Long Term Trends and Sources of Sound in United States Waters

Passive acoustic monitoring is a valuable tool for observing the status of marine environments. Comparisons of underwater soundscapes over temporal and spatial scales can provide data to inform marine conservation efforts, including protection of threatened and endangered species. This dissertation utilizes passive acoustic data collected via a broadly spaced array of autonomous hydrophones, the National Oceanic and Atmospheric Administration and National Park Service Noise Reference Station Network. The Noise Reference Station Network is the first effort to continuously sample widespread ocean areas across the United States using identically calibrated passive acoustic instrumentation. Using these data, I measure and compare diverse acoustic environments and management contexts of marine soundscapes in all major regions of United States waters. The chapters of this dissertation quantify the levels and drivers of ambient sound in marine protected and biologically important areas at different scales. Chapter 2 compares the sound levels and trends at five widespread deep-water (>500 m depth) sites (Alaskan Arctic, Olympic Coast National Marine Sanctuary, Channel Islands National Marine Sanctuary, Gulf of Mexico, and Northeast Canyons and Monuments National Monument). Chapter 3 evaluates the acoustic environments of four shallow (500 m depth) sites (Gulf of Mexico, Cordell Bank National Marine Sanctuary, Hawaii, Northeast Canyons and Monuments National Monument, and Alaskan Arctic). The results of the four manuscripts included in this dissertation provide decision-making information for regulatory agencies to manage acoustically sensitive ecological areas

The Soundcheck of the Sea : Comparing Marine Soundscapes on a Continental Scale

Monitoring marine ambient sound using standardized methods supports assessments of ocean sound levels across widespread ecosystems. This thesis quantifies differences among coastal and deep-water marine soundscapes in the Atlantic and Pacific oceans. The sources of sound in a soundscape are compartmentalized into three components and compared over time and among different areas to give insight into the status of ocean ecosystems, revealing the presence of vocalizing animals, anthropogenic activity, and environmental changes such as weather (e.g., wind, rain) and ice coverage. Assessment of acoustic differences across discrete soundscapes supports the work of policy and planning leaders to address issues dealing with monitoring protected areas and marine species (marine mammals, fish), and the contribution of anthropogenic sources to ambient sound associated with energy production (oil exploration, renewable energy development) and socioeconomic activity (container shipping, commercial fisheries, and sport watercraft). These data also define a baseline to evaluate changes over time, including the presence of anthropogenic activities, and the efficacy of management approaches addressing both protected areas and species.Keywords: passive acoustic monitoring, soundscapes, marine conservation, ocean ambient soun

Assessing variation in faecal glucocorticoid concentrations in gray whales exposed to anthropogenic stressors

Funding: This work was supported by the Office of Naval Research Marine Mammals and Biology Program [grant number: N00014-20-1-2760]; the NOAA National Marine Fisheries Service Office of Science and Technology Ocean Acoustics Program (2016 and 2017) [grant number: 50–27]; and the Oregon State University Marine Mammal Institute, NOAAPacific Marine Environmental Laboratory, and Oregon Sea Grant Program Development funds (2018) [grant number: RECO-40-PD]. L.S.L. was supported by Brazil’s Science Without Borders program, Brazilian National Council for Scientific and Technological Development, the Harvard Laspau Institute, the Mamie Markham Research Award (OSU) and Cetacean Society International.Understanding how individual animals respond to stressors behaviourally and physiologically is a critical step towards quantifying long-term population consequences and informing management efforts. Glucocorticoid (GC) metabolite accumulation in various matrices provides an integrated measure of adrenal activation in baleen whales and could thus be used to investigate physiological changes following exposure to stressors. In this study, we measured GC concentrations in faecal samples of Pacific Coast Feeding Group (PCFG) gray whales (Eschrichtius robustus) collected over seven consecutive years to assess the association between GC content and metrics of exposure to sound levels and vessel traffic at different temporal scales, while controlling for contextual variables such as sex, reproductive status, age, body condition, year, time of year and location. We develop a Bayesian Generalized Additive Modelling approach that accommodates the many complexities of these data, including non-linear variation in hormone concentrations, missing covariate values, repeated samples, sampling variability and some hormone concentrations below the limit of detection. Estimated relationships showed large variability, but emerging patterns indicate a strong context-dependency of physiological variation, depending on sex, body condition and proximity to a port. Our results highlight the need to control for baseline hormone variation related to context, which otherwise can obscure the functional relationship between faecal GCs and stressor exposure. Therefore, extensive data collection to determine sources of baseline variation in well-studied populations, such as PCFG gray whales, could shed light on cetacean stress physiology and be used to extend applicability to less-well-studied taxa. GC analyses may offer greatest utility when employed as part of a suite of markers that, in aggregate, provide a multivariate measure of physiological status, better informing estimates of individuals’ health and ultimately the consequences of anthropogenic stressors on populations.Publisher PDFPeer reviewe

Assessing variation in faecal glucocorticoid concentrations in gray whales exposed to anthropogenic stressors

Processed data and analysis code to run the Bayesian Generalized Additive Models to quantify the relationships between fecal glucocorticoid concentrations and anthropogenic stressors (sound levels and vessel counts) in gray whales (Eschrichtius robustus