In a shifting ocean environment, what are the impacts on Pacific oysters?

Written by

Seeking to understand the impacts of environmental stressors on Pacific oysters is the driving force behind a years-long research project involving scientists from the University of Washington and NOAA, and in collaboration with the oyster industry. A new paper about the project was made available online in Aquaculture on June 17, 2025. Critical in aquaculture, Pacific oysters are the dominant oyster species grown on the US West Coast, with the industry in the Pacific Northwest alone valued at over $270 million a year.

Oyster farm viewed from above, close to the shoreline.
Craig Norrie
An oyster farm viewed from the sky.

But this study drills down into the species one step further, looking into the differential performance of diploid, mated triploid, and induced triploid Pacific oysters under different environmental conditions. Compared to diploid oysters, triploid oysters have an additional set of chromosomes, they grow faster and are functionally sterile. As a result, they comprise a large proportion of oysters grown both in the Pacific Northwest and worldwide. Recent studies have found that the waters off the West Coast were acidifying faster than anywhere else in the world, and so studying the impact of changing oceans on oysters—and how it affects those with different chromosome numbers—can assist the shellfish aquaculture industry in making more informed decisions about their species portfolio.

Racks and cages pictured at low tide that are used on oyster farms.
Craig Norrie
The racks and cages used to grow oysters.

The team of researchers, led by Craig Norrie from the UW School of Aquatic and Fishery Sciences (SAFS), sought to understand how stressors such as temperature, dissolved oxygen (DO), and pCO2 , impacted Pacific oysters across a 4-week period. The study focused on whole organism physiological responses—growth, mortality and respiration—for genetically related juvenile diploid, chemically induced triploid, and mated triploid Pacific oysters.

What researchers found was an overall high survival in all groups across a broad range of temperature and DO levels. “They are a pretty hardy species, so to an extent you can see why survival was reasonably high in the temperature experiment—these guys are grown from Baja California up to Alaska so can tolerate a broad array of conditions,” Norrie said. “However, farmers report that over the summer period when its warmer, triploids generally die more—the high survival in our study could be due to the fact that they were younger oysters.”

For DO, this was a more surprising result for researchers. “It was reasonably surprising that they survived so well under different dissolved oxygen levels—everyone needs to breathe, right? How did they manage to hold their breath for so long?” Norrie asked. “Again, this could be because they grow in such a broad range of conditions.”

pCO2  was a different story. At mid pCO2, between 1450 and 1700 μatm (microatmospheres, a unit of pressure), mated triploids had lower survival than the other groups in the study, which suggests that production method or genetic background may contribute to their resilience or susceptibility to stress. “Oysters can adapt to local conditions over a few generations, and this can make them better equipped to deal with the conditions that they are likely to encounter naturally,” Norrie said. And this means in the case of these oysters which didn’t perform so well under low pH conditions, a lack of exposure in their family history to may mean they haven’t developed resilience to this environmental stressor. However, the team found that when pCO2 reached extreme levels of 2100 μatm, all oysters in the study died. This suggests that if conditions become extreme enough, there is the possibility that all oysters, regardless of ploidy or production method, will be impacted.

Four tanks in a laboratory.
Craig Norrie
The experimental tanks used for the project which examined the responses of Pacific oysters to environmental stressors.

As a culturally and economically important industry, developing new insights into how aquaculture will be impacted by changing oceans is critical. Considering the stressors that will be placed on species such as Pacific oysters will allow those working in aquaculture to make informed decisions on which type of oysters to select to ensure the future resilience of the industry.

The research team included Joth Davis from Baywater Shellfish, Shallin Busch and Paul McElhany from NOAA, and research scientists, professors, and undergraduate students from the University of Washington: Dereck Cordova (undergraduate student in the IBIS program), Hailey Dockery (undergraduate researcher), Craig Norrie (research scientist and project lead), and Jacqueline Padilla-Gamiño (SAFS professor).

Why study diet? New research video featuring the southern resident killer whales

Written by

Understanding what a species eats – and how that changes over time – not only gives us a window into the lives of wild animals, but also gives us the power to be responsible stewards of their ecosystems.

Genetic metabarcoding is changing the way we look at diet and foraging ecology in whales. With each new sample, we gain new insight into the feeding behavior of these enigmatic species. Learn more about how the Whale And Dolphin Ecology Lab (WADE), led by SAFS Assistant Professor Amy Van Cise, is using genetic metabarcoding to understand and conserve southern resident killer whales in the Salish Sea.

Video produced and edited by the UW Whale And Dolphin Ecology Lab. Interviews with the Lummi Nation, The Center for Whale Research, and SeaDoc Society. Funding provided by the Rose Foundation.

Genetic metabarcoding to study marine mammals

Written by

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.

Two people pictured in the lab, one holding a syringe used for DNA work.
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.

Mollie Ball in the lab holding a syringe while doing DNA research.
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.

Arial (l) and Mollie (r) clap in the lab while looking at a computer screen.
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.

A sweet surprise: Polar bear glucose reveals new insights into their reproduction and conservation

Written by

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.

Four polar bears pictured on a snowy landscape.
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.

Two polar bear cubs with their mother on a snowy landscape.
Mike Lockhart, USGS
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.

This research was led by University of Washington SAFS doctoral student Sarah Teman in Dr. Kristin Laidre’s lab, in collaboration with scientists from the Cincinnati Zoo Center for Conservation & Research of Endangered Wildlife (CREW) and the U.S. Geological Survey (USGS).

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.

A zoomed out photo of three polar bears on a snowy landscape.
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.

This project was funded by the National Science Foundation Graduate Research Fellowship Program, the Institute of Museum and Library Services, and the USGS Ecosystems Mission Area.

For inquiries, contact Sarah Teman at steman@uw.edu

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

Force, form, and function: New method explains stingray skeleton architecture

Written by

When John Michael Racy looks at a stingray, he doesn’t just see an elegant elasmobranch—he sees a wealth of tantalizing engineering challenges. The UW mechanical engineering student’s research out of A&A’s Illimited Lab and the Friday Harbor Lab’s Lab 8, published in the Journal of the Royal Society Interface, is revealing how generative design can be used to analyze the complex shapes found in biological rigid structures like skeletons.

With his co-authors, aeronautics and astronautics Ph.D. student Bart Boom and Professor Adam Summers, who holds appointments in both the UW School of Aquatic and Fishery Sciences and the biology department, Racy turned to generative design to understand the complex forces that shape the elements of the stingray fin skeleton. These small elements, called radials, are made from mineralized cartilage and have evolved sophisticated forms that traditional research methods struggle to analyze.

Two rays pictured side-by-side
UW Aeronautics & Astronautics
P. iwamae, the long-tailed river stingray, left; and A. nichofii, the banded eagle ray, right, the two species involved in this research.

Read the full story by UW Aeronautics & Astronautics

Building community among students

Written by

Building community among the different student groups at SAFS and Marine Biology—undergraduates, graduates and postdocs—the SAFS Undergrad Community Building Event was held was held for the fourth year running.

Taking place on 13 May, undergraduates were invited to walk around and speak to grads and postdocs about different topics including grad school, what life looks like after graduation, and finding your way in science.

Organized through the SAFS DEI Committee, the event was inspired by the graduate student peer mentoring program and the desire to build a community within SAFS that includes undergrads.

A group of people sit and stand in a lobby area.
Taylor Triviño
SAFS undergrads were invited to walk around and talk to different graduates and postdocs.

Graduate student, Taylor Triviño, who helped to organize the event, shared her thoughts:

“This is my second year helping to organize the event and I find it very rewarding connecting our undergraduate students and graduate students in the department. I overheard great conversations about life after graduation, what grad school looks like, and stories about finding your path in science. Academia can be a tricky place to navigate especially as a first-generation student, so being able to share my experience can reveal some of the hidden curriculum that no one tells you about but expects you to know. The graduate students in SAFS come from diverse backgrounds, experiences, and disciplines where we each can speak about how we got to Seattle and how different each of our paths have been. I’m hoping to continue to organize this event each spring to strengthen our community, uplift the undergraduates, and share how amazing the work we do here at SAFS is.” – Taylor Triviño

High schoolers design and teach a lesson on Pacific salmon and chemicals

Written by

What brought a group of high schoolers to SAFS to teach a lesson on Pacific salmon and chemicals? It all started with an interest in ecology in 9th grade biology class, and a quest to find a relevant, local topic that they could base a research project on. Since then, Iris Zhang, Ivy Wei, and Sylvia Mei from Redmond High School—now sophomores in 10th grade—found a graduate student researching this topic, and developed a lesson centered on the effects of 6PPD-quinone on salmon.

“After asking our biology teachers for ideas, one suggested looking into the impact of tire residue on salmon populations,” Ivy, Sylvia, and Iris shared. “The more we learned, the more fascinated we became—especially when we realized how local and urgent the issue was.” Present in vehicle tires is the chemical 6PPD, which prevents them from breaking down due to reactions with ozone in the air. When this chemical reacts with ozone, it forms 6PPD-quinone (6PPD-q), which then runs off into stormwater when it rains. 6PPD-q has been found to be toxic to aquatic organisms, such as coho salmon.

Screenshot of three high schoolers preparing a lesson on salmon and chemicals
Top to bottom: Sylvia Mei, Iris Zhang, and Ivy Wei researching the topic of salmon and chemicals in preparation for developing a lesson.

Here’s where Amirah Casey enters into the story. After reaching out to Dr. Nat Scholz, program manager of the NOAA Ecotoxicology team, he put the high schoolers into contact with Amirah, a SAFS graduate student studying the effects of urbanization and climate change on natural systems. “Amirah offered us the opportunity to co-develop a curriculum centered on the effects of 6PPD-quinone on salmon,” Sylvia, Iris, and Ivy said. The lesson is part of a wider outreach effort to middle-schoolers, undertaken by SEAS (Students Explore Aquatic Sciences), a group based in SAFS.

“These students have created an awesome simulation and lesson, and in April, they came to UW to present this to the SEAS board members and other graduate students, who were all very impressed with their work,” Amirah said.

Opting to make this lesson as enjoyable as possible, the high school group decided to structure it as a mystery. “The most entertaining part about creating the lesson was definitely how we decided to frame our lesson as a mystery,” they said. “Figuring out how to present the information in a way that wouldn’t reveal the final answer was an obstacle for us, but it encouraged us to problem solve and we came up with fun solutions throughout this process.” A unique benefit for them was also casting their minds back to being middle schoolers and thinking of the ways in which the lesson could be of most interest to that age group. “When going through and editing the lesson, we tried to take the perspective of being a middle schooler and this encouraged us to do our best at including enjoyable activities and questions,” they shared.

Three students stand at the front of the room to give a presentation, while two people sit at the table to watch.
Amirah Casey
L-R: Sylvia, Ivy, and Iris, presenting their lesson, ‘The Mysterious Salmon Killer’, to SEAS board members.

One of the main components of the curriculum was an interactive simulation that focused on mirroring the effects of 6PPD-q on coho salmon in different stream types. “Students going through the lesson work in small groups, each with their own container setup representing an environmental condition. Inside each container were laminated salmon cutouts to simulate live fish in the ecosystem,” Iris, Ivy, and Sylvia said. “We purposefully set this lesson up as an investigation where students are introduced to the problem and must figure out the culprit to the mysterious salmon deaths.”

Not only did they get to design a lesson, but the group also got the chance to present it in a visit to SAFS, building skills that will come in handy throughout the rest of their future educational and career journeys. “We were thrilled when we were given the opportunity to present to the SEAS members. It was very exciting to see our work with Amirah turn into an interesting and engaging lesson,” they said. “Although we’ve had experience presenting short lessons to our peers before, this was our first time presenting a full-length lesson with interactive activities and worksheets. The SEAS board members were very lovely to present to, extremely welcoming, and helped us feel confident. Plus, they helped us imitate a real middle-school classroom by pretending to be students!”

Four students (three high school and one graduate) stand in front of a presentation screen.
L-R: Sylvia, Iris, and Ivy with their graduate student mentor, Amirah Casey after presenting their lesson in a visit to SAFS.

Subject experts and educators: that’s how Ivy, Sylvia, and Iris describe themselves now as a result of this project. “While creating this lesson plan, we became specialized in an issue impacting our local environment: the toxic effects of 6PPD-q on salmon populations in Puget Sound area. Not only did we get to try out the role of being an educator—which gave us a deeper appreciation for our teachers—but we also became scientists who were conducting research to understand more about the impacts of this chemical,” they said.

Continuing on the scientist route is the goal for this group of high schoolers. “While it’s still early, we know we want to pursue some branch of biology, and this project has taught us important research skills and helped us become more aware of current environmental issues,” they said. What’s next for them after high school? “We hope to build off the skills gained from this project to do our own research in university, such as conducting hands-on lab experiments—be that on an environmental issue or another field of biology,” Sylvia, Iris, and Ivy said. “Ultimately, we feel incredibly lucky to have had the opportunity to work on something so meaningful with an amazing mentor, and we know that the skills and experiences we’ve gained on this journey will stay with us.”

Check out Amirah Casey’s StoryMap about the challenges faced by Pacific salmon