Animal Sciences Commons^™

The Effect Of Dietary Thiaminase On Cardiac Function And Morphology In Lake Trout (Salvelinus Namaycush), Peter Baker

Electronic Thesis and Dissertation Repository

Thiamine deficiency from the consumption of invasive, high-thiaminase prey fishes is considered to be a major barrier for lake trout restoration in the Great Lakes. In fishes, an understudied aspect of thiamine deficiency is its effect on cardiac function. I examined the effects of dietary thiaminase on cardiac function and morphology in lake trout, specifically as they relate to thermal tolerance. Two hatchery strains of lake trout (Seneca and Slate) were raised on a control or thiaminase diet for nine months. The thiaminase diet was associated with significant ventricle enlargement, impaired cardiac function, and reduced thermal tolerance; these effects were …

Using Spatial Methods To Analyse Anthropogenic Predation Risk And Movement Ecology Of White-Tailed Deer (Odocoileus Virginianus), Rhiannon D. Kirton

Electronic Thesis and Dissertation Repository

Hunting has been used as a central tool by wildlife managers to maintain populations of game species, however, we still lack a good understanding of exactly how hunting influences deer biology. Technological advances in GPS data over the last two decades now enable us to perform more detailed analysis on the effects of human hunters on wildlife populations. This research explores the spatial ecology of hunters and White-tailed deer in the Cross Timbers ecoregion of Oklahoma. Using new statistical methodologies to analyse simultaneous GPS tracking data on deer and hunters to study their spatial interactions. The results show how new …

Diversity And Drivers Of Oribatid Mites (Acari: Oribatida) In Boreal Peatlands, Carlos Rafael De Araujo Barreto

Electronic Thesis and Dissertation Repository

Boreal peatlands are important ecosystems for carbon cycling, storing 1/3 of the world’s terrestrial carbon in only ~3% of the globe, making them a key component of potential mitigation strategies in response to global climate warming. Experiments have shown that warming can affect plant and microbial communities in ways that potentially shift peatlands from carbon sinks to sources. Soil food webs, including the microarthropod community, are key in carbon cycling but are relatively understudied both in peatlands and under experimental warming. My research capitalized on a large-scale experimental field manipulation of warming in two contrasting peatland sites in Northern Ontario, …

Food Caching Decisions In Canada Jays (Perisoreus Canadensis), Robert J. Martin

Electronic Thesis and Dissertation Repository

Food scarce periods pose serious challenges for birds, particularly when those periods coincide with demanding life history stages such as overwintering. For resident birds in the Northern hemisphere, resource scarcity typically occurs simultaneously with winter conditions. In order to combat these compounded stressors, some species cache food to ensure a reliable supply of resources. Food caching is the storing of food items for subsequent retrieval and consumption after some delay. Canada Jays (Perisoreus canadensis) are year-round residents of the North American boreal forest and some high elevation areas in the United States, and cache food to combat resource …

Effects Of Dietary Thiaminase On Reproductive Traits In Three Populations Of Atlantic Salmon Targeted For Reintroduction Into Lake Ontario, Kimberly T. Mitchell

Electronic Thesis and Dissertation Repository

The fitness of reintroduced salmonids in Lake Ontario can be reduced by high levels of thiaminase in exotic prey consumed at the adult stage. If sensitivity to dietary thiaminase differs among the three Atlantic salmon populations targeted for reintroduction into Lake Ontario, this could significantly influence their performance. I quantified the effects of experimental diets that contained high or low (control) levels of thiaminase on thiamine concentrations, survival, growth rate, and reproductive traits (sperm and egg quality) in Atlantic salmon from the three candidate source populations. Fish that consumed the high-thiaminase diet had comparable growth rates, but lower survival and …

Hitchhiker's Guide To Migration: Effects Of Experimental Parasitic Infection And Other Immune Challenges On Migratory Traits Of Sparrows, Tosha R. Kelly

Electronic Thesis and Dissertation Repository

Seasonal migration exposes animals to a variety of habitats and parasites, and if infected migratory birds migrate successfully there is great potential for birds to transport infectious diseases long distances. Our current understanding of whether birds contribute to the spread of disease relies upon observational field studies that are limited in their ability to discern cause from effect. Using captive and field-based experiments for my doctoral research, I answered three research questions: (1) are nocturnal migratory restlessness (Zugunruhe) and body condition affected by mounting an acute phase immune response during migration; (2) what are the impacts of parasitic …

The Effect Of Shelter Availability On Foraging In Atlantic Salmon (Salmo Salar), Christian A. Therrien

Electronic Thesis and Dissertation Repository

Shelter is an environmental feature that provides protection from danger and its use is an important anti-predator behavior for juvenile Atlantic salmon (Salmo salar). However, how shelter availability influences the foraging of these fish in the wild is not well documented. I predicted that juvenile Atlantic salmon would alter their foraging behavior in a low shelter environment and that this effect would differ between individuals from two populations that are targeted for reintroduction into Lake Ontario. I measured the foraging activity of juvenile Atlantic salmon from the two populations while they were held in pens in a Lake …

Modelling Walleye Population And Its Cannibalism Effect, Quan Zhou

Electronic Thesis and Dissertation Repository

Walleye is a very common recreational fish in Canada with a strong cannibalism tendency, such that walleyes with larger sizes will consume their smaller counterparts when food sources are limited or a surplus of adults is present. Cannibalism may be a factor promoting population oscillation. As fish reach a certain age or biological stage (i.e. biological maturity), the number of fish achieving that stage is known as fish recruitment. The objective of this thesis is to model the walleye population with its recruitment and cannibalism effect. A matrix population model has been introduced to characterize the walleye population into three …

Evolutionary Genetic Aspects Of Host Association In Generalist Ectoparasites, Benoit Talbot

Electronic Thesis and Dissertation Repository

Despite the use of the host for dispersal by most parasite species, the extremely loose relationship typical between highly mobile hosts and generalist ectoparasites may lead to very different gene flow patterns between the two, leading in turn to different spatial genetic structure, and potentially different demographic history. I examined how similar gene flow patterns are between Cimex adjunctus, a generalist ectoparasite of bats present throughout North America, and two of its key bat hosts. I first analyzed the continent-scale genetic structure and demographic history of C. adjunctus and compared it to that of two of its hosts, the …

The Mixed Source Chinook Salmon Fishery In Lake Huron: A Comparison Of Spawning And Foraging Habitat Use By Naturalized And Hatchery Fish, Stephen A.C. Marklevitz

Electronic Thesis and Dissertation Repository

Chinook salmon (Oncorhynchus tshawytscha) were introduced into the Great Lakes to restore top-down control of the food web and create new recreational fisheries. Soon after introduction, naturalized spawning populations became established, and with continued stocking of hatchery fish, created a mixed source fishery. My research provides new ecological information about the contributions of naturalized fish to the mixed source Chinook salmon fishery in Lake Huron. I examined spawning and foraging habitat use by naturalized and hatchery Chinook salmon using multiple methods to identify sources of individual fish (external tags, hatchery fin clips, and otolith microchemistry). In the Sydenham …

Fear Of Predators Compromises Parental Care And Juvenile Survival In A Songbird, Philip Blair Dudeck

Electronic Thesis and Dissertation Repository

Predators kill, but the risk of being killed is also a powerful force affecting survival because scared prey eat less, thereby increasing the likelihood of starvation. Young of most animals are extremely vulnerable to predators and may alter their behaviour to limit detection. I investigated the previously unexplored effects that predation risk has on the behaviour of newly fledged offspring and their parents, and the impact this has on offspring survival. I manipulated predation risk using sound and found that parent song sparrows reduced their feedings, providing 60% less food overall. Critically, not only did this parental response estimate survival …

Fish Out Of Salt Water: Smoltification In Subyearling Chinook Salmon From The Laurentian Great Lakes, Steve Sharron

Electronic Thesis and Dissertation Repository

The timing of smoltification in juvenile anadromous salmonids is important to ensure individuals match their preparedness with their migration timing and the optimal conditions in the environment. I performed the first study of smoltification in adfluvial juvenile Chinook salmon naturalized in the Laurentian Great Lakes. In a hatchery study, I found that juveniles from one of these populations have similar patterns of smoltification timing to individuals from anadromous populations. Their Na⁺/K⁺ ATPase activity, a common indicator or smolt status, peaked at 7.7 μmoles ADP/mg protein/hour on July 1 in freshwater. During the peak period, individual body size …

Ecological And Evolutionary Interactions Between Song Sparrows (Melospiza Melodia) And Their Bloodborne Parasites, Yanina Sarquis-Adamson

Electronic Thesis and Dissertation Repository

Local adaptation is the result of natural selection operating at a local scale, such that trade-offs in fitness across different environments result in individuals having higher fitness in their place of origin than when transported into a foreign environment. Populations may become locally adapted to features of their abiotic environment, or in the case of coevolutionary arms races between hosts and parasites, to other species comprising their biotic environment. If host populations are adapted to their local (sympatric) parasites, or conversely if parasites are adapted to their local hosts, then interactions with local parasite strains may influence the fitness consequences …

Identifying The Role Of Non-Native Species In The Enhanced Trophic Transfer Of Mercury In The Food Web Of Lake Erie, A North American Great Lake, Kaylin M.S. Liznick

Electronic Thesis and Dissertation Repository

Increasing mercury (Hg) concentrations in top predatory fish is concerning for human and wildlife health. This study examined the amount of Hg available to the food web of Lake Erie, and explored the role that two recently established non-native species, dreissenid mussels and round goby, have played in the trophic transfer of Hg to sport fish. A comprehensive sampling of total Hg (THg) and methylmercury (MeHg) within Lake Erie water, sediment and seston with high temporal and spatial resolution describes environmental concentrations. In addition, biotic THg and MeHg are quantified in benthic invertebrates and three fish species. A steep spatial …

Environmental Factors Influencing Spring Migration Chronology Of Lesser Scaup (Aythya Affinis), Taylor A. Finger

Electronic Thesis and Dissertation Repository

Weather likely affects the timing and rate of migration by waterfowl to their breeding grounds. I hypothesized that timing of migration by lesser scaup during spring is affected by annual variation in temperature, precipitation and ice cover. I used satellite telemetry data, waterfowl survey data and corresponding weather data to evaluate competing models that explained variation in timing and rate of migration by lesser scaup. Timing of spring migration occurred earlier and faster when lesser scaup encountered warmer temperatures and greater precipitation, both of which are known to influence thermoregulation and habitat availability for waterfowl. Migration chronology of lesser scaup …

The Effects Of Extrinsic And Intrinsic Factors On The Reproductive Biology Of Male Western Bean Cutworm Moths, Striacosta Albicosta (Smith), Jasmine Farhan

Electronic Thesis and Dissertation Repository

Pheromones are important in the mating systems of nocturnal moths as they are relied on to find and/or assess mates. Extrinsic and intrinsic factors have been shown to influence female emission of and male response to pheromones. My thesis focuses on the reproductive biology of males of the western bean cutworm, Striacosta albicosta, a pest of beans and corn that has recently began expanding its range eastwardly. I conducted a field-based experiment to determine the effects of extrinsic factors on pheromone trap catches. I also conducted laboratory based mating experiments to determine the effect of male age on acceptance …

Interactions Among Biotic And Abiotic Controls Of Carbon Dynamics In A Global Change Field Experiment, Eric R D Moise

Electronic Thesis and Dissertation Repository

Climate warming and increased atmospheric nitrogen deposition may substantially influence biosphere C cycling over the next century by altering ecosystem processes such as productivity and decomposition. Field studies are commonly used to explore plant responses to global change, although the underlying mechanisms can be difficult to isolate owing to the lack of control of factors such as plant-animal interactions. Ultimately, indirect effects via herbivore and detritivore responses may feedback to influence plant responses to the experimental treatments. The goal of this thesis was to explore interactions among biotic and abiotic drivers of carbon dynamics within the context of experimental warming …

Assessing And Analyzing Bat Activity With Acoustic Monitoring: Challenges And Interpretations, Amanda M. Adams

Electronic Thesis and Dissertation Repository

Acoustic monitoring is a powerful technique for learning about the ecology of bats, but understanding sources of variation in the data collected is important for unbiased interpretation. The objectives of this dissertation were to investigate sources of variation in acoustic monitoring and make recommendations for acoustic survey design and analysis. I addressed this goal in three ways: i) variation resulting from differences in bat detectors, ii) methods for objective identification of peak activity, and iii) the use of stationary transects to address within-site spatial variation.

First, I compared variation of detection of echolocation calls among commonly available bat detectors and …

Dynamics Of Fat And Lean Mass In Refuelling Migrant Passerines Measured Using Quantitative Magnetic Resonance, Lisa V. Kennedy

Electronic Thesis and Dissertation Repository

Although fat deposition during stopover in migrating passerine birds has been extensively studied, changes in lean mass during refuelling are not well understood. I used quantitative magnetic resonance (QMR) analysis to measure the deposition of fat and lean mass for both recaptured and single capture migrant passerines in spring and fall at Long Point, Ontario. Both the recapture analysis and single capture regression analysis indicated a substantial contribution of lean mass to overall increases in total body mass. Some of the variation in the relative deposition of fat and lean mass was explained by sex, age and season. I then …

Introduced Chinook Salmon (Oncorhynchus Tshawytscha) In Lake Huron: Do They Spawn At The Right Time?, Meghan T. Gerson

Electronic Thesis and Dissertation Repository

Chinook salmon (Oncorhynchus tshawytscha), following their introduction to the Great Lakes, have successfully colonized many tributaries. Under the hypothesis that colonization success is facilitated by intrinsic factors (i.e., preadaptation), I predicted that patterns of reproductive timing in an introduced population would show similarities with those in their native range. To test this prediction, attributes of reproductive timing were characterized in Chinook salmon from the Sydenham River, Ontario. In their native range, female Chinook salmon exhibit a seasonal decline in reproductive lifespan, a decline in fat stores, low egg retention at death (< 0.5%), and spawning at temperatures below 12.8°C. In contrast, Sydenham River Chinook salmon showed no seasonal decline in reproductive lifespan or fat stores and nineteen of twenty females had egg retention greater or equal to 0.5%. Also, many individuals (30%) spawned when water temperatures exceeded 12.8°C. Thus, individuals do not appear to be pre-adapted in this system.