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Cetacean strandings and unusual mortality events: Why do cetaceans beach?

By Alejandro Fernandez Ajo, PhD student in the Department of Biology, Northern Arizona University, visiting scientist in the GEMM Lab working on the gray whale physiology and ecology project  

When a cetacean (whales and dolphins) is ashore or trapped in nearshore waters and cannot return to the open waters, it is considered stranded. Frequently, the stranded animal is in distress, dying, or dead. Although rare, the stranded cetacean can be a healthy animal trapped due to changes in tide or disorientation. Every year many cetacean strandings are reported from along the coasts around the world, and likely many more stranding events go unnoticed when they occur in remote areas. In all cases, the question is: why do cetaceans beach?

Southern right whales stranded at the coast of Peninsula Valdés, Patagonia-Argentina. Photo: Matias DiMartino / Southern Right Whale Health Monitoring Program.

There may be different causes for whales and dolphins to strand on beaches, either dead or alive. Understanding and investigating the causes of cetaceans strandings is critical because they can be indicators of ocean health, can help identify anthropogenic sources of disturbance, and can give insights into larger environmental issues that may also have implications for human health (NOAA). In this context, when scientists are analyzing a stranding event, they consider both possibilities that the event was natural or human-caused and classify strandings according to specific characteristics to study the causes of these events.

Types of cetacean strandings:

Live or Dead Stranding:

A stranding can involve live animals or dead animals if the death occurs in the sea and the body is thrown ashore by wind or currents. In live strandings, when they occur near urbanized areas, usually significant efforts are made to rescue and return the animals to the water; with small odontocetes, sometimes there is success, and animals can be rescued. However, when large whales are beached alive, their own weight out of the water can compress their organs and can cause irreversible internal damage. Although not externally visible, such damage can sometimes cause the death of the animal even after returning to the sea.

According to the number of individuals:

Single strandings occur when only a single specimen is affected at the time. The cetaceans that most frequently strand individually are the baleen (or mysticete) whales, such as right and humpback whales, due to their often solitary habits.

Mass strandings comprise two or more specimens, and in some cases, it can involve tens or even a few hundred animals. The mass strandings are more frequently observed for the odontocetes, such as pilot whales, false killer whales, and sperm whales with more complex social structures and gregarious habits.

Left: Single southern right whale calf stranded at the coast of Peninsula Valdés, Patagonia-Argentina. Ph.: Mariano Sironi / ICB. Right: Mass stranding of common dolphins in Patagonia-Argentina. Photo: www.elpais.com

Unusual Mortality Events

The Marine Mammal Protection Act defines an unusual mortality event (UME) as a stranding event that is unexpected, involves a significant die-off of any marine mammal population, and demands immediate response. Seven criteria make a mortality event “unusual.” Source: https://www.fisheries.noaa.gov.

  1. A marked increase in the magnitude or a marked change in morbidity, mortality, or strandings when compared with prior records.
  2. A temporal change in morbidity, mortality, or strandings is occurring.
  3. A spatial change in morbidity, mortality, or strandings is occurring.
  4. The species, age, or sex composition of the affected animals is different than that of animals that are normally affected.
  5. Affected animals exhibit similar or unusual pathologic findings, behavior patterns, clinical signs, or general physical condition (e.g., blubber thickness).
  6. Potentially significant morbidity, mortality, or stranding is observed in species, stocks, or populations that are particularly vulnerable (e.g., listed as depleted, threatened, or endangered, or declining). For example, stranding of three or four right whales may be cause for great concern, whereas stranding of a similar number of fin whales may not.
  7. Morbidity is observed concurrent with or as part of an unexplained continual decline of a marine mammal population, stock, or species.

The purpose of the classification of a mortality event as a UME is to activate an emergency response that aims to minimize deaths, determine the event cause, or causes, determine the effect of the event on the population, and identify the role of environmental parameters in the event. Such classification authorizes a federal investigation that is led by the expertise of the Working Group on Marine Mammal Unusual Mortality Events to investigate the event. This working group is comprised of experts from scientific and academic institutions, conservation organizations, and state and federal agencies, all of whom work closely with stranding networks and have a wide variety of experience in biology, toxicology, pathology, ecology, and epidemiology.

Southern right whale necropsy and external measurements. Source: Southern Right Whale Health Monitoring Program / ICB.

What can be learned from strandings and UMEs?

Examining stranded marine mammals can provide valuable insight into marine mammal health and identify environmental factors leading to strandings. Through forensic examinations, the aim is to identify possible risks to whales’ health and evaluate their susceptibility to diseases, pollutants, and other stressors. This information can contribute to cetacean conservation through informed management strategies. However, the quality of the data derived from a necropsy (the postmortem examination of carcasses) is highly contingent upon how early the stranding event is reported. As soon as the animal is deceased, decomposition starts, hindering the possibilities of detailed investigations of the cause of death.

Therefore, a solid network that can report and respond quickly to a stranding event is fundamental; this includes trained personnel, infrastructure, funding, and expertise to respond in a manner that provides for animal welfare (in the case of live strandings) and obtains data on marine mammal health and causes of death. Moreover, a coordinated international organization that integrates national marine mammal stranding networks has also been identifying as a critical aspect to enable adequate response to such mortality events. In many locations and countries around the world, funding, logistical support, and training remain challenging to stranding response.

In response to these concerns and needs, at the last World Marine Mammal Conference, which took place in Barcelona in December of 2019, The Global Stranding Network was founded to “enhance and strengthen international collaboration to (1) ensure consistent, high-quality response to stranded marine mammals globally, and (2) support conservation efforts for species under threat of extinction.” Monitoring marine mammal health worldwide can guide conservation and help identify priority areas for management (Gulland and Stockin, 2020).

What to do in case of finding a whale or dolphin on the beach?

When strandings occur, it is essential to know how to act. Unfortunately, untrained people, often with good intentions, can worsen the situation of stress and injury to the animal or can put themselves at risk of injury or exposure to pathogens. If you find a cetacean alive or dead on the beach, the most important things to do are:

  1. Record information about the location and the animal´s characteristics (the species, if known; the animal’s approximate size; and status (alive or dead)).
  2. Give immediate notice to the responsible authorities so that specialized help arrives as soon as possible. Report a Stranded or Injured Marine Animal.
  3. Keep at a safe distance: the animal may appear dead to the naked eye and not be. It is important to remember that cetaceans are wild animals and that in stressful situations such as strandings, they can try to defend themselves.
  4. Do not touch the animal: one of the causes of strandings is diseases; therefore, it is advisable not to contact the individuals to avoid exposure to potential pathogens.
  5. If the animal is alive, keep a distance from the animal, especially from its head and tail. Prevent children or dogs from approaching the animal.
  6. Keep calm and do not make noise that could disturb the stranded animal.
  7. Do not take the animal out of the water if it is on the shore or return it to the sea if it is on the beach: Such movement could cause serious injuries, or even death.
  8. Do not feed the animal or give it water: keep the blowhole clear because it is where they breathe.

Source: Whale Conservation Institute of Argentina

Important contacts in case of reporting a Stranded or injured Marine Mammal:

  1. National Oceanic and Atmospheric Administration
  2. Oregon Marine Mammal Stranding Network

References:

https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-unusual-mortality-events

https://www.fisheries.noaa.gov/insight/understanding-marine-mammal-unusual-mortality-events#what_criteria_define_an_ume?

https://ballenas.org.ar/programa-de-monitoreo-sanitario-ballena-franca-austral-pmsbfa/

https://globalstrandingnetwork.com/about

https://iwc.int/strandings

Proceedings of the workshop “Harmonizing Global Stranding Response.” (2020) World marine mammal Conference Barcelona, Catalonia, Spain. Editors: Gulland F and Stockin K; Ecs Special Publication Series No. 62.

Mazzariol S., Siebert U., Scheinin A., Deaville R., Brownlow A., Uhart M.., Marcondes M., Hernandez G., Stimmelmayr R., Rowles T., Moore K., Gulland F., Meyer M., Grover D., Lindsay P., Chansue N., Stockin K. (2020). Summary of Unusual Cetaceans Strandings Events worldwide (2018-2020). SC-68B/E/09 Rev1.

Drivers of close encounters between albatross and fishing vessels

By Rachael Orben

In September of 2016, Leigh Torres, associate professor at Oregon State University, and I attended the 6th International Albatross and Petrel Conference. Somehow, amid all of the science that filled the week, Leigh first saw the Global Fishing Watch fishing map. She shouted with joy. She immediately envisioned a study to assess interactions between seabirds and fishing boats, and started considering a spatial overlap analysis between telemetry tracks of albatross with the Global Fishing Watch database. Such a study could help reduce bycatch, or the incidental catch of non-target species, like seabirds, in fisheries. Five years later, we executed that study in partnership with Global Fishing Watch, one of the first to look at fine-scale overlap between fishing vessels and marine life on the high seas (Orben et al. 2021).   

Transparent data means opportunity for analysis

Despite knowing that bycatch from fisheries is a real, significant problem for many albatross populations, we have long struggled to know where birds go, where boats fish, and where the two interact in the vast ocean, especially in largely unregulated international waters. Albatross are long-lived seabirds and 15 out of the 22 species are threatened with extinction. Scientists have been tracking albatross for three decades, but assessing individual seabird encounters with vessels has traditionally been limited by a lack of transparency in fishing activity data. Some seabirds are attracted to fishing vessels because of the bait and offal, but we don’t know the whole story of why some birds approach vessels while others don’t.

When we first put our relatively large datasets together – 9,992 days of albatross tracking data from 150 birds and Global Fishing Watch fishing effort data from 2012-2016 – we weren’t sure what we would find. The ocean is a big place, and so finding where one bird and one vessel overlap is kind of like trying to find a needle in a haystack. Would we have enough encounters between birds and boats for an analysis? Would birds encounter fishing vessels as often as we think?

Measuring encounters between albatross and vessels

After overlaying the tracking data with a gridded daily layer of fishing effort, we identified potential encounters between birds and fishing boats. We identified when an albatross could detect a vessel, at a radius or 30 kilometers, and when an albatross had a close encounter with a vessel, within a radius of 3 kilometers (following methods developed in Collet Patrick & Weimerskirch, 2015). Then, we investigated factors that influenced the occurrence and duration of close encounters, considering the bird’s behavior, environmental conditions and habitat, fishing vessel and fisheries characteristics, and temporal variables, such as time of day and month.

Species variation of encounters

We conducted our analysis for three species of albatross that forage in the north Pacific ocean, Laysan albatross, black-footed albatross, and short-tailed albatross.

  • Adult black-footed albatrosses approached vessels for a close encounter 61.9 percent of the time they detected a fishing vessel. 
  • Adult Laysan albatross had close encounters with a fishing boat 35.7 percent of the time they detected a vessel. 
  • Juvenile short-tailed albatross had a lower frequency of close encounters (28.6 percent), 

Understanding close encounters and their duration

Due to a low sample size of encounters, we were unable to investigate the reason for close encounters or their duration for black-footed albatrosses. More tracking data is critical to understand factors influencing the impact of vessels on this vulnerable species.

Laysan albatross were more likely to approach fishing vessels when fishing effort was high, but fishing boat density was low. Laysan albatross also had close encounters with vessels more frequently while they were foraging. Due to sample size, we could not further investigate the reason for the duration of encounters for this species.

Short-tailed albatrosses were also more likely to approach fishing vessels when they were searching for prey, fishing effort was high, and fishing boat density was low. They were more likely to have close encounters with vessels during the day and in habitats with water depths from 75-1500 meters. 

Vessel attendance by short-tailed albatrosses was longer when sea surface temperatures were warmer and less productive, and during periods with lower wind speeds. 

A useful approach

The information available to fisheries managers in order to reduce bycatch is most often limited to data collected from the perspective of the fishing vessels. Our analysis provides an alternative view – an albatross’ view of when and where boats are encountered in the seascape. While our analysis didn’t specifically look at bycatch, our estimates of proximity between birds and boats can be considered a proxy for  increased bycatch risk.

For the endangered short-tailed albatross, bycatch events are few, but they come with high consequences for the bird population and fishing industry. Extending our study in a dynamic ocean management framework to provide an early warning system to predict when short-tailed albatross might make close and longer encounters with fishing vessels could be the next step. Furthermore, our analysis methods to assess when, where and why marine animals interact with fishing vessels can be applied to many other marine species in order to understand and reduce conflicts with fisheries. 

This blog was for the Global Fishing Watch blog at globalfishingwatch.org

References

Collet, J., Patrick, S. C., & Weimerskirch, H. (2015). Albatrosses redirect flight towards vessels at the limit of their visual range. Marine Ecology Progress Series, 526, 199–205. http://doi.org/10.3354/meps11233

Orben, RA J Adams, M Hester, SA Shaffer, R Suryan, T Deguchi, K Ozaki, F Sato, LC Young, C Clatterbuck, MG Conners, DA Kroodsma, LG Torres. 2021. Across borders: External factors and prior behavior influence North Pacific albatross associations with fishing vessels. Journal of Applied Ecology. https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.13849

Love thy mother: maternal care in cetaceans

By Lisa Hildebrand, PhD student, OSU Department of Fisheries & Wildlife, Geospatial Ecology of Marine Megafauna Lab

Last week marked the one year anniversary of the pandemic reality we have all been living. It has been an extremely challenging year, with everyone experiencing different kinds of difficulties and hurdles. One challenge that likely unites the majority of us is having to forego seeing our loved ones. For me personally, this is the longest time I have not seen my family (445 days and counting) and I know I am not alone in this situation. My homesickness started a train of thought about cetacean parental care and inspired me to write a blog about this topic. As you can see from the title, this post focuses on maternal care, rather than parental care. This bias isn’t due to my lack of research on this topic or active exclusion, but rather because there are currently no known cetacean species where paternal participation in offspring production and development extends beyond copulation (Rendell et al. 2019). Thus, this blog is all about the role of mothers in the lives of cetacean calves.

Like humans, cetacean mothers invest a lot of energy into their offspring. Most species have a gestation period of 10 or more months (Oftedal 1997). For baleen whale females in particular, pregnancy is not an easy feat given that they only feed during summer feeding seasons. They must therefore acquire all of the energy they will need for two migrations, birth, and (almost) complete lactation, before they will have access to food on feeding grounds again. For pregnant gray whales, a mere 4% loss in average energy intake on the foraging grounds will prevent her from successfully producing and/or weaning a calf (Villegas-Amtmann et al. 2015), demonstrating how crucial the foraging season is for a pregnant baleen whale. Once a calf is born, lactation ensues, ranging in length between approximately 6-8 months for most baleen whale species to upwards of one or two years in odontocetes (Oftedal 1997). The very short lactation period in baleen whales is offset by the large volume (for blue whales, up to 220 kg per day) and high fat percentage (30-50%) of milk that mothers provide for their calves (Oftedal 1997). In contrast, odontocetes (or toothed whales) have a more prolonged period of lactation with less fatty milk (10-30%). This discrepancy in lactation period lengths is in part because odontocete species do not undertake long migrations, which allows females to feed year-round and therefore allocate energy to nursing young for a longer time. 

Blue whale calf nursing in New Zealand in 2016. Footage captured via unmanned aerial system (UAS; drone) piloted by Todd Chandler for GEMM Lab’s OBSIDIAN project. Source: GEMM Lab.

Aside from the energetically costly task of lactation, cetacean mothers must also assist their calves as they learn to swim. Echelon swimming is a common position of mother-calf pairs whereby the calf is in very close proximity to its mother’s mid-lateral flank and provides calves with hydrodynamic benefits. Studies in bottlenose dolphins have shown that swimming in echelon results in a 24% reduction in mean maximum swim speeds and a 13% decrease in distance per stroke (Noren 2008) for mothers, while concurrently increasing average swim speeds and distance per stroke of calves by 28% and 19%, respectively (Noren et al. 2007). While these studies have only been conducted in odontocete species, echelon swimming is also observed in baleen whales (Smultea et al. 2017), indicating that baleen whale females may experience the same reductions in swimming efficiency. Furthermore, mothers will forgo sleep in the first days after birth (killer whales & bottlenose dolphins; Lyamin et al. 2005) and/or shorten their dive foraging times to accommodate calf diving ability (bottlenose dolphins [Miketa et al. 2018] & belugas [Heide-Jørgensen et al. 2001]). Females must endure these losses in foraging opportunities and decreased swimming efficiency when they are at their most nutritionally stressed to ensure the well-being and success of their offspring.

It is at the time of weaning (when a calf becomes independent), that we start to see differences in the maternal role between baleen and toothed whale mothers. Odontocetes have much stronger sociality than baleen whales causing offspring to stay with their mothers for much longer periods. Among the largest toothed whales, such as killer and sperm whales, offspring stay with their mothers in stable matrilineal units for often a lifetime. Among the smaller toothed whales, such as bottlenose dolphins, maternal kin maintain strong bonds in dynamic fission-fusion societies. In contrast, post-weaning maternal care in baleen whales is limited, with the mother-calf pair typically separating soon after the calf is weaned (Rendell et al. 2019). 

Conceptual diagram depicting where baleen (Mysticeti) and toothed (Odontoceti) whales fall on the continuum of low to high social structure and matrilineal kinship structure. The networks at the top depict long-term datasets of photo-identified individuals (red nodes = females, blue nodes = males, yellow nodes = calves) with thickness of connecting lines representing strength of association between individuals. Figure and caption [adapted] from Rendell et al. 2019.

The long-term impact of social bonds in odontocetes is evident through examples of vertically transmitted behaviors (from mother to calf) in a number of species. For example, the use of three unique foraging tactics (sponge carrying, rooster-tail foraging, and mill foraging) by bottlenose dolphin calves in Shark Bay, Australia, was only significantly explained by maternal use of these tactics (Sargeant & Mann 2009). In Brazil, individuals of four bottlenose dolphin populations along the coast cooperatively forage with artisanal fishermen, which involves specialized and coordinated behaviors from both species. This cooperative foraging tactic among dolphins is primarily maintained across generations via social learning from mothers to calves (Simões-Lopeset al. 2016). The risky tactic of intentional stranding by killer whales on beaches to capture elephant seal pups requires a high degree of skill and high parental investment to reduce the associated risk of stranding (Guinet & Bouvier 1995). 

Evidence for vertical transmission of specialized foraging tactics in baleen whales currently does not exist. Bubble-net feeding is a specialized tactic employed by humpback whales in three oceanic regions where multiple individuals work together to herd and trap prey (Wiley et al. 2011). However, it remains unknown whether this behavior is vertically transmitted. Simultaneous video tags from a mother-calf humpback whale pair in the Western Antarctic Peninsula documented synchrony in dives, with the calf’s track lagging behind the mother’s by 4.5 seconds, suggesting that the calf was following its mother (Tyson et al. 2012). Synchronous diving likely allows calves to observe their mothers and practice their diving, and could offer a pathway for them to mimic foraging behaviors and tactics displayed by mothers. 

While there currently may not be evidence for vertical transmission of specialized foraging tactics among the baleen whales, there is documentation of matrilineal fidelity to both foraging (Weinrich 1998, Barendse et al. 2013, Burnham & Duffus 2020) and breeding grounds (Carroll et al. 2015). Matrilineal site fidelity to foraging grounds is not exclusive to baleen whales and has also been documented in a number of odontocete species (Palsbøll et al. 1997, Turgeon et al. 2012). 

  • A gallery of some GEMM Lab documented mother-calf gray whale pairs. All images captured under NOAA/NMFS permit #21678. Exclamation (mom; left) and Angie (calf; right).
  • Scarlett (mom; left) and Brown (calf; right).
  • Clouds (mom; back) and Cheetah (calf; front).
  • Xena (mom; back) and Evie (calf; front).
  • Knife (mom; left) and Daffodil (calf; right).
  • Pristine (mom; front) and Three Stars (calf; back).
  • Triplet (mom; right) and White Knuckle (calf; left).

In the GEMM Lab, we are interested in exploring the potential long-term bonds, role and impact of Pacific Coast Feeding Group (PCFG) gray whale mothers on their calves. GEMM Lab PhD student Clara Bird is digging into whether specialized foraging tactics, such as bubble blasts and headstands, are passed down from mothers to calves. I hope to assess whether using the PCFG range as a foraging ground (rather than the Arctic region) is a vertically transmitted behavior or whether environmental factors may play a larger role in the recruitment and dynamics of the PCFG. It will take us a while to get to the bottom of these questions, so in the meantime hug your loved ones if it’s safe to do so or, if you’re in my boat, continue to talk to them virtually until it is safe to be reunited.

References

Barendse, J., Best, P. B., Carvalho, I., and C. Pomilla. 2013. Mother knows best: occurrence and associations of resighted humpback whales suggest maternally derived fidelity to a southern hemisphere coastal feeding ground. PloS ONE 8:e81238.

Burnham, R. E., and D. A. Duffus. 2020. Maternal behaviors of gray whales (Eschrichtius robustus) on a summer foraging site. Marine Mammal Science 36:1212-1230.

Carroll, E. L., Baker, C. S., Watson, M., Alderman, R., Bannister, J., Gaggiotti, O. E., Gröcke, D. R., Patenaude, N., and R. Harcourt. 2015. Cultural traditions across a migratory network shape the genetic structure of southern right whales around Australia and New Zealand. Scientific Reports 5:16182.

Guinet, C., and J. Bouvier. 1995. Development of intentional stranding hunting techniques in killer whale (Orcinus orca) calves at Crozet Archipelago. Canadian Journal of Zoology 73:27-33.

Heide-Jørgensen, M. P., Hammeken, N., Dietz, R., Orr, J., and P. R. Richard. 2001. Surfacing times and dive rates for narwhals and belugas. Arctic 54:207-355.

Lyamin, O., Pryaslova, J., Lance, V., and J. Siegel. 2005. Continuous activity in cetaceans after birth. Nature 435:1177.

Miketa, M. L., Patterson, E. M., Krzyszczyk, E., Foroughirad, V., and J. Mann. 2018. Calf age and sex affect maternal diving behavior in Shark Bay bottlenose dolphins. Animal Behavior 137:107-117.

Noren, S. R. 2008. Infant carrying behavior in dolphins: costly parental care in an aquatic environment. Functional Ecology 22:284-288.

Noren, S. R., Biedenbach, F., Redfern, J. V., and E. F. Edwards. 2007. Hitching a ride: the formation locomotion strategy of dolphin calves. Functional Ecology 22:278-283.

Oftedal, O. T. Lactation in whales and dolphins: evidence of divergence between baleen- and toothed-species. Journal of Mammary Gland Biology and Neoplasia 2:205-230.

Palsbøll, P. J., Heide-Jørgensen, M. P., and R. Dietz. 1996. Population structure and seasonal movements of narwhals, Monodon monoceros, determined from mtDNA analysis. Heredity 78:284-292.

Rendell, L., Cantor, M., Gero, S., Whitehead, H., and J. Mann. 2019. Causes and consequences of female centrality in cetacean societies. Philosophical Transactions of the Royal Society B 374:20180066.

Sargeant, B. L., and J. Mann. 2009. Developmental evidence for foraging traditions in wild bottlenose dolphins. Animal Behavior 78:715-721.

Simões-Lopes, P. C., Daura-Jorge, F. G., and M. Cantor. 2016. Clues of cultural transmission in cooperative foraging between artisanal fishermen and bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae). Zoologia (Curitiba) 33:e20160107.

Smultea, M. A., Fertl, D., Bacon, C. E., Moore, M. R., James, V. R., and B. Würsig. 2017. Cetacean mother-calf behavior observed from a small aircraft off Southern California. Animal Behavior and Cognition 4:1-23.

Turgeon, J., Duchesne, P., Colbeck, G. J., Postma, L. D., and M. O. Hammill. 2011. Spatiotemporal segregation among summer stocks of beluga (Delphinapterus leucas) despite nuclear gene flow: implication for the endangered belugas in eastern Hudson Bay (Canada). Conservation Genetics 13:419-433.

Tyson, R. B., Friedlaender, A. S., Ware, C., Stimpert, A. K., and D. P. Nowacek. 2012. Synchronous mother and calf foraging behaviour in humpback whales Megaptera novaeangliae: insights from multi-sensor suction cup tags. Marine Ecology Progress Series 457:209-220.

Villegas-Amtmann, S., Schwarz, L. K., Sumich, J. L., and D. P. Costa. 2015. A bioenergetics model to evaluate demographic consequences of disturbance in marine mammals applied to gray whales. Ecosphere 6:1-19.

Weinrich, M. 1998. Early experience in habitat choice by humpback whales (Megaptera novaeaengliae). Journal of Mammalogy 79:163-170.

Wiley, D., Ware, C., Bocconcelli, A., Cholewiak, D., Friedlaender, A., Thompson, M., and M. Weinrich. 2011. Underwater components of humpback whale bubble-net feeding behavior. Behavior 148:575-602.

Defining Behaviors

Clara Bird, PhD Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

When I started working on my thesis, I anticipated many challenges related to studying the behavioral ecology of gray whales. From processing five-plus years of drone footage to data analysis, there has been no shortage of anticipated and unexpected issues. I recently hit an unexpected challenge when I started video processing that piqued my interest. As I’ve discussed in a previous blog, ethograms are lists of defined behaviors that help us properly and consistently collect data in a standardized approach. Ethograms form a crucial foundation of any behavior study as the behaviors defined ultimately affect what questions can be asked and what patterns are detected. Since I am working off of the thorough ethogram of Oregon gray whales from Torres et al. (2018), I had not given much thought to the process of adding behaviors to the ethogram. But, while processing the first chunk of drone videos, I noticed some behaviors that were not in the original ethogram and struggled to decide whether or not to add them. I learned that ethogram development can lead down several rabbit holes. The instinct to try and identify every movement is strong but dangerous. Every minute movement does not necessarily need to be included and it’s important to remember the ultimate goal of the analysis to avoid getting bogged down.

Fundamental behavior questions cannot be answered without ethograms. For example, Baker et al. (2017) developed an ethogram for bottlenose dolphins in Ireland in order to conduct an initial quantitative behavior analysis. They did so by reviewing published ethograms for bottlenose dolphins, consulting with multiple experts, and revising the ethogram throughout the study. They then used their data to test inter-observer variability, calculate activity budgets, and analyze how the activity budgets varied across space and time.

Howe et al. (2015) also developed an ethogram in order to conduct quantitative behavior analyses. Their goals were to use the ethogram and subsequent analyses to better understand the behavior of beluga whales in Cook Inlet, AK, USA and to inform conservation. They started by writing down all behaviors they observed in the field, then they consolidated their notes into a formal ethogram that they used and refined during subsequent field seasons. They used their data to analyze how the frequencies of different behaviors varied throughout the study area at different times. This study served as an initial analysis investigating the effect of anthropogenic disturbance and was refined in future studies.

My research is similarly geared towards understanding behavior patterns to ultimately inform conservation. The primary questions of my thesis involve individual specialization, patterns of behavior across space, the relationship between behavior and body condition, and social behavior (check out this blog to learn more). While deciding what behaviors to add to my ethogram I’ve had to remind myself of these main questions and the bigger picture. The drone footage lets us see so much detail that it’s tempting to try to define every movement we can observe. One rabbit hole I’ve had to avoid a few times is locomotion. From the footage, it is possible to document fluke beats and pectoral fin strokes. While it could be interesting to investigate how different whales move in different ways, it could easily become a complicated mess of classifying different movements and take me deep into the world of whale locomotion. Talking through what that work would look like reminded me that we cannot answer every question and trying to assess all exciting side projects can cause us to lose focus on the main questions.

While I avoided going down the locomotion rabbit hole, there were some new behaviors that I did add to my ethogram. I’ll illustrate the process with the examples of two new behaviors I recently added: fluke swish and pass under (Clips 1 and 2). Clip 1 shows a whale rapidly moving its fluke to the side. I chose to add fluke swish because it’s such a distinct movement and I’m curious to see if there’s a pattern across space, time, individual, or nearby human activity that might explain its function. Clip 2 shows a calf passing under its mom.  It’s not nursing because the calf doesn’t spend time under its mom, it just crosses underneath her. The calf pass under behavior could be a type of mom-calf tactile interaction. Analyzing how the frequency of this behavior changes over time could show how a calf’s dependency on its mom changes over as it ages.

In defining these behaviors, I had to consider how many different variations of this behavior would be included in the definition. This process involves considering at what point a variation of that behavior could serve a different function, even without knowing the function of the original behavior. For fluke swish this process involved deciding to only count a behavior as a fluke swish if it was a big, fast movement. A small and slow movement of the fluke a little to the side could serve a different function, such as turning, or be a random movement.

Clip 1: Fluke swish behavior (Video filmed under NOAA/NMFS research permit #16111​​ by certified drone pilot Todd Chandler).
Clip 2: Pass under behavior (Video filmed under NOAA/NMFS research permit #16111​​ by certified drone pilot Todd Chandler).

The next step involved deciding if the behavior would be a ‘state’ or ‘point’ event. A state event is a behavior with a start and stop moment; a point event is instantaneous and assigned to just a point in time. I would categorize a behavior as a state event if I was interested in questions about its duration. For example, I could ask “what percentage of the total observation time was spent in a certain behavior state?” A point event would be a behavior where duration is not applicable, but I could ask a question like “Did whale 1 perform more point event A than whale 2?”. Both fluke swish and pass under are point events because they only happen for an instant. In a pass under the calf is passing under its mom for just a brief point in time, making it a point event. The final step was to name the behavior. As I discussed in this blog, the name of the behavior does not matter as much as the definition but it is important that the name is clear and descriptive. We chose the name fluke swish because the fluke rapidly moves from side to side and pass under because the calf crosses under its mom.

Frankly, in the beginning, I was a bit overwhelmed by the realization that the content of my ethogram would ultimately control the questions I could answer. I could not help but worry that after processing all the videos, I would end up regretting not defining more behaviors. However, after reading some of the literature, chatting with Leigh, and reviewing the initial chunk of videos several times, I am more confidence in my judgment and my ethogram. I have accepted the fact that I can’t anticipate everything, and I am confident that the behaviors I need to answer my research questions are included. The process of reviewing and updating my ethogram has been a rewarding challenge that resulted in a valuable lesson that I will take with me for the rest of my career.

References

Baker, I., O’Brien, J., McHugh, K., & Berrow, S. (2017). An ethogram for bottlenose dolphins (Tursiops truncatus) in the Shannon Estuary, Ireland. Aquatic Mammals, 43(6), 594–613. https://doi.org/10.1578/AM.43.6.2017.594

Howe, M., Castellote, M., Garner, C., McKee, P., Small, R. J., & Hobbs, R. (2015). Beluga, Delphinapterus leucas, ethogram: A tool for cook inlet beluga conservation? Marine Fisheries Review, 77(1), 32–40. https://doi.org/10.7755/MFR.77.1.3

Torres, L. G., Nieukirk, S. L., Lemos, L., & Chandler, T. E. (2018). Drone up! Quantifying whale behavior from a new perspective improves observational capacity. Frontiers in Marine Science, 5(SEP). https://doi.org/10.3389/fmars.2018.00319

Putting Physiological Tools to Work for Whale Conservation

By Alejandro Fernandez Ajo, PhD student at the Department of Biology, Northern Arizona University, Visiting scientist in the GEMM Lab working on the gray whale physiology and ecology project  

About four years ago, I was in Patagonia, Argentina deciding where to focus my research and contribute to whale conservation efforts. At the same time, I was doing fieldwork with the Whale Conservation Institute of Argentina at the “Whale Camp” in Península Valdés. I read tons of papers and talked with my colleagues about different opportunities and gaps in knowledge that I could tackle during my Ph.D. program. One of the questions that caught my attention was about the unknown cause (or causes) for the recurrent high calf mortalities that the Southern Right Whale (SRW) population that breeds at Peninsula Valdés experienced during the 2000s (Rowntree et al. 2013). Still, at that time, I was unsure how to tackle this research question.

Golfo San José, Península Valdés – Argentina. Collecting SRW behavioral data from the cliff’s vantage point. Source: A. Fernandez Ajo.

Between 2003 and 2013, at least 672 SRWs died, of which 91% were calves (Sironi et al. 2014). These mortalities represented an average total whale death per year of 80 individuals in the 2007-2013 period, which vastly exceeded the 8.2 average deaths per year of previous years by a ten-fold increase (i.e., 1993-2002) (Rowntree et al. 2013). In fact, this calf mortality rate was the highest ever documented for any population of large whales. During this period, from 2006 to 2009, I was the Coordinator of the Fauna Area in the Patagonian Coastal Zone Management Plan, and I collaborated with the Southern Right Whale Health Monitoring Program (AKA: The Stranding Program) that conducted field necropsies on stranded whales along the coasts of the Península and collected many different samples including whale baleen.

Southern Right Whale, found stranded in Patagonia Argentina. Source: Instituto de Conservación de Ballenas.

In this process, I learned about the emerging field of Conservation Physiology and the challenges of utilizing traditional approaches to studying physiology in large whales. Basically, the problem is that there is no possible way to obtain blood samples (the gold standard sample type for physiology) from free-swimming whales; whales are just too large! Fortunately, there are currently several alternative approaches for gathering physiological information on large whales using a variety of non-lethal and minimally invasive (or non-invasive) sample matrices, along with utilizing valuable samples recovered at necropsy (Hunt et al. 2013). That is how I learned about Dr. Kathleen Hunt’s novel research studying hormones from whale baleen (Hunt et al., 2018, 2017, 2014). Thus, I contacted Dr. Hunt and started a collaboration to apply these novel methods to understand the case of calf mortalities of the SRW calves in Patagonia utilizing the baleen samples that we recovered with the Stranding program at Península Valdés (see my previous blog post).

What is conservation physiology?

Conservation physiology is a multidisciplinary field of science that utilizes physiological concepts and tools to understand underlying mechanisms of disturbances to solve conservation problems. Conservation physiology approaches can provide sensitive biomarkers of environmental change and allow for targeted conservation strategies. The most common Conservation Physiology applications are monitoring environmental stressors, understanding disease dynamics and reproductive biology, and ultimately reducing human-wildlife conflict, among other applications.

I am now completing the last semester of my Ph.D. program. I have learned much about the amazing field of Conservation Physiology and how much more we need to know to achieve our conservation goals. I am still learning, yet I feel that through my research I have contributed to understanding how different stressors impact the health and wellbeing of whales, and about aspects of their biology that have long been obscured or unknown for these giants. One contribution I am proud of is our recent publication of, “A tale of two whales: putting physiological tools to work for North Atlantic and southern right whales,” which was published in January 2021 as a book chapter in “Conservation Physiology: Applications for Wildlife Conservation and Management” published by Oxford University Press: Oxford, UK.

This book outlines the significant avenues and advances that conservation physiology contributes to the monitoring, management, and restoration of wild animal populations. The book also defines opportunities for further growth in the field and identifies critical areas for future investigation. The text and the contributed chapters illustrate several examples of the different approaches that the conservation physiology toolbox can tackle. In our chapter, “A tale of two whales,” we discuss developments in conservation physiology research of large whales, with the focus on the North Atlantic right whale (Eubalaena glacialis) and southern right whale (Eubalaena australis), two closely related species that differ vastly in population status and conservation pressures. We review the advances in Conservation Physiology that help overcome the challenges of studying large whales via a suite of creative approaches, including photo-identification, visual health assessment, remote methods of assessing body condition, and endocrine research using non-plasma sample types such as feces, respiratory vapor, and baleen. These efforts have illuminated conservation-relevant physiological questions for both species, such as discrimination of acute from chronic stress, identification of likely causes of mortality, and monitoring causes and consequences of body condition and reproduction changes.

Link to this Book here: https://oxford.universitypressscholarship.com/view/10.1093/oso/9780198843610.001.0001/oso-9780198843610

Book chapter: https://oxford.universitypressscholarship.com/view/10.1093/oso/9780198843610.001.0001/oso-9780198843610-chapter-12

Book Overview:

This book provides an overview of the different applications of Conservation Physiology, outlining the significant avenues and advances by which conservation physiology contributes to the monitoring, management, and restoration of wild animal populations. By using a series of global case studies, contributors illustrate how approaches from the conservation physiology toolbox can tackle a diverse range of conservation issues, including monitoring environmental stress, predicting the impact of climate change, understanding disease dynamics, and improving captive breeding, and reducing human-wildlife conflict. The variety of taxa, biological scales, and ecosystems is highlighted to illustrate the far-reaching nature of the discipline and allow readers to appreciate the purpose, value, applicability, and status of the field of conservation physiology. This book is an accessible supplementary textbook suitable for graduate students, researchers, and practitioners in conservation science, ecophysiology, evolutionary and comparative physiology, natural resources management, ecosystem health, veterinary medicine, animal physiology, and ecology.

References

Hunt KE, Fernández Ajó A, Lowe C, Burgess EA, Buck CL. 2021. A tale of two whales: putting physiological tools to work for North Atlantic and southern right whales. In: “Conservation Physiology: Integrating Physiology Into Animal Conservation And Management”, ch. 12. Eds. Madliger CL, Franklin CE, Love OP, Cooke SJ. Oxford University press: Oxford, UK.

Sironi, M., Rowntree, V., Di Martino, M. D., Beltramino, L., Rago, V., Franco, M., and Uhart, M. (2014). Updated information for 2012-2013 on southern right whale mortalities at Península Valdés, Argentina. SC/65b/BRG/06 report presented to the International Whaling Commission Scientific Committee, Portugal. <https://iwc.int/home>.

Rowntree, V.J., Uhart, M.M., Sironi, M., Chirife, A., Di Martino, M., La Sala, L., Musmeci, L., Mohamed, N., Andrejuk, J., McAloose, D., Sala, J., Carribero, A., Rally, H., Franco, M., Adler, F., Brownell, R. Jr, Seger, J., Rowles, T., 2013. Unexplained recurring high mortality of southern right whale Eubalaena australis calves at Península Valdés, Argentina. Marine Ecology Progress Series, 493, 275-289. DOI: 10.3354/meps10506

Hunt KE, Moore MJ, Rolland RM, Kellar NM, Hall AJ, Kershaw J, Raverty SA, Davis CE, Yeates LC, Fauquier DA, et al., 2013. Overcoming the challenges of studying conservation physiology in large whales: a review of available methods. Conserv Physiol 1: cot006–cot006.

Hunt, K.E., Stimmelmayr, R., George, C., Hanns, C., Suydam, R., Brower, H., Rolland, R.M., 2014. Baleen hormones: a novel tool for retrospective assessment of stress and reproduction in bowhead whales (Balaena mysticetus). Conserv. Physiol. 2, cou030. https://doi.org/10.1093/conphys/cou030

Hunt, K.E., Lysiak, N.S., Moore, M.J., Rolland, R.M., 2016. Longitudinal progesterone profiles in baleen from female North Atlantic right whales (Eubalaena glacialis) match known calving history. Conserv. Physiol. 4, cow014. https://doi.org/10.1093/conphys/cow014

Hunt, K.E., Lysiak, N.S., Robbins, J., Moore, M.J., Seton, R.E., Torres, L., Buck, C.L., 2017. Multiple steroid and thyroid hormones detected in baleen from eight whale species. Conserv. Physiol. 5. https://doi.org/10.1093/conphys/cox061

Hunt, K.E., Lysiak, N.S.J., Matthews, C.J.D., Lowe, C., Fernández Ajó, A., Dillon, D., Willing, C., Heide-Jørgensen, M.P., Ferguson, S.H., Moore, M.J., Buck, C.L., 2018. Multi-year patterns in testosterone, cortisol and corticosterone in baleen from adult males of three whale species. Conserv. Physiol. 6, coy049. https://doi.org/10.1093/conphys/coy049

What makes a species, a species?

By Lisa Hildebrand, PhD student, OSU Department of Fisheries & Wildlife, Geospatial Ecology of Marine Megafauna Lab

Over the roughly 2.5 years that I have researched the Pacific Coast Feeding Group (PCFG) of gray whales, I have thought more and more about what makes a population, a population. From a management standpoint, the PCFG is currently not considered a separate population or even a sub-population of the Eastern North Pacific (ENP) gray whales. Rather, the PCFG is most commonly referred to as a ‘sub-group’ of the ENP. In my opinion, there are valid arguments both for and against the PCFG being designated as its own population. I will address those arguments briefly at the end of this post, but first, I want you to join on me on a journey that is tangential to my question of ‘what makes a population, a population?’ and one that started at the last Marine Mammal Institute Monthly Meeting (MMIMM).

During 2021’s first MMIMM, our director Dr. Lisa Ballance proposed that we lengthen our monthly meeting duration from 1 hour to 1.5 hours. The additional 30 minutes was to allow for an open-ended, institute-wide discussion of a current hot topic in marine mammal science. This proposal was immediately adopted, and the group dove into a discussion about the discovery of a new baleen whale species in the northeastern Gulf of Mexico: Rice’s whale (Balaenoptera ricei). Let me pause here very briefly to reiterate – the discovery of a new baleen whale species!! The fact that anything as large as 12 m could remain undiscovered in our oceans is really quite fascinating and shows that our scientific quest will likely never run out of discoverable subjects. Anyway, the discovery of this new species is supported by several lines of evidence. Unfortunately (but understandably), MMI’s discussion of these topics had to cease after 30 minutes, however I had more questions. I wanted to know what had sparked the researchers to believe that they had discovered a new cetacean species. 

Scientific illustration of Bryde’s whale. Source: NOAA Fisheries.

I started my research by skimming through some news articles about the Rice’s whale discovery. In a Smithsonian Magazine article, I saw a quote by Dr. Patricia Rosel, the lead author of the study detailing Rice’s whale, that read: “But we didn’t have a skull.”. That quote made me pause. A skull? Is that what it takes to discover and establish a new species? This desired piece of evidence seemed rather puzzling and a little antiquated to me, given that the field of genetics is so advanced now and since it is no longer an accepted practice to kill a wild animal just to study it (i.e., scientific whaling). I backtracked through the article to learn that in the 1990s, renowned marine mammal scientist Dale Rice (after whom Rice’s whale was named) recognized that a small population of baleen whale occurred in the northeastern part of the Gulf of Mexico year-round. At the time, this population was believed to be a sub-population of Bryde’s whale. It wasn’t until 2008, that NOAA scientists were able to conduct a genetic analysis of tissue samples from this population, only to find that these whales were genetically distinct from other Bryde’s whales (Rosel & Wilcox 2014). Yet, this information was not enough for these whales to be established as their own species. A skull really was needed to prove that these whales were in fact a new species. Thankfully (for the scientists) but sadly (for the whale), one of these individuals stranded in Sandy Key, Florida, in 2019, and a dedicated team of stranding responders from Florida Fish and Wildlife, Mote Marine Lab, NOAA, Dolphins Plus, and Marine Animal Rescue Society worked tirelessly in difficult conditions to comprehensively document and preserve this animal. Through the diligent work of this, and previous, stranding response teams, Dr. Rosel and her team were provided the opportunity to examine the skull needed to determine population-status. The science team determined that the bones atop the skull around the blowhole provided evidence that these whales were not only genetically, but also anatomically, different from Bryde’s whales. It was this incident, triggered by that short quote in the Smithsonian article, that brought me to my journey of asking ‘what makes a species, a species?’.

Given that I had just read that Dr. Rosel needed a skull to establish Rice’s whale as its own species, I assumed that my search for ‘how to establish a new species’ would end quickly in me finding a list of requirements, one of which would be ‘must present anatomical/skeletal evidence’. To my surprise, my search did not end quickly, and I did not find a straightforward list of requirements. Instead, I discovered that my question of ‘what makes a species, a species?’ does not have a black-and-white answer and involves a lot of debate.

The skull of this stranded whale was a large piece of evidence in establishing Rice’s whale as its own species. Source: Smithsonian Magazine from NOAA / Florida Fish and Wildlife Commission

Kevin de Queiroz, a vertebrate, evolutionary, and systematic biologist who has published extensively on theoretical and conceptual topics in systematic and evolutionary biology, believes that the issue of species delimitation (‘what makes a species, a species?’) has been made more complicated by a larger issue involving the concept of species itself (‘what is a species?’) (De Queiroz 2007). To date, there are 24 recognized species concepts (Mayden 1997). In other words, there are 24 different definitions of what a species is. Perhaps the most common example is the biological species concept where a species is defined as a group of individuals that are able to produce viable and fertile offspring following natural reproduction. Another example is the ecological species concept whereby a species is a group of organisms adapted to a particular set of resources and conditions, called a niche, in the environment. Problematically, many of these concepts are incompatible with one another, meaning that applying different concepts leads to different conclusions about the boundaries and numbers of species in existence (De Queiroz 2007).

This large number of species concepts is due to the different interests of certain subgroups of biologists. For example, highlighting morphological differences between species is central to paleontologists and taxonomists, whereas ecologists will focus on niche differences. Population geneticists will attribute species differences to genes, while for systematists, monophyly will be paramount. It goes on and on. And so does the debate about the concept of species. It seems that there currently is not one clear, defined consensus on what a species is. Some biologists argue that a species is a species if it is genetically different, while others will insist that skeletal and morphological evidence must be present. From what I can tell, it seems that scientists describe and (attempt to) establish a new species by publishing their lines of evidence, after which experts in the field discuss and evaluate whether a new species should be established. 

In the field of marine mammal science, the Society of Marine Mammalogy’s Taxonomic Committee is charged with maintaining a standard, accepted classification and nomenclature of marine mammals worldwide. The committee annually considers and evaluates new, peer-reviewed literature that proposes changes (including additions) to marine mammal taxonomy. I expect that the case of Rice’s whale will be on the committee’s docket this year. Given that Rosel and co-authors presented geographic, morphological, and genetic evidence to support the establishment of Rice’s whale, I would not be surprised if the committee adds it to their curated list.

After taking this dive into the ‘what makes a species, a species?’ question, let’s see if we can apply some of what we’ve learned to the ‘what makes a population, a population?’ question regarding the PCFG and ENP gray whales. Following the ecological species concept, an argument for the recognition of the PCFG as its own population would be that they occupy an entirely different environment during their summer foraging season than the ENP whales. Not only are the geographic ranges different, but PCFG whales also show behavioral differences in their foraging tactics and targeted prey. The argument against the PCFG being classified as its own population is largely supported by genetic analysis that has revealed ambiguous evidence that the PCFG and ENP are not genetically isolated from one another. While one study has shown that there is maternal cultural affiliation within the PCFG (meaning that calves born to PCFG females tend to return to the PCFG range; Frasier et al. 2011), another has revealed that mixing between ENP and PCFG gray whales on the breeding grounds does occur (Lang et al. 2014). So, even though these two groups feed in areas that are very far apart (ENP: Arctic vs PCFG: US & Canadian west coast) and certain individuals do show a propensity for a specific feeding ground, the genetic evidence suggests that they mix when on their breeding grounds in Baja California, Mexico. Depending on which species concept you align with, you may see better arguments for either side.

PCFG gray whale along the Oregon coast during the GEMM Lab’s 2020 GRANITE summer field season. Image captured under NOAA/NMFS permit #21678. Source: GEMM Lab.

You may be wondering why it is important to even ponder questions like ‘what makes a species, a species?’ and ‘what makes a population, a population?’. Does it really matter if the PCFG are considered their own population? Would anything really change? The answer is, most likely, yes. If the PCFG were to be recognized as their own population, it would likely have an immediate effect on their conservation status and subsequently on how the population needed to be managed. Rather than being under the umbrella of a large, (mostly) stable population of ~25,000 individuals, the PCFG would consist of only ~250 individuals. A group this small would possibly be considered “endangered”, which would require much stricter monitoring and management to ensure that their numbers did not decline from year to year, especially due to anthropogenic activities. 

For a long time, I felt like taxonomy was a bit of an archaic scientific field. In my mind, it was something that biologists had focused their time and energy on in the 18th century (most notably Carl Linnaeus, whose taxonomic classification system is still used today), but something that many biologists have moved on from focusing on in the 21st century. However, as I have developed and grown over the last years as a scientist, I have learned that scientific disciplines are often heavily intertwined and co-dependent on one another. As a result, I am able to see the enormous value and need for taxonomic work as it plays a large part in understanding, managing, and ultimately, conserving species and populations.

Literature cited

De Queiroz, K. 2007. Species concepts and species delimitation. Systematic Biology 56(6):879-886.

Frasier, T. R., Koroscil, S. M., White, B. N., and J. D. Darling. 2011. Assessment of population substructure in relation to summer feeding ground use in the eastern North Pacific gray whale. Endangered Species Research 14:39-48.

Lang, A. R., Calambokidis, J., Scordino, J., Pease, V. L., Klimek, A., Burkanov, V. N., Gearin, P., Litovka, D. I., Robertson, K. M., Mate, B. R., Jacobsen, J. K., and B. L. Taylor. 2014. Assessment of genetic structure among eastern North Pacific gray whales on their feeding grounds. Marine Mammal Science 30(4):1473-1493.

Mayden, R. L. 1997. A hierarchy of species concepts: the denouement of the species problem in The Units of Biodiversity – Species in Practice Special Volume 54 (M. F. Claridge, H. A. Dawah, and M. R. Wilson, eds.). Systematics Association.

Rosel, P. E., and L. A. Wilcox. 2014. Genetic evidence reveals a unique lineage of Bryde’s whale in the northeastern Gulf of Mexico. Endangered Species Research 25:19-34.

The past and present truths of “Big Miracle”

By Rachel Kaplan, PhD student, OSU College of Earth, Ocean, and Atmospheric Sciences and Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

As we all try to find ways to be together safely this winter, the GEMM Lab has started a fun series of virtual movie nights. Just before the holidays, we watched “Big Miracle,” which tells the story of the historic whale entrapment event in Utqiagvik, Alaska (formerly called “Barrow”) that captured the world’s attention. 

The 2012 film stars Drew Barrymore, who plays a Greenpeace activist, and John Krasinski, a television reporter covering the story.

In late September 1988, three gray whales became trapped in the sea ice just off Point Barrow. Local attempts to free the whales quickly became national news that captured the attention of millions, including President Ronald Reagan, pop legend Michael Jackson – and elementary-schooler Leigh Torres. 

After the movie, Leigh told us about how she had religiously followed television updates on the rescue as a child. Hearing her memories of the event and its part in inspiring her to pursue a career in whale research was one of the best parts of watching the movie together as a lab.   

Tuning in from my parents’ house in Fairbanks, Alaska, the story felt surprisingly close to home for me too. I had never heard Inupiaq spoken in a feature film before, and I was stunned to recognize the landscape around Utqiaġvik and realize that some of the movie was filmed on location. It was also the first movie I’d seen represent the myriad of human dimensions that surround whale research and policy, including Indigenous rights, oil and fishing industry interests, and environmental perspectives. 

Certain elements of the movie also made me uncomfortable, and thus made me wonder about the movie’s accuracy. Why were the main characters in the film people from outside Alaska? How did the rescue logistics and decision-making processes really play out in Utqiaġvik? Why did the whales become trapped in the first place? 

I was curious to learn more about the whales, and how Utqiaġvik experienced both the massive rescue effort and the Hollywood-ized retelling of its story. During a great Zoom conversation, I learned more from Craig George, a whale biologist who has worked in Utqiaġvik since the 1970s and was involved during the entire 1988 rescue mission.

Like all Hollywood movies based on real events, “Big Miracle” mixes facts with a healthy dose of fiction and storytelling. The movie portrays the three entrapped whales as a family unit, given the names Wilma, Fred, and Bam Bam. Craig described them in more scientific terms – three subadult gray whales, all 25-30 feet in length. He and the other biologists onsite collected data throughout the three-week rescue effort, recording the whales’ behavior, dive times, and vocalizations. They calculated that the whales’ respiration rates were double that of typical rates, revealing the whales’ distress. 

The rescue team named the whales Crossbeak, Bone, and Bonnet based on each individual’s notable morphological traits. Photo: Craig George

“The community effort to free the whales was amazing,” Craig said. “Low-tech approaches and local knowledge are typically most effective in the Arctic, and all the best ideas relied on the Inupiaq knowledge of the area.” 

With the aim of leading the whales offshore to safer waters, a team of volunteers cut a series of breathing holes at regular intervals in the sea ice. The approach seemed to work well, and so the ice-breaking crew was puzzled when the whales stopped using the new holes – until they realized the area was underlain by shoals that the whales were unwilling to cross. They began cutting in a new direction, and the whales appeared in the new hole instantly, before the opening was even completed.

“The whales were trying to tell us the direction they wanted to go,” Craig said. “It was really astonishing, because there was definitely a dynamic between us. We tried to train them to work with us, and they also trained us.” 

 A team of volunteers cut holes in the sea ice, creating a path to open water, while journalists document the moment. Photo: Craig George

Over three weeks, the rescue effort grew from local to international. Companies donated chainsaws and fuel, and people following the news outside Alaska flew to Utqiaġvik to volunteer their help. Several attempts to break the ice, including an ice-based pontoon tractor and an ice-breaking helicopter, failed. Working around the clock, and in temperatures below -20F, volunteers continued cutting breathing holes in the ice for the whales.

Finally, one hurdle remained between the whales and open water – a massive pressure ridge of grounded sea ice, about 20 ft high and just as deep. It was impossible to cut through with chainsaws. Two Russian icebreakers, the Vladimir Arseniev and the Admiral Makarov were enlisted to come break the ridge and clear the way to open water – no small diplomatic feat during the Cold War. 

Ultimately, Craig said, the real story’s ending isn’t quite as picture-perfect as the one in “Big Miracle” – no one actually knows whether the whales made it out or not.

“We know that the whales swam out the icebreaker track, because their blood was found on ice shards,” he said. “They might have made it out, but we never saw them again and don’t know for sure.”

This map shows the path of holes cut through the sea ice, icebreaker track, and pressure ridge of ice. “Barrow” is the former name of Utqiaġvik. Source: Geoff Carroll and Craig George

Nearly 40 years later, Craig says the story still comes up often in Utqiaġvik, but in a different context – climate change. In 1988, the sea ice froze up in late September. In 2020, however, there was no shore-fast ice until early December. Craig remembers that, during the rescue, temperatures dropped to -24°F one night — colder than Utqiaġvik had experienced yet in January 2020, when we last spoke. Today’s dramatically different conditions have impacts for the entire Arctic ecosystem, as well as the people who rely on it to survive.

Watching “Big Miracle” sparked so many questions about the past, and talking with Craig gave me just as many questions about the future. How will changing ocean conditions impact gray whales, and other Arctic whales? How will the social and environmental dynamics that “Big Miracle” depicted – environmentalism, resource exploitation, and Indigenous rights – adapt and evolve in a changing Arctic? What will the Alaskan Arctic look like in another 40 years?

The ecologist and the economist: Exploring parallels between disciplines

By Dawn Barlow1 and Johanna Rayl2

1PhD Candidate, Oregon State University Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

2PhD Student, Northwestern University Department of Economics

The Greek word “oikos” refers to the household and serves as the root of the words ecology and economics. Although perhaps surprising, the common origin reflects a shared set of basic questions and some shared theoretical foundations related to the study of how lifeforms on earth use scarce resources and find equilibrium in their respective “households”. Early ecological and economic theoretical texts drew inspiration from one another in many instances. Paul Samuelson, fondly referred to as “the father of modern economics,” observed in his defining work Foundations of Economic Analysis that the moving equilibrium in a market with supply and demand is “essentially identical with the moving equilibrium of a biological or chemical system undergoing slow change.” Likewise, early theoretical ecologists recognized the strength of drawing on theories previously established in economics (Real et al. 1991). Similar broad questions are central to researchers in both fields; in a large and dynamic system (termed “macro” in economics) scale, ecologists and economists alike work to understand where competitive forces find equilibrium, and an in individual (or micro) scale, they ask how individuals make behavior choices to maximize success given constraints like time, energy, wealth, or physical resources.

The central model economists have in mind when trying to understand human choices involves “constrained optimization”: what decision will maximize a person, family, firm, or other agent’s objectives given their limitations? For example, someone that enjoys relaxing but also seeks a livable income must choose how much time to devote to working versus relaxing, given the constraint of having just 24 hours in the day, and given the wage they receive from working. An economist studying this decision may want to learn about how changes in the wage will affect that person’s choice of working hours, or how much they dislike working relative to relaxing. Along similar lines, early ecologists theorized that organisms could be selected for one of two optimization strategies: minimizing the time spent acquiring a given amount of energy (i.e., calories from food), or maximizing total energy acquisition per unit of time (Real et al. 1991). Foundational work in the field of economics clarified numerous technical details about formulating and solving such optimization problems. Returning to the example of the leisure time decision, economic theory asks: does it matter if we model this decision as maximizing income given wages and limited time, or as minimizing hours spent working given a desired lifetime income?; can we formulate a “utility function” that  describes how well-off someone is with a given income and amount of leisure?; can we solve for the optimal amount of leisure with pen and paper? The toolkit arising from this work serves as a jumping off point for all contemporary economic research, and the kinds of choices understood under this framework is vast, from, where should a child attend school?; to, how should a government allocate its budget across public resources?

Early work in ecology drew from foundational concepts in economics, following the realization that the strategies by which organisms exploit resources most efficiently also involve optimization. This parallel was articulated by MacArthur and Pianka in their foundational 1966 paper Optimal Use of a Patchy Environment, in which they state: “In this paper we undertake to determine in which patches a species would feed and which items would form its diet if the species acted in the most economical fashion. Hopefully, natural selection will often have achieved such optimal allocation of time and energy expenditures.” Subsequently, this idea was refined into what is known in ecology as the marginal value theorem, which states that an animal should remain in a prey patch until the rate of energy gain drops below the expected energy gain in all remaining available patches (Charnov 1976). In other words, if it is more profitable to switch prey patches than to stay, an animal should move on. These optimization models therefore allow ecologists to pose specific evolutionary and behavioral hypotheses, such as examining energy acquisition over time to understand selective forces on foraging behavior.

As the largest animals on the planet, blue whales have massive prey requirements to meet energy demands. However, they must balance their need to feed with costs such as oxygen consumption during breath-holding, the travel time it takes to reach prey patches at depth, the physiological constraints of diving, and the necessary recuperation time at the surface. It has been demonstrated that blue whales forage selectively to optimize this energetic budget. Therefore, blue whales should only feed on krill aggregations when the energetic gain outweighs the cost (Fig. 1), and this pattern has been empirically demonstrated for blue whale populations in the Gulf of St. Lawrence, Canada (Doniol-Valcroze et al. 2011), in the California Current, (Hazen et al. 2015) and in New Zealand (Torres et al. 2020).

Figure 1. Figure reprinted from Hazen et al. 2015, illustrating how a blue whale should theoretically optimize foraging success in two scenarios. Energy gained from feeding is shown by the blue lines, whereas the cost of foraging in terms of declining oxygen stores during a dive is illustrated by the red lines. On the left (panel B), the whale maximizes its energy gain by increasing the number of feeding lunges (shown by black circles) at the expense of declining oxygen stores when prey density is high. On the right (panel C), the whale minimizes oxygen use by reducing the number of feeding lunges when prey density is low.

The notion of the marginal value theorem is likewise at work in countless economic settings. Economic theory predicts that a farmer cultivating two crops would allocate resources into each crop such that the returns to adding more resources into each crop are the same. If not, she should move resources from the less productive crop to the one where marginal gains are larger. A fisherman, according to this notion, continues to fish longer into the season until the marginal value of one additional day at sea equals the marginal cost of their time, effort, and expenses. These predictions are intuitive by the same logic as the blue whale choosing where to forage, and derive from the mathematics of constrained and unconstrained optimization. Reassuringly, empirical work finds evidence of such profit-maximizing behavior in many settings. In a recent working paper, Burlig, Preonas, and Woerman explore how farmers’ water use in California responds to changes in the price of electricity, which effectively makes groundwater irrigation more expensive due to electric pumping. They find that farmers are very responsive to these changes in marginal cost. Farmers achieve this reduction in water use predominantly by switching to less water-intensive crops and fallowing their land (Burlig, Preonas, and Woerman 2020).

Undoubtedly there are fundamental differences between an ecosystem with interacting biotic and abiotic components and the human-economic environment with its many social and political structures. But for certain types of questions, the parallels across the shared optimization problems are striking. The foundational theories discussed here have paved the way for subsequent advances in both disciplines. For example, the field of behavioral ecology explores how competition and cooperation between and within species affects fitness of populations. Reflecting on early seminal work lends some perspective on how an area of research has evolved. Likewise, exploring parallels between disciplines sheds light on common threads, in turn revealing insights into each discipline individually.

References:

Burlig, Fiona, Louis Preonas, and Matt Woerman (2020). Groundwater, energy, and crop choice. Working Paper.

Charnov EL (1976) Optimal foraging: The marginal value theorem. Theoretical Population Biology 9:129–136.

Doniol-Valcroze T, Lesage V, Giard J, Michaud R (2011) Optimal foraging theory predicts diving and feeding strategies of the largest marine predator. Behavioral Ecology 22:880–888.

Hazen EL, Friedlaender AS, Goldbogen JA (2015) Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density. Science Advces 1:e1500469–e1500469.

MacArthur RH, Pianka ER (1966) On optimal use of a patchy environment. The American Naturalist 100:603–609.

Real LA, Levin SA, Brown JH (1991) Part 2: Theoretical advances: the role of theory in the rise of modern ecology. In: Foundations of ecology: classic papers with commentaries.

Samuelson, Paul (1947). Foundations of Economic Analysis. Harvard University Press.

Torres LG, Barlow DR, Chandler TE, Burnett JD (2020) Insight into the kinematics of blue whale surface foraging through drone observations and prey data. PeerJ 8:e8906.

GEMM Lab 2020: A Year in the Life

By Lisa Hildebrand, PhD student, OSU Department of Fisheries & Wildlife, Geospatial Ecology of Marine Megafauna Lab

Despite the trials and tribulations of 2020, the GEMM Lab has persevered and experienced many successes and high points. Join me, perhaps with a holiday beverage of choice in-hand, for a summary of what the lab and its members have achieved this year.

The GEMM Lab celebrated several milestones this year. We were all extremely excited and proud when halfway through the year, in July, GEMM Lab PI, Dr. Leigh Torres, was promoted to Associate Professor and granted indefinite tenure in the Department of Fisheries & Wildlife. Leigh joined the department in 2014 and has since completed 13 research projects, is leading 10 current research projects, has graduated 7 graduate students, and is currently advising 4 PhD students and a postdoctoral scholar. A big hurrah to Leigh, our inspiring and tireless captain at the GEMM Lab helm!!

Leigh isn’t the only GEMM Lab member to have received a new title. In March, Leila successfully defended her PhD thesis entitled “Body condition and hormone assessment of eastern North pacific gray whales (Eschrichtius robustus) and associations to ambient noise” and thus graduated from being a PhD candidate to being Dr. Leila Soledade Lemos. Leila is currently a postdoctoral associate at Florida International University. I (Lisa Hildebrand) defended my Master’s thesis “Tonight’s specials include mysids, amphipods, and more: An examination of the zooplankton prey of Oregon gray whales and its impact on foraging choices and prey selection” just a few weeks ago and now bear the title of Master of Science. I am excited to announce that I won’t be leaving the GEMM Lab anytime soon as I will continue to  work with Leigh as I pursue my PhD. Our final new title recipient is Dawn who at the start of December advanced to PhD candidacy after successfully passing her written comprehensive exams in mid-November and her oral comprehensive exams in early December.

  • Leila during her socially-distanced PhD defense seminar. Source: L. Torres.
  • Lisa during her Zoom Master’s defense seminar. Source: L. Hildebrand

Summer is a busy time in the GEMM Lab, largely because it is the time when gray whales are distributed along our Oregon coast for their feeding season and therefore when both of our gray whale projects (GRANITE, or Gray whale Response to Ambient Noise Informed by Technology and Ecology, and the Port Orford foraging ecology project) collect another year of data. With the COVID-19 pandemic in its early stages in the spring (when we start to prep for our field seasons), it was uncertain whether we would be able to get into the field at all. However, after weeks of drafting up and submitting COVID-19 safety plans and precautions, Leigh was able to get both of our gray whale field seasons approved to go ahead this summer! This task was not easy since both projects require some form of travel and sampling methods that do not always allow for 6-feet of distance between team members. Furthermore, the Port Orford project requires the whole team to live and work out of OSU’s Port Orford Field Station together. Despite the hurdles, both projects had successful field seasons. If you want to hear more about the specifics of the field seasons, check out the field season summary blog.

Gray whales weren’t the only species to grab our attention in the field this year. OPAL (Overlap Predictions about Large whales) had a successful second year with Leigh and MMI faculty research assistant Craig Hayslip taking to the skies in United States Coast Guard helicopters four times a month. The project seeks to identify co-occurrence between whales and fishing effort in Oregon to reduce entanglement risk. Leigh and Craig documented numerous cetacean species including blue, fin, humpback, sperm whales, and killer whales. To help with this work, we are so excited to officially have Solène Derville back in the GEMM Lab as a postdoctoral scholar who will work on statistical models aimed at predicting habitat use and distribution patterns of whales off the Oregon coast. While our wish to physically welcome Solène back to Oregon this year did not quite pan out, we are hopeful that she will make the journey from New Caledonia to Oregon in 2021!

The data collected during the helicopter flights will be complimented by the marine mammal observer data that various members of the GEMM Lab have collected over the last four years aboard NOAA Ship Bell M. Shimada as part of the Northern California Current Ecosystem survey. These surveys typically occur three times a year (February, May, September). Although the pandemic threw a wrench into the May cruise, the September cruise was able to go ahead with Dawn and Clara on-board as the two marine mammal observers. It was a very successful cruise, with abundant marine mammal sightings and good survey conditions. Read more about those cruises in Clara and Dawn’s blogs.

While the GEMM Lab did not undertake any field work in New Zealand this year, Leigh and Dawn did travel there in February to meet with scientific colleagues, representatives of the oil and gas industry, and environmental managers, including the New Zealand Minister of Conservation, the Honorable Eugenie Sage. The trip allowed Leigh and Dawn to present their research on blue whales and discuss management implications. These meetings have been highly beneficial as they shared their latest research and results to assist with the development of a marine mammal sanctuary within the industrial region where their research is conducted.

The GEMM Lab prides itself on having strong outreach components to our research, ensuring that young students (high school and undergraduate) from diverse backgrounds have an opportunity to learn STEM skills. Some outreach opportunities were not possible in 2020, but the GEMM Lab continued our efforts where possible. Clara taught a photogrammetry workshop for the Marine Studies Initiative student club Ocean11, where students were taught how to measure whales from drone images. The success of the workshop (and earlier iterations of it in 2019) led to Clara turning it into a lab for Dr. Renee Albertson’s FW 469 Physiology/Behavior of Marine Megafauna class. As one of the program coordinators for the Fisheries & Wildlife Mentorship Program, I co-hosted an Intro to R & RStudio workshop this fall. Rachel taught a remote intensive science communication workshop during her first term in grad school. Although COVID-19 meant that one-on-one mentorships had to be a little more distant, over the course of the year, the GEMM Lab still supervised a total of 7 students that assisted our work in a variety of ways (field and/or lab work, data analyses, independent projects) on a number of projects going on in the lab.

In a typical year, GEMM Lab members would have undertaken quite a lot more travel, largely to attend conferences. Due to COVID-19, most conferences were either cancelled or held virtually. Leigh gave the plenary talk at the annual State of the Coast Conference, one of the favorite conferences of the GEMM Lab as it brings together scientists, stakeholders, managers, students, and the public to discuss Oregon-centric topics. Dawn gave an oral presentation at the International Marine Conservation Congress. The talk was titled “Wind, green water, and blue whales: Predictive models forecast blue whale distribution in an upwelling system to mitigate industrial impacts” as part of a symposium focused on evidence-based solutions for the management of large marine vertebrate species. Clara presented at the annual Research Advances in Fisheries, Wildlife & Ecology symposium hosted by the graduate student association in the Department of Fisheries & Wildlife. Clara’s talk, which was about her proposed PhD research, was titled “Drone footage reveals patterns of gray whale behavior across space, time, and the individual”.

While our travel may have been reduced this year, the lab certainly has had a prolific year of writing! The 19 new publications in 16 scientific journals include contributions from Leigh (6), Leila (5), Rachael (4), Solène (3), Clara (3), Dawn (2), and Ale (1). Scroll down to the end of the post to see the full list.

We are also very excited about a new addition to the lab. Rachel Kaplan, who is co-advised by Leigh and Dr. Kim Bernard in the College of Earth, Ocean, and Atmospheric Sciences, started her PhD at OSU in the fall. Rachel is one of this year’s recipients of the highly-competitive National Science Foundation’s Graduate Research Fellowship. Receiving the fellowship allowed Rachel to wrap up her job at the Bigelow Laboratory for Ocean Sciences in Maine and move to Oregon. The journey wasn’t easy (Rachel moved in the midst of the pandemic and during the height of the wildfires that raged across the U.S. West Coast) but she made it here safely! For her PhD, Rachel will try to understand how oceanographic factors and prey patches shape the distribution of whales in Oregon waters (with data collected through the OPAL project) to work towards solutions to the high rates of whale entanglements in fishing gear that have occurred on the West Coast since 2014. Welcome Rachel! 

While we persevered through tough times this year and have been lucky to celebrate many accomplishments, nothing prepared us for the shock that we all felt, and are still feeling deeply, about the loss of our fellow GEMM Lab graduate student Alexa Kownacki just over a month ago. Alexa’s optimism, generosity, and kindness were unparalleled, and the hole that she leaves in the lab and in our lives individually is gaping. The lab wrote a collaborative blog about Alexa a few weeks ago and we have created a website in her honor, where we encourage everyone to post photos, tributes or stories about Alexa. It has been so comforting to us to read people’s memories of Alexa that allow us to learn new things about her and remind us of our own memories. Alexa, we think of you every day and we miss you.

Alexa in her element

If you are reading this post, we would like to say thank you for all the support and interest in our work – we really appreciate it! Our blog’s viewership this year (a whopping 25,588 views!) has increased over a seven-fold since its creation in 2015 (3,462 views). We hope you will continue to join us on our journeys in 2021. Until then, stay safe, mask up & happy holidays from the GEMM Lab!

A GEMM Lab Happy Hour Zoom

Publications

Ajó, A. A. F., Hunt, K. E., Giese, A. C., Sironi, M., Uhart, M., Rowntree, V. J., Marón, C. F., Dillon, D., DiMartino, M., & Buck, C. L. (2020). Retrospective analysis of the lifetime endocrine response of southern right whale calves to gull wounding and harassment: A baleen hormone approach. General and Comparative Endocrinology, 296, 113536.

Albert, C., …, Orben, R. A., et al. (2020). Seasonal variation of mercury contamination in Arctic seabirds: a pan-arctic assessment. Science of the Total Environment, 750, 142201.

Barlow, D. R., Bernard, K. S., Escobar-Flores, P., Palacios, D. M., & Torres, L. G. (2020). Links in the trophic chain: modeling functional relationships between in situ oceanography, krill, and blue whale distribution under different oceanographic regimes. Marine Ecology Progress Series, 642, 207-225.

Baylis, A. M. M., Tierney, M., Orben, R. A., González de la Peña, D., & Brickle, P. (2020). Non-breeding movements of Gentoo penguins at the Falkland Islands. Ibis, doi:10.1111/ibi.12882.

Bird, C., & Bierlich, K.. (2020).  CollatriX: A GUI to collate MorphoMetriX outputs. Journal of Open Source Software, 5(51), 2328. doi:10.21105/joss10.21105/joss.02328.

Bird, C., Dawn, A. H., Dale, J., & Johnston, D. W. (2020). A Semi-Automated Method for Estimating Adélie Penguin Colony Abundance from a Fusion of Multispectral and Thermal Imagery Collected with Unoccupied Aircraft Systems. Remote Sensing, 12(22), 3692. doi:10.3390/rs12223692.

Chero, G., Pradel, R., Derville, S., Bonneville, C., Gimenez, O., & Garrigue, C. (2020). Reproductive capacity of an endangered and recovering population of humpback whales in the Southern Hemisphere. Marine Ecology Progress Series, 643, 219-227.

Derville, S., Torres, L. G., Zerbini, A. N., Oremus, M., & Garrigue, C. (2020). Horizontal and vertical movements of humpback whales inform the use of critical pelagic habitats in the western South Pacific. Scientific Reports, 10, 4871.

DiGiacomo, A. E., Bird, C., Pan, V. G., Dobroski, K., Atkins-Davis, C., Johnston, D. W., & Ridge, J. T.. (2020). Modeling Salt Marsh Vegetation Height Using Unoccupied Aircraft Systems and Structure from Motion. Remote Sensing, 12(14), 2333. doi:10.3390/rs12142333.

Garrigue, C., Derville, S., Bonneville, C., Baker, C. S., Cheeseman, T., Millet, L., Paton, D., & Steel, D. (2020). Searching for humpback whales in a historical whaling hotspot of the Coral Sea, South Pacific. Endangered Species Research, 42, 67-82.

Hauser-Davis, R. A., Monteiro, F., Chávez da Rocha, R. C., Lemos, L., Duarte Cardoso, M., & Siciliano, S. (2020). Titanium as a contaminant of emerging concern in the aquatic environment and the current knowledge gap regarding seabird contamination. Ornithologia, 11, 7-15.

Hindell, M. A., … Torres, L. G., et al. (2020). Tracking of marine predators to protect Southern Ocean ecosystems. Nature, 580(7801), 87-92.

Jones, K. A., Baylis, A. M. M., Orben, R. A., Ratcliffe, N., Votier, S. C., Newton, J., & Staniland, I. J. (2020). Stable isotope values in South American fur seal pup whiskers as proxies of year-round maternal foraging ecology. Marine Biology, 167(10), 1-11.

Kroeger, C. E., Crocker, D. E., Orben, R. A., Thompson, D. R., Torres, L. G., Sagar, P. M., Sztukowski, L. A., Andriese, T., Costa, D. P., & Shaffer, S. A. (2020). Similar foraging energetics of two sympatric albatrosses despite contrasting life histories and wind-mediated foraging strategies. Journal of Experimental Biology, 223, jeb228585.

Lemos, L. S., Olsen, A., Smith, A., Chandler, T. E., Larson, S., Hunt, K., & Torres, L. G. (2020). Assessment of fecal steroid and thyroid hormone metabolites in eastern North Pacific gray whales. Conservation Physiology, 8, coaa110.

Monteiro, F., Lemos, L. S., et al. (2020). Total and subcellular Ti distribution and detoxification processes in Pontoporia blainvillei and Steno bredanensis dolphins from southeastern Brazil. Marine Pollution Bulletin, 153, 110975.

Quinete, N., Hauser-Davis, R. A., Lemos, L. S., Moura, J. F., Siciliano, S., & Gardinali P. R. (2020). Occurrence and tissue distribution of organochlorinated compounds and polycyclic aromatic hydrocarbons in Magellanic penguins (Spheniscus magellanicus) from the southeastern coast of Brazil. Science of the Total Environment, 749, 141473.

Soledade Lemos, L., Burnett, J. D., Chandler, T. E., Sumich, J. L., & Torres, L. G. (2020). Intra- and inter-annual variation in gray whale body condition on a foraging ground. Ecosphere, 11(4), e03094.

Torres, L. G., Barlow, D. R., Chandler, T. E., & Burnett, J. D. (2020). Insight into the kinematics of blue whale surface foraging through drone observations and prey data. PeerJ, 8, e8906.

Five mind-blowing facts about sperm whales

By Solène Derville, Postdoctoral Scholar, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

Having worked almost exclusively on humpback whales for the past 5 years, I recently realized how specialized I have become when I was asked to participate in an expedition targeting another legendary cetacean, which I discovered I knew so little about: the sperm whale. On November 18th I boarded a catamaran with a team of 8 other seamen, film makers and scientists, all ready to sail off the west coast of New Caledonia in the search of this elusive animal. The expedition was named “Code CODA” in reference to the unique patterned series of clicks produced by sperm whales.

As I prepared for the expedition, I did my scientific literature homework and felt a growing awe for sperm whales. At every step of my research, whether I investigated their morphology, physiology, social behavior, feeding habits… everything about them appeared to be exceptional. Below is a list summarizing five mind-blowing facts everyone should know about sperm whales.

A sperm whale sketch I made on the boat in preparation for this blog post (Illustration credit: Solène Derville)

Sea giants

 Sperm whales are the largest of the odontocetes species, which is the group of “toothed whales” that also includes dolphins, porpoises and beaked whales. They show a strong sexual dimorphism, unusual for a cetacean, as adult males can be about twice as big as adult females. Indeed, male sperm whales can reach up to 18 m and 56 tons (approximately the weight of 9 elephants!). Their massive block-shaped head is perhaps their most distinctive feature. It contains the largest brain in the animal kingdom and as a comparison, it is claimed that an entire car could fit in it! By its morphology alone, the sperm whale hence appears like an all-round champion of cetaceans.

Abyssal divers

 Sperm whales are some of the best divers among air-breathing sea creatures. They have been recorded down to 2,250 m, and sperm whale carcasses have been found entangled in deep-sea cables suggesting that they can dive even deeper. In these dark and cold waters, sperm whales hunt for fish and squids (and sometimes check out ROVs, see videos of a surprising deep sea encounter made in 2015 off the coast of Louisiana, on Nautilus Live). They are renowned for attacking giant (Architeuthis spp) and colossal (Mesonychoteuthis hamiltoni) squids, which can reach more than 10 m in length. The squid sucker scars born by sperm whales give evidence of these titan combats. Because sperm whales only have teeth on the lower jaw, they cannot chew and may end up eating their prey alive. But every problem has its solution… sperm whales have evolved the longest digestive system in the world: it can reach 300 m long! Their stomach is divided into four compartments, the first of which is covered by a thick and muscular lining that can resist the assault of live prey.

Deluxe poopers  

The digestion of sperm whale prey happens in the next digestive compartments, but one component will resist: the squids’ beaks! As beaks accumulate in the digestive system (up to 18,000 beaks were found in a specimen!), they cause an irritation that is responsible for the production of a waxy substance known as ‘ambergris’. After a while, this substance is thought to be occasionally secreted along with the whale’s poop (although it has been speculated that large pieces of ambergris might be expelled by the mouth… charming!). Ambergris may be found floating at sea or washed up on coastlines, where it may make one happy beachcomber! The latest report of such a lucky finding of ambergris in 2016 was estimated at more than US$71,000 for a 1.57 kg lump. Indeed, ambergris is a valued additive used in perfume, although it has now mostly been replaced by synthetic equivalents. The use of ambergris in cooking, incense or medication in ancient Egypt and the Middle Ages is also reported.

Ambergris lump found in the UK in 2018 (photo credit: APEX, source: https://www.bbc.com/news/uk-england-devon-42703991)

Caring whales

Sperm whales are highly social animals. They are organized in “clans” with their own vocal repertoire and behavioral traits that differ geographically. Clans are formed by several connected social units, which are ruled by a complex matrilineal system. While adult males typically live solitary lives, females remain in family units composed of their close female relatives. Within these groups, females take communal care of the calves, even nursing the calves of other females. Every female can act as a babysitter to the group’s calves at the surface while the clan members perform deep foraging dives of approximately 40 min. Juvenile males may also provide care to the younger calves in the group as they remain in the group far past weaning, up to 9 to 19 years old. When attacked by predators (mostly killer whales), all the group members will protect the younger and most vulnerable individuals by adopting a compact formation, either the “marguerite” (facing inwards with their tails out and the young at the center for protection) or the “heads-out” version.

Social interaction in a pod of sperm whales… much like the whale version of a cuddle (photo credit: Tony Wu)

Powerful sonars

Like other toothed whales, sperm whales use sound to echolocate and communicate. But again, sperm whales stand out from the crowd with the unique spermaceti organ that allows them to produce the most powerful sound in the animal kingdom, reaching a source level of about 230 dB within frequencies of 5 to 25 kHz (this is louder than the sound of a jet engine at take-off). The spermaceti organ is a large cavity surrounded by a tough and fibrous wall called “the case”, and is filled with up to 1,900 liters of a fatty and waxy liquid called “spermaceti”. The spermaceti oil is chemically very different from the oils found in the melons (heads) of most other species of odontocetes, which also explains why sperm whales were particularly targeted by whalers of the 19th and 20th centuries. Indeed, the spermaceti oil has exceptional lubricant properties, and thus was used in fine machinery and even in the aerospace industry.

Original figure from Raven & Gregory 1933

Sperm whales are among the most widely distributed animals in the world, as they roam waters from the ice-edge to the equator. While pre-whaling global abundance is thought to have been 1,110,000 sperm whales, the most recent estimate suggests that only about a third of this number currently populates the ocean. It is our absolute duty to make sure that these marvelous, superlative animals recover from our past mistakes and that they can be admired by future generations.

Sources:

Gero, Shane, Jonathan Gordon, and Hal Whitehead (2013) “Calves as Social Hubs: Dynamics of the Social Network within Sperm Whale Units.” Proceedings of the Royal Society B: Biological Sciences 280 (1763). https://doi.org/10.1098/rspb.2013.1113

Graber, Cynthia (2007) “Strange but True: Whale Waste Is Extremely Valuable.” Scientific American. https://www.scientificamerican.com/article/strange-but-true-whale-waste-is-valuable/

Møhl, Bertel, Magnus Wahlberg, Peter T. Madsen, Anders Heerfordt, and Anders Lund (2003) “The Monopulsed Nature of Sperm Whale Clicks.” The Journal of the Acoustical Society of America, 114 (2): 1143–54. https://doi.org/10.1121/1.1586258

Raven, H C, and William K Gregory (1933) “The Spermaceti Organ and Nasal Passages of the Sperm Whale (Physeter Catodon) and Other Odontocetes.” American Museum Novitates, no. 677.

Whitehead, Hal (2018) “Sperm Whale.” Encyclopedia of Marine Mammals, 919–25. https://doi.org/10.1016/b978-0-12-804327-1.00242-9