Honours Theses

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Weddell seal (Leptonychotes weddellii) proportional call type usage with seasons and light periods, and the relationships between call types near Davis, Antarctica.
(University of New Brunswick, 2025-03) Brattain, Allison; John M. Terhune; Kurt M. Samways
Weddell seals (Leptonychotes weddellii) have an extensive vocal repertoire. I investigated whether their proportional call type usage patterns vary across seasons and light periods, and the relationships between call types. Calls were recorded near Davis, Antarctica, and analyzed using R Studio and Raven Pro. A total of 6315 calls were identified, representing 16 call types. Call types were categorized and examined by season, light period, and season by light period using Chi-square tests. Clustering methods reclassified calls into broader groups based on common physical structures. For the 16 call types, proportional call usage did not significantly differ across seasons, but did significantly differ across light periods. Whistle Descending calls revealed significant difference across seasons by light period. The clustering analysis identified three call categories, showing seasonal significance, but no light period effect. This suggests no call types or groups are linked to reproduction, enhancing our understanding of Weddell seal behaviour.
An in vitro evaluation of the antibiotic and antimycotic properties of the colletotrichamides, a family of novel polyketide natural products
(University of New Brunswick, 2025-03) Kline, Madeline; Dr. Christopher Gray
The rise of antibiotic-resistant bacteria poses an alarming global health crisis, necessitating the urgent development of novel antimicrobial agents. We have recently discovered a new family of antibiotic polyketides, the colletotrichamides A-E, that were isolated from an endophytic Colletotrichum species fungus. In this study we evaluated the antibiotic activity of the colletotrichamides against a panel of 10 bacterial and fungal pathogens using absorbance- and fluorescence-based in vitro bioassays. Compounds that inhibited microbial growth by more than 90% in preliminary screening assays underwent dose-response analysis to determine their IC50 values. Colletotrichamide C demonstrated the highest activity overall, exhibiting strong inhibition against Candida albicans and Enterococcus faecium. Our results indicate that the colletotrichamides have the potential to contribute to the development of novel antimicrobial agents and, although further research is needed to elucidate their mechanisms of action and in vivo efficacy, underscores the importance of natural product research in antibiotic discovery efforts.
Investigating copper acclimation in mummichog; Implications for ionoregulation and physiological tolerance
(University of New Brunswick, 2025-04) Jordan, Madison; Dr. Alex M. Zimmer
At elevated concentrations, copper (Cu) disrupts osmoregulation in aquatic organisms. Acclimation can occur at sublethal concentrations, though responses may be species-specific, and mechanisms remain unclear. This study investigated osmoregulatory effects of acute Cu exposure in Fundulus heteroclitus, and whether acclimation mitigates toxicity. Fish were acclimated in seawater to 0 or 0.1 mg/L Cu for 7 d, then euthanized or exposed to 0-2 mg/L Cu for 48 h. Muscle moisture (MM) and tissue Na were measured as osmoregulatory status indicators. Acclimation nor exposure significantly affected MM. Acclimation and acute exposure significantly affected tissue Na in acutely exposed fish, with an increase at 2 mg/L and lower levels in acclimated fish overall. Findings suggest Cu acclimation may alleviate ionoregulatory disruptions observed at higher acute exposure concentrations, but does not fully mitigate toxicity. Preliminary in vitro data indicate Na⁺/K⁺-ATPase activity declines with increasing Cu, warranting further investigation on Na⁺/K⁺-ATPase desensitization in Cu acclimation.
Identifying a Non-Lethal Fatty Acid Sampling Method in Fish
(University of New Brunswick, 2025-05) Comeau, Lauren
Fatty acid profiling is crucial for understanding fish health and diet.This study evaluates the potential of fish fin tissues as non-lethal alternatives to muscle tissue for fatty acid profiling. Lipid extractions from muscle, adipose fin, inner-caudal, and outer-caudal tissues were analyzed using gas chromatography. Principal component analysis (PCA) and Euclidean distance analyses revealed a strong similarity between adipose and muscle tissue. Inner-caudal tissue showed a strong correlation with muscle, with moderate intra-fin variability. Outer-caudal tissue exhibited the most distinct fatty acid profile and high intra-fin composition variability, suggesting it provides a useful alternative. This study demonstrates that adipose fin tissue provides a reliable non-lethal alternative for fatty acid profiling in fish, given its strong correlation with muscle tissue, minimal variation, and consistency in fatty acid composition and concentration. Non-lethal fatty acid sampling methods support ecological research and conservation efforts, laying the foundation for more sustainable fish health and dietary studies.
Relationship between infaunal invertebrates and abiotic factors in intertidal mudflats on the Northwest Fundy shore, Bay of Fundy
(University of New Brunswick, 2025-04) López, Fátima López; Dr. Heather Hunt
Intertidal mudflats are unique ecosystems supporting diverse biotic communities, including infaunal organisms that live buried in sediments. Infaunal invertebrates have adapted to burrow, move, respire, and process sediment particles for food. This study explores how sediment organic content, carbonate content, grain size, pH and alkalinity influence abundance of four infaunal species (Tubificoides benedii, Corophium volutator, Macoma balthica and Hediste diversicolor) along the Northwest Bay of Fundy shore, based on Fall 2023 sampling at 10 sites. Results indicate that site had a significant effect on species abundance. The environmental variables that had the most influence on Tubificoides benedii, Corophium volutator, Macoma balthica, and Hediste diversicolor in generalized linear mixed models were sediment organic content, alkalinity and carbonate content. Hediste diversicolor appeared to also be influenced by sediment pH. Further investigation into the effects of sediment pH and alkalinity is needed to enhance understanding of ecology of mudflat invertebrates and provide a foundation for future species or environment specific studies.
Predicting hatch of the American lobster (Homarus americanus) in the southwest Bay of Fundy: how to model late spring embryo development
(University of New Brunswick, 2025-03) Lincourt, Connor J.M.; Rémy Rochette
Hatch timing of the American lobster (Homarus americanus) is important for the seasonal events larvae will experience post hatch. The hatch of lobster embryos occurs outside fishing seasons and hence cannot readily be monitored by observing the clutch of ovigerous females caught by fishers. An alternative approach to predicting hatch is using temperature to model embryonic development until predicted hatch. This study modelled embryonic development and predicted hatch using 3 different temperature scenarios (female, environment, and static) and investigated the thermoregulatory behaviour of ovigerous females in relation to hatch. Using static temperature was found to not be useful to model development and environmental temperature can be used to model embryonic development until evidence is found to show its inappropriate. Females were not found to thermoregulate to time the hatch of their embryos. Overall, further research should be done to see if environmental temperature can accurately predict hatch.
Audial, visual and statistical discrimination of similar calls made by sei and blue whales
(University of New Brunswick, 2025-03) MacDonald, Kerkeslin; Dr. Kimberley Davies; Dr. Katherine Indeck
In the Gulf of St. Lawrence (GoSL), current near real-time acoustic detection methods for baleen whale calls are misclassifying blue whale (Balaenoptera musculus) acoustic presence as sei whale (Balaenoptera borealis), likely due to their similar calls and the lack of a blue whale call library in the low-frequency detection and classification system (LFDCS) used to inform near real-time analysis protocols. This study aimed to quantify misclassifications using manual analysis of archival data and to determine how LFDCS classifications change with a blue whale call library incorporated. Data were collected from 8 glider deployments in the GoSL from 2020-2023. Manual analysis revealed sei whale acoustic presence was correctly identified by near real-time detection methods 1-3% of the time. Furthermore, analyses with the expanded call library resulted in LFDCS correctly classifying 31% of manually validated blue whale periods. Updating the near real-time analysis protocols will be critical for improving acoustic detections.
Tissue library and DNA dataset creation for the investigation of migration patterns of Atlantic Bluefin Tuna (Thunnus thynnus) in Atlantic Canada
(University of New Brunswick, 2025-04) Maheux, Stephanie; Rebekah Oomen
Atlantic Bluefin Tuna (Thunnus thynnus) are a migratory fish species that travel from the Gulf of Mexico, the Mediterranean Sea and the Slope Sea to forage in Atlantic Canada, however, the logistical specifics of these migrations are still unclear. The objective of this study was to create a tissue library and genomics database consisting of bluefin tuna samples with which their stock of origin can be identified. With those identifications, general migration timings of each stock through Canada can be determined. Muscle tissue was collected from 226 individuals across Eastern Nova Scotia. Of those samples, DNA was extracted from 51 and sequenced using Low-coverage Whole Genome Sequencing. This DNA created a high-quality genomics database with which researchers can use to genotype bluefin individuals, and, by cross referencing stock with date of capture, can be used to better understand bluefin migration timing.
Cross-shelf variation in habitat characteristics of arctic whales in Baffin Bay measured using ocean gliders
(University of New Brunswick, 2025-02) Mueller-Classen, Keely; Dr Kimberley Davies
Zooplankton distribution and abundance play a crucial role in shaping the foraging behavior of bowhead whales, Balaena mysticetus, in Arctic marine ecosystems. Understanding how physical oceanographic conditions influence the vertical and horizontal zooplankton abundance is essential for assessing critical foraging habitats. In this study, we analyzed depth-integrated zooplankton abundance and maximum zooplankton abundance across distinct water masses on and off the West Greenland continental shelf using Cabot 198 ocean glider. The glider transited along six transects that travelled cross-shelf, collecting 176 vertical profiles of zooplankton abundance and environmental variables including temperature, salinity, and bathymetric depth. Zooplankton were primarily concentrated within the upper 300m of the water column, with diel vertical migration (DVM) observed, as aggregations shifted from the top 100 m at night to depths below 200 m during the day. Bathymetric depth was a significant predictor of total depth-integrated zooplankton abundance (individuals/m², p < 0.001). The highest zooplankton densities were recorded in association with Arctic and Atlantic Waters. These findings suggest that Arctic and Atlantic-influenced waters provide key foraging grounds for bowhead whales by supporting prey densities exceeding previously established foraging thresholds.
Developing Genomic Resources Towards Understanding the Influence of an Introgressed Inversion on Atlantic Bluefin Tuna’s Recovery.
(University of New Brunswick, 2025-03) Scher, Abigail K.; Dr. Rebekah A. Oomen
The influence of introgression on the recovery of depleted populations is currently an empirically understudied evolutionary process, despite its function in providing adaptive genetic variation which may favour adaptation and speciation. Atlantic bluefin tuna (Thunnus thynnus; hereafter, ABFT) exemplifies a unique case of introgression, where a chromosomal inversion was introduced into their population from another tuna species. Given that tuna have undergone a recent rapid demographic recovery from near extinction levels due to overexploitation, it is opportune to investigate the correlation between the inversion and ABFT’s recovery. Resources were developed for the target application of investigating the correlation. Tissue, DNA and high-quality sequence banks, spanning a decade, were created and assessed temporally, using low coverage whole genome sequencing for the sequence bank. DNA content decreased as storage duration increased; however, DNA quality remained stable. Additionally, a comparative genomic approach was employed to putatively locate the inversion on chromosome 24.
Examining the Effect of Fermentation Medium on the Antibiotic Activity of Fungal Extracts
(University of New Brunswick, 2025-04) Smith, Emilee A.; Christopher A. Gray
Fermentation medium can influence the production of bioactive compounds by endophytes, affecting their antimicrobial properties. This study employed a panel of 10 microbial pathogens to examine the antimicrobial activity of extracts derived from 35 endophytes grown in potato dextrose broth (PDB) and malt extract broth (MEB). Factorial ANOVAs showed that extract bioactivity was significantly influenced by growth medium (p < 0.001 for 31 isolates) and pathogen (p < 0.001 for all isolates) and revealed a significant interaction between these factors (p < 0.001 for all isolates). Extracts of isolates grown in PDB generally exhibited greater activity in our bioassays, suggesting that it promotes the production of antimicrobial compounds. However, no consistent trend linked medium-dependant activity to pathogen type, indicating that metabolite production is also influenced by the metabolic ability of individual endophytes. These findings highlight the importance of selecting an appropriate fermentation medium to maximize the bioactivity of endophyte extracts.
Effects of low pH exposure on the osmo-respiratory compromise in banded killifish (Fundulus diaphanus)
(University of New Brunswick, 2025-04) Stavert, Zachery Robert; Alex Zimmer; Ben Speers-Roesch
Low pH affects freshwater fish in several ways, with the effects on gas exchange and ion regulation being particularly important. These processes are connected through the osmo-respiratory compromise, the trade-off between gas exchange and ion regulation. Exercise exacerbates this trade-off, and low pH may further amplify these effects. This study explored the osmo-respiratory compromise in the acid-tolerant banded killifish (Fundulus diaphanus). Fish were acclimated to pH 7 (control) and pH 5 for 14 d and then subjected to trials measuring Na+ net flux and oxygen consumption rate (MO₂) following exhaustive exercise. I tested the hypothesis that low pH would exacerbate ion loss following chase, in accordance with the osmo-respiratory compromise. Contrary to expectations, fish acclimated to low pH exhibited more positive Na+ net flux rates and showed no reduction in aerobic capacity. These results suggest that banded killifish can quickly acclimate to low pH conditions, maintaining Na+ regulation and aerobic scope.
Using eDNA to estimate juvenile salmon abundance in Fundy National Park
(University of New Brunswick, 2025-04) Thwaites, Leah M.; Scott A. Pavey; Jagger Watters-Gray
Environmental DNA (eDNA) is an emerging field that shows many benefits such as low effort and cost-effective sampling of aquatic environments. However, a variety of environmental factors influence the conservation of eDNA in water which make direct correlations between eDNA and fish abundance difficult to research. This study seeks to understand if incorporating the hydrodynamics and environmental variability of a river network will allow us to estimate juvenile salmon abundance using eDNA. We used eDNA sampling techniques and the eDITH R-Package to estimate juvenile salmon abundance throughout a river network. Based on the results of the analysis, we compared the estimated abundance results to electrofishing data to determine the comparability of our eDNA method with electrofishing. Although our results did not correlate with electrofishing abundance, producing Spearman’s correlation coefficients of R = -0.47, R = -0.49, and R = 0.41, they laid a critical foundation for future work that will adjust eDNA concentrations based on environmental variables. While abundance could not be accurately estimated and significant findings were inconsistent across trips, with adjustments, eDITH has potential to estimate relative population changes and aid in general monitoring of aquatic species.
Police-Citizen Mental Health Call Duration and Associations with Call Outcomes
(University of New Brunswick, 2025-04) Carey, Amy; Mary Ann Campbell
An understudied factor in police-mental health calls is the influence of call duration. The longer a call takes to resolve, the greater the opportunity for use of crisis intervention to de-escalate the situation. Alternatively, longer calls may have significant resource impacts on a shift with other waiting calls. To clarify whether call duration matters in police response, the current study assessed the average duration of police mental health calls, factors influencing call duration, and the degree call duration relates to crisis intervention response by police officers using a sample of 200 police-mental health calls in New Brunswick, Canada (52% men; 82% White/European; age range: 10-87 yrs). Variables were extracted from body worn camera and police records. Calls lasted a median of 43 min, with much variability (range 2 to 642 min). Hierarchical regression found that longer call duration was significantly predicted by being a non-White client, displays of non-communicative/non-responsive behaviour, and intimidating/threatening behaviour towards others, whereas shorter call duration was predicted when clients displayed generally aggressive behaviour. Weapon presence, uncooperative behaviour, causing a disturbance, or voicing violent ideations were unrelated to call duration. Longer call duration was correlated with higher volume of crisis intervention skills used but not the overall quality of the crisis response. These findings provide a window into the factors that influence how long an officer takes during mental health calls and the factors that may shape the immediacy of their actions.
Childhood Trauma and Substance Use in an Undergraduate Population: Revisiting the Role of Impulsivity
(University of New Brunswick, 2025-04) Scherf, Julia; Caroline Brunelle
The comorbidity between traumatic childhood experiences and subsequent substance use has been well established. Negative urgency is defined as a need to act rashly in response to negative emotions, and positive urgency is the urge to act impulsively in the context of positive emotions. The purpose of this study is to explore if negative and positive urgency partially account for the relationship between childhood trauma and the use of substances in university students. A total of 209 students (Mage = 20.81, SD = 4.68) were recruited from the University of New Brunswick and completed a questionnaire package online, which included measures of childhood trauma, urgency, frequency of substance use and problematic use of various substances. Results showed significant positive correlations between childhood trauma and cannabis/alcohol problems, between childhood trauma and positive and negative urgency and between alcohol and cannabis problems and positive and negative urgency scores. Mediation analysis showed a significant indirect effect of negative urgency between childhood trauma and alcohol problems, but not for cannabis problems. The study suggests that interventions that reduce negative urgency may be promising to mitigate the effects of trauma on substance use behaviours.
The Effects of Visual Masking on Recognition: A Replication of Westerman and Greene’s (1997) Study
(University of New Brunswick, 2025-04) Chaaban, Kamal Abou; Jonathan Wilbiks
Masking is the impairment of perception of visual stimuli when they are quickly followed by other stimuli. The perceptual interference effect occurs when visual stimuli are obscured and the brain activates pathways to compensate for the lack of information, and in turn, improves later explicit memory. Many models of word recognition suggest that the speed and ease with which this higher-level information is attained is proportional to the word’s linguistic frequency and familiarity. The purpose of this study was to replicate Westerman and Greene’s (1997) study by testing the theory that there is a mnemonic benefit for masking high frequency, familiar words. A total of 71 psychology students from the University of New Brunswick Saint John Campus participated in an online pilot experiment that tested the familiarity of select words, and an additional sample of 41 students participated in a subsequent in-person replication experiment that tested their ability to recognize masked and unmasked words. Two repeated-measures analyses of variance were conducted. The results supported the hypothesis that there is a mnemonic benefit for masking high frequency, familiar words, and no effect for low frequency, unfamiliar words. The results are discussed in the context of the word frequency effect and automatic processing.
The Relationship Between Authoritarianism and Mental Health Moderated by Religiosity
(University of New Brunswick, 2025-04) Wood, Jarrett; David Speed
Authoritarianism, which is the obedience to an authority figure and proclivity to use censorship and aggression to enforce the beliefs of the authority figure, is negatively correlated to various health outcomes. Religiosity, which is the strength of an individual’s religious belief, is also associated with many health outcomes. Religion and authoritarianism have been found to be positively correlated but no research has been done to see if they interact with each other. The purpose of the study is to investigate whether authoritarianism is associated with worse mental health and to see if higher religiosity in conjunction with higher authoritarianism has an amplified negative relationship to mental health. Data from the 2021 American General Social Survey (N ≥ 980) was used to explore the relationship between authoritarianism, religiosity, and mental health. A hierarchical linear regression was used to examine whether authoritarianism was moderated by religiosity in the relationship with health outcomes. The results suggest that allowing a communist to speak is positively correlated to mental health but allowing a Muslim and allowing an anti-religionist to speak are not correlated to mental health. Religiosity was not found to be correlated to any mental health outcomes either, which does not support the previous Belief-As-Benefit-Effect literature. When the relationship between mental health and allowing a communist to speak was moderated by religiosity, it was found that individuals who would not allow a communist to speak were more likely to report better mental health at higher levels of religiosity.
Growth Mindset in Intelligence and Personal Attributes: Examining the Role of Personality Traits, Self-Efficacy, Resilience, and Coping
(University of New Brunswick, 2025-04) McLellan, Liam R; Lilly Both
The purpose of this study was to examine the role of personality traits, self-efficacy, resilience, and coping as predictors of mindset in intelligence and personal attributes. Mindsets can be defined as mental frameworks in which people hold beliefs about themselves or others, and these mindsets can have a large impact on the way individuals navigate situations. Fixed mindsets involve a belief that traits are unchangeable, whereas growth mindsets refer to traits as malleable. Personality traits, self-efficacy, resilience, and coping have all been correlated with mindsets, but these variables have not been examined in one model to assess their unique contributions. Questionnaires examining each of these variables were administered to 136 participants on Qualtrics. These participants were recruited from psychology classes at the University of New Brunswick in Saint John. The results indicated gender differences, with women scoring higher on mindset in intelligence, agreeableness, and negative emotionality, but lower on resilience compared to men. The two domains of mindset were highly correlated. Growth mindset in intelligence was correlated with higher scores on agreeableness, self-efficacy, and resilience. Growth mindset in personal attributes was significantly correlated with higher scores on agreeableness. Regression analyses revealed that self-efficacy contributed significantly to mindset in intelligence, as did resilience in a separate model. Regression analyses predicting mindset in personal attributes did not produce statistically significant models. These results are discussed in the context of factors impacting mindsets in undergraduate students.
Preparing for the Inevitable: Investigating the Role of Anticipatory Grief and Psychological Flexibility on Mental Well-Being
(University of New Brunswick, 2025-04) Moore, Robyn; Lisa Best
Anticipatory grief (AG) arises when individuals process emotions before an expected loss, often due to terminal illness or decline. Various factors influence AG, including coping strategies and psychological flexibility (PF), which is the ability to stay present and adapt behaviour to align one’s behaviours with personal values. PF may help mitigate AG by reducing experiential avoidance (EA), the tendency to suppress distressing thoughts. Research examining the impact of AG on psychological well-being after a loss is mixed. Thus, the primary goal of this study was to examine the impact of AG and bereavement on the well-being of individuals who experienced either sudden or anticipated loss of a loved one within the past 24 months. A total of 195 participants completed a questionnaire package to assess variables associated with bereavement, anxiety, depression, coping, and PF. Results indicated that individuals who experienced an anticipated loss reported lower anxiety and higher overall PF than those with sudden loss. AG, bereavement, and EA were correlated with depression and anxiety. Interestingly, PF and coping were not positively correlated. Regression analyses indicated that bereavement, not AG, significantly predicted anxiety and depression. Aspects of PF and EA accounted for significant variance in models predicting anxiety. Qualitative responses describing relationship to the deceased provided further support that AG exacerbates depression and anxiety. Overall, the findings highlight the need to understand the distinction between bereavement and AG, emphasizing AG’s unique emotional impact on anxiety in those facing an expected loss.
Movement as Medicine: The Moderating Effect of Physical Activity on the Mental Health of Adolescents Impacted by a Childhood Traumatic Brain Injury
(University of New Brunswick, 2025-04) Reilly, Tristin; Vanessa Morris
Research has demonstrated a positive relationship between traumatic brain injuries (TBIs), mental illness, and physical activity, though much of this work has been cross-sectional or limited in follow-up. The current study used longitudinal data from the Adolescent Brain Cognitive Development (ABCD) study to explore the long-term effects of childhood TBI on adolescent mental health, specifically symptoms of anxiety and depression. This study addressed three research questions: (1) Are childhood TBIs associated with increased symptoms of anxiety in adolescence? (2) Are childhood TBIs associated with increased symptoms of depression in adolescence? (3) Does physical activity moderate the relationship between childhood TBI and symptoms of anxiety and depression in adolescence? Data from 8,374 participants were analyzed. Correlation and moderation analyses were conducted to assess associations between TBI and mental health outcomes, and the moderating role of physical activity. Correlational analyses revealed that childhood TBI was weakly but significantly associated with higher anxiety and depression symptoms. Physical activity was weakly associated with lower symptoms of both. Moderation analyses showed that physical activity did not significantly moderate the relationship between TBI and either mental health outcome. However, TBI and physical activity were each significant independent predictors: TBI was associated with greater symptom severity, while higher physical activity was associated with fewer symptoms overall. These findings suggest that while physical activity may broadly support adolescent mental health, it does not buffer the specific effects of childhood TBI. This underscores the need for early intervention and continued investigation into long-term outcomes.

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