Dr. Clara Bird, Postdoctoral Scholar, OSU Department of Fisheries, Wildlife, and Conservation Sciences, GEMM Lab & LABIRINTO
In one of my first GEMM lab blogs (over six years ago!) I wrote that for my thesis I was going to, “…use the drone footage to analyze gray whale behavior and how it varies across space, time, and individual.”, and I’m happy to say that I more or less accomplished that goal. Now as I write my last blog for the GEMM lab, a whole PhD and postdoc later, I want to take this opportunity to share what we’ve learned about Pacific Coast Feeding Group (PCFG) gray whale behavior from my PhD and postdoc work.
A behavioral specialization
Given the impressive diversity of foraging tactics used by PCFG gray whales (Torres et al., 2018), a central question from the start was, “do all individuals use all behaviors, or is there variation in which whales use each behavior?”. This interest in individual specialization led to several blogs and became the question I asked in my first PhD chapter (read an introduction to specialization here and summaries of the drivers of specialization here and here). In my first chapter, I used drone data to study the relationship between individual behavior use, body length and condition, and habitat type. We found a strong relationship between foraging behavior and individual length (which is also a proxy for age). Longer, older, whales were more likely to feed using the headstanding tactic while shorter, younger, whales were more likely to feed using forward swimming tactics (Figure 1; Bird et al., 2024a). Together, these results suggest an ontogenetic shift (i.e., a shift associated with age) in foraging behavior use. Furthermore, we found that different tactics were more likely to be used in different habitats; headstanding was more likely to occur in reef habitats while the forward swimming tactics were more likely to occur in rock habitat. Overall, this chapter showed us that PCFG gray whale foraging behavior varies by length/age and habitat, indicating a lack of generalization across the group.
Figure 1. The relationship between individual total length and the probability of a behavior being used. In each box, the x-axis represents total length, and the y-axis represents the probability of that behavior (shown in the box title) being used. Figure from Bird et al. (2024a).
A behavioral adaptation
If you’ve ever watched gray whales off the coast and seen a large bubble rise to the surface, then you’ve seen a bubble blast! While we observed these bubble blasts, described as “underwater release of air that rises to surface and forms a circle/puka.” (Torres et al., 2018), fairly often in the field (Figure 2), we were never quite sure of their function, leading to my second chapter.
Figure 2. Sequential photos extracted from drone video of bubble blasts performed by PCFG gray whales during a headstand (a), side-swim stationary (b), and subsurface feeding (c). Images 1–5 in each panel show a bubble blast event from the start of the exhalation (1) to the whale continuing to feed after the bubble has diffused at the surface (5). Figure from Bird et al., (2024b).
We initially wondered if bubble blasts served a prey corralling function (like humpback whale bubble nets), but the timing and location did not fit that idea. We instead wondered if bubble blasts were being used to regulate buoyancy. The whales we study forage in water nearly as shallow (<15 m) as they are long (~12 m), meaning that they must work against their buoyancy to dive. So, like a diver releasing air from their vest to sink, we hypothesized that these whales release air from their lungs (in the form of a bubble blast) to be able to dive more efficiently. Building on this idea, we specifically hypothesized that a whale would be more likely to bubble blast if they were bigger (i.e., because they had larger lungs) and fatter (i.e., they are more buoyant due to increased blubber). To test this hypothesis, we modeled the relationship between bubble blast use, total length, and body condition and found that the probability of an individual whale bubble blasting increased with total length and body condition. Furthermore, we found that whales who bubble blasted performed longer dives than those who did not, supporting our hypothesis that bubble blasts improved dive efficiency (Bird et al., 2024b).
Behavior and energetics
The interpretation of results from my first two chapters involved many questions regarding energetics. As we’ve described in previous blogs (here and here), it is important to understand how much energy different behaviors require because energetics helps us understand foraging success. Following the results of my first chapters, we wanted to better understand if different foraging behaviors cost different amounts of energy and if bubble blasts affected the energetic cost of a dive. To ask these questions we used individual breathing patterns as a proxy for energy expenditure (read more on the method here) and explored how breathing patterns were related to individual length, body condition, and behavior (including dive duration, foraging tactic, and bubble blast use). We found that the energetic cost of a dive increased with individual length, body condition, and dive duration (Figure 3.A1-3). Interestingly, we found no relationship between foraging tactic, bubble blast use and energetic expenditure (Bird et al., 2025; Figure 3.A4). However, my second chapter showed that both foraging behavior and bubble blast use affect dive duration (Bird et al., 2024b), indicating that effects of behavior on energetics come via the dive duration variable.
Figure 3. Estimated relationships between (1) total length (TL), (2) Body Area Index (BAI), (3) preceding dive duration (s) and (4) preceding dive foraging tactic and bubble blast occurrence and (A) total inhalation duration (s). Here total inhalation duration is the sum of all inhalations following a dive; a higher value indicates higher energy expenditure during the dive.In A4 the foraging tactics have been abbreviated as follows: HS = Headstand, Side.Sw.St = Side-swim stationary, Fwd.Sw. = Forward swimming tactics, Sub.St = Subsurface stationary, Surf. = Surface tactics.Figure from Bird et al., (2025).
Social patterns
As a postdoctoral scholar I had the opportunity to pivot from PCFG foraging behavior to social behavior. We generally think of baleen whales as solitary animals with loose social structure when on their foraging grounds, including gray whales while in nearshore Oregon waters. But social structure is not well studied in gray whales and can provide important insight into how information or disease might pass through a population. To look for social patterns we first assigned whales to a group if they were seen within 10 minutes and 100 meters of each other; whales seen in the same group were determined to be “associated”. If we saw whales interact with each other (e.g., touch each other, swim in a synchronized movement) they were determined to be “interacting”. We then tallied the number of times each possible pair of whales had been seen associating and/or interacting. The higher the tally, the stronger the association. Using that dataset, we assessed if some whales were more central (i.e., had strong associations or more associations with other whales) than others and if centrality was related to sex and age. We also assessed if whales were more likely to associate with other whales of similar sex or age. Finally, we reviewed our notes from the field and drone footage and documented the kinds of social interactions we’ve observed. While we’re still wrapping up this work, I’m excited to share that we’ve found that gray whales have more social structure than previously thought, including relationships with age and sex, and documented several interesting social interactions (Figure 4). I am excited to see what more years of data collection reveal about their social patterns, especially with an emphasis on how they might be learning from each other.
Figure 4. A social interaction documented from the drone. Here one whale is pursuing the other. Collected under NMFS permit #27426.
Tying it all together
Looking ahead, I’m most curious to better understand how the PCFG successfully feed in this shallow habitat. The findings of my third chapter show that the energetic cost of foraging increases with body condition (Bird et al., 2025). I hypothesize that this increase is because it becomes physically more difficult to dive as they become more buoyant (due to the increased fat). So, while bubble blasts appear to be a behavioral adaptation to reduce buoyancy (Bird et al., 2024b), there could be a point at which a whale is too fat to continue feeding in this shallow environment. Could this be why PCFG gray whales are skinnier than the Eastern North Pacific (ENP) gray whales that feed in the deeper arctic waters (Torres et al., 2022)? Given recent evidence that the PCFG may be facing a possible population decline (Pirotta et al., 2025), these questions are more relevant than ever.
The one theme that weaves throughout all this work is the importance of individual variation. Thanks to our incredible dataset, built from years of hard work and accessible whales that keep returning to our study site, we are able to follow individuals over time and uncover the links between habitat, individual size, body condition and sex, behavior, energetics, and the whales themselves.
While I am sad to be leaving the GEMM lab, I am certainly proud of all that we have learned so far and excited to see what’s next (as an avid reader of the blog of course).
Did you enjoy this blog? Want to learn more about marine life, research, and conservation? Subscribe to our blog and get a weekly alert when we make a new post! Just add your name into the subscribe box below!
References
Bird CN, Pirotta E, New L, Bierlich KC, Donnelly M, Hildebrand L, Fernandez Ajó A, Torres LG. 2024a. Growing into it: evidence of an ontogenetic shift in grey whale use of foraging tactics. Animal Behaviour 214:121–135. DOI: 10.1016/j.anbehav.2024.06.004.
Bird CN, Pirotta E, New L, Bierlich KC, Hildebrand L, Fernandez Ajó A, Torres LG. 2024b. Bubble blasts! An adaptation for buoyancy regulation in shallow foraging gray whales. Ecology and Evolution 14:e70093. DOI: 10.1002/ece3.70093.
Bird CN, Pirotta E, New L, Cornelius JM, Sumich JL, Colson KM, Bierlich KC, Hildebrand L, Ajó AAF, Doron A, Torres LG. 2025. Size and body condition drive the energetic cost of a baleen whale foraging in shallow habitat. PeerJ13:e20247. DOI: 10.7717/peerj.20247.
Pirotta E, New L, Fernandez Ajó A, Bierlich KC, Bird CN, Buck CL, Hildebrand L, Hunt KE, Calambokidis J, Torres LG. 2025. Body size, nutritional state and endocrine state are associated with calving probability in a long-lived marine species. Journal of Animal Ecology 94:1–13. DOI: 10.1111/1365-2656.70068.
Torres LG, Bird CN, Rodríguez-González F, Christiansen F, Bejder L, Lemos L, Urban R J, Swartz S, Willoughby A, Hewitt J, Bierlich KC. 2022. Range-Wide Comparison of Gray Whale Body Condition Reveals Contrasting Sub-Population Health Characteristics and Vulnerability to Environmental Change. Frontiers in Marine Science 9:1–13. DOI: https://doi.org/10.3389/fmars.2022.867258.
Torres LG, Nieukirk SL, Lemos L, Chandler TE. 2018. Drone up! Quantifying whale behavior from a new perspective improves observational capacity. Frontiers in Marine Science 5:1–14. DOI: 10.3389/fmars.2018.00319.
By Nicole Principe, second-year PhD student, OSU Dept of Fisheries, Wildlife and Conservation Sciences, GEMM Lab
On November 15, 2025, a juvenile humpback whale stranded alive on the Oregon Coast, showing clear evidence of entanglement in gear linked to the 2023-2024 Oregon commercial Dungeness crab fishery1(Fig. 1). A large, multi-organization response followed, including groups from the West Coast Marine Mammal Stranding Network, OSU’s Marine Mammal Institute, Pacific Marine Mammal Center, Cascadia Research Collective, Oregon Coast Aquarium, SeaLife Response, Rehabilitation, Research, and more. After an unsuccessful attempt to help the whale return to sea, trained responders and veterinarians made the difficult decision to humanely euthanize it to prevent further suffering. A full necropsy (animal autopsy) was conducted afterwards to better understand the health of the whale and why it stranded
Figure 1. A stranded humpback whale off the coast of Yachats, OR. (West Coast Marine Mammal Stranding Network)
This event drew significant public attention, with community members gathering on the beach to witness this rare and emotional scene. Seeing a large, sentient animal like a humpback whale stranded on land is deeply upsetting and it naturally raised questions: Why did this happen? Was the whale sick or injured? Why couldn’t it be rescued? These are important and understandable questions and answering them openly is a core part of marine mammal science and education.
I worked as a marine mammal stranding technician in the Southeast US for almost two years, leading responses on numerous deceased and live stranded dolphins and whales. These experiences gave me insights about the realities of marine mammal response, how stranding networks operate, why marine mammals strand, how the public can safely assist when strandings occur, and efforts being done to mitigate human-related threats.
What is a Marine Mammal Stranding?
Before getting into the details of how responses work, it’s important to define what a marine mammal stranding is. The word “stranding” is used to describe sick, injured, entangled, distressed, or dead seals, sea lions, dolphins, porpoises, and whales. Cases vary with animals either washing ashore dead or live stranding on a beach or in shallow water and being unable to return to the water without assistance (Fig. 2). A mass-stranding involves two or more individual cetaceans of the same species stranding together. Each situation is different and requires various resources, equipment, and personnel2.
Figure 2. A) A single stranded dolphin (WDC), B) A mass stranding of pilot whales (Deb Pierce), C) A stranded gray whale in Washington (Cascadia Research Collective)
Stranding Networks
The National Oceanic and Atmospheric Administration (NOAA) Marine Mammal Health and Stranding Response Program (MMHSRP) was established under the Marine Mammal Protection Act and is the governing authority that oversees national responses to stranded pinnipeds and cetaceans. The MMHSRP works in collaboration with federal and state facilities as well as via networks of regional stranding responders, involving aquariums, academic institutions, and non-governmental organizations (NGOs). Network members have a Stranding Agreement from NOAA Fisheries, ensuring that all activities performed are safe for both responders and animals3.
Many stranding networks are made up of only a small number of paid employees and rely on support and assistance from community volunteer members. These networks also rely heavily on federal funding to maintain operations, including funding staff, ordering laboratory and necropsy supplies, facility maintenance, vessel and truck costs, sample shipment, pathology testing, and more. The John H. Prescott Marine Mammal Rescue Assistance Grant Program is a critical source of funding for many stranding groups. From 2001 through 2023, the Prescott Program awarded more than $75.4 million in grants to networks across the U.S4. Proposed budget cuts by the current administration put stranding networks at risk of losing this critical funding, which could impact the level of responses, limit necropsies, or reduce long-term monitoring efforts that are essential for detecting emerging threats to ocean and human health.
Key Steps to A Stranding Response
Figure 3. The steps to a marine mammal stranding response. (Geraci & Lousnbury, 2025).
Step 1 – Stranding Network Receives a Call
Most marine mammal stranding networks operate a 24/7 hotline for the public to report stranded animals. These calls are critical for gathering information such as species, size, condition (alive or dead), location, and any visible injuries or entanglement. Photos and continued communication with the caller can greatly help responders coordinate an appropriate response.
Step 2 – Coordinating a Response
Every stranding is logistically complex, and response strategies differ greatly depending on whether the animal is alive or deceased.
Deceased animals
If an animal is found dead, it may be examined in the field or transported to a lab for further analysis. Accessing the carcass can be challenging due to tides, weather, terrain, and remoteness, often requiring coordination with volunteers and local agencies such as park officials, fire departments, or the Coast Guard.
Live Strandings
Live strandings are time-sensitive and require rapid decision-making. Once intervention is deemed necessary, responders may attempt to return the animal to sea, transport it to a rehabilitation facility, or, in some cases, humanely euthanize it. These decisions are based on the animal’s condition, likelihood of survival, resources available, and safety of both the animal and responders2.
Returning an animal to sea is a viable option only when the animal is deemed healthy and they can safely be returned to their natural habitat. Smaller animals like dolphins and porpoises may be more easily returned to the water or transported to a more appropriate location for release. Whales are typically given one to two tidal cycles to refloat on their own, but their own body weight causes immense pressure once stranded, which can lead to respiratory and circulatory collapse. Pulling a large whale back into the ocean can dislocate the tail, cause paralysis, or even break the spinal cord1. Rare, but successful refloats of whales have happened only when the animal wasn’t exhausted, the sea conditions and the slope of the beach were suitable, and heavy machinery and boats were accessible and usable5.
Rehabilitation and release can be successful for some species, particularly pinnipeds and certain small cetaceans, but outcomes vary widely6,7. Large whales, especially baleen whales, rarely survive rehabilitation due to their size and biological needs8.
Euthanasia is an option when it is necessary to end suffering of an animal in irreversibly poor condition, and the procedure can be carried out humanely, no rehab or care facility is available, rescue is not feasible, or the animal continually re-strands2. This option should only be done after all other options have been considered, proper authorities with NOAA have given approval, and a trained veterinarian is available to safely do the procedure. Oftentimes, veterinarians will administer a sedative to keep the animal calm before euthanasia. While the outcome can be sad, euthanasia is never a choice of convenience. It reflects a commitment to animal welfare, ensuring that when recovery is not possible, the animal does not endure unnecessary pain or distress.
Live Strandings Do’s and Don’ts
Well-intentioned public involvement can sometimes complicate response to a live stranding. Approaching a distressed animal puts human safety at risk and is illegal under the Marine Mammal Protection Act9. Attempting to push a stranded animal back into the water can increase stress, risk injury or drowning, or lead to re-stranding.
Before responders arrive, the public can help by keeping noise levels low, keeping pets away, and following instructions from authorities (Fig. 4). Once on site, response teams may establish boundaries to protect both people and the animal. Community support, such as providing access to private beaches or properties, supplying water or food, or assistance when requested, can play an important role in a smooth response.
Figure 4. Do’s and don’ts for live stranded marine mammals. (Katharina J. Peters and Rebecca M. Boys)
Step 3 – Performing a Necropsy
A critical step after a marine mammal stranding is performing the necropsy to gain further insight into the cause of death. Preliminary information about the stranding itself is recorded, followed by identifying species and sex. Photos are taken of each part of the animal and measurements are collected to obtain morphometric data. A careful external examination is required to identify any signs of human interaction (i.e., entanglement, boat strike) or evidence of disease (i.e., skin lesions, blisters).
Upon opening the animal, each organ is examined and noted for abnormalities. Samples are collected from each organ for histopathology (to identify disease), virology, parasitology, or contaminant analysis. The number of samples that can be collected is influenced by how far along in the decomposition process the carcass is in, and how safely accessible the animal is (e.g., based on tides, daylight, weather).
Step 4 – Identifying Cause of Death
Determining the cause of death for stranded marine mammals is not always possible and rarely straightforward. But broadly, the causes of mortality fall into two categories: environmental factors and anthropogenic factors.
Environmental factors of mortality
Infectious and non-infectious diseases are among the leading causes of marine mammal mortality10. These include bacterial, viral, fungal, and parasitic infections that can affect multiple organ systems, impair feeding, and ultimately lead to emaciation or starvation11-13. Some pathogens, like cetacean morbillivirus and brucellosis, have caused large-scale mortality events and raise concerns for human health, highlighting the need for global monitoring14,15.
Marine mammals are also exposed to pollutants that bioaccumulate in marine ecosystems, including legacy contaminants such as DDT, PCBs, and heavy metals16-19. High contaminant loads have been linked to immunosuppression, increased disease susceptibility, reproductive impairment, endocrine disruption, and neoplasia20-23.
Harmful algal blooms (HABs) and the toxins they produce, such as domoic acid, have also caused mass mortality events in pinnipeds, sea otters, and cetaceans24-27. As HABs increase in frequency and intensity worldwide, they represent a growing threat to both marine mammals and ecosystem health.
Anthropogenic factors of mortality
In addition to natural and environmental causes, many marine mammal strandings are directly linked to human activities in the ocean. Collisions with vessels can result in severe injury or death and are often identified in stranded animals by propeller wounds or evidence of blunt force trauma observed during necropsy. While large, fast-moving ships are responsible for many fatalities involving large whales28,29, smaller recreational vessels also pose substantial risks to coastal species such as bottlenose dolphins and manatees30,31.
Entanglement in fishing gear is also a major source of human-caused mortality for marine mammals worldwide, affecting thousands of animals each year. Smaller species may drown from heavy gear, while large whales can become entangled and drag gear for weeks or months, leading to exhaustion, impaired feeding, infection, and drowning32.
Why do Marine Mammal Strandings Matter?
Marine mammal strandings play a critical role in monitoring ecosystem health. Through strandings and subsequent necropsies, scientists can identify the primary causes of mortality and detect patterns that would otherwise remain hidden in the open ocean. Marine mammals are particularly effective sentinels because they are long-lived, occupy mid- to high-trophic levels, and accumulate pollutants and toxins in their tissues, often providing early warning signs of emerging environmental stressors10.
Multiple stressors from both environmental and human-related threats can compound on a species, resulting in population declines. Continued monitoring through surveys on living animals and information gathered from stranded animals help provide data on what threats are most critical to inform conservation and management decisions and protect both marine ecosystems and human communities.
Preventing Strandings
Many efforts are being made to reduce mortality in marine mammals stemming from direct human impacts. NOAA has established regulations to implement speed restrictions in certain places and times to reduce lethal collisions. There is also a Whale Alert App that boaters can use to see where whales have recently been detected and avoid those areas. Remaining alert and vigilant on the water and transiting slowly in areas where marine mammals may be present can greatly reduce the risk of vessel strikes.
A significant amount of work worldwide is being done to better understand whale entanglements and develop solutions to reduce these events. In the GEMM Lab, Project OPAL was developed to identify co-occurrence between whales and fishing effort in Oregon to reduce entanglement risk. This collaborative project brings together scientists, managers from the Oregon Department of Fish and Wildlife, the commercial Oregon Dungeness crab fishery, and environmental nonprofits to discuss research methods and findings, and develop best practices and regulations to limit risk of entanglement while also ensuring a vibrant and profitable fishery.
If You Come Across a Stranded Marine Mammal
If you see a marine mammal stranding in Oregon, please make your first call to (541) 270-6830 to alert trained responders quickly. If you are in other U.S. regions, the hotlines can be found here.
Neves, M. C., Neto, H. G., Cypriano-Souza, A. L., da Silva, B. M. G., de Souza, S. P., Marcondes, M. C. C., & Engel, M. H. (2020). Humpback Whale (Megaptera novaeangliae) Resighted Eight Years After Stranding. Aquatic Mammals, 46(5), 483–487.
Mazzoil, M. S., McCulloch, S. D., Youngbluth, M. J., Kilpatrick, D. S., Murdoch, E. M., Mase-Guthrie, B., Odell, D. K., & Bossart, G. D. (2008). Radio-Tracking and Survivorship of Two Rehabilitated Bottlenose Dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida. Aquatic Mammals, 34(1), 54–64.
McHugh, K. A., Barleycorn, A. A., Allen, J. B., Bassos-Hull, K., Lovewell, G., Boyd, D., Panike, A., Cush, C., Fauquier, D., Mase, B., Lacy, R. C., Greenfield, M. R., Rubenstein, D. I., Weaver, A., Stone, A., Oliver, L., Morse, K., & Wells, R. S. (2021). Staying Alive: Long-Term Success of Bottlenose Dolphin Interventions in Southwest Florida. Frontiers in Marine Science, 7.
Moore, M., Early, G., Touhey, K., Barco, S., Gulland, F., & Wells, R. (2007). Rehabilitation And Release Of Marine Mammals In The United States: Risks And Benefits. Marine Mammal Science, 23(4), 731–750.
Bossart, G. D. (2010). Marine Mammals as Sentinel Species for Oceans and Human Health. Veterinary Pathology, 48(3), 676–690.
Bogomolni, A., Pugliares, K., Sharp, S., Patchett, K., Harry, C., LaRocque, J., Touhey, K., & Moore, M. (2010). Mortality trends of stranded marine mammals on Cape Cod and southeastern Massachusetts, USA, 2000 to 2006. Diseases of Aquatic Organisms, 88, 143–155.
McFee, W. E., & Lipscomb, T. P. (2009). Major Pathologic Findings And Probable Causes Of Mortality In Bottlenose Dolphins Stranded In South Carolina From 1993 To 2006. Journal of Wildlife Diseases, 45(3), 575–593.
Sanderson, C. E., & Alexander, K. A. (2020). Unchartered waters: Climate change likely to intensify infectious disease outbreaks causing mass mortality events in marine mammals. Global Change Biology, 26(8), 4284–4301.
Taubenberger, J. K., Tsai, M.m Krafft, A. E., Lichy, J. H., Reid, A. H., Schulman, F. Y. & Lipscomb, T. P. (1996). Two morbilliviruses implicated in bottlenose dolphin epizootics. Emerging Infectious Diseases, 2(3), 213-216.
Whatmore, A. M., Dawson, C. E., Groussaud, P., Koylass, M. S., King, A. C., Shankster, S. J., Sohn, A. H., Probert, W. S., & McDonald, W. L. (2008). Marine mammal Brucella genotype associated with zoonotic infection. Emerging Infectious Diseases, 14(3), 517-518.
Becker, P. R. (2000). Concentration of Chlorinated Hydrocarbons and Heavy Metals in Alaska Arctic Marine Mammals. Marine Pollution Bulletin, 40(10), 819–829.
Fair, P. A., Mitchum, G., Hulsey, T. C., Adams, J., Zolman, E., McFee, W., Wirth, E., & Bossart, G. D. (2007). Polybrominated Diphenyl Ethers (PBDEs) in Blubber of Free-Ranging Bottlenose Dolphins (Tursiops Truncatus) from Two Southeast Atlantic Estuarine Areas. Archives of Environmental Contamination and Toxicology, 53(3), 483–494.
Lee, K., Alava, J. J., Cottrell, P., Cottrell, L., Grace, R., Zysk, I., & Raverty, S. (2022). Emerging Contaminants and New POPs (PFAS and HBCDD) in Endangered Southern Resident and Bigg’s (Transient) Killer Whales (Orcinus orca): In Utero Maternal Transfer and Pollution Management Implications. Environmental Science & Technology, 57(1), 360–374.
Noël, M., & Brown, T. M. (2021). Contaminants as a Conservation Threat to Marine Mammals. Wildlife Biodiversity Conservation, 401–420.
Colborn, T., & Smolen, M.J.(2003). Cetaceans and contaminants. In Vos, J. G., Bossart, G. D., Fournier, M., & O’Shea, T. (Eds.). Toxicology of Marine Mammals (pp. 291-232). Taylor & Francis, London.
Murphy, S., Pierce, G. J., Law, R. J., Bersuder, P., Jepson, P. D., Learmonth, J. A., Addink, M., Dabin, W., Santos, M. B., Deaville, R., Zegers, B. N., Mets, A., Rogan, E., Ridoux, V., Reid, R. J., Smeenk, C., Jauniaux, T., López, A., Alonso Farré, J. M., & González, A. F. (2010). Assessing the effect of persistent organic pollutants on reproductive activity in common dolphins and harbour porpoises. Journal of Northwest Atlantic Fishery Science, 42, 153–173.
Ross, P. S. (2002). The Role of Immunotoxic Environmental Contaminants in Facilitating the Emergence of Infectious Diseases in Marine Mammals. Human and Ecological Risk Assessment: An International Journal, 8(2), 277–292.
Tanabe, S. (2002). Contamination and toxic effects of persistent endocrine disrupters in marine mammals and birds. Marine Pollution Bulletin, 45(1-12), 69–77.
Fire, S. E., Wang, Z., Byrd, M., Whitehead, H. R., Paternoster, J., & Morton, S. L. (2011). Co-occurrence of multiple classes of harmful algal toxins in bottlenose dolphins (Tursiops truncatus) stranding during an unusual mortality event in Texas, USA. Harmful Algae, 10(3), 330–336.
Häussermann, V., Gutstein, C. S., Bedington, M., Cassis, D., Olavarria, C., Dale, A. C., Valenzuela-Toro, A. M., Perez-Alvarez, M. J., Sepúlveda, H. H., McConnell, K. M., Horwitz, F. E., & Försterra, G. (2017). Largest baleen whale mass mortality during strong El Niño event is likely related to harmful toxic algal bloom. PeerJ, 5, e3123.
Miller, M. A., Kudela, R. M., Mekebri, A., Crane, D., Oates, S. C., Tinker, M. T., Staedler, M., Miller, W. A., Toy-Choutka, S., Dominik, C., Hardin, D., Langlois, G., Murray, M., Ward, K., & Jessup, D. A. (2010). Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters. PLoS ONE, 5(9), e12576.
Smith, J., Cram, J. A., Berndt, M. P., Hoard, V., Shultz, D., & Deming, A. C. (2023). Quantifying the linkages between California sea lion (Zalophus californianus) strandings and particulate domoic acid concentrations at piers across Southern California. Frontiers in Marine Science, 10.
Laist, D. W., Knowlton, A. R., Mead, J. G., Collet, A. S., & Podesta, M. (2001). COLLISIONS BETWEEN SHIPS AND WHALES. Marine Mammal Science, 17(1), 35–75.
Schoeman, R. P., Patterson-Abrolat, C., & Plön, S. (2020). A Global Review of Vessel Collisions With Marine Animals. Frontiers in Marine Science, 7.
Calleson, C., & Kipp Frohlich, R. (2007). REVIEW: Slower boat speeds reduce risks to manatees. Endangered Species Research, 3, 295–304.
Wells, R. S., & Scott, M. D. (1997). Seasonal Incidence Of Boat Strikes On Bottlenose Dolphins Near Sarasota, Florida. Marine Mammal Science, 13(3), 475–480.
Cassoff, R., Moore, K., McLellan, W., Barco, S., Rotstein, D., & Moore, M. (2011). Lethal entanglement in baleen whales. Diseases of Aquatic Organisms, 96(3), 175–185.
