307 research outputs found
Comparing metabolic rate estimates of two similar salmonids: Salvelinus confluentus and Salvelinus fontinalis
No full textBull Trout (Salvelinus confluentus) occur in many major watersheds in northwestern North America and are identified as “Threatened” or a “Species of Special Concern” in both Canada and the United States. Non-native fishes, including Brook Trout (Salvelinus fontinalis), are one assumed major contributor to declines of Bull Trout populations. Further understanding of how introduced species are affecting Bull Trout populations may help with their recovery. Metabolic rate is an estimate of the amount of energy being used by an organism, and one of the common ways of estimating metabolic rate in fish is through respirometry. In the following research chapters, I conducted intermittent-flow respirometry experiments both in a laboratory setting and a field setting to compare physiological performance via standard metabolic rate (SMR), maximum metabolic rate (MMR) and aerobic scope (AS) of Bull Trout and Brook Trout across a range of ecologically relevant temperatures. The temperatures tested are found in the habitat both species currently occupy, as well as temperatures that may be seen in future climate scenarios. Brook Trout tested in Chapter 2 maintained a relatively stable AS across the range of temperatures tested (5, 10, 15, 20, 23°C) and appear to be thermal generalists, well adapted to live in various thermal environments. Brook Trout showed a peak in AS at 15°C, increasing SMR with temperature, and a peak in MMR estimates between 15 and 20°C. Results from Chapter 3 revealed that wild juvenile Bull Trout and Brook Trout have comparable SMR, MMR, and AS when living in sympatry in the natural environment, at least at the temperatures tested (~3°C and ~10°C). Brook Trout have historically been seen as a major threat to Bull Trout populations based on prior studies that have looked at interactions between the species and generally found an advantage for Brook Trout over Bull Trout. However, the results from this study showed similar metabolic rates in both species living in sympatry. The results further suggest that Brook Trout may not have the physiological or temperature related advantages that are expected, at least in regards to aerobic scopeOctober 202
Metabolic rate and critical thermal maximum CT(max) estimates for westslope cutthroat trout, Oncorhynchus clarkii lewisi
No full textGlobal warming is changing the thermal habitat of cold-water freshwater fishes, which can lead to decreased fitness and survival and cause shifts in species distributions. The Alberta population of westslope cutthroat trout (Oncorhynchus clarkii lewisi) is listed as ‘Threatened’ under the Canadian Species at Risk Act. The major threats to the species are the alteration in habitat and water flow, competition and hybridization with non-native trout species and climate change. Here, we conducted (i) intermittent-flow respirometry experiments with adult native westslope cutthroat trout and non-native rainbow trout (Oncorhynchus mykiss) and (ii) critical thermal maximum experiments (CT(max)) with adult westslope cutthroat trout to obtain valuable input data for species distribution models. For both species, standard metabolic rate (SMR) was lower at 10°C compared to 15°C and westslope cutthroat trout had higher SMR than rainbow trout. Although there were inter-specific differences in SMR, forced aerobic scope (using a standardized chase protocol) was different at 10°C, but no significant differences were observed at 15°C because of relative smaller differences in maximum metabolic rate between the species. CT(max) of westslope cutthroat trout acclimated to 10°C was 27.0 ± 0.8°C and agitation temperature was 25.2 ± 1.0°C. The results from this study will inform and parametrize cumulative effects assessments and bioenergetics habitat modelling for the recovery planning of the species
Acute Sedentary Behaviour and Markers of Cardiometabolic Risk: A Systematic Review of Intervention Studies
No full textNorth Americans spend half their waking hours engaging in sedentary behaviour. Although several recent interventions suggest that short bouts of uninterrupted sedentary behaviour may result in acute increases in cardiometabolic risk, this literature has not been reviewed systematically. This study performed a systematic review of the impact of uninterrupted sedentary behaviour lasting ≤7 days on markers of cardiometabolic risk (insulin sensitivity, glucose tolerance, and fasting insulin, glucose, and lipid levels) in humans. Interventions were identified through systematic searches of Medline and Embase and screened by 2 independent reviewers. A total of 25 interventions were identified that examined the impact of imposed sedentary behaviour on biomarkers of interest. The majority of these studies focused on healthy young men, with very little identified research on females or other age groups. We found consistent, moderate quality evidence that uninterrupted sedentary behaviour ≤7 days results in moderate and deleterious changes in insulin sensitivity, glucose tolerance, and plasma triglyceride levels. In contrast, there is inconsistent, very low-quality evidence linking uninterrupted sedentary behaviour with changes in insulin, glucose, and HDL- and LDL-cholesterol levels. These findings suggest that uninterrupted bouts of sedentary behaviour should be avoided in order to prevent or attenuate transient increases in metabolic risk
Comparing whole body and red muscle mitochondrial respiration in an active teleost fish, Brook Trout (Salvelinus fontinalis)
No full textUnderstanding how metabolic costs change in relation to increasing temperature under future climate changes is important to predict how ectotherms will be affected across the globe. In fish, whole body respiration is traditionally used to estimate aerobic performance via an organism’s minimum and maximum oxygen consumption rates. However, mitochondria play a crucial role in the aerobic cascade and may be a useful surrogate of aerobic performance. To test if whole body oxygen consumption and mitochondrial capacity are correlated, we estimated whole body metabolic and mitochondrial respiration rates (using permeabilized red muscle fibres) in Brook Trout (Salvelinus fontinalis (Mitchill, 1814) at 10, 15, and 20 °C. Standard metabolic rate increased with acclimation temperature while maximum rates were less sensitive. All mitochondrial respiration rates increased with acclimation temperature, suggesting that red muscle mitochondrial preparations may correlate to the minimal metabolic demands in this species. When expressed as relative rates of electron flow, the red muscle fibres showed no effect of temperature on mitochondrial coupling efficiency. However, there was a pattern of declining capacity to augment respiration via complex II with increasing temperature with a concomitant increase in the capacity of the phosphorylating system relative to maximal rates of mitochondrial electron flow.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Metabolic performance and thermal preference of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi and non-native trout across an ecologically relevant range of temperatures
No full textThe physiology and behaviour of fish are strongly affected by ambient water temperature. Physiological traits related to metabolism, such as aerobic scope (AS), can be measured across temperature gradients and the resulting performance curve reflects the thermal niche that fish can occupy. We measured AS of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) at 5, 10, 15, 20, and 22C and compared temperature preference (Tpref) of the species to non-native Brook Trout, Brown Trout, and Rainbow Trout. Intermittent-flow respirometry experiments demonstrated that metabolic performance of Westslope Cutthroat Trout was optimal at ~15 C and decreased substantially beyond this temperature, until lethal temperatures at ~25 C. Adjusted preferred temperatures across species (Tpref) were comparatively high, ranging from 17.8-19.9 C, with the highest Tpref observed for Westslope Cutthroat Trout. Results suggest that although Westslope Cutthroat Trout is considered a cold-water species, they do not prefer or perform as well in cold water (≤ 10C), thus, can occupy a warmer thermal niche than previously thought. The metabolic performance curve (AS) can be used to develop species‐specific thermal criteria to delineate important thermal habitats and guide conservation and recovery actions for Westslope Cutthroat Trout.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Ruins of the past: the use and perception of abandoned structures in the Maya lowlands
No full textTravix W. Stanton and Aline Magnoni, editors.Includes bibliographical references and index.From the Formative to the present, Maya peoples have continuously built, altered, abandoned, and re-used structures, imbuing them with new meanings at each transformation. Ruins of the Past is the first volume to focus on how previously built structures in the Maya Lowlands were used and perceived by later peoples, exploring the topic through concepts of landscape, place, and memory.--Book jacket.Foreword / Wendy Ashmore -- Places of remembrance: the use and perception of abandoned structures in the Maya lowlands / Travis W. Stanton and Aline Magnoni -- Forgotten structures, haunted houses, and occupied hearts: ancient perspectives and contemporary interpretations of abandoned sites and buildings in the Mirador Basin, Guatemala / Richard D. Hansen, Wayne K. Howell, and Stanley P. Guenter -- The transformation of abandoned architecture at Piedras Negras / Mark B. Child and Charles W. Golden -- Structure abandonment and landscape transformation: examples from the Three Rivers region / Lauren A. Sullivan [and others] -- Manipulating memory in the wake of dynastic decline at El Perú-Waka': termination deposits at abandoned structure M13-1 / Olivia C. Navarro Farr, David A. Freidel, and Ana Lucía Arroyave Prera -- Establishing and reusing sacred place: a diachronic perspective from Blackman Eddy, Belize / M. Kathryn Brown and James F. Garber -- Anatomy of a post-collapse society: identity and interaction in early postclassic Copán / T. Kam Manahan -- Landscape transformations and changing perceptions at Chunchucmil, Yucatán / Aline Magnoni, Scott R. Hutson, and Travis W. Stanton -- Edzná: a lived place through time / Antonio Benavides C. -- Memories, meanings, and historical awareness: post-abandonment behaviors among the lowland Maya / Marcello A. Canuto and Anthony P. Andrews -- Afterword / Denise Fay Brown
Arthur William Upfield: a biography
No full textThis dissertation is an exhaustive account of the life and work of Arthur William Upfield (1890-1964). It is presented as a critical biography and narrates the life of the writer, in his socio-cultural milieu, from birth. It also positions Upfield as a writer who dealt with issues of Aboriginality at a time when this was a singularly polemical subject. My work is informed by the theory of Zygmunt Bauman and others and is posited in the context of late-modern biography theory.
English-born, Upfield arrived in Australia in 1911 and took work in the bush, serving overseas with the Australian army at the outbreak of World War I and marrying an Australian army nurse in Egypt. Returning with his wife and son to Australia in 1921 he intermittently carried his swag until he was employed patrolling the Western Australian number 1 rabbit-proof fence for three years to 1931. By that time he had published four novels, including two crime novels featuring his fictional creation, the part-Aboriginal, part-European, Detective-Inspector Napoleon Bonaparte ('Bony'), arguably the first fully-developed character in Australian popular fiction.
Leaving the fence, Upfield settled with his family in Perth and wrote full-time until joining the Melbourne Herald in 1933. Retrenched, he resumed career writing to be further interrupted by a war-time intelligence posting in 1939. In 1943 the first Bony mysteries were published in America, where Upfield's critical success was maintained until his death. In 1945 he left his wife for Jessica Uren, to whom he remained devoted.
Upfield's in all twenty-nine Bony novels, many of which have been translated across eleven languages, afforded him notable success both at home and abroad, in good part due to his descriptive gifts and the uniqueness of his fictional character, the part-Aboriginal Bony
Life through a wider scope: Brook Trout (Salvelinus fontinalis) exhibit similar aerobic scope across a broad temperature range
No full textBrook Trout (Salvelinus fontinalis) have been widely introduced throughout the world and are often considered as direct competitors with native salmonid species. Metabolic rate is one metric we can examine to improve our understanding of how well fish perform in different habitats, including across temperature gradients, as metabolism can be directly influenced by environmental temperatures in ectotherms. We estimated the standard metabolic rate, maximum metabolic rate and aerobic scope of lab-reared juvenile Brook Trout (~1 year) using intermittent-flow respirometry across a range of temperatures (5-23°C) likely experienced in the wild. We included a diurnal temperature cycle of ± 1.5°C for each treatment temperature to simulate temporal variation observed in natural waterbodies. Standard metabolic rate and maximum metabolic rate both increased with acclimation temperature before appearing to plateau around 20°C, while mass specific aerobic scope was found to increase from 287.25±13.03 mg O2·kg-1·h-1 at 5°C to a mean of 384.85±13.31 mg O2·kg-1·h-1 at 15°C before dropping at higher temperatures. Although a slight peak was found at 15°C, the generally flat thermal performance curve for aerobic scope suggests Brook Trout are capable of adjusting to a relatively wide range of thermal regimes, appearing to be eurythermal, or a thermal generalist at least for salmonids. The ability of this population to maintain similar physiological performance across a wide range of temperatures may help explain why Brook Trout succeed in a variety of different thermal habitats.This work was supported by Fisheries and Oceans Canada Species at Risk Program and Strategic Program for Ecosystem Research; Dr. J. R. Treberg funding provided by NSERC grant #2018-06052
- …
