A view from above: using drones for coastal research in California

Newly based at the University of Washington is the Marine Landscape Ecology Lab (MLEL), led by SAFS Professor, Corey Garza. Conducting research along the Californian coast using drones, Corey’s lab is currently working on two projects funded by the California Ocean Protection Council.

In a collaborative effort with UC Santa Cruz, Stanford University, and the Middlebury Institute for International Studies, the team is trying to understand how the interaction between oceanographic conditions and the presence of marine mammals, impacts the presence of great white sharks.

Michael Espriella
A view from above: an image of sea lions on a rocky island taken using a drone.

Precipitated by recent great white shark attacks on humans in the Monterey area, California is exploring ways to try and avoid this by exploring the conditions which increase the likelihood of great white sharks being closer to shore.

Using drones to map the central California coast and the presence of pinnipeds such as sea lions, fur seals, and elephant seals, all of which are prey for great whites, the MLEL team is helping deliver new insights into what factors increase great white shark presence. As prey species stick closer to the shore, this leads sharks closer to the coast. In turn, this raises the frequency of interactions with humans who are in coastal waters, swimming, surfing, and diving.

Corey Garza/MLEL
Preparing for lift off: the MLEL drone pictured on the ground on the Californian coast.

Another factor at play is oceanographic conditions and how it impacts pinnipeds. Data has shown that pinnipeds are more commonly present onshore in April, and the team is working to get more information on monthly variation, plus improve understanding about what factors cause pinnipeds to aggregate in different coastal locations. El Niño and La Niña-related driven changes in coastal conditions may alter the abundance and distribution of prey commonly preferred by pinnipeds. This can result in pinnipeds seeking out coastal areas where their preferred prey are abundant.

With the overarching aim of public education, the institutions involved are researching a number of aspects:

  • The MLEL carries out drone mapping of the coastline to record variation in pinniped abundance.
  • UC Santa Cruz is mapping and track pinnipeds to see where they are diving and swimming.
  • Stanford is tagging sharks and using telemetry to see where they’re going and utilizing oceanographic instrumentation to monitor changes in the coastal environment.
  • The Middlebury Institute for International Studies is developing educational materials to support public outreach.

How does research fit into a public education and awareness campaign? By providing the scientific information behind California’s efforts to make local people and tourists more knowledgeable about what conditions and times of year result in a higher frequency of great white sharks.

Michael Espriella
An aerial image from the MLEL drone shows sea lions on a rocky island.

A second project underway with Corey and his MLEL team is developing high-resolution digital elevation models (DEMs) of the rocky intertidal, also known as the rockpool area, along the entire California coastline from San Diego to Humboldt County. Building on biological monitoring data collected the Multi-Agency Rocky Intertidal Network (MARINe), a collaborative monitoring program led by UC Santa Cruz since the mid-1990s, this project will integrate MARINEe’s long-term monitoring data with digital elevation models.

Corey Garza/MLEL
Michael Espriella, a post-doc, flies a drone during the projects conducted along the Californian coastline.

Using drones to map the topography of the intertidal mussel beds across 100 sites, the team will use the topography data collected by the drones to create DEMs. These DEMs will be used to support modeling to predict how sea level rise may change the future distribution and composition of rocky intertidal communities in California.

Barbara Block
Jason Ching, technician in the Marine Landscape and Ecology Lab, launches a drone from a boat.

The rocky intertidal is the frontline when it comes to climate change and associated rising sea levels. It’s also an incredibly important ecosystem from both a habitat and economic point of view. On the habitat side, the rocky intertidal is a site home to keystone species that help maintain biodiversity for the entire ecosystem, as uncovered by Robert (Bob) Paine’s foundational ecology work with ochre sea stars and mussels.

From an economic standpoint, this part of the Californian rocky intertidal is home to black and red abalone, recreational fish nurseries, and mussel beds, which are an important foraging habitat for the Pacific spiny lobster, just to name a few.

Heading out once a month to conduct drone research for both projects, the MLEL team consists of four members including Corey: graduate student Olivia Bible, post-doc Michael Espriella, and technician, Jason Ching. 

Interested in related work? Check out Eos’ article with Corey Garza about tracking ocean warming and its impact on California’s mussel beds using time-series photos.


Taking a deeper look: using fish eye lenses to explore invasive fish impacts on native fish communities

Fighting for the little guy. That’s one of the things Jess Diallo, PhD candidate at SAFS, likes about her work. Her research encapsulates this idea as she explores the impact of invasive fish on native fish food webs, based in a tributary to the lower Colorado River.

Part of Julian Olden’s Freshwater Ecology and Conservation Lab, Jess’ fieldwork in 2021 involved collecting samples for stable isotope analysis, including fish eye lenses, to provide a deeper look into how fish move throughout the food web.

“The two main characters in this story are roundtail chub, a native fish, and green sunfish, an invasive species,” Jess shared. “It’s important to study the impact of invasive species on native populations as the whole ecosystem can be impacted by the predation and competition threat that they pose,” she added.

Jess Diallo
Jess holds a desert sucker on the banks of Burro Creek during fieldwork in 2021. Males of this species develop an orange band on their side during the spawning season, which runs from April-May.

The invasive fish living in her study site, the Burro Creek basin of the Bill Williams River, a tributary of the lower Colorado River, consist of species introduced throughout the last century, which are now the focus of sport fishing, including bullhead and green sunfish. Native species in this system include roundtail chub, desert sucker and Sonora sucker.

“Using fish eye lenses to conduct stable isotope analysis is a really cool method,” Jess said. “The eye lens grows in concentric spherical layers, building on itself over time. And when you dissect this tissue, you can look through time into how the fish moved through the food web.”

Jess Diallo
A fish eye lens as it is dissected under a microscope (diameter approximately 1mm). A layer of tissue was peeled from the lens on all sides before being further prepared for stable isotope analysis.

This method allows Jess to see clear shifts in diet throughout an individual’s life, for example from a juvenile fish eating insects, to growing larger and graduating up to eating other fish. Food consumption provides a clear signature in stable isotope analysis, and Jess is interested in exploring how invasive and native fish interact in the food web throughout their lifetime, and the comparison with native fish-only communities.

Studying five species of fish in total, Jess has seen some clear results from the stable isotope data she has collected. “The lifetime trophic trajectories of native fish species are, on average, displaced within the food web when they’re in streams containing invasive species, compared to native-only communities,” Jess shared.

This displacement is seen in lower values of Carbon-13 and Nitrogen-15, meaning a dietary shift from terrestrial to aquatic plant carbon sources and a lower position on the food chain.

Beka Stiling
Taking a deeper look: Jess dissecting a fish eye lens in Julian Olden’s Freshwater Conservation and Ecology Lab during the summer of 2021.

Sharing why some streams are inhabited by native-only fish and others have the presence of invasive species, Jess noted that it’s down to the hydrology and climate of the area: “Burro Creek has intermittent streams that flow when there’s rainfall, but become isolated pools during the dry season. This fragmented system means that when invasive fish were introduced in a reservoir on the lower Bill Williams River, their progress upstream was slowed by dry stream sections.”

Another area of Jess’ work is using otoliths, the ear stones of fish which can be used to age them, to link the chronological record of stable isotope values to time. “These two parts of a fish, their eye lenses and their otoliths, are two records of a fish’s lifetime. This is really novel research, linking the otoliths to eye lenses, especially for community ecology, so it’s really exciting work to be involved in,” she said.

Jess Diallo
Beauty in detail: Jess appreciates how detailed and beautiful the structure of otoliths are when viewed under a microscope. Pictured are two roundtail chub lapillar otoliths, belonging to the same fish image below.

Jess wants to be able to take all of the individual fish and different species present in the river and put them all on the same timescale. “This is where both methods come in. The fragile, crystalline structure of fish eye lenses mean you can only measure the size of each layer as it’s peeled back, a bit like an onion. These measurements are proportional to fish body size,” she shared. “By using otolith data too, we hope to be able to go from fish body size to fish age and shed insight into the impact of things like season and hydrology on the food web”.

Jess Diallo
A polished roundtail chub lapillar otolith, seen through a microscope (measuring aproximately 2mm from top to bottom). The dark rings, or annuli, denote the age of the fish, estimated to be 10 years.

“This work has really highlighted for me the beauty in the tiny things –  fish eye lenses, otoliths – and the wealth of information they hold,” Jess said about her research. It has also been an important learning experience when conducting science. Not only did Jess conduct her research in an area facing a myriad of different factors such as water extraction and different land use issues between private and government entities, adding in fish conservation presented a new optic.

“My research was also a steep learning curve and I hope to be able to share new methods and best practices in the future,” Jess said. “This type of research combining stable isotope data from fish eye lenses with otoliths hasn’t been done before, and trying to figure out the best way to peel an eye lens or polish a lapillar otolith taught me an awful lot about these species.” Dissecting at least 400 fish and working on between 1-15 tissue samples from each one, Jess hopes to contribute her learnings through a methods paper to other researchers in the fish ecology field.


A weekly SAFS Cafe, every Wednesday

Join us every Wednesday at 3.30pm for coffee, treats and community conversation this Winter 2024 Quarter!

Take a break from your busy week and join your fellow SAFS community – students, staff, researchers, faculty – every week.

Wednesdays, 3.30pm, SAFS third floor kitchen


Bringing the Seafood Globalization Lab to SAFS: welcome to Jessica Gephart

Joining SAFS as Assistant Professor in January 2024, Jessica Gephart brings to the school her expertise in global food trade systems. Always having an interest in scientific problems, Jessica started off her career in aquatic ecology and modeling before becoming involved in a side project in her lab at the time, focused on food systems and food trade. “I was interested in the modeling approaches that parallel these systems and realized that a lot of studies didn’t look at fish at all. Most food system studies looked exclusively at crops and livestock,” Jessica shared.

Jessica Gephart begins her position as Assistant Professor at SAFS in January 2024.

She began to think about how answers changed if fish were brought into the picture, and how this would impact questions around sustainability in these systems: “I discovered that there was a much bigger question here, and it needed more attention.”

With her background in ecosystem ecology, Jessica made the decision to move more in the direction of food systems, and specifically aquatic food systems, and began a deep dive into the trade side of fisheries using network-based approaches. “One thing I find surprising is when it comes to the big questions about characterizing our food systems, a lot of basic information is unknown,” she said. “When I first started working in this space, questions about linking consumption to environmental impacts led me to questions about distinguishing between wild caught and farmed fish. But the way that data is collected about aquatic food systems, these questions aren’t answered, and we didn’t know the most basic things like the quantity of trade of wild versus farmed.”

Seafood is a critical global food resource, providing nearly 20% of global animal protein and supplying essential fatty acids and micronutrients, and is one of the most highly-traded foods across the globe. Setting up her Seafood Globalization Lab at SAFS, where she will be recruiting students to work on research projects with her, Jessica shared that one of the reasons she loves working on food is because of how interdisciplinary it is. “You have to recognize that you don’t have all of the answers in this field. And this opens up so many opportunities to learn from other people and disciplines about their approach to solving parallel or related questions,” she said.

She’s excited to build up her lab and build up her own connections in her new role at the University of Washington: “Building the right team of people who have the pieces of the puzzle to put it together – I love that. In food systems, you pull on one thread and it winds up being a huge, complicated problem, and that’s exciting.” Jessica’s lab brings together people to work on research involving global trade data, local consumption data, and environmental impact data to understand the opportunities and risks of seafood globalization for sustainable production and food security.

Jessica working on global aquatic food trade system research.

When working on global aquatic food trade system research, it uncovers some surprising issues: “There isn’t routine collection of consumption data. A lot is estimated based on how much is produced and then comparing with import and export data. This means there is so much uncertainty in understanding consumption patterns at a national and global level,” Jessica shared.

Being part of a school with a strong legacy and reputation in fisheries management is something Jessica is particularly looking forward to. “I’m excited to join fishery scientists and other ecosystem scientists and open up more dialogue across methods. And I’m excited to connect my work related to trade with the world of fisheries management,” she said. The location of SAFS within the College of the Environment is also another bonus for her: “I’ve already been making some great connections with other programs and folks working on policy and environmental forensics where they’re working on related issues such as the connection between forestry and the illegal fish trade.”

Global food trade is a hot topic worldwide right now. Jessica explains why: “Part of it is because there is a rapid recognition of the need to understand aquatic organisms as food and look at fisheries and aquaculture resources not just from a natural resource viewpoint, but also the role they play in communities, livelihoods and diets.” Working across both marine and inland fisheries, capture and aquaculture, Jessica’s work spans these spaces to answer questions around where, what, and how much, is traded in order to identify opportunities for aquatic foods to contribute to more sustainable food systems.


Listening closely: using acoustics to study Greenland’s marine mammals

Recently completing her PhD focused on marine mammals in Greenland, Marie Zahn’s work in the Arctic provides a deeper look into two species: narwhals and belugas.

Conducting her research at the School of Aquatic and Fishery Sciences (SAFS) as a member of the Laidre Lab, Marie explored the marine habitat and sounds produced by narwhals and belugas using oceanographic and acoustic data collected from West Greenland.

Kristin Laidre
A pod of beluga whales in Baffin Bay, West Greenland.

Belugas and narwhals make a variety of sounds, such as whistles and echolocation clicks, all used for communicative and sensory purposes. Scientists use underwater recordings to identify when marine mammal species are present to learn about their distribution and behavior. But for the beluga and narwhal it can be difficult to distinguish between their sounds when they’re present in the same areas. One of the main questions tackled by Marie in her dissertation was: can echolocation clicks be used to distinguish between narwhals and belugas in acoustic recordings?

The short answer is yes. To tackle this question, Marie used multiple acoustic datasets from West Greenland, including recordings from hydrophones attached to moorings on the seafloor left for years at a time. These long-term datasets are valuable recordings of the animals present in the Arctic waters around Greenland. But Marie had to figure out how to differentiate between beluga and narwhal echolocation in order to determine what species were present.

Echolocation clicks are high-frequency signals used by toothed whales for navigation and identifying their physical surroundings – when sound waves bounce off an object, they return to the whale and provide information on what the object is. Most of the energy produced by narwhals and belugas is in a pitch above the human hearing range, so they are inaudible to us, but scientists record and create plots to show how much energy exists at different frequency bands. They can then use this data to calculate different characteristics of the sound based on how much energy exists at certain frequencies. With this information they can tell apart the two species, a process known as acoustic classification.

Beth Phillips
Research Vessel Sanna (Greenland Institute of Natural Resources) during a survey in Northwest Greenland to deploy and recover ocean moorings.

So how do belugas and narwhals sound different? Marie’s research has shown that belugas produce higher frequency echolocation signals – around 30 kHz and higher – whereas narwhal clicks have a clear lower limit of energy and drop off around 20 kHz. She also demonstrated that the ratio of total energy within specific frequency bands, called one-third octave levels, is a robust metric for beluga and narwhal acoustic classification. These one-third octave ratios may be useful for accurately identifying toothed whale species in other parts of the world. Insights generated from passive acoustics like those in Marie’s doctoral work allow scientists to differentiate between the species present in Greenlandic waters.

Research such as this is important as the Arctic is warming at rates 3 times faster than the rest of the globe, with ecosystems and habitats changing dramatically in short periods of time. Each sub-population of belugas and narwhals face different threats at varying magnitudes, and understanding the behavior and habitat use of these populations in the Arctic is important.

Subpopulations of belugas and narwhals in West Greenland are generally still understudied but face a number of growing risks. Climate change, habitat loss, and increases in vessel traffic are just some of these threats. Passive acoustics is an important tool to deliver deeper insight into how these species are being impacted by habitat change and how they might be changing their behavior as a result. For instance, belugas and narwhals actively communicate with their pods as they migrate. This same migration route overlaps with vessel traffic through the Northwest Passage in West Greenland that leads to Alaska. It is known that vessels, such as big tankers, can obscure whale communication and disturb animals. Passive acoustic monitoring that measures underwater noise levels and species presence can provide data on long-term changes in beluga and narwhal migration and behavior.

Kristin Laidre
Recovery of ocean mooring by small boat in Northwest Greenland near a glacier front. The yellow float is visible and is the upper end of all the mooring components.

Passive acoustics gives researchers the where, when, and what animals are present in a particular location. Marie went a step further in the last chapter of her dissertation and used oceanographic data, like temperature and salinity, to study the characteristics of narwhal and beluga habitat.

Focusing on coastal waters near glacier fronts in Northwest Greenland that narwhals return to every summer, she looked deeper into the seasonality of ocean conditions. Narwhals are known to go right up to the glacier face and hang out in the bays and fjords, but researchers haven’t known why. Is it because of feeding opportunities or protection for rearing calves? Are there specific features of these glaciers and fjords that attract them there?

With two years of continuous temperature and salinity measurements, Marie found a clear seasonal pattern in ocean properties near glaciers in Northwest Greenland. As temperatures warm during summer, glacier ice and sea ice melt and cold, fresh water is released along the coast.

Kristin Laidre
Back deck of R/V Sanna showing ocean mooring equipment and instrumentation.

The Greenland Ice Sheet melts every year during the summer, with large volumes of meltwater draining through various pathways to the coastline and being discharged from the base of the glaciers underwater. These large meltwater plumes create an interesting biological event that acts as an upwelling system. The buoyant meltwater which is less dense than the deep water its surrounded by moves straight up the surface, mixing water and bringing nutrients up. This enhances biological productivity in these areas and could be why narwhals return to these locations year after year.

Studies have shown narwhals prefer habitats with colder temperatures. Working on a separate paper led by Kristin Laidre that links the acoustic presence of narwhals with other environmental variables such as temperature and salinity, Marie shares that it may be the cold, fresh meltwater released from summer ice melt and upwelling plumes that attract narwhals.

By studying temperature and salinity over time, researchers can understand the major processes occurring and how it impacts the biology and ecology of the system, painting a better picture of what’s important in this habitat.


Announcing the SAFS 2023 Outstanding Staff Award

This year’s Outstanding Staff Award has been presented to two exemplary colleagues who went above and beyond in their work in the face of a UW-wide financial system transition: Kenyon Foxworthy and Taylor Draper.

Based in the SAFS admin suite, Kenyon is the Operations Finance Manager and Taylor is the Front Desk and Fiscal Supervisor. Both have been recognized for their patience and perseverance with the roll-out of the new UWFT system.

Ensuring salaries were paid on time, developing workarounds and patches when the new system didn’t work as intended, and coaching faculty on new protocols in the midst of a challenging financial period, were just some of the ways both Kenyon and Taylor went above and beyond.

Each day brought new challenges, but Kenyon and Taylor completed an insurmountable list of new duties, on top of their normal daily workload, with efficiency, effectiveness, and a positive outlook.

We celebrate their invaluable contribute to SAFS, thank them for their work, and congratulate them on receiving the 2023 Outstanding Staff Award.