Category: GRANITE

How Humans and Cetaceans Shape Each Other

Marc Rams i Rios, PhD Student, Oregon State University Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

When I moved to Oregon to begin my PhD, I pictured long days on the water watching gray whales feed and travel along the coast. That does happen, and it is as incredible as I imagined. But I have learned that studying cetaceans is about much more than observing whales. It is also about people: how cultures – past and present – perceive these animals and share space with them.

In addition to marine mammals, I have always loved history and geography. Now, as I start my work with the GRANITE Project in the GEMM Lab, I find myself thinking about how these relationships between humans and whales unfold across time and space. In this post, I want to share a few examples of how whales have shaped human traditions for hundreds, even thousands of years, across societies that have never crossed. Then I will discuss how our research fits into this larger picture of human–cetacean connections.

Our journey begins in India, where the Ganges River dolphin inhabits a river that millions of people consider sacred. Its presence has long been linked to the health of the river, giving the species spiritual and cultural significance. Over the past century, the river’s ecological integrity has declined due to pollution, altered flow, and habitat disturbances, and this has caused the dolphin population to diminish1, 2. Conservation efforts that improve water quality, restore natural flow, and reduce disturbances not only help the dolphin recover but also protect the river and the human communities that rely on it1, 2. In this way, cultural reverence for the dolphin drives conservation measures that benefit both people and ecosystems1, 2.

© WWF Mohd Shahnawaz Khan

From there we move to Aotearoa, New Zealand, where Māori tradition speaks of tohorā, or whales, as guardians and ancestors3. They appear in ancestral stories as guides and protectors, and whale strandings have historically brought communities together in collective response. The Māori principles of kaitiakitanga, or guardianship, continue to shape marine conservation decisions today, guiding policies that integrate ecological and cultural values4. Here, whales are not seen as resources. They are part of a living genealogy that binds people to the sea and the life it sustains. In fact, team members of the SAPPHIRE project in the GEMM lab frequently engage with multiple iwi (Māori tribes) across Aotearoa through hui (meetings) where knowledge, stories, and culture are shared about blue whales and their ecosystem.

Traveling nearly to the antipodes, we arrive on the Atlantic coast of Brazil, in the town of Laguna, where an extraordinary partnership has endured for centuries. Artisanal fishers work alongside bottlenose dolphins, who drive schools of fish toward the shore and signal the right moment to cast the nets5, 6, 7. This cooperation benefits both species, and the knowledge behind it is passed down through generations of humans and dolphins through observation and shared practice5, 6, 7. It is a powerful example of how species can learn from one another, creating connections that challenge the idea of humans and wildlife as competitors and showing the potential for collaboration across species5, 6, 7. The LABIRINTO Lab in MMI has studied this interspecific relationship for decades, helping us learn about the patterns and endurance of these cultures.

PELD-SELA: Long-term ecological project on the Laguna Estuarine System and Adjacent Areas Projects. (n.d.). https://thelabirinto.com/projects1/

At the top of the Americas, in the Arctic, Inuit communities have hunted bowhead whales for thousands of years. These hunts are not only a source of food but also form the foundation of cultural identity and social life8. Knowledge of the ice, weather, and whale behavior is passed down through generations, and the hunt itself is embedded in ceremonies and practices that sustain the community8. Today, these traditions continue under strict quotas set through international agreements, carefully balancing cultural continuity with conservation9. The MMBEL lab in MMI studies the communication and ecology of bowhead whales to support the survival of this iconic species and the culture of Inuit people.

Emory Kristoff, National Geographic

Finally, our journey brings us to Oregon, where gray whales feed along a coastline rich with reefs, kelp beds, and sandy bottoms. These waters support a variety of human activities, from commercial fishing to recreation, creating risks such as entanglement, vessel strikes, and disturbance10, 11. Even well-intentioned actions like whale watching can cause harm if not carefully managed12, 13. Around the world, many communities have shifted from whaling to whale watching, transforming former hunting grounds into tourism destinations. While this is a positive change, it still requires monitoring. Noise can stress whales, boats can disrupt their behavior, and too much interaction can alter natural feeding and social patterns12, 13. In Oregon, research on gray whale habitat use and feeding home ranges helps inform management and conservation14.

Tradewind Charters Whale Watching and Fishing

This is where project GRANITE, Gray whale Response to Ambient Noise Informed by Technology and Ecology, comes in15. The project studies how whales respond to human activities by using drones to monitor health and behavior, photo-ID to track individuals, prey mapping to understand feeding choices, and acoustic recorders to capture the soundscape15, 16, 17. Equally important is collaborating directly with fishers and resource managers to reduce risks and develop solutions that benefit both whales and people. Healthy whale populations support communities too, through ecotourism, cultural continuity, education, and the ecological services whales provide. Conservation is reciprocal: caring for whales strengthens the ocean systems that sustain us all.

The tools and techniques developed by GRANITE, including drones, acoustic monitoring, and prey mapping, are not limited to Oregon. They can be applied globally, contributing to the protection of cetaceans in diverse habitats15. In this way, Oregon becomes more than the final stop on our tour. It is a place where centuries of human–whale relationships, lessons from around the world, and modern science converge. These examples across the world remind us that conservation is about more than preventing harm. It is about fostering a future where humans and whales thrive together, as they have shared the ocean for millennia.

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References

1 Sinha, R. K., & Kannan, K. (2014). Ganges river dolphin: An overview of biology, ecology, and conservation status in India. AMBIO, 43(8), 1029–1046. https://doi.org/10.1007/s13280-014-0534-7

2 Braulik, G., Atkore, V., Khan, M. S., & Malla, S. (2021). Review of scientific knowledge of the Ganges river dolphin. WWF. https://riverdolphins.org/wp-content/uploads/2021/07/Ganges-River-dolphin-Scientific-Knowledge-Review-July2021.pdf

3 Taonga, N. Z. M. for C. and H. T. M. (n.d.). Whales in Māori tradition. Teara.govt.nz. https://teara.govt.nz/en/te-whanau-puha-whales/page-1

4 McAllister, T., Hikuroa, D., & Macinnis‑Ng, C. (2023). Connecting science to Indigenous knowledge: Kaitiakitanga, conservation, and resource management. New Zealand Journal of Ecology, 47(1), 3521. https://doi.org/10.20417/nzjecol.47.3521

5 Simões‑Lopes, P. C., Fabián, M. E., & Menegheti, J. O. (1998). Dolphin interactions with the mullet artisanal fishing on southern Brazil: A qualitative and quantitative approach. Revista Brasileira de Zoologia, 15(3), 709–726. https://doi.org/10.1590/S0101-81751998000300008

6 Daura Jorge, F. G., Cantor, M., Ingram, S. N., Lusseau, D., & Simões Lopes, P. C. (2012). The structure of a bottlenose dolphin society is coupled to a unique foraging cooperation with artisanal fishermen. Biology Letters, 8(5), 702–705. https://doi.org/10.1098/rsbl.2012.0174

7 Cantor, M., Farine, D. R., & Daura‑Jorge, F. G. (2023). Foraging synchrony drives resilience in human–dolphin mutualism. Proceedings of the National Academy of Sciences, 120(6), e2207739120. https://doi.org/10.1073/pnas.2207739120

8 Jensen, A. M. (2012). The material culture of Iñupiat whaling: An ethnographic and ethnohistorical perspective. Arctic Anthropology, 49(2), 143–161. https://doi.org/10.1353/arc.2012.0020

9 Description of the USA Aboriginal Subsistence Hunt: Alaska. (n.d.). Iwc.int. https://iwc.int/management-and-conservation/whaling/aboriginal/usa/alaska

10 Derville, S., Buell, T. V., Corbett, K. C., Hayslip, C., & Torres, L. G. (2023). Exposure of whales to entanglement risk in Dungeness crab fishing gear in Oregon, USA. Biological Conservation, 281, 109989. https://doi.org/10.1016/j.biocon.2023.109989

11 Silber, G. K., Weller, D. W., Reeves, R. R., Adams, J. D., & Moore, T. J. (2021). Co‑occurrence of gray whales and vessel traffic in the North Pacific Ocean. Endangered Species Research, 44, 177–201. https://doi.org/10.3354/esr01093

12 Sullivan, F. A., & Torres, L. G. (2018). Assessment of vessel disturbance to gray whales to inform sustainable ecotourism. Journal of Wildlife Management, 82(5), 896–905. https://doi.org/10.1002/jwmg.21462

13 Sprogis, K. R., Videsen, S., & Madsen, P. T. (2020). Vessel noise levels drive behavioural responses of humpback whales with implications for whale‑watching. eLife, 9, e56760. https://doi.org/10.7554/eLife.56760

14 Lagerquist, B. A., Palacios, D. M., Winsor, M. H., Irvine, L. M., Follett, T. M., & Mate, B. R. (2019). Feeding home ranges of Pacific Coast Feeding Group gray whales. Journal of Wildlife Management, 83(4), 925–937. https://doi.org/10.1002/jwmg.21642

15 GRANITE: Gray whale Response to Ambient Noise Informed by Technology and Ecology | Marine Mammal Institute | Oregon State University. (n.d.). Mmi.oregonstate.edu. https://mmi.oregonstate.edu/gemm-lab/granite-gray-whale-response-ambient-noise-informed-technology-ecology

16 Pirotta, E., Bierlich, K. C., New, L., Bird, C. N., Fernandez Ajó, A., Hildebrand, L., Buck, C. L., Hunt, K. E., Calambokidis, J., & Torres, L. G. (2025). Body size, nutritional state and endocrine state are associated with calving probability in a long‑lived marine species. Journal of Animal Ecology. Advance online publication. https://doi.org/10.1111/1365-2656.70068

17 Bierlich, K. C., Kane, A., Hildebrand, L., Bird, C. N., Fernandez Ajó, A., Stewart, J. D., Hewitt, J., Hildebrand, I., Sumich, J., & Torres, L. G. (2023). Downsized: Gray whales using an alternative foraging ground have smaller morphology. Biology Letters, 19(7), 20230043. https://doi.org/10.1098/rsbl.2023.0043

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New GEMM Lab study indicates troubled times for PCFG gray whales

Dr. Enrico Pirotta (CREEM, University of St Andrews) and Dr. Leigh Torres (GEMM Lab, MMI, OSU)

The health of animals affects their ability to survive and reproduce, which, in turn, drives the dynamics of populations, including whether their abundance trends up or down. Thus, understanding the links between health and reproduction can help us evaluate the impact of human activities and climate change on wildlife, and effectively guide our management and conservation efforts. In long-lived species, such as whales, once a decline in population abundance is detected, it can be too late to reverse the trend, so early warning signals are needed to indicate how these populations are faring.

We worked on this complex issue in a study that was recently published in the Journal of Animal Ecology. In this paper, we developed a new statistical approach to link three key components of the health of a Pacific Coast Feeding Group (PCFG) gray whale (namely, its body size, body condition, and stress levels) to a female’s ability to give birth to a calf. We were able to inform these metrics of whale health using an eight-year dataset derived from the GRANITE project of aerial images from drones for measurements of body size and condition, and fecal samples for glucocorticoid hormone analysis as an indicator of stress. We combined these data with observations of females with or without calves throughout the PCFG range over our study period.

We found that for a female to successfully have a calf, she needs to be both large and fat, as these factors indicate if the female has enough energy stored to support reproduction that year (Fig. 1). Remarkably, we also found indication that females with particularly high stress hormone levels may not get pregnant in the first place, which is the first demonstration of a link between stress physiology and vital rates in a baleen whale, to our knowledge.

Figure 1. Taken from Pirotta et al. (2025), Fig. 5. Combined relationship of PCFG gray whale length and nutritional state (combination of body size and condition) in the previous year with calving probability, colored by whether the model estimated an individual to have calved or not at a given reproductive opportunity.

Our study’s findings are concerning given our previous research indicating that gray whales in this PCFG sub-group have been growing to shorter lengths over the last couple of decades (Pirotta et al. 2023), are thinner than animals in the broader Eastern North Pacific gray whale population (Torres et al, 2022), and show an increase in stress-related hormones when exposed to human activities (Lemos et al, 2022; Pirotta et al. 2023). Furthermore, in our recent study we also documented that there are fewer young individuals than expected for a growing or stable population (Fig. 2), which can be an indicator of a population in decline since there may not be many individuals entering the reproductive adult age groups. Altogether, our results act as early warning signals that the PCFG may be facing a possible population decline currently or in the near future.

Figure 2. Taken from Pirotta et al. (2025), Fig. 1. Age structure diagram for 139 PCFG gray whales in our dataset. Each bar represents the number of individuals of a given age in 2023, with the color indicating the proportion of individuals of that age for which age is known (vs. estimated from a minimum estimate following Pirotta, Bierlich, et al., 2024). The red line reports a smooth kernel density estimate of the distribution.

These findings are sobering news for Oregon residents and tourists who enjoy watching these whales along our coast every summer and fall. We have gotten to know many of these whales so well – like Scarlett, Equal, Clouds, Lunita, and Pacman, who you can meet on our IndividuWhale website – that we wonder how they will adapt and survive as their once reliable habitat and prey-base changes. We hope our work sparks collective and multifaceted efforts to reduce impacts on these unique PCFG whales, and that we can continue the GRANITE project for many more years to come to monitor these whales and learn from their response to change.

This work exemplifies the incredible value of long-term studies, interdisciplinary methods, and effective collaboration. Through many years of research on this gray whale group, we have collected detailed data on diverse aspects of their behavior, ecology and life history that are critical to understanding their response to disturbance and environmental change, which are both escalating in the study region. We are incredibly grateful to the following members of the PCFG Consortium for contributing sightings and calf observation data that supported this study: Jeff Jacobsen, Carrie Newell, NOAA Fisheries (Peter Mahoney and Jeff Harris), Cascadia Research Collective (Alie Perez), Department of Fisheries and Oceans, Canada (Thomas Doniol-Valcroze and Erin Foster), Mark Sawyer and Ashley Hoyland, Wendy Szaniszlo, Brian Gisborne, Era Horton.

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References:

Lemos, Leila S., Joseph H. Haxel, Amy Olsen, Jonathan D. Burnett, Angela Smith, Todd E. Chandler, Sharon L. Nieukirk, Shawn E. Larson, Kathleen E. Hunt, and Leigh G. Torres. “Effects of Vessel Traffic and Ocean Noise on Gray Whale Stress Hormones.” Scientific Reports 12, no. 1 (2022): 18580. https://dx.doi.org/10.1038/s41598-022-14510-5.

Pirotta, Enrico, K. C. Bierlich, Leslie New, Lisa Hildebrand, Clara N. Bird, Alejandro Fernandez Ajó, and Leigh G. Torres. “Modeling Individual Growth Reveals Decreasing Gray Whale Body Length and Correlations with Ocean Climate Indices at Multiple Scales.” Global Change Biology 30, no. 6 (2024): e17366. https://doi.org/https://doi.org/10.1111/gcb.17366. https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.17366.

Pirotta, Enrico, Alejandro Fernandez Ajó, K. C. Bierlich, Clara N Bird, C Loren Buck, Samara M Haver, Joseph H Haxel, Lisa Hildebrand, Kathleen E Hunt, Leila S Lemos, Leslie New, and Leigh G Torres. “Assessing Variation in Faecal Glucocorticoid Concentrations in Gray Whales Exposed to Anthropogenic Stressors.” Conservation Physiology 11, no. 1 (2023). https://dx.doi.org/10.1093/conphys/coad082.

Torres, Leigh G., Clara N. Bird, Fabian Rodríguez-González, Fredrik Christiansen, Lars Bejder, Leila Lemos, Jorge Urban R, et al. “Range-Wide Comparison of Gray Whale Body Condition Reveals Contrasting Sub-Population Health Characteristics and Vulnerability to Environmental Change.” Frontiers in Marine Science 9 (2022). https://doi.org/10.3389/fmars.2022.867258. https://www.frontiersin.org/article/10.3389/fmars.2022.867258