From Stress To Health: Evaluating Linkages From Comprehensive Physiological Stress Panels to Cetacean Health
Abstract
Research Problem: The effects of sound and other stressors on cetacean populations have been the subject of several decades of study, and yet several areas of uncertainty remain, chief among them a lack of clarity on the nature and strength of relationships between individual physiological stress and resultant impacts on individual health. Assessment of the stress-health relationship in cetaceans has been constrained by a limited set of stress and health biomarkers available, with physiological stress often assessed by a single metric of fecal glucocorticoids, while health is often assessed with a single metric of body condition. These unitary metricshave had utility, but they provide only a narrow window into individual physiological status. Today many other biomarkers of the stress and health status of cetaceans are available, which can be integrated to produce broader, more informative "stress panels" and "health panels".Technical Approach: To better characterize the links between physiological stress and health in free-living cetaceans, we propose to apply new multivariate stress panels and health panels in our ongoing long-term study of the Pacific Coast FeedingGroup (PCFG) sub-population of Eastern North Pacific gray whales (Eschrichtius robustus). This population has study advantages including an accessible population, high sample collection rate, repeated sampling of known individuals, well-characterized metrics of body condition (from photogrammetry) and stressor exposure (acoustics, vessel traffic), and an established statistical framework. We propose to perform two new field season to expand our study to ten years (2016-2025), amassing a total of ~237 fecal samples from known individuals with linked photographic records and stressor-exposure data, which we will analyze with comprehensive new stress andhealth panels. Specifically, we propose to add three new metrics of stress to our dataset: fecal aldosterone (increases with stress), the epinephrine metabolite vanillylmandelic acid (VMA; increases with stress), and dehydroepiandrosterone (DHEA: decreases with stress), as well as three new metrics of health: epidermal condition, scarring/healing, and age-specific body length (inferred growthrate). An exploratory arm of our study will analyze tissue biopsy samples to assess toxicant exposure, specifically mercury and selenium, known to influence relationships of stress and health in mammals. Objectives: (1) Analyze ~237 fecal samples (177 archived samples from 2016-23, and ~60 samples from 2024-25) for aldosterone, DHEA, and VMA; (2) Add measures of epidermal health condition, injuries/scarring and body length (2016-2025); (3) Mercury and selenium analysis of ~30 biopsy samples (2024-25); (4) Compile the complete dataset within our existing statistical frameworks to examine linkages from stress to health.Anticipated Outcomes: Through assessment and integration of these additional biomarkers of stress and health with our long-term dataset and our existing statistical framework, we will clarify the nature, direction and strength of linkages between physiological stress and health, relevant not just to the PCFG population but also other cetacean species. Impact on DoD capabilities: Our work will be useful for Navy-relevant assessment of impacts of disturbance on cetacean health, e.g., more accurate predictions of what noise types and durations are likely to affect cetacean health to a degree relevant for population impacts. Information from this project can also be folded into related modeling efforts exploring influences of multiple stressors on cetacean vital rates (e.g., population consequences of multiple stressors, PCoMS). Thus, our work has potential to broadly inform efforts of the Office of Naval Research (ONR) and the Department of Defense (DoD) on the effects of ocean sound and anthropogenic activities on marine mammals.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 08, 2024
- Source ID
- N000142412560
Entities
People
- Kathleen Hunt
Organizations
- George Mason University
- Office of Naval Research
- United States Navy