow trout, both nucleotides may be important physiological modulators of hemoglobin oxygen affinity in this fish.

Effective conservation strategies for imperiled species require an understanding of processes that influence fitness throughout the organism's life cycle and across the range of habitats needed to complete that cycle. I evaluated factors that affect population viability of bull trout Salvelinus confluentus, a threatened freshwater char species, throughout individual life stages and over the entire life cycle. I assessed the relationship between bull trout egg incubation success and environmental variables. Egg survival was negatively related to the percent of fine sediment in redds and positively related to hydraulic conductivity and the strength of downwelling. Next, I quantified juvenile bull trout survival rates and described movement patterns for this life stage. Juvenile bull trout emigrated from natal headwaters into larger rivers throughout the entire year and across a range of sizes. Estimates of juvenile survival rates improved dramatically when emigration was incorporated into the analysis. I integrated my observations of bull trout survival, growth, and movement to create a life-cycle model, which I used to better understand how populations respond to changes in specific demographic rates. Bull trout populations were particularly sensitive to changes in juvenile growth and survival. The relative effect of changes to fertility rates and adult survival varied depending upon whether a population was composed primarily of large, migratory, or smaller, resident individuals. Dispersal helped to lower the probability of extinction for small or declining populations when neighboring populations were stable. My research demonstrates that bull trout require access to habitats throughout entire watersheds to maintain population viability. My results suggest that limiting anthropogenic sources of fine sediment and maintaining areas of channel complexity that promote downwelling can be important for bull trout embryo survival. Management decisions should also consider the diverse behavior of juvenile bull trout and the wide range of habitat they use. Additionally, connectivity between populations is likely to be important for declining populations to persist. The diversity of life-history strategies expressed by bull trout helps maintain demographic stability within and among populations. As such, preservation of habitat integrity and full life-history diversity is imperative for conservation and recovery of bull trout populations range-wide.

The purposes of this paper are threefold: 1) To provide a justification for the increased use of native plants in mountain land development, not only in northeastern Utah, but in the entire western United States. 2) To investigate and delineate what the physical needs of a plant materials list are. 3) To provide a nearly comprehensive list of basically unused plants native to northeastern Utah and to highlight their landscaping potentials based on the earlier investigation. Also touched upon, to help landscape architectural students and professionals alike, are two cursory case studies and a chapter which deals briefly with the problems of nursery supply of native plants and the potential and future research.

Due to the significant threats posed by nonnative fish species worldwide, it is important to understand how life-history strategies of individual species interact with environmental conditions to explain the success or failure of nonnative fish invasions. Brown trout are prolific invaders, but often exhibit upstream distributional limits in Intermountain West streams, potentially due to a maladaptive reproductive life-history strategy influenced by hydrologic conditions in high-elevation areas. We used redd counts, egg survival experiments, and temperature modeling to investigate the reproductive life-history strategy of brown trout and its potential for success along an elevational stream gradient. We documented brown trout spawning in stream reaches at elevations higher than where we typically encounter brown trout during summer electrofishing surveys, indicating the potential for upstream invasion. We observed a decline in egg survival at higher elevation, cooler water sites, but did not document complete recruitment failure at these sites, again indicating the potential for successful invasion at this life-stage. Temperature data indicate that during most years, incubating brown trout eggs would likely fail to emerge from the gravel prior to peak spring flows in these high-elevation stream reaches, suggesting that damaging spring floods may cause significant egg and sac-fry mortality at high elevations, and may determine invasion success in these areas. Our results highlight the importance of identifying specific mechanisms of recruitment failure in order to better predict nonnative fish invasions in the future.

Movement patterns and habitat use of Bonneville cutthroat trout (Oncorhynchus clarki Utah) in tributaries of the Logan River watershed are greatly affected by habitat alterations created by North American Beaver (Castor canadensis). Evaluation of cutthroat trout habitat use in these watersheds is also complicated by biotic interactions with invasive brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis). My objectives in this thesis were to 1.) Evaluate the passage of beaver dams by each trout species in the Temple Fork watershed and 2.) Evaluate the habitat use of cutthroat trout in the presence of brown trout and brook trout over a range of spatial scales. To address these objectives, 1381 trout were fitted with passive integrated transponder tags. Their locations were recorded using a combination of annual capture/recapture surveys, stationary in-stream antennas, and monthly continuous mobile antenna surveys. To address objective 1, fish were located above and below 22 beaver dams to establish whether fish passed dams and to identify downstream and upstream passage; 187 individual trout were observed making 481 passes of all 22 beaver dams. Native Bonneville cutthroat trout passed dams more frequently than both non-native brown trout and brook trout. It was determined that spawning timing affected seasonal changes in dam passage for each species. Physical characteristics of dams such as height and upstream location affected the passage of each species. Movement behaviors of each trout species were also evaluated to help ex- plain dam passage. These data suggest beaver dams are not acting as barriers to movement for cutthroat and brook trout but may be impeding the movements of invasive brown trout. To address objective 2, a hierarchical classification of stream habitat was created using the River Styles framework. The River Styles framework not only establishes a relationship between habitats at different scales, but also attempts to understand the processes that create and maintain those habitats. The location of each fish observation was associated with habitats at the stream, landscape unit, River Style, and geomorphic unit levels. Habitat use of each species of fish was evaluated at each spatial scale using all fish observations over the four-year study period. Hotspot locations, or locations used consistently by a species of fish consistently through time, were also evaluated across the entire study period and over each year. It was found that brook trout almost exclusively use the beaver ponds and beaver-altered habitats in Spawn Creek. Brown trout were not found in the upper- most parts of both Spawn Creek and Temple Fork. They were also found more than the other species in pools created by bedrock or man-made control features, suggesting that they select highly stable habitats. Cutthroat trout were found more than brown trout in beaver-altered habitats and lateral scour pools, suggesting that they select more dynamic, naturally occurring habitats.

Stream restoration has become a popular management tool for attempting to increase and/or restore fish populations by improving habitat. A section of the Strawberry River, Utah recently underwent a stream restoration project, where the main goals of the project included increasing spawning activity, rearing potential, and resident populations of Bear Lake cutthroat trout Oncorhynchus clarkia utah. The impact of the restoration project on cutthroat trout was investigated by first characterizing preferred habitat for different life stages, investigating habitat as a limiting factor in the system, and then assessing the quality of available habitat by comparing restored/unrestored sections of stream and pre-restoration/post-restoration of the same sections of stream. Results indicated cutthroat trout in the Strawberry River preferred faster water velocities, shallower depths, moderate substrates sizes, and riffle habitat types for spawning. In contrast, juvenile and adult life stages preferred deeper sections of stream, the presence of cover, and pool habitat types. Limiting factor analyses suggested spawner abundance may be limiting in the Strawberry River and maximum daily temperatures during the summer may be the strongest limiting habitat factor for juvenile and resident adult cutthroat trout. Restoration generally appeared to initiate a shift towards more favorable habitat, especially in terms of increasing near-bed velocity and increasing the proportion of preferred substrate sizes for spawning, and increasing the percentage of pools for juvenile and resident adult life stages. The potential benefits of the restoration remained somewhat ambiguous, a result of relatively small differences observed between study reaches, limited pre-restoration data, high spatial and inter-annual variability within and among control study reaches, and the inherently delayed reaction of ecological responses to physical changes from restoration. However, these issues can be resolved through continued monitoring. Long-term monitoring would allow for the accounting of natural variability to further tease out differences resulting from restoration and differences resulting from natural fluctuations. Additional monitoring would also capture long-term responses, which has the potential to be significant considering the relatively slow response of riparian vegetation to restoration. This study also provides a baseline dataset and template for future long-term monitoring efforts.