By: Alexa Kownacki, Ph.D. Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab
As technology has developed over the past ten years, toxins
in marine mammals have become an emerging issue. Environmental toxins are
anything that can pose a risk to the health of plants or animals at a dosage.
They can be natural or synthetic with varying levels of toxicity based on the
organism and its physiology. Most prior research on the impacts toxins before
the 2000s was conducted on land or in streams because of human proximity to
these environments. However. with advancements in sampling methods, increasing
precision in laboratory testing, and additional focus from researchers, marine
mammals are being assessed for toxin loads more regularly.
Marine mammals live most of their lives in the ocean or other aquatic systems, which requires additional insulation for protection from both cold temperatures and water exposure. This added insulation can take the form of lipid rich blubber, or fur and hair. Many organic toxins are lipid soluble and therefore are more readily found and stored in fatty tissues. When an organic toxin like a polychlorinated biphenyl (PCB) is released into the environment from an old electrical transformer, it persists in sediments. As these sediments travel down rivers and into the ocean, these toxic substances slowly degrade in the environment and are lipophilic (attracted to fat). Small marine critters eat the sediment with small quantities of toxins, then larger critters eat those small critters and ingest larger quantities of toxins. This process is called biomagnification. By the time a dolphin consumes large contaminated fishes, the chemical levels may have reached a toxic level.
Marine mammal scientists are teaming with biochemists and ecotoxicologists to better understand which toxins are more lethal and have more severe long-term effects on marine mammals, such as decreased reproduction rates, lowered immune systems, and neurocognitive delays. Studies have already shown that higher contaminant loads in dolphins cause all three of these negative effects (Trego et al. 2019). As a component of my thesis work on bottlenose dolphins I will be measuring contaminant levels of different toxins in blubber. Unfortunately, this research is costly and time-consuming. Many studies regarding the effects of toxins on marine mammals are funded through the US government, and this is where the public can have a voice in scientific research.
Prior to the 1960s, there were no laws regarding the discharge of toxic substances into our environment. When Rachel Carson published “Silent Spring” and catalogued the effects of pesticides on birds, the American public began to understand the importance of environmental regulation. Once World War II was over and people did not worry about imminent death due to wartime activities, a large portion of American society focused on what they were seeing in their towns: discharges from chemical plants, effluents from paper mills, taconite mines in the Great Lakes, and many more.
However, it was a very different book regarding pollutants in the environment that caught my attention – and that of a different generation and part of society – even more than “Silent Spring”. A book called “The Lorax”. In this 1972 children’s illustrated book by Dr. Seuss, a character called the Lorax “speaks for the trees”. The Lorax touches upon critical environmental issues such as water pollution, air pollution, terrestrial contamination, habitat loss, and ends with the poignant message, “Unless someone like you cared a whole awful lot, nothing is going to get better. It’s not.”
Within a decade, the US Environmental Protection Agency (EPA) was formed and multiple acts of congress were put in place, such as the National Environmental Policy Act, Clean Air Act, Clean Water Act, and Toxic Substances Control Act, with a mission to “protect human health and the environment.” The public had successfully prioritized protecting the environment and the government responded. Before this, rivers would catch fire from oil slicks, children would be banned from entering the water in fear of death, and fish would die by the thousands. The resulting legislation cleaned up our air, rivers, and lakes so that people could swim, fish, and live without fear of toxic substance exposures.
Fast forward to 2018 and times have changed yet again due to fear. According to a Pew Research poll, terrorism is the number one issue that US citizens prioritize, and Congress and the President should address. The environment was listed as the seventh highest priority, below Medicare (“Majorities Favor Increased Spending for Education, Veterans, Infrastructure, Other Govt. Programs.”). With this societal shift in priorities, research on toxins in marine mammals may no longer grace the covers of the National Geographic, Science, or Nature, not for lack of importance, but because of the allocation of taxpayer funds and political agendas. Meanwhile, long-lived marine mammals will still be accumulating toxins in their blubber layers and we, the people, will need to care a whole lot, to save the animals, the plants, and ultimately, our planet.
“Majorities Favor Increased Spending for Education,
Veterans, Infrastructure, Other Govt. Programs.” Pew Research Center for the
People and the Press, Pew Research Center, 11 Apr. 2019,
Marisa L. Trego, Eunha Hoh, Andrew Whitehead, Nicholas M. Kellar, Morgane Lauf, Dana O. Datuin, and Rebecca L. Lewison. Environmental Science & Technology201953 (7), 3811-3822. DOI: 10.1021/acs.est.8b06487
By Alejandro Fernánez Ajó, PhD student at NAU and GEMM Lab research technician
commercial whaling is currently banned and several whale populations show
evidence of recovery, today´s whales are exposed to a variety of other human
stressors (e.g., entanglement in fishing gear, vessel strikes, shipping noise,
climate change, etc.; reviewed in Hunt et al., 2017a). The recovery and
conservation of large whale populations is particularly important to the
oceanic environment due to their key ecological role and unique biological
traits, including their large body size, long lifespan and sizable home ranges
(Magera et al., 2013; Atkinson et al., 2015; Thomas and Reeves, 2015). Thus,
scientists must develop novel tools to overcome the challenges of studying
whale physiology in order to distinguish the relative importance of the different
impacts and guide conservation actions accordingly (Ayres et al., 2012; Hunt et
To this end,
baleen hormone analysis represents a powerful tool for retrospective assessment
of patterns in whale physiology (Hunt et al., 2014, 2016, 2017a, 2017b, 2018;
Lysiak et. al., 2018; Fernández Ajó et al., 2018; Rolland et al., 2019).
Moreover, hormonal panels, which include multiple hormones, are helping to
better clarify and distinguish between the physiological effects of different
sources of anthropogenic and environmental stressors (Ayres et al., 2012;
Wasser et al., 2017; Lysiak et al., 2018; Romero et al., 2015).
What is Baleen? Baleen is a stratified epithelial tissue consisting of long, fringed plates that grow downward from the upper jaw, which collectively form the whale´s filter-feeding apparatus (Figure 1). This tissue accumulates hormones as it grows. Hormones are deposited in a linear fashion with time so that a single plate of baleen allows retrospective assessment and evaluation of a whales’ physiological condition, and in calves baleen provides a record of the entire lifespan including part of their gestation. Baleen samples are also readily accessible and routinely collected during necropsy along with other samples and relevant information.
Why are the
Southern Right Whales calves (SRW) dying in Patagonia?
I am a Fulbright Ph.D. student in the Buck Laboratory at Northern Arizona University since Fall 2017, a researcher with the Whale Conservation Institute of Argentina (Instituto de Conservación de Ballenas) and Field Technician for the GEMM Lab over the summer. I focus my research on the application and development of novel methods in conservation physiology to improve our understanding of how physiological parameters are affected by human pressures that impact large whales and marine mammals. I am especially interested in understanding the underlaying causes of large whale mortalities with the aim of preventing their occurrence when possible. In particular, for my Ph.D. dissertation, I am studying a die-off case of Southern Right Whale (SRW) calves, Eubalaena australis, off Peninsula Valdés (PV) in Patagonia-Argentina (Figure 2).
2000, annual calf mortality at PV was considered normal and tracked the
population growth rate (Rowntree et al., 2013). However, between 2007 and 2013,
558 whales died, including 513 newborn calves (Sironi et al., 2018). Average
total whale deaths per year increased tenfold, from 8.2 in 1993-2002 to 80 in
2007-2013. These mortality levels have never before been observed for the
species or any other population of whales (Thomas et al., 2013, Sironi et al.,
Among several hypotheses proposed to explain these elevated calf mortalities, harassment by Kelp Gulls, Larus dominicanus, on young calves stands out as a plausible cause and is a unique problem only seen at the PV calving ground. Kelp gull parasitism on SRWs near PV was first observed in the 1970’s (Thomas, 1988). Gulls primarily harass mother-calf pairs, and this parasitic behavior includes pecking on the backs of the whales and creating open wounds to feed on their skin and blubber. The current intensity of gull harassment has been identified as a significant environmental stressor to whales and potential contributor to calf deaths (Marón et al., 2015b; Fernández Ajó et al., 2018).
Figure 3: The significant preference for calves as a target of gull attacks highlights the impact of this parasitic behavior on this age class. The situation continues to be worrisome and serious for the health and well-being of newborn calves at Península Valdés. Left: A Kelp Gull landing on whale´s back to feed on her skin and blubber (Photo credit: Lisandro Crespo). Right: A calf with multiple lesions on its back produced by repeated gull attacks (Photo credit: ICB).
Quantifying gull inflicted wounds
Photographs of gull wounds on whales taken during necropsies and were quantified and assigned to one of seven objectively defined size categories (Fig. 4): extra-small (XS), small (S), medium (M), large (L), extra-large (XL), double XL (XXL) and triple XL (XXXL). The size and number of lesions on each whale were compared to baleen hormones to determine the effect of the of the attacks on the whales health.
hormones are applied
factors such as injuries, predation avoidance, storms, and starvation promote
an increase in the secretion of the glucocorticoids (GCs) cortisol and
corticosterone (stress hormones), which then induce a variety of physiological
and behavioral responses that help animals cope with the stressor. Prolonged exposure
to chronic stress, however, may exceed the animal’s ability to cope with such
stimuli and, therefore, adversely affects its body condition, its health, and
even its survival. Triiodothyronine (T3), is the most biologically active form
of the thyroid hormones and helps regulate metabolism. Sustained food
deprivation causes a decrease in T3 concentrations, slowing metabolism to
conserve energy stores. Combining GCs and T3 hormone measures allowed us to
investigate and distinguish the relative impacts of nutritional and other
sources of stressors.
Combining these novel methods produced unique results about whale physiology. With my research, we are finding that the GCs concentrations measured in calves´ baleen positively correlate with the intensity of gull wounding (Figure 4, 1 and 2), while calf’s baleen thyroid hormone concentrations are relative stable across time and do not correlate with intensity of gull wounding (Figure 4 – 3). Taken together these findings indicate that SRW calves exposed to Kelp gull parasitism and harassment experience high levels of physiological stress that compromise their health and survival. Ultimately these results will inform government officials and managers to direct conservation actions aimed to reduce the negative interaction between Kelp gulls and Southern Right Whales in Patagonia.
Baleen hormones represent a powerful tool for
retrospective assessments of longitudinal trends in whale physiology by helping
discriminate the underlying mechanisms by which different stressors may affect
a whale’s health and physiology. Moreover, while most sample types used for
studying whale physiology provide single time-point measures of current
circulating hormone levels (e.g., skin or respiratory vapor), or information
from previous few hours or days (e.g., urine and feces), baleen tissue provides
a unique opportunity for longitudinal analyses of hormone patterns. These
retrospective analyses can be conducted for both stranded or archived
specimens, and can be conducted jointly with other biological markers (e.g.,
stable isotopes and biotoxins) to describe migration patterns and exposure to pollutants.
Further research efforts on baleen hormones should focus on completing
biological validations to better understand the hormone measurements in baleen
and its correlation with measurements from alternative sample matrices (i.e.,
feces, skin, blubber, and respiratory vapors).
Crocker, D., Houser, D., Mashburn, K., 2015. Stress physiology in marine
mammals: how well do they fit the terrestrial model? J. Comp. Physiol. B. 185,
Booth, R.K., Hempelmann, J.A., Koski, K.L., Emmons, C.K., Baird, R.W.,
Balcomb-Bartok, K., Hanson, M.B., Ford, M.J., Wasser, S.K., 2012. Distinguishing
the impacts of inadequate prey and vessel traffic on an endangered killer whale
(Orcinus orca) population. PLoS ONE.
7, e36842. https://doi.org/10.1371/journal.pone.0036842.
Ajó, A.A., Hunt, K., Uhart, M., Rowntree, V., Sironi, M., Marón, C.F., Di
Martino, M., Buck, L., 2018. Lifetime glucocorticoid profiles in baleen of
right whale calves: potential relationships to chronic stress of repeated
wounding by Kelp Gull. Conserv. Physiol. 6, coy045. https://doi.org/10.1093/conphys/coy045.
Lysiak, N., Moore, M., Rolland, R.M., 2017a. Multi-year longitudinal profiles
of cortisol and corticosterone recovered from baleen of North Atlantic right
whales (Eubalaena glacialis). Gen.
Comp. Endocrinol. 254: 50–59. https://doi.org/10.1016/j.ygcen.2017.09.009.
Hunt, K.E., Lysiak, N.S., Matthews, C.J.D., Lowe, C., Fernández-Ajo, 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.
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.
Lysiak, N.S., Moore, M.J., Seton, R.E., Torres, L., Buck, C.L., 2017b. Multiple
steroid and thyroid hormones detected in baleen from eight whale species.
Conserv. Physiol. 5, cox061. https://doi.org/10.1093/conphys/cox061.
Moore, M.J., Rolland, R.M., Kellar, N.M., Hall, A.J., Kershaw, J., Raverty,
S.A., Davis, C.E., Yeates, L.C., Fauquier, D.A., Rowles, T.K., Kraus, S.D.,
2013. Overcoming the challenges of studying conservation physiology in large
whales: a review of available methods. Conserv. Physiol. 1: cot006. https://doi.org/10.1093/conphys/cot006.
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. doi: https://doi.org/10.1093/conphys/cou030.
Trumble, S., Knowlton, A., Moore, M., 2018. Characterizing the duration and
severity of fishing gear entanglement on a North Atlantic right whale
(Eubalaena glacialis) using stable isotopes, steroid and thyroid hormones in
baleen. Front. Mar. Sci. 5: 168. https://doi.org/10.3389/fmars.2018.00168.
Beltramino, L., Di Martino, M., Chirife, A., Seger, J., Uhart, M., Sironi, M.,
Rowntree, V.J., 2015b Increased wounding of southern right whale (Eubalaena
australis) calves by Kelp Gulls (Larus dominicanus) at Península Valdés,
Argentina., PLoS ONE. 10, p. e0139291. https://doi.org/10.1371/journal.pone.0139291.
Rowntree, V.J., Sironi, M., Uhart, M., Payne, R.S., Adler, F.R., Seger, J.,
2015a. Estimating population consequences of increased calf mortality in the
southern right whales off Argentina. SC/66a/BRG/1 presented to the IWC
Scientific Committee, San Diego, USA. Available at: https://iwc.int/home
R.M., Graham, K.M., Stimmelmayr, R., Suydam, R. S., George, J.C., 2019. Chronic
stress from fishing gear entanglement is recorded in baleen from a bowhead
whale (Balaena mysticetus). Mar. Mam. Sci. https://doi.org/10.1111/mms.12596.
Platts, S.H., Schoech, S.J., Wada, H., Crespi, E., Martin, L.B., Buck, C.L.,
2015. Understanding Stress in the Healthy Animal – Potential Paths for
Progress. Stress. 18(5), 491-497.
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. Mar. Ecol. Prog. Ser. 493:275–289. https://doi.org/10.3354/meps10506.
Sironi, M. Rowntree, V.,
Di Martino, M., Alzugaray, L.,Rago, V., Marón, C.F., Uhart M., 2018. Southern
right whale mortalities at Península Valdes, Argentina: updated information for
2016-2017. SC/67B/CMP/06 presented to the IWC Scientific Committee, Slovenia.
Available at: https://iwc.int/home.
Rowntree, V., Snowdon, C., Valenzuela, L., Marón C., 2009. Kelp Gulls (Larus
dominicanus) feeding on southern right whales (Eubalaena australis) at
Península Valdes, Argentina: updated estimates and conservation implications.
SC/61/BRG19. presented to the IWC Scientific Committee, Portugal. Available at:
Uhart, M., McAloose, D., Sironi, M., Rowntree, V.J., Brownell, Jr. R., Gulland,
F.M.D., Moore, M., Marón, C., Wilson, C., 2013. Workshop on the southern right
whale die-off at Península Valdés, Argentina. SC/60/BRG15 presented to the IWC
Scientific Committee, South Korea. Available at: https://iwc.int/home
Lundin, J.I., Ayres, K., Seely, E., Giles, D., Balcomb, K., Hempelmann, J.,
Parsons, K., Booth, R., 2017. Population growth is limited by nutritional
impacts on pregnancy success in endangered Southern Resident killer whales
(Orcinus orca). PLoS ONE. 12, e0179824. https://doi.org/10.1371/journal.pone.0179824.
By Leila Lemos, PhD Student (hopefully PhD candidate soon)
Here I am with the first GEMM Lab blog post of 2018.
Many people begin a New Year thinking about the future and planning goals to achieve in the following year, and that’s exactly how I am starting my year. After two and a half years of my PhD program, my classes and thesis project are nearing the end. However, a large hurdle stands between me and my finish line: my preliminary exams (as opposed to final exams that happen when I defend my thesis).
Oregon State University requires two sets of preliminary examinations (a.k.a. “prelims”) in order to become a PhD candidate. Thus, planning my next steps is essential in order to accomplish my main objective: a successful completion of these two exams.
The first set of exams comprises written comprehensive examinations to be taken over the course of a week (Monday to Friday), where each day belongs to a different member of my committee. The second type of exam is an oral preliminary examination, conducted by my doctoral committee. The written and oral prelims may cover any part of my proposed research topic as described in the proposal I submitted during my first PhD year.
In order to better understand this entire process, I met with Dr. Carl Schreck, a Fisheries and Wildlife Department professor and one of the members of my committee. He has been through this prelim process many times with other students and had good advice for me regarding preparation. He told me to meet with all of my committee members individually to discuss study material and topics. However, he said that I should first define and introduce myself with a title to each committee member, so they know how to base and frame exam questions. But, how do I define myself?
As part of my PhD committee, Dr. Schreck is familiar with my project and what I am studying, so he suggested the title “Conservation Physiologist”. But, do I see myself as a Conservation Physiologist? Will this set-up have implications for my future, such as the type of job I am prepared for and able to get?
I can see it is important to get this title right, as it will influence my exam process as well as my scientific career. However, it can be hard and somewhat tricky when trying to determine what is comprised by your work and what are the directions you want to take in your future. I believe that defining the terms conservationist and physiologist, and what they encompass, is a good first step.
To me, a conservation specialist works for the protection of the species, their habitats, and its natural resources from extinction and biodiversity loss, by identifying and mitigating the possible threats. A conservation specialist’s work can help in establishing new regulations, conservation actions, and management interventions. As for an animal physiology specialist, their research may focus on how animals respond to internal and external elements. This specialist often studies an animal’s vital functions like reproduction, movement, growth, metabolism and nutrition.
According to Cooke et al. (2013), conservation specialists focus on population characteristics (e.g., abundance and structure) and indicators of responses to environmental perturbations and human activities. Thus, merging conservation and physiology disciplines enables fundamental understanding of the animal response mechanisms to such threats. Using animal physiology as a tool is valuable for developing cause-and-effect relationships, identifying stressor thresholds, and improving ecological model predictions of animal responses. Thus, conservation physiology is an inter-disciplinary field that provides physiological evidence to promote advances in conservation and resource management.
My PhD project is multidisciplinary, where the overall aim is to understand how gray whales are physiologically responding to variability in ambient noise, and how their hormone levels vary across individual, time, body condition, location, and noise levels. I enjoy many aspects of the project, but what I find myself most excited about is linking information about sex, age, body condition, and cortisol levels to specific individuals we observe multiple times in the field. As we monitor their change in body condition and hormones, I am highly motivated to build these whale ‘life-history stories’ in order to better understand patterns and drivers of variability. Although we have not yet tied the noise data into our analyses of whale health, I am very interested to see how this piece of the puzzle fits into these whale ‘life-history stories’.
In this study, animal physiology facilitates our stories. Scientific understanding is the root of all good conservation, so I believe that this project is an important step toward improved conservation of baleen whales. Once we are able to understand how gray whales respond physiologically to impacts of ocean noise, we can promote management actions that will enhance species conservation.
Thus, I can confidently say, I am a Conservation Physiologist.
Over the next three months I will be meeting with my committee members and studying for my prelims. I hope that this process will prepare me to become a PhD candidate by the time my exams come around in March. Then, I will have accomplished my first goal of 2018, so I can go on to plan for the next ones!
Cooke SJ, Sack L, Franklin CE, Farrell AP, Beardall J, Wikelski M, and Chown SL. What is conservation physiology? Perspectives on an increasingly integrated and essential science. Conserv Physiol. 2013; 1(1): cot001. Published online 2013 Mar 13. doi: 10.1093/conphys/cot001.