Biological Sciences - Theses, Dissertations, and other Required Graduate Degree Essays

Receive updates for this collection

The role of science in wildlife management: From grizzly bears in British Columbia to hunted species across Canada and the United States

Author: 
Date created: 
2017-11-09
Abstract: 

Agencies often claim, and societies often assume, a scientific basis to natural resource management. Science does have potential for informing management, for example by providing rigorous approaches for advancing understanding of managed systems and predicting management outcomes. However, the extent to which science informs real-world management is rarely tested. I offer a simple conceptualization of the management process and show how it identifies multiple focal points for testing the scientific basis of management systems. I illustrate this first with hunt management of grizzly bears (Ursus arctos horribilis) in British Columbia (BC), Canada. I find that the number of kills often exceeds agency-defined sustainable limits, associated with unaddressed uncertainty. I refine approaches from fisheries management to illustrate how uncertainty could be buffered against when setting hunting targets. I then assess the ecology of grizzly bear-human conflict in BC. I find limited support for the common hypotheses that conflict- and hunt-related kills reduce subsequent conflict rates, despite both being management responses. Instead, I find that food availability is correlated with conflict rates, suggesting that more effective management might focus on protecting natural foods. I then focus on protected areas. I use a spatial capture-recapture approach to characterize spatial patterns of grizzly bears in the Great Bear Rainforest and find that existing protected areas do no better, or worse, than random at capturing areas with high densities of grizzly bear activity centres, suggesting protected areas shortcomings. Finally, I explore the process of management itself across Canada and the USA, where hunting is guided by a model which asserts that management is ‘science-based’. However, in 667 management plans from agencies across the continent, I find key hallmarks of science (evidence, measurable objectives, transparency, independent review) largely lacking, raising doubts about a scientific basis. These chapters illustrate how shortcomings at various stages of the management process might undermine the ostensible scientific basis of an overall management system. I argue that assessing the role of science in management is important not only for enabling the evolution of management systems, but also for honest and transparent governance, by clarifying where science begins and ends in decision-making.

Document type: 
Thesis
Senior supervisor: 
John Reynolds
Chris Darimont
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) Ph.D.

Microplastic pollution in the Arctic Ocean: Assessing ingestion and potential health effects in Calanus and Neocalanus copepods

Author: 
Date created: 
2019-08-16
Abstract: 

Microplastics (MPs; plastic particles 1 µm–5 mm) are an emerging contaminant in the world’s oceans; found from surface to seabed in many forms. Evidence for ingestion of MPs exists for a variety of organisms including zooplankton, bivalves, and fishes, raising concern about potential effects in marine food webs. Although studies have reported MPs in the remote Arctic Ocean, data are nonexistent on the ingestion and associated health effects in calanoid copepods (zooplankton). Copepod samples were collected at 56 stations along 10 transect lines spanning the Northeast Pacific and Arctic Oceans and digested according to a novel enzymatic method developed during this thesis. Using light microscopy, MPs were quantified and characterized in Calanus and Neocalanus copepods. Polymer identity was confirmed for each microparticle isolated using Fourier-transform infrared spectroscopy (FTIR). Microplastic ingestion was confirmed at 6 of the 12 Arctic sampling stations. Particle density (PD) ranged from 2.79–15.28 MPs per gram wet weight sample. Differences in PD among survey regions and sampling stations were not significant. RNA:DNA ratios were determined as an indicator of health (i.e., growth and condition) and a station-specific relative RNA:DNA index (RRD) was calculated to account for differences in temperature; both were examined in relation to MP ingestion in Calanus glacialis copepods. A positive trend was observed between station-specific PD and both RNA:DNA ratios and RRD; neither correlation was statistically significant (RNA:DNA ratios: rp = 0.52, p = 0.154; RRD: rp = 0.45, p = 0.220), however the strength of the relationship is notable. The results of this thesis confirm MP ingestion in copepods in the Arctic Ocean, and constitute the first examination of associated health effects in the keystone copepod of Arctic Ocean ecosystems.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Leah Bendell
Peter S. Ross
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.Sc.

Pathogen growth inhibition and disease suppression on cucumber and canola plants with ActiveFlower™ (AF), a foliar nutrient spray containing boron

Author: 
Date created: 
2019-07-30
Abstract: 

The effectiveness of ActiveFlower (AF), a fertilizer containing 3% boron in reducing pathogen growth and diseases on cucumber and canola plants was evaluated. In vitro, growth of S. sclerotiorum with AF at 0.1, 0.3 and 0.5 mL/100 mL showed pronounced inhibition at 0.5 mL/100 mL. In greenhouse experiments, the number of powdery mildew colonies on cucumber was significantly reduced by AF at the higher concentrations applied as weekly foliar sprays. On detached canola leaves, AF at 0.5 mL/100 mL and boric acid (BA) at 10 mL/L significantly reduced lesion size of S. sclerotiorum. Phenolic content and boron levels in foliage receiving AF applications were significantly increased. There were no significant differences in lignin. These results indicate that boron present in AF contributed to the disease suppressive effect.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Zamir Punja
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.Sc.

Dense core vesicle transport and synaptic capture in neurons

Author: 
Date created: 
2019-08-01
Abstract: 

Dense core vesicles (DCVs) transport signalling molecules, such as brain-derived neurotrophic factor (BDNF), to neuronal synapses utilizing the kinesin KIF1A. BDNF is critical for neuronal function, therefore it is important to understand DCV trafficking and synaptic capture. I used live-cell imaging to characterize DCVs carrying fluorescently tagged BDNF in hippocampal neurons to assess how they translocate to presynaptic sites. Transport was processive both anterogradely and retrogradely and DCVs can be captured regardless of the direction in which they are traveling. Next, I studied whether absence of doublecortin-like kinase 1 (DCLK1), a KIF1A motility modulator, allows for DCV capture at synapses. Using super-resolution microscopy, DCLK1 co-localized only with a small fraction of axonal DCVs. Despite low co-localization of DCLK1 and DCVs, DCLK1 was absent from most synapses (64%). These observations suggest that DCLK1 may not regulate DCV transport in axons but may regulate movement of other KIF1A cargo.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Michael Silverman
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.Sc.

Ideal free eagles: Bald eagle distribution patterns and use of kleptoparasitism on salmon rivers

Author: 
Date created: 
2019-05-15
Abstract: 

During the autumn, migrating bald eagles (Haliaeetus leucocephalus) aggregate on coastal rivers to scavenge post-spawning salmon carcasses. In this thesis, I measured the abundance of eagles and salmon carcasses on a set of four adjacent rivers along the east coast of Vancouver Island, British Columbia. Salmon carcasses first appeared in late September, increased in abundance until mid-November, and thereafter declined. The total number of eagles tracked the temporal and spatial abundance of salmon carcasses, and generally distributed across the rivers according to the predictions of Ideal Free Distribution. I determined that the incidence of kleptoparasitism matched the distribution of eagles, and found that kleptoparasitism attempts between eagles were affected by the age of the attacker and the behavioural tactic used. Overall, my results indicate that salmon abundance affects the regional distribution patterns and use of kleptoparasitism among aggregations of foraging eagles.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Ron Ydenberg
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.Sc.

Environmental change and sockeye salmon life histories across space and time

Date created: 
2019-06-12
Abstract: 

Animals with complex life cycles migrate to exploit resources from different environments, but are exposed to multiple stressors and challenges. Here I investigated stressors across ontogenetic shifts in sockeye salmon. First, I examined migration and condition of juvenile sockeye salmon fry as they migrate from the Babine River, British Columbia, to upstream lake rearing habitat. High water velocities increased challenges to successful upstream migration to the lake, but lake rearing habitat was associated with larger fry (30% longer, 150% heavier). Second, I examined how multiple ocean stressors impact freshwater fecundity using a nearly 7-decade dataset from Fraser and Skeena sockeye salmon. Good ocean conditions and low biomass of salmon competitors were associated with younger, larger, more fecund sockeye. Spawning channel enhancement was associated with a small additional increase in fecundity. Collectively, my thesis highlights intricacies in the effects of multiple stressors on sockeye salmon across their complex life cycle.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Jonathan Moore
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.Sc.

Science for community fisheries: Population assessment and climate impact monitoring for Heiltsuk-led salmon stewardship

Author: 
Date created: 
2019-05-14
Abstract: 

Small scale fisheries support the livelihoods of more than 20 million people and provide food security for millions more around the world, yet science has been slow to embrace the challenge of managing these fisheries. Salmon are foundational for the ecosystems and economies of coastal British Columbia, supporting food, social and ceremonial (FSC) fisheries for 196 First Nations. Despite their cultural and ecological importance, and their vulnerability to ongoing anthropogenic change, we lack the data necessary for management and conservation of wild salmon in much of BC, particularly the remote north and central coast (NCC). Juvenile sockeye rear in lakes for one or two years, so population sizes are often limited by the size and productivity of rearing lakes. Using limnological data collected by Fisheries and Oceans Canada, we built a landscape model of sockeye lake productivity and predicted population capacity for 157 lakes on the NCC. We used these predictions of capacity as priors in a hierarchical-Bayesian stock-recruit model, to estimate productivity, capacity, and conservation benchmarks for 70 sockeye populations. Sockeye are particularly vulnerable to changes in climate, with elevated rates of pre-spawn mortality among migrating adult sockeye at high temperature. Working with the Heiltsuk First Nation, QQs Projects Society, and the Hakai Institute, we established a community-based population monitoring program using a traditional-style salmon weir to capture and tag fish for mark-recapture and telemetry-based estimates of annual population size and temperature-mediated mortality among migrating adult sockeye in the Koeye River. We found rapid declines in survival to spawning when temperatures exceeded 15 °C. Furthermore, river entry measured by the number of fish tagged each day, ceased when the river level dropped below 0.4 m. When water levels are low, migrating sockeye may experience prolonged delays in marine waters, increasing vulnerability to fisheries and predators. Climate impacts on coastal sockeye may therefore be driven by the dual effects of warming temperature and low-water delays. This work will support the development of a Heiltsuk sockeye management plan, establishing management goals and conservation strategies across a territory spanning 15,000 km2 and more than 20 sockeye populations on the NCC.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Jonathan Moore
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) Ph.D.

The lethal and sublethal effects of the anti-sea lice formulation Salmosan® on the Pacific spot prawn (Pandalus platyceros)

Author: 
Date created: 
2019-04-25
Abstract: 

Sea lice outbreaks in salmonid aquaculture can impact both farmed and wild salmon. Anti-sea lice chemotherapeutants used to treat these outbreaks are released directly into the water column after treatment, potentially exposing non-target organisms. Salmosan® (active ingredient: azamethiphos) has recently been approved for use in British Columbia as a sea lice treatment. In the present study, the lethal and sublethal effects of Salmosan® were examined in intermolt and post-molt Pacific spot prawns (Pandalus platyceros). Post-molt prawns were found to be more sensitive than intermolt prawns, and this sensitivity was exacerbated at higher exposure temperatures. Repeated (3 x) 1‑h LC50 values for post-molt prawns were 39.8, 27.1, and 17.1 µg/L at 5, 11 and 17 °C, respectively. All intermolt prawns survived 3 x 1-h exposures up to 100 µg/L azamethiphos at 5, 11 and 17 °C. Intermolt prawns held at 17 °C molted 83 – 91% sooner and experienced 70 – 73% greater mortality than those held at 5 or 11 C; azamethiphos did not affect either of these parameters. In a separate experiment, intermolt prawns displayed an 86 – 103% reduction in antennule flicking, a chemoreception-mediated behavior, at 24 h following repeated (3 x) 1-h exposures to 50 and 100 µg/L azamethiphos. These results may aid in the development of regulatory protocols and guidelines for the use of anti-sea lice pesticides in Canada.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Chris Kennedy
Department: 
Science: Biological Sciences Department
Thesis type: 
(Project) M.E.T.

Floral and honeydew foraging ecology of select mosquito species

Author: 
Date created: 
2019-04-26
Abstract: 

Both male and female mosquitoes exploit a wide variety of plant sugar resources, including floral nectar and aphid honeydew, as important sources of carbohydrates. Mosquitoes are generally considered nectar thieves that do not pollinate the flowers they visit, and volatile semiochemicals are believed to be the primary driver of mosquito attraction to plant sugar sources. Using the northern house mosquito, Culex pipiens, and its nectar host the common tansy, Tanacetum vulgare, we showed mosquito-induced seed-set. We found that semiochemicals from T. vulgare flowers are attractive to Cx. pipiens and the yellow fever mosquito, Aedes aegypti, that visual and olfactory inflorescence cues in combination attract more mosquitoes than olfactory cues alone, and that plant CO2 enhances the attractiveness of a 20-component synthetic blend of tansy inflorescence odourants. This blend included 9 odourants found in human odour, which are also attractive. Electroretinograms revealed that Cx. pipiens eyes can sense ultra-violet (UV) wavelengths, with peak sensitivity at 335 nm. Experiments found that UV inflorescence cues of T. vulgare and the common hawkweed, Hieracium lachenalii, enhance the attractiveness of inflorescence odour to female Cx. pipiens through floral patterns of UV-absorption and UV-reflection. We then established the attraction of Ae. aegypti to honeydew odourants from the green peach aphid, Myzus persicae, and the pea aphid, Acyrthosiphon pisum, feeding on fava bean, Vicia faba. We collected and analyzed headspace odourants from honeydew of A. pisum feeding on V. faba. An 8-component synthetic blend of these odourants and synthetic odourant blends of crude and sterile honeydew we prepared from literature data all attracted female Ae. aegypti. The synthetic blend containing microbial odour constituents proved more effective than the blend without these constituents. Our data support the hypotheses that mosquitoes are pollinators, that the entire inflorescence Gestalt of olfactory, CO2 and UV cues is more attractive to mosquitoes than floral odourants alone, that olfactory cues attract mosquitoes to honeydew, and that microbe-emitted volatiles play a role in mosquito attraction to honeydew.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Gerhard Gries
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) Ph.D.

Investigations into the roles of thyroid hormone and retinoic acid on opsin expression in juvenile rainbow trout

Author: 
Date created: 
2019-03-27
Abstract: 

Thyroid hormone (TH) and retinoic acid (RA) are powerful modulators of photoreceptor differentiation during vertebrate retinal development. In the embryos and young juveniles of salmonid fishes and rodents, TH induces switches in opsin expression within individual cones, a phenomenon that also occurs in adult rodents following prolonged (12 week) hypothyroidism. The ability of TH to modulate opsin expression in the differentiated retina of fish, and the role of RA in inducing opsin switches, if any, is unknown. Here I investigate the action of TH and RA on single cone opsin expression and the absorbance of visual pigments in juvenile rainbow trout. Prolonged TH exposure increased the wavelength of maximum absorbance (λmax) of the rod, and the medium (M, green) and long (L, red) wavelength visual pigments, and affected single cone opsin expression in the alevin. RA did not induce any opsin switches nor change the visual pigment absorbance of photoreceptors.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Inigo Novales Flamarique
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.Sc.