GRANITE: Gray whale Response to Ambient Noise Informed by Technology and Ecology

Background
Summary

Investigators: Dr. Leigh Torres, Dr. Joe Haxel, Dr. Kathleen Hunt, Dr. Leslie New, Lisa Hildebrand, Clara Bird, Dr. KC Bierlich, Dr. Alejandro Fernández Ajó, Dr. Enrico Pirotta, Natalie Chazal, Dr. Leila Lemos, Todd Chandler

Cetaceans are acoustically active, dependent on, and sensitive to the surrounding soundscape. Therefore, understanding the scales, intensities and types of impacts from ocean noise on their ecology and populations is a critical step toward improved management and protection. Studies have shown behavioral impacts on various cetacean species from acute ocean noise events, such as seismic air guns, mid-frequency sonar and elevated vessel traffic. Yet, it is unclear how chronic, elevated ambient noise levels may affect the physiology, behavior and ecology of individuals, or how these impacts may translate into biologically significant events with long-term consequences for individuals or populations (e.g., the Population Consequences of Multiple Stressors (PCoMS) model).

In 2015, the GEMM Lab initiated a multifaceted and non-invasive research project to evaluate the hormonal variability and health of gray whales that forage along the Oregon coast between May and October each year. These whales are part of the Pacific Coast Feeding Group (PCFG) and forage in the coastal habitat off Oregon, where they are exposed to variable ambient ocean noise conditions (e.g., storms, vessel traffic).

This is a large, multidisciplinary and highly collaborative project, with many inter-connected objectives: (1) measure and characterize the coastal soundscape of Oregon, (2) describe the variation in reproductive and stress hormones in gray whale fecal samples, (3) evaluate the trends in gray whale body condition and morphology by demographic unit and temporal period, (4) assess the foraging ecology and population dynamics of the PCFG relative to variation in habitat and prey availability, (5) quantify how various foraging behaviors relate to individual, habitat, and body condition, and (6) link these previously described data sets and results to evaluate the relationships between ambient ocean noise levels and gray whale health.

Throughout this project, we employ multiple innovative methods to observe and measure gray whale ecology and physiology, and ultimately assess the role of variable ocean noise on whale stress. We monitor coastal ambient ocean noise using hydrophones, assess gray whale reproductive and stress hormone levels through fecal sample collection and analysis, use drones to document whale behavior and body condition, deploy GoPro camera drops and collect zooplankton samples to describe prey availability, and deploy suction cup accelerometer tags (with video and acoustic sensors) to describe underwater whale movements and surroundings.

Findings from our project will be used to inform regulatory decisions regarding allowable noise thresholds in the vicinity of baleen whale habitats, aiding species conservation through informed management practices.

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Compilation of images from the GRANITE project. Clockwise from top left: Gray whale breaches in the front of the Yaquina Lighthouse, Newport, OR, USA; Underwater image of gray whale feeding; The GEMM Lab team collecting a gray whale fecal sample; Aerial drone image of a gray whale mom-calf pair. All images captured under NOAA/NMFS permit #16111.

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Publications:

Pirotta, E., K.C. Bierlich, L. New, L. Hildebrand, C.N. Bird, A. Fernandez Ajó, and L.G. Torres, Modeling individual growth reveals decreasing gray whale body length and correlations with ocean climate indices at multiple scales. Global Change Biology, 2024. 30(6): p. e17366. https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.17366

Pirotta, E., A. Fernandez Ajó, K.C. Bierlich, C.N. Bird, C.L. Buck, S.M. Haver, J.H. Haxel, L. Hildebrand, K.E. Hunt, L.S. Lemos, L. New, and L.G. Torres, Assessing variation in faecal glucocorticoid concentrations in gray whales exposed to anthropogenic stressors. Conservation Physiology, 2023. 11(1). https://doi.org/10.1093/conphys/coad082

Torres, L.G., S.M. Brander, J.I. Parker, E.M. Bloom, R. Norman, J.E. Van Brocklin, K.S. Lasdin, and L. Hildebrand, Zoop to poop: assessment of microparticle loads in gray whale zooplankton prey and fecal matter reveal high daily consumption rates. Frontiers in Marine Science, 2023. 10. https://www.frontiersin.org/articles/10.3389/fmars.2023.1201078

Torres, L.G., C.N. Bird, F. Rodríguez-González, F. Christiansen, L. Bejder, L. Lemos, J. Urban R, S. Swartz, A. Willoughby, J. Hewitt, and K. Bierlich, Range-Wide Comparison of Gray Whale Body Condition Reveals Contrasting Sub-Population Health Characteristics and Vulnerability to Environmental Change. Frontiers in Marine Science, 2022. 9. https://www.frontiersin.org/article/10.3389/fmars.2022.867258

Lemos, L.S., J.H. Haxel, A. Olsen, J.D. Burnett, A. Smith, T.E. Chandler, S.L. Nieukirk, S.E. Larson, K.E. Hunt, and L.G. Torres, Effects of vessel traffic and ocean noise on gray whale stress hormones. Scientific Reports, 2022. 12(1): p. 18580. https://doi.org/10.1038/s41598-022-14510-5

Lemos, Leila S., Amy Olsen, Angela Smith, Jonathan D. Burnett, Todd E. Chandler, Shawn Larson, Kathleen E. Hunt, and Leigh G. Torres. "Stressed and slim or relaxed and chubby? A simultaneous assessment of gray whale body condition and hormone variability." Marine Mammal Science (2021). https://doi.org/10.1111/mms.12877

Lemos, Leila, Amy Olsen, Angela Smith, Todd E Chandler, Shawn Larson, Kathleen Hunt, and Leigh G Torres. "Assessment of fecal steroid and thyroid hormone metabolites in eastern North Pacific gray whales." Conservation Physiology, Volume 8, Issue 1 (2020). https://doi.org/10.1093/conphys/coaa110.

Soledade Lemos, Leila, Jonathan D. Burnett, Todd E. Chandler, James L. Sumich, and Leigh G. Torres. "Intra- and Inter-Annual Variation in Gray Whale Body Condition on a Foraging Ground." Ecosphere 11, no. 4 (2020): e03094. https://dx.doi.org/10.1002/ecs2.3094.

Torres, Leigh G., Sharon L. Nieukirk, Leila Lemos, and Todd E. Chandler. "Drone Up! Quantifying Whale Behavior from a New Perspective Improves Observational Capacity." Original Research, Frontiers in Marine Science 5, no. 319 (2018-September-10 2018). https://dx.doi.org/10.3389/fmars.2018.00319.

Supplemental material: Full compilation video of gray whale behaviors

Burnett, Jonathan D., Leila Lemos, Dawn Barlow, Michael G. Wing, Todd Chandler, and Leigh G. Torres. "Estimating Morphometric Attributes of Baleen Whales with Photogrammetry from Small Uass: A Case Study with Blue and Gray Whales." Marine Mammal Science 35, no. 1 (2019): 108-39. https://dx.doi.org/10.1111/mms.12527.

Media and videos: