The significance of blubber hormone sampling in conservation and monitoring of marine mammals

By: Alexa Kownacki, Ph.D. Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

Marine mammals are challenging to study for many reasons, and specifically because they inhabit the areas of the Earth that are uninhabited by people: the oceans. Monitoring marine mammal populations to gather baselines on their health condition and reproductive status is not as simple as trap and release, which is a method often conducted for terrestrial animals. Marine mammals are constantly moving in vast areas below the surface. Moreover, cetaceans, which do not spend time on land, are arguably the most challenging to sample.

One component of my project, based in California, USA, is a health assessment analyzing hormones of the bottlenose dolphins that frequent both the coastal and the offshore waters. Therefore, I am all too familiar with the hurdles of collecting health data from living marine mammals, especially cetaceans. However, the past few decades have seen major advancements in technology both in the laboratory and with equipment, including one tool that continues to be critical in understanding cetacean health: blubber biopsies.

Biopsy dart hitting a bottlenose dolphin below the dorsal fin. Image Source: NMFS

Blubber biopsies are typically obtained via low-powered crossbow with a bumper affixed to the arrow to de-power it once it hits the skin. The arrow tip has a small, pronged metal attachment to collect an eraser-tipped size amount of tissue with surface blubber and skin. I compare this to a skin punch biopsies in humans; it’s small, minimally-invasive, and requires no follow-up care. With a small team of scientists, we use small, rigid-inflatable vessels to survey the known locations of where the bottlenose dolphins tend to gather. Then, we assess the conditions of the seas and of the animals, first making sure we are collecting from animals without potentially lowered immune systems (no large, visible wounds) or calves (less than one years old). Once we have photographed the individual’s dorsal fin to identify the individual, one person assembles the biopsy dart and crossbow apparatus following sterile procedures when attaching the biopsy tips to avoid infection. Another person prepares to photograph the animal to match the biopsy information to the individual dolphin. One scientist aims the crossbow for the body of the dolphin, directly below the dorsal fin, while the another photographs the biopsy dart hitting the animal and watches where it bounces off. Then, the boat maneuvers to the floating biopsy dart to recover the dart and the sample. Finally, the tip with blubber and skin tissue is collected, again using sterile procedures, and the sample is archived for further processing. A similar process, using an air gun instead of a crossbow can be viewed below:

GEMM Lab members using an air gun loaded with a biopsy dart to procure marine mammal blubber from a blue whale in New Zealand. Video Source: GEMM Laboratory.

Part of the biopsy process is holding ourselves to the highest standards in our minimally-invasive technique, which requires constant practice, even on land.

Alexa practicing proper crossbow technique on land under supervision. Image Source: Alexa Kownacki

Blubber is the lipid-rich, vascularized tissue under the epidermis that is used in thermoregulation and fat storage for marine mammals. Blubber is an ideal matrix for storing lipophilic (fat-loving) steroid hormones because of its high fat content. Steroid hormones, such as cortisol, progesterone, and testosterone, are naturally circulating in the blood stream and are released in high concentrations during specific events. Unlike blood, blubber is less dynamic and therefore tells a much longer history of the animal’s nutritional state, environmental exposure, stress level, and life history status. Blubber is the cribs-notes version of a marine mammal’s biography over its previous few months of life. Blood, on the other hand, is the news story from the last 24 hours. Both matrices serve a specific purpose in telling the story, but blubber is much more feasible to obtain from a cetacean and provides a longer time frame in terms of information on the past.

A simplified depiction of marine mammal blubber starting from the top (most exterior surface) being the skin surface down to the muscle (most interior). Image Source: schoolnet.org.za

I use blubber biopsies for assessing cortisol, testosterone, and progesterone in the bottlenose dolphins. Cortisol is a glucocorticoid that is frequently associated with stress, including in humans. Marine mammals utilize the same hypothalamic-pituitary-adrenal (HPA) axis that is responsible for the fight-or-flight response, as well as other metabolic regulations. During prolonged stressful events, cortisol levels will remain elevated, which has long-term repercussions for an animal’s health, such as lowered immune systems and decreased ability to respond to predators. Testosterone and progesterone are sex hormones, which can be used to indicate sex of the individual and determine reproductive status. This reproductive information allows us to assess the population’s composition and structure of males and females, as well as potential growth or decline in population (West et al. 2014).

Alexa using a crossbow from a small boat off of San Diego, CA. Image Source: Alexa Kownacki

The coastal and offshore bottlenose dolphin ecotypes of interest in my research occupy different locations and are therefore exposed to different health threats. This is a primary reason for conducting health assessments, specifically analyzing blubber hormone levels. The offshore ecotype is found many kilometers offshore and is most often encountered around the southern Channel Islands. In contrast, the coastal ecotype is found within 2 kilometers of shore (Lowther-Thieleking et al. 2015) where they are subjected to more human exposure, both directly and indirectly, because of their close proximity to the mainland of the United States. Coastal dolphins have a higher likelihood of fishery-related mortality, the negative effects of urbanization including coastal runoff and habitat degradation, and recreational activities (Hwang et al. 2014). The blubber hormone data from my project will inform which demographics are most at-risk. From this information, I can provide data supporting why specific resources should be allocated differently and therefore help vulnerable populations. Further proving that the small amount of tissue from a blubber biopsy can help secure a better future for population by adjusting and informing conservation strategies.

Literature Cited:

Hwang, Alice, Richard H Defran, Maddalena Bearzi, Daniela. Maldini, Charles A Saylan, Aime ́e R Lang, Kimberly J Dudzik, Oscar R Guzo n-Zatarain, Dennis L Kelly, and David W Weller. 2014. “Coastal Range and Movements of Common Bottlenose Dolphins (Tursiops Truncatus) off California and Baja California, Mexico.” Bulletin of the Southern California Academy of Sciences 113 (1): 1–13. https://doi.org/10.3390/toxins6010211.

Lowther-Thieleking, Janet L., Frederick I. Archer, Aimee R. Lang, and David W. Weller. 2015. “Genetic Differentiation among Coastal and Offshore Common Bottlenose Dolphins, Tursiops Truncatus, in the Eastern North Pacific Ocean.” Marine Mammal Science 31 (1): 1–20. https://doi.org/10.1111/mms.12135.

West, Kristi L., Jan Ramer, Janine L. Brown, Jay Sweeney, Erin M. Hanahoe, Tom Reidarson, Jeffry Proudfoot, and Don R. Bergfelt. 2014. “Thyroid Hormone Concentrations in Relation to Age, Sex, Pregnancy, and Perinatal Loss in Bottlenose Dolphins (Tursiops Truncatus).” General and Comparative Endocrinology 197: 73–81. https://doi.org/10.1016/j.ygcen.2013.11.021.

The Intersection of Science and Politics

By Alexa Kownacki, Ph.D. Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

As much as I try to keep politics out of my science vocabulary, there are some ties between the two that cannot be severed. Often, science in the United States is very linked to the government because funding can be dependent on federal, state, and/or local government decisions. Therefore, it is part of our responsibility as scientists to be, at least, informed on governmental proceedings.

The United States has one agency that is particularly important to those of us conducting marine science: the National Oceanic and Atmospheric Administration (NOAA). NOAA’s mission is science, service, and stewardship with three major components:

  1. To understand and predict changes in climate, weather, oceans and coasts
  2. To share that knowledge and information with others
  3. To conserve and manage coastal and marine ecosystems and resources

noaa org chart
Organizational Chart of NOAA. (Image source: OrgCharting)

Last year, the U.S. Senate confirmed Retired Rear Admiral Timothy Gallaudet, Ph.D., as the Assistant Secretary of Commerce for Oceans and Atmosphere for the Department of Commerce in NOAA. This position is an appointment by the current President of the United States, and is tasked with overseeing the daily functions and the strategic and operational future of NOAA. NOAA oversees the National Marine Fisheries Service (NMFS), which is an agency responsible for the stewardship and management of the nation’s living marine resources. NMFS is a major player when it comes to marine science, particularly through the determination of priorities for research and management of marine species and habitats within the United States’ exclusive economic zone (EEZ).

In dark blue, the United States’ Exclusive Economic zones, surrounding land masses in green. (Figure by K. Laws)

Recently, I had the opportunity to hear Dr. Gallaudet speak to scientists who work for, or in conjunction with, a NMFS office. After the 16% budget cut from the fiscal year 2017 to 2018, many marine scientists are concerned about how budget changes will impact research. Therefore, I knew Dr. Gallaudet’s visit would provide insight about the future of marine science in the United States.

Dr. Gallaudet holds master’s and doctoral degrees in oceanography from Scripps Institution of Oceanography, as well as a bachelor’s degree from the United States Naval Academy. He spent 32 years in the Navy before stepping into his current role as Assistant Secretary. Throughout the meeting, Dr. Gallaudet emphasized his leadership motto: All in, All Good, and All for One.

Dr. Gallaudet also spoke about where he sees NOAA moving towards: the private sector.

A prominent conservation geneticist asked Dr. Gallaudet how NOAA can better foster advanced degree-seeking students. The geneticist commented that a decade ago there were 10-12 PhD students in this one science center alone. Today, there is “maybe one”. Dr. Gallaudet responded that the science centers should start reaching out to private industry. In response to other questions, he continued to redirect scientists toward United States-based corporations that could join forces with government agencies. He believes that if NMFS scientists share data and projects with local biotechnology, medical, and environmental companies, the country can foster positive relationships with industry. Dr. Gallaudet commented that the President wants to create these win-win situations: where the US government pairs with for-profit companies. It is up to us, as the scientists, how we make those connections.

As scientists, we frequently avoid heated political banter in the hopes of maintaining an objective and impartial approach to our research. However, these lines can be blurred. Much of our science depends on political decisions that mold our future, including how funding is allocated and what goals are prioritized. In 2010, Science Magazine published an online article, “Feeding your Research into the Policy Debate” where Elisabeth Pain highlighted the interdisciplinary nature of science and policy. In Pain’s interview with Troy Benn, a PhD student in Urban Ecology at the time, Benn comments that he learned just how much scientists play a role in policy and how research contributes to policy deliberations. Sometimes our research becomes of interest to politicians and sometimes it is the other way around.

From my experiences collaborating with government entities, private corporations, and nonprofit organizations, I realize that science-related policy is imperative. California established a non-profit, the California Ocean Science Trust (OST), for the specific objective supporting management decisions with the best science and bridging science and policy. A critical analysis of the OST by Pietri et al., “Using Science to Inform Controversial Issues: A Case Study from the California Ocean Science Trust”, matches legislation with science. For example, the Senate Bill (SB) 1319, better known as the California Ocean Protection Act (COPA), calls for “decisions informed by good science” and to “advance scientific understanding”. Science is explicitly written into legislation and I think that is a call to action. If an entire state can mobilize resources to create a team of interdisciplinary experts, I can inform myself on the politics that have potential to shape my future and the future of my science.

An image of the NOAA ship Bell M. Shimada transiting between stations. Multiple members of the GEMM Lab conducted surveys from this NOAA vessel in 2018. (Image source: Alexa Kownacki)