Working with Assistant Professor Amy Van Cise in the Whale and Dolphin Ecology Lab, Arial Brewer (PhD, SAFS) and Mollie Ball (BS, Marine Biology) were preparing metabarcoding libraries. This means barcoding DNA (or eDNA) in a manner that allows for the simultaneous identification of many taxa within the same sample.
Mark Stone, UW
Arial Brewer is using genetic metabarcoding to describe the microbiome of beluga whales from the endangered Cook Inlet population.
Mollie was on the indexing step, where she adds individual index tags to each of her DNA samples. Arial was one step further—on the gel electrophoresis step—where she visualizes DNA on a gel to make sure it was well amplified in the previous step.
Mark Stone, UW
Mollie Ball adds individual index tags to each of her DNA samples, in her project to determine the diet of Arctic predators.
For Arial, she was using this method to describe the microbiome of beluga whales from the endangered Cook Inlet population. Meanwhile, Mollie was using genetic metabarcoding to determine the diet of Arctic predators such as spotted seals, bearded seals and beluga whales, from gastric fluids and fecal samples.
Mark Stone, UW
Arial Brewer and Mollie Ball conducting research in the Dolphin and Whale Ecology Lab with Assistant Professor Amy Van Cise.
Find out more about their work with Amy Van Cise in the WADE Lab.
Polar bears are metabolic marvels, sustained by a lifestyle of eating fat-rich seals that puts even the keto diet to shame. Each year, bears cycle through periods of intense feasting and prolonged fasting, packing on most of their weight in spring. For reproductive females, seasonal bulking is crucial – it fuels the winter denning and fasting period when they give birth.
Females emerge in spring with their cubs, giving biologists a prime chance to assess the population and count new recruits. Yet, a challenge remains: when a lone adult female is observed, does it mean she denned and lost her cubs, or never denned at all? How can reproductive failure in polar bears be detected? Solving problems like these is key to guiding conservation efforts to protect polar bears.
Karyn Rode (USGS)
An adult female polar bear with three yearlings.
A familiar tool may hold a clue: A1c, a marker of average blood sugar over the past few months. While most people know A1c as a test to monitor diabetes, a team of research biologists saw potential beyond the doctor’s office. A new study published in the Journal of Mammalogy on June 28 explores whether A1c could reveal if a polar bear had recently denned, which – combined with the absence of cubs – may signal reproductive failure.
The study found that polar bears that recently denned had higher A1c levels than those that had not. Why? Fasting polar bears develop insulin resistance – an adaptation that helps maintain blood sugar levels during extended periods without food. While insulin resistance is a hallmark of type 2 diabetes in humans, in bears, it’s an important physiological response to fasting. Pregnancy adds to this effect, resulting in higher blood sugar in pregnant and perinatal females.
Mom and pups: Two young-of-the-year polar bear cubs with their mother on the sea ice.
Thanks to its long-term signature, A1c could be a useful tool for field biologists to detect denning and reproductive events. Monitoring polar bear health is more crucial now than ever, in the face of climate change. Efforts like these can make a real difference in conserving polar bears and the Arctic ecosystem they depend on.
To measure A1c, the team analyzed blood samples from wild polar bears in Alaska’s Southern Beaufort Sea, collected during USGS-led population health assessments. A1c is rarely measured in wildlife, so Teman and Dr. Laidre partnered with CREW’s polar bear reproduction experts, led by Dr. Erin Curry, to develop a workable approach. The solution: adapt and validate a test originally designed for dogs and cats to reliably function for polar bears.
“Creative, collaborative science is where cool ideas turn into actual tools to protect wildlife,” Teman said.
Kristin Laidre
Three polar bears—an adult female with two yearlings—wander across an Arctic landscape.
The next phase of this research will track A1c levels in the same polar bears throughout the year to better understand seasonal fluctuations – particularly in the weeks leading up to and following denning. The team received a Research and Conservation Grant award from the International Association for Bear Research and Management to continue this work using zoo-housed polar bears.
Citation: Sarah J Teman, Todd C Atwood, Kristin L Laidre, Emily E Virgin, Karyn D Rode, Louisa A Rispoli, Erin Curry, Hemoglobin A1c is a retrospective indicator of denning in polar bears (Ursus maritimus), Journal of Mammalogy, 2025;, gyaf033, https://doi.org/10.1093/jmammal/gyaf033
Climate change threatens the health of polar bears across the Arctic. A study published in Conservation Physiology on March 5, introduces a new approach to measuring the health of polar bear populations, drawing inspiration from a well-known concept in human medicine: allostatic load.
Allostatic load refers to the “wear and tear” on the body that results from chronic stress. In humans, high allostatic load increases the risk for disease and death. A team of scientists used allostatic load principles to create a health scoring model for polar bears in Alaska and Canada’s Southern Beaufort Sea, where the population has declined by 25-50%. The model included measures of nutritional, immune, and chronic stress—factors that are all highly relevant, given the threats facing polar bears. This project was carried out by biologists from the University of Washington School of Aquatic and Fishery Sciences (UW SAFS), United States Geological Survey (USGS), and Fish and Wildlife Health Consulting.
USGS
Two polar bears, an adult female and her cub, on land at Kaktovik, Alaska.
Polar bears depend on sea ice as a hunting platform, and ice loss can lead to poorer nutritional condition. In summer and fall, when the ice retreats northward, bears in the Southern Beaufort Sea must choose between following the ice into less productive hunting areas or moving onto land until the ice refreezes. Increasingly, bears are coming ashore and scavenging human-provisioned foods—an option that may expose them to new pathogens and increase disease risk. Additionally, coming ashore heightens bears’ exposure to human disturbance in areas of expanding oil and gas development, potentially adding further stress to an already vulnerable population.
“Trying to survive with so many stressors is like carrying a backpack that keeps getting heavier. Eventually, it becomes too much to bear,” said Sarah Teman, lead author of the study and UW PhD student working with UW Professor, Kristin Laidre. “By studying allostatic load, we can understand how much ‘weight’ each bear is carrying, and how that affects populations.”
The scientists measured allostatic load through a suite of samples collected from polar bears during annual population health assessments. This involved analyzing blood samples to assess metabolism, fluid balance, organ function, and immune cells, along with hair samples to measure cortisol, a stress hormone.
USGS
A family of polar bears on Barter Island, Alaska.
One finding stood out to the team: adult females that summer on land have higher allostatic load than those that remain on the sea ice. This may be driven by onshore food sources that fail to meet their nutritional needs, coupled with immune stress. The number of adult females summering on land has tripled over the last few decades, as the length of the sea ice melt season has increased.
Other findings contradicted the scientists’ predictions. For instance, they found no overall trend of increasing allostatic load across the population. However, at the individual level, allostatic load fluctuated—rising in some bears over time, while decreasing in others. This suggests that allostatic load may be best understood through individual monitoring. The next step is to link measures of individual health to population vital rates, such as reproductive success.
“Now more than ever, it’s important to develop tools to measure polar bear health,” Teman said. “This gives us insight into the stressors they face, and how we can support their survival in a changing Arctic.”
Each year, UW students embark on the SAFS-NOAA Marine Mammal Laboratory internship program, spending a month or so working on projects related to marine mammals such as whale, seals, sea lions and porpoises. Project topics include marine mammal behavior, population dynamics, life history, migration patterns, distribution, and trends in abundance, with research taking place with the Marine Mammal Laboratory, a division of the NOAA Alaska Fisheries Science Center (AFSC). This year during June to August, two students – Kenna Daily (ESRM) and Sofia Denkovski (Marine Biology) – split their time working on two Alaska pinniped projects: remote camera imagery and food habits.
Under the mentorship of Molly McCormley from AFSC, they helped assess the efficacy of NOAA’s machine learning model for detecting Steller sea lions in digital images. They manually reviewed over 21,000 images of Steller sea lions rookery sites in the Aleutian Islands, marking locations of branded sea lion individuals which will be compared to observations found by the machine learning model.
NOAA
Screenshot of the PhotoCount program used by Kenna and Sofia to review remote camera images for marked Steller sea lions. Known individuals are marked with a letter or symbol (indicates where they were born) and a unique number. In this example, Steller sea lion ~176 (behavior = Unknown) was identified in an image taken 26 May 2018 on Attu Island, Alaska.
While being mentored by Katie Luxa, also from AFSC, Kenna and Sofia processed ~300 frozen Steller sea lion and northern fur seal diet samples (i.e., scats and spews). The fish otoliths, bones, and squid beaks they recovered from samples are now ready to be identified by Marine Mammal Lab staff. They also helped prep northern fur seal vibrissae for stable isotope analysis and inventoried over 1,600 cephalopod specimens in the Lab’s food habits reference collection.
NOAA
Photo of fish bones in a metal sieve. This was part of a very large spew (regurgitation) sample from a Steller sea lion (Eumetopias jubatus) that was processed by Sofia. There were several different species present; the large V-shaped bone in the middle is a lower jaw from a wolffish (family Anarhichadidae).
In addition to their research tasks, Kenna and Sofia used this unique opportunity to connect with other MML and Alaska Fisheries Science Center researchers, setting up one-on-one meetings to learn more about their study animals and research projects. Their mentors reported that Kenna and Sofia did a fantastic job. They were enthusiastic, their work was impeccable, and they asked excellent questions, with both students being invited to stay on as part-time (<4 hrs/week) lab volunteers.
Over the last two decades, there has been huge growth in the availability of different ‘omics methods used to study marine mammals. From elusive beaked whales and near extinct vaquitas to more common dolphins and sea lions, understanding the ecology, evolution, and health of marine mammal populations around the globe is critical for conservation efforts. A new paper published in Marine Mammal Science, involving 19 scientists from around the globe, has laid out best practices for collecting and preserving marine mammal biological samples in the ‘omics era.
The branches of science known informally as omics are various disciplines in biology whose names end in the suffix -omics, such as genomics, proteomics, metabolomics, metagenomics, phenomics and transcriptomics.
Marine mammal scientists are working on different species, in different locations, and asking different questions, using tissue samples collected from wild marine mammals. Those tissue samples give scientists access to vast amounts of information, allowing them to answer questions ranging from a population’s recent foraging habits, health status, or contaminant load to its deeper evolutionary history or its resilience in the face of climate change. They provide scientists, and us, a window into the secret lives of these elusive animals and hints about how we can be better stewards of their ecosystems, but they come at a price – literally.
NOAA (permit # 21348)
NOAA scientists collect data near a pod of Bigg’s killer whales.
Most marine mammals live far from shore, and spend the majority of their lives underwater. To collect tissue samples from these animals, large teams of scientists will venture out onto the ocean for months at a time. Many marine mammal species have huge home ranges, such as the 9,000 mile migration range of humpback whales; simply finding them is a monumental task. Adding to the challenge, collecting samples from marine mammals is inherently invasive and scientists work under strict permits to minimize both the number of times samples need to be taken, and the impact on the animal during collection.
Arial Brewer (permit # 21348)
Jeff Hogan (Killer Whale Tales/NOAA) presents a freshly collected fecal sample from a Southern Resident killer whale.
Phillip Morin from NOAA Southwest Fisheries Science Center, who has been working in genetics for over 35 years, understands all too well the difficulty in getting quality samples for genomics. “A good illustration is the sample used for the vaquita reference genome, which is one of only two live-cell samples ever obtained from this species. The vaquita, a member of the porpoise family, is the most endangered marine mammal in the world,” he shared. “A conservation project in 2017 took two years of extensive planning with over 90 experts from nine countries, and 11 days at sea, to try to capture vaquita for captive management. As part of that project, we worked to get the appropriate samples collected, transported quickly to the cell culture lab across the international border, and cultured to preserve live cells for DNA and RNA extraction.”
Because of all of these challenges, each tissue sample could represent an investment of tens of thousands of dollars. Caring for those samples and preserving them in a way that will allow them to be used by many generations of future scientists, and with many generations of emerging techniques, is a priority that is always at the forefront of a marine mammal scientists’ mind. “For some populations or species, decades of sampling effort have resulted in only 10s of samples, highlighting how critical it is to figure out the best collection and preservation techniques,” says Amy Van Cise, Assistant Professor at the University of Washington School of Aquatic and Fishery Sciences (SAFS).
NOAA (permit # 21348)
NOAA scientists collect a fecal sample from the water using a pole net.
What are some of the best practices for collecting and preserving marine mammal samples that research teams have gone through such effort to collect? This is the overarching question bringing together a team spanning 11 different institutions, including Van Cise, with the goal of creating a unifying set of guidelines that will ensure these samples can be shared among labs, analyzed with a variety of new and emerging technologies, and used for years to come. “What’s impressive about this study is that it brings together scientists examining different types of questions,” shared Amy Apprill from Woods Hole Oceanographic Institution (WHOI). Apprill’s particular focus is on microbiome analysis, which sheds insight into the health of marine mammals as a result of changing oceans and human impact.
Microbiome analysis is a great example of an emerging technology that’s revolutionizing how we study marine mammal health. Unlike humans, it’s difficult to assess the health of wild animals, and nearly impossible when those animals live in the ocean. “Wherever you are in the world, a doctor can sample and test your blood and those results are understandable and comparable around the globe,” Apprill said. Marine mammals don’t schedule regular doctor’s appointments, but emerging ‘omics technologies are making it possible to determine whether an individual is sick or healthy using tissue samples. Apprill is one of the scientists at the forefront of the effort to characterize the microbiomes of healthy and diseased individuals. “As we obtain samples from different animal health states, we’re gaining valuable data that builds a type of health metric,” Apprill said. This type of work can only be successful if researchers can examine samples collected by many scientists around the world. Similar to the way hospitals have standardized the way they test for diseases and assess human health, Apprill said that, “as scientists in marine mammal research, we need a similar system of guidelines, best practices, and protocols to follow, so that our samples have the maximum use.”
Kim Parsons (NOAA/ NMFS/ NWFSC) processes cetacean tissue biopsies in a makeshift lab onboard a survey vessel in Southeast Alaska.
Images courtesy of NOAA Fisheries, Marine Mammal Laboratory.
The gold standard for sample preservation is collecting it quickly from the animal, either when alive or recently dead before the cells start degrading, and freezing it to -80°C or colder immediately. However if this isn’t possible in the field, then what is the best alternative? The answer depends on the anticipated research needs, availability and transportability of preservatives, and time until samples reach a permanent storage site. While there is no single solution for all situations, some methods provide broader preservation characteristics, allow international transport, and/or greater stability prior to freezing.
“In science, there are a thousand ways you could conduct each step,” Apprill shared. “But you don’t want to spend valuable time, effort, and resources figuring out those steps if someone else already has the best method and protocol laid out.”
Arial Brewer (permit # 21348)
NOAA scientists approach a pod of Southern Resident killer whales for data collection.
The ways we can use ‘omics techniques are rapidly expanding every year, adding another layer of importance to the need for high-quality, well-preserved samples. “Just like forensics held on to human samples from crime scenes while the world was waiting for DNA capabilities to expand, marine mammal science works the same way. As technological advancement expands really quickly, it’s imperative to preserve samples in a way that the wealth of information contained in them can be uncovered in the future,” Morin said.
