GEOGRAPHIC INFLUENCES ON THE SKIN MICROBIOME OF HUMPBACK WHALES

Assessing the health state of wild marine mammals and their populations is challenging, and there is a growing need to develop reliable proxies for health determination. Climate change and other anthropogenic factors are influencing disease prevalence and virulence in the marine environment and there is a need to improve tools and techniques for monitoring the health status of wild marine mammals that are listed as threatened or endangered. The skin is the largest mammalian organ and serves as the first line of defense between the host and their external environment. Most research has focused on human health and has found that the skin microbiome can serve as a protective mechanism by adding to the skin’s defense against colonization of potential pathogenic bacteria. The skin is relatively well-sampled in marine mammals and may serve as a useful proxy for health status, as demonstrated in humans. However, before skin microbiomes become useful health diagnostic tools for marine mammals, more information is needed about the factors influencing variability within the skin microbial community. I analyzed the skin microbiome of 72 apparently healthy humpback whales primarily from Antarctica, as well as Alaska, Hawaii, American Samoa, and the Gulf of Maine. Phylogenetic and statistical analyses revealed two dominant families of bacteria (Moraxellaceae and Flavobacteriaceae) found on each individual whale. However, there were significant differences in the skin microbiomes amongst whales from different geographic areas, both globally as well as amongst regions within Antarctica. These findings provide support that there is a species-specific microbiome on humpback skin that varies according to geographic factors. This initial characterization of the healthy humpback skin microbiome in Antarctica is helpful for future health diagnostic efforts aimed especially at heath-compromised animals. This research ultimately aims to be the building blocks for exploring how the skin microbiome can be used as a diagnostic tool for monitoring marine mammal health

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

<b>Shaped by their environment: variation in blue whale morphology across three productive coastal ecosystems</b>

Shaped by their environment: variation in blue whale morphology across three productive coastal ecosystemsDawn R. Barlow1*, K.C. Bierlich1, William K. Oestreich2, Gustavo Chiang3, John W. Durban4, Jeremy A. Goldbogen5, David W. Johnston6, Matthew S. Leslie7, Michael Moore8, John P. Ryan2, Leigh G. Torres11Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Newport, Oregon USA2Monterey Bay Aquarium Research Institute, Moss Landing, California, USA3Centro de Investigación para la Sustentabilidad (CIS) & Departamento de Ecología y Biodiversidad, Universidad Andrés Bello, Santiago, Chile4Marine Mammal Institute, Oregon State University, Newport, Oregon, USA5Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, California, USA6Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University Marine Laboratory, Beaufort, North Carolina, USA7 National Climate Adaptation Science Center, United States Geological Survey, Reston, Virginia, USA8Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA*[email protected]: Species ecology and life history patterns are often reflected in animal morphology. Blue whales are globally distributed, with distinct populations that feed in different productive coastal regions worldwide. Thus, they provide an opportunity to investigate how regional ecosystem characteristics may drive morphological differences within a species. Here, we compare physical and biological oceanography of three different blue whale foraging grounds: (1) Monterey Bay, California, USA, (2) the South Taranaki Bight (STB), New Zealand, and (3) the Corcovado Gulf, Chile. Additionally, we compare the morphology of blue whales from these regions using unoccupied aircraft imagery. Monterey Bay and the Corcovado Gulf are seasonally productive and support the migratory life history strategy of the Eastern North Pacific (ENP) and Chilean blue whale populations, respectively. In contrast, the New Zealand blue whale population remains in the less productive STB year-round. All three populations were indistinguishable in total body length. However, New Zealand blue whales were in significantly higher body condition despite lower regional productivity, potentially attributable to their non-migratory strategy that facilitates lower risk of spatiotemporal misalignment with more consistently available foraging opportunities. Alternatively, the migratory strategy of the ENP and Chilean populations may be successful when their presence on the foraging grounds temporally aligns with abundant prey availability. We document differences in skull and fluke morphology between populations, which may relate to different feeding behaviors adapted to region-specific prey and habitat characteristics. These morphological features may represent a trade-off between maneuverability for prey capture and efficient long-distance migration. As oceanographic patterns shift relative to long-term means under climate change, these blue whale populations may show different vulnerabilities due to differences in migratory phenology and feeding behavior between regions. </p