Two tags were attached to this swordfish off the coast of Florida in August. A small antenna on the fin sends data when the fish breaks the surface. The black rubber bulb takes detailed measurements of water pressure and temperature. The two tags, made by Wildlife Computers, communicate with the scientists via satellite. Steve Dougherty
Researchers from the University of Washington are using high-tech tags to record the movements of swordfish — big, deep-water, migratory, open-ocean fish that are poorly studied — and get a window into the ocean depths they inhabit.
The researchers tagged five swordfish in late August off the coast of Miami: Max, Simone, Anthony, Rex and Oliver. Their movements can now be viewed in near-real time. And although swordfish are a prized catch, these ones aren’t at higher risk, researchers say, since the website updates only every few hours and these fast-swimming fish spend most of their time far from shore.
“These are animals that migrate into the ocean’s twilight zone that we know next to nothing about,” said Peter Gaube, an oceanographer at the UW Applied Physics Laboratory. “Swordfish in different regions have very different behavior. We hope to learn more about these amazing animals and their environment as they migrate between regions.”
This is the first time satellite position tags have successfully been placed on swordfish caught off the coast of the United States.
Earlier tags on swordfish relied on measurements of temperature and light to approximate the animal’s position, which resulted in errors greater than 60 miles (100 km). The new tags act together as a pair: One records detailed temperature, light and depth measurements as the fish is swimming, while the other beams back the precise location when the fish surfaces each day.
By comparing the saved observations with computer reconstructions of ocean conditions, the researchers can re-create an individual fish’s precise travel path in three dimensions, allowing for the first time scientists to understand where these animals feed and providing new insight into deep-sea ecosystems.
Peter Gaube (wearing purple gloves) and Camrin Braun (far right) attach a satellite tag on a swordfish in August 2019 off the coast of Florida. Steve Dougherty
Gaube and collaborator Camrin Braun, a UW assistant professor of aquatic and fishery sciences and instructor for Marine Biology’s Top Predator course in spring 2020, have placed similar satellite tags on other ocean predators, including great white sharks, blue sharks, whale sharks and manta rays.
“Swordfish are different from the surface-oriented fish that have been tagged, like sharks or whales — these are deep-sea fish,” Braun said. “But because they migrate up and down every day, they break the surface, and the new types of tags allow incredibly fast communication.”
Swordfish often jump at the surface, a behavior that helps make them a popular target for sport fishing.
“That’s why we’re so excited,” Braun said. “Swordfish are a particularly good platform to help us make observations in the deep ocean, while at the same time giving us a better understanding of why and how this predator makes a living.”
A newly tagged swordfish swims back into the ocean twilight zone in August 2019 off the coast of Miami. As of early October, this fish had traveled 350 miles to the north. Steve Dougherty
Recently, the UW researchers customized satellite tags made by Wildlife Computers of Redmond, Washington, to work on swordfish. These top predators swim long distances, commonly reach 10 feet (3 meters) in length, and are named for the long, flat bill they use to slash and injure prey.
The fish can swim at 50 miles per hour and typically spend the day at a third of a mile (550 meters) deep. They rise to the surface at night, along with millions of other fish and squid, upon which the swordfish feed.
A recent paper by Braun, Gaube and collaborators, published in June in the ICES Journal of Marine Science, analyzed 16 swordfish tagged with simpler tags in the western Atlantic, off Florida and the Grand Banks, and in the Northeast Atlantic, off the coast of Portugal. The results show that juvenile swordfish tagged off Portugal tended to stick to that area, while the mostly adult individuals tagged in the western Atlantic swam long distances between the Grand Banks off Newfoundland and the waters near Cuba.
This swordfish is now being tracked on an online map. Swordfish are in a family of their own, can grow to 10 feet long, and are among the fastest long-distance swimmers in the sea. Steve Dougherty
With the new Florida-based project the team hopes not only to learn more about swordfish but to further explore the mesopelagic, or “twilight zone” of the Atlantic Ocean. These partially lit waters from a tenth to half a mile (200 to 800 meters) in depth are hard to reach and poorly studied, even as fishing is beginning to target these environments.
In January the researchers plan to tag more swordfish in the Red Sea, off the coast of Saudi Arabia.
“This will provide the baseline data we need to understand this ecosystem before it is exploited any further,” Gaube said.
The initial phase of the Florida swordfish-tagging project was funded by the Woods Hole Oceanographic Institution. Researchers are looking for support from community members, in the sportfishing community, environmental groups or others, to monitor other swordfish and gather more data.
Next, the team is designing new tags that can hold more sensors that could measure properties such as acceleration, depth, water temperature, muscle temperature and stomach temperature. The next-generation tags could also include cameras that could be set to trigger based on various behaviors, such as when the fish dives to a certain depth. They hope to eventually use results from the Florida tagging project to guide shipboard sampling of the marine environment alongside swordfish “oceanographers.”
A drone image showing a village in northwestern Senegal and agricultural land, separated by a river with lush vegetation. Researchers use rigorous field sampling and aerial images to precisely map communities that are at greatest risk for schistosomiasis infection. Andrew Chamberlin/Stanford University
Satellite images, drone photos and even Google Earth could help identify communities most at risk for getting one of the world’s worst tropical diseases.
A team led by the University of Washington and Stanford University has discovered clues in the environment that help identify transmission hotspots for schistosomiasis, a parasitic disease that is second only to malaria in its global health impact. The research, publishing the week of Oct. 28 in the Proceedings of the National Academy of Sciences, uses rigorous field sampling and aerial images to precisely map communities that are at greatest risk for schistosomiasis.
“This is a game-changer for developing-country public health agencies, because it will make it possible for them to efficiently find the villages that need their help the most,” said lead author Chelsea Wood, an assistant professor in the UW School of Aquatic and Fishery Sciences.
More than 200 million people have schistosomiasis, which is treatable but has been difficult to eliminate from some regions of the world. Schistosomes, the worms that cause this disease, grow within freshwater snails, where they multiply and are released into the waters of rivers, lakes and streams. The worms infect people by penetrating their skin when they swim, bathe or wade. Schistosomiasis causes bloody urine and stool and abdominal pain, and can damage the liver, spleen, intestines, lungs and bladder. In children, the infection can stunt growth and impair cognitive development.
Children washing sheep in Penene, Senegal, May 2015. Chelsea Wood/University of Washington
The disease is found across sub-Saharan Africa, as well as in South America, the Caribbean, the Middle East, and East and Southeast Asia. Though schistosomiasis is treatable with the drug praziquantel, it’s easy for a person to become re-infected after treatment if they swim or bathe in freshwater where the parasite is present.
The World Health Organization recently recognized that efforts to slow transmission of the disease through drug distribution weren’t working in some regions. In addition to drug distribution, WHO now recommends targeting the types of snails that transmit the parasitic worms, which is how this research team got involved.
“The ecological side of the problem is what’s holding us back from schistosomiasis control and elimination — and now ecologists are stepping in and filling that gap,” Wood said. “It’s an exciting time because there’s so much for us to learn. The kind of innovation we have introduced is just the beginning of what ecologists have to contribute to the control of schistosomiasis.”
Researchers process the vegetation from a sampling point in northwestern Senegal, May 2016. Chelsea Wood/University of Washington
The researchers worked across more than 30 sites in northwestern Senegal, where villages use a local river and lake for everything from bathing and swimming to washing dishes and clothes. This location was the epicenter of the largest schistosomiasis outbreak ever recorded, in the mid-1980s.
The researchers first set out to methodically count and map the distribution of snails across each site over two years. The fieldwork was difficult and exhausting — they couldn’t let the schistosome-infested water touch their skin while they waded chest-deep to sample mud and plants. It was hot and humid, and the thick shoreline vegetation was full of mosquitoes, spiders, snakes — and even feral dogs.
Co-author Andrew Chamberlin performs deep-water floating vegetation sampling at Mbarigot, Senegal, May 2017. Chelsea Wood/University of Washington
Their fieldwork demonstrated that snails were found in the river in patchy and inconsistent distributions over time. Snails might be present in one location, then completely absent three months later. Given the snails’ ephemeral nature, the researchers realized that targeting aggregations of snails for removal might not be an efficient way to reduce schistosomiasis transmission.
Instead, they shifted their focus to the habitat where snails live. The snails thrive in unrooted, floating vegetation that is visible in images from satellites and drones.
Considering these habitat features, plus other data they had gathered about each site such as snail density, village size and location, they used models to evaluate which factors could best predict schistosomiasis transmission. The total area of a water access point and the area of floating vegetation were the two best indicators that human infection would occur nearby.
These habitat features are all easy to measure in drone or satellite imagery.
Freshwater snails that transmit schistosomiasis thrive in unrooted, floating vegetation that can be seen in aerial images. In this photo, the dark, patchy vegetation in the water is the ideal habitat for snails. Andrew Chamberlin/Stanford University
“Counting snails is not an easy undertaking, and it also produces data that are not as useful as the data you can get from a drone,” Wood said. “Once we understand the association between snail presence and particular habitat features, we can use drone and satellite imagery to detect those habitat features. This cuts the time needed to evaluate the risk of schistosomiasis infection down to a fraction of what it would be if you were just looking at snails.”
Public health agencies in Senegal can now look at aerial images across their jurisdiction, find areas with the most floating vegetation in water access points and target those villages for schistosomiasis treatment, the researchers explained.
There are many uses for the water access point at Ndiawdoune, Senegal, including dishwashing, bathing, fishing and water for livestock. Chelsea Wood/University of Washington
“Now we can take these aerial images season to season and have an idea of how the pathogenic landscape changes in time and space. This can give us a better idea of infection rates,” said co-author Giulio De Leo, a biology professor at Stanford University. “This project has been a tremendous effort and an example of collaborative research that would be impossible by a single person or a single lab.”
The team is also trying to use machine learning to automate the identification of floating vegetation in photos, making it even easier for agencies to use the information. They plan to test their approach in other parts of Africa at a broader scale, using publicly available infection data and satellite imagery.
“We’re cautiously optimistic, but we still have some work to do to generalize our findings to new contexts,” said co-author Susanne Sokolow, a research scientist at Stanford University. “If, indeed, we find that the predictors for schistosomiasis are scalable and automatable, then we will have a powerful new tool in the fight against the disease, and one that fills a critical capacity gap: a way to efficiently target environmental interventions alongside human treatment to combat the disease.”
Other co-authors are Isabel Jones, Andrew Chamberlin and Andrea Lund of Stanford University; Kevin Lafferty of U.S. Geological Survey at University of California, Santa Barbara; Armand Kuris of University of California, Santa Barbara; Merlijn Jocque of Royal Belgian Institute of Natural Sciences; Skylar Hopkins of Virginia Tech; Evan Fiorenza and Grant Adams of the University of Washington; Julia Buck of University of North Carolina Wilmington; Ana Garcia-Vedrenne of University of California, Los Angeles; Jason Rohr of University of Notre Dame; Fiona Allan, Bonnie Webster and Muriel Rabone of London’s Natural History Museum; Joanne Webster of Royal Veterinary College, University of London; and Lydie Bandagny, Raphaël Ndione, Simon Senghor, Anne-Marie Schacht, Nicolas Jouanard and Gilles Riveau of Biomedical Research Center EPLS in Saint Louis, Senegal.
This research was funded by University of Michigan, the Alfred P. Sloan Foundation, the Wellcome Trust, the Bill and Melinda Gates Foundation, Stanford University, the National Institutes of Health and the National Science Foundation.
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For more information, contact Wood at chelwood@uw.edu or 831-324-3076 (mobile) and De Leo at deleo@stanford.edu, 831-521-4104 (mobile) or 831-655-6202 (office).
A CT-scanned image of the piranha Serrasalmus medinai. Note the ingested fish fins in its stomach. University of Washington
Piranha fish have a powerful bite. Their teeth help them shred through the flesh of their prey or even scrape plants off rocks to supplement their diet.
Years ago, scientists discovered that piranhas lose all of the teeth on one side of their mouth at once and regrow them, presumably to replace dulled teeth with brand new sharp spears for gnawing on prey. But no museum specimens have ever shown this theory to be true, and there’s no documentation of piranhas missing an entire block of teeth.
A live piranha, Serrasalmus. Matthew Kolmann
With the help of new technologies, a team led by the University of Washington has confirmed that piranhas — and their plant-eating cousins, pacus — do in fact lose and regrow all the teeth on one side of their face multiple times throughout their lives. How they do it may help explain why the fish go to such efforts to replace their teeth.
The findings were published Aug. 26 in the journal Evolution & Development.
“I think in a sense we found a solution to a problem that’s obvious, but no one had articulated before,” said senior author Adam Summers, a professor of biology and of aquatic and fishery sciences at UW Friday Harbor Laboratories on San Juan Island.
“The teeth form a solid battery that is locked together, and they are all lost at once on one side of the face. The new teeth wear the old ones as ‘hats’ until they are ready to erupt. So, piranhas are never toothless even though they are constantly replacing dull teeth with brand new sharp ones.”
A CT-scanned image, left, of the red-bellied piranha (Pygocentrus nattereri) shows a set of lower teeth growing below the existing teeth. An advanced imaging technique, right, of the same fish illuminates the replacement teeth on both the bottom and top of the jaw. University of Washington/George Washington University
Societies and cultures are birthed on the banks of some of the world’s great rivers—the Nile, the Amazon, the Yangtze, and the Ganges. These rivers continue to endure as the economic arteries that carve through regions and countries. Transportation, commerce, drinking water, agriculture, fisheries, and power for homes and industries all depend on the constant flow of water. Many are seen as sacred, gifted to the people through divine means, establishing deep-seated convictions while raising difficult questions about control and management.
Ethen Whattam, an undergraduate student in the UW School of Aquatic and Fishery Sciences, recently returned from India, where he spent 10 months studying as a recipient of the Boren Scholarship. Whattam, along with the other student awardees, was given the opportunity to immerse himself in the Hindi language and culture, while researching a topic of his choice critical to U.S. national security interests. Defined broadly, the scope of national security allows for varying areas of research including public health, disease prevention, human trafficking, and in Whattam’s case, hydropolitics.
Because Whattam has always been fascinated by the intersection of the environment and security, the rapid development in India presented an enticing challenge. The country’s historical and religious dependency on water, along with its concerns of pollution, provided the perfect opportunity to dive into these complex issues head-first.
“I was learning a new language, culture, and the science used at both the local and national level to study the ever-changing water supply. I was bringing it all together,” he says.
Traveling throughout the Indian subcontinent, Whattam saw firsthand how its major rivers are vital to the lives of millions of people, the profound impact they have on international relations, and how this experience would help shape his future career.
“It was pretty damn cool,” he sums up.
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India is uniquely situated at the confluence of two major river basins, the Indus River Basin to the north and the Brahmaputra Basin, which includes the mighty Ganges or Ganga, to the east. With headwaters from high in the Himalayas, these long meandering river systems pass through multiple countries, creating complex, often delicate, relations with India’s neighbors.
The Ganges and the Brahmaputra and Barak rivers make up the Brahmaputra River Basin, home to over 625 million people. The vast majority are farmers who rely on the water for their crops and livestock. The river basin itself encompasses a wide area made up of parts of India, Tibet, Bhutan, Nepal, and Bangladesh.
Map of the region, with the Indus, Ganges and Brahmaputra basins outlined in white. Thinner outlines are national borders. Viste and Sorteberg
When describing the region, Whattam recounts a series of devastating floods in the Brahmaputra Basin in 2017 that killed 130 people and left millions stranded. In the wake of the disaster, India accused China of breaking an agreement to share hydrological data on the Brahmaputra and Sutlej rivers, which originate in China-controlled Tibet.
“You have 30 million people living downstream who need this data to understand when the floods are coming, when to evacuate people, and when to preserve water from the dams and not let them flow,” Whattam says.
Speculation later arose that China purposely held back data in retaliation for a 73-day military stand-off between Indian and Chinese soldiers in Doklam near Bhutan around the same time. However, China claims its hydrological systems were washed away by floods and it was, therefore, unable to share its data. Relations have recently improved, and China was notably lauded by issuing a warning to India in August 2018 of rising waters in the Tsangpo/Brahmaputra river. This advanced warning gave Indian authorities enough time to prepare for the coming floods, mitigating the damage.
In the Indus Basin, the tumultuous relations between India and Pakistan are amplified by India’s control of the headwaters of rivers that flow between the countries.
“You’ve got two nuclear powers fighting over water, and India, as the upstream country, has control of all of it,” Whattam says. “Upwards of 50% of the water that Pakistan needs is controlled by their enemy.”
The situation reached a tipping point in 2019 after the Pulwama terrorist attack in the Indian controlled Jammu and Kashmir territory. Holding Pakistan responsible, India warned it would “stop” the flow of water from its rivers into Pakistan, reaffirming previous sentiments from India’s Prime Minister Narendra Modi that “blood and water cannot flow together.”
“This was one of the first times that I’ve seen something like this happen from a transboundary or water relations standpoint,” Whattam says. “India was essentially saying, ‘[Pakistan] you need to figure out your terrorist solution, and if you don’t, we’re going to turn off the water.’ They are using water as leverage to force change.”
As an outside observer, Whattam saw many of these events unfold in real-time while living in India. Having become conversationally fluent in Hindi, he was able to add additional context to these issues by speaking with local people and understanding the local news. He points out that conflicts like these change the dynamics of entire regions, further illustrating how international relations, the economy, terrorism, and public health and safety are all interconnected through water resources.
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“They came from the Ganga, and it is their mother.”
Ethen Whattam
In India, all rivers are of great religious importance, but the Ganges, in particular, is the most sacred. Known as “mother Ganga,” it is considered a tirtha, or a crossing point between heaven and earth, as well as the mother of all Hindu people. Ganges water is so sacred that many devotees keep jars of it in their homes; Whattam himself was even tasked by locals to return with jugs full of it from his frequent trips to the river.
Every three years, hundreds of millions of Hindus make the pilgrimage to the banks of India’s most holy rivers for the festival of Kumbh Mela. In 2019, the Kumbh Mela was held in Prayagraj (formerly Allahabad) at the confluence of the Ganges, the Yamuna, and the mythical Saraswati rivers. In what is the world’s largest gathering of people, the faithful bathe in the waters of the holy rivers to wash away their sins and liberate themselves from their cycle of reincarnation.
When Whattam found out about the massive festival in Prayagraj, he realized it was a once in a lifetime event that he had to check it out for himself.
“It was a wild, wild experience, with around 120 million people coming to the festival,” he says “The amount of diversity encapsulated in this small area increased my understanding of India’s diverse religious and cultural practices.”
Allahabad, India – March 04, 2019:Thousands of Hindu devotees come to the confluence of the Ganges and the Yamuna River for holy dip during the festival Kumbh Mela. It is the world’s largest religious gathering. iStock
The Ganges, like all rivers in India, is threatened by a variety of factors that put millennia-old-traditions, like Kumbh Mela, at risk. The Himalayan glaciers at the source of these rivers are melting at an unprecedented rate due to climate change, resulting in less water downstream. The water itself is also severely polluted by untreated sewage and industrial waste along much of its length.
Whattam explains how in the neighboring cities upstream of Prayagraj there is a high density of tanneries. Here, the leather industry uses extremely toxic chemicals to soften and preserve the hides, including carcinogenic compounds of chromium. With no proper treatment and recovery methods in place, these pollutants flow freely into the Ganges.
In an attempt to combat some of the point-source pollution and ensure cleaner water for bathers, the Indian government forced a shutdown of all tannery facilities in the upstream cities of Kanpur and Unnao in the months leading up to 2019’s Kumbh Mela. Since December 2018, almost 300 businesses have closed and remained shuttered, leaving 300,000 workers jobless.
“Suddenly you had all of these Muslims from the tannery factories out of work,” he says. Whattam clarifies that to Hindus, cows are considered sacred, so they do not work for these businesses. The sanctions therefore unilaterally impacted a predominantly Muslim owned and operated industry.
“You have all these interesting dynamics happening where the river can be clean for bathing and drinking, but at the cost of people’s jobs and livelihoods. The water problems that India is experiencing now are sinuating through all of these social issues—race, religion, and class status.”
~
While the government attempts to combat point-source pollution, some local citizen-based efforts are taking a different approach to clean up India’s rivers and improve public health. NGOs, such as Barefoot College, work with women from rural and poor areas on various issues, including education, skill development, health, and clean water. Barefoot College’s landmark program teaches women to become solar engineers, empowering them to use and share their knowledge in their home villages around the world.
Whattam had the opportunity to spend a few weeks with Barefoot College at its campus in the village of Tilonia in Rajasthan, India. The women there had a laboratory facility where they were sampling water from the local village wells. He observed even with rudimentary equipment, they were able to run tests and identify which chemicals are in the water and if it was safe to drink.
“The program empowered these women to be leaders in their community by going out and testing the wells for all these people,” Whattam says. “They were using data and creating charts to show their husbands saying, ‘Hey we can’t drink the water today! We need to go somewhere else to collect water!’”
The women also had the additional responsibility of tending to nurseries full of native plants that would be replanted in order to help revive the surrounding rivers and ecosystems.
“These are women who have never been to school and never even known what a science experiment was. Before [Barefoot College], they would have been at home making naan… and now they’re scientists–now they’re leaders in their community,” Whattam says. “It showed me how science travels throughout the world and how the pursuit of knowledge is what everybody wants; it was fantastic to see.”
~
The Boren Awards are principally language scholarships, providing funding opportunities for undergraduates and graduate students to obtain long-term linguistic skills and experience cultural immersion abroad. The program’s central mission is to provide the U.S. government with experts in languages critical to U.S. national security. Preference is placed on applicants who are interested in a career with the federal government.
Upon completion of the Boren and graduation from an institution, recipients are then obligated to work for the U.S. government for one year.
“You kind of have to pay it back and use the skills that you’ve acquired,” Whattam says, recommending the scholarship to anyone who has a passion to study abroad and learn a new language and who also wants to work in government.
When it comes to water policy and hydropolitics here in the U.S., he already sees plenty of areas for application, including locally in the Pacific Northwest. The U.S. and Canada are currently revisiting the landmark Columbia River Treaty, an international agreement governing the flow of water between British Columbia and six U.S. states. Since first implemented in 1964, the revised treaty will be an opportunity to address modern issues and challenges, including climate change, salmon conservation, and indigenous rights.
Looking back on his journey throughout India, Whattam reflects on a popular local saying.
ऊट के मुँह में ज़ीरा है
Translated from Hindi it means “like a cumin seed in a camel’s mouth.” A common idiom, it refers to something which is too little or insufficient to solve something massive, just as one cumin seed would do nothing to satiate a hungry camel.
To Whattam, it means how “in India, you never know how the day is going to turn out and any slight obstacle is tiny compared to the overall experience.”
In a broader context, it also speaks to the large-scale political and socioeconomic shifts occurring in India around water. That there is no one solution that solves all issues, but rather it will take the collective ingenuity and dedication of the people, like the many Whattam met in his travels, to tackle them head-on.
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For more information about the Boren Awards visit their website at https://borenawards.org/ or contact your undergraduate/graduate advisor for help with the application process.
The Northern clingfish can hold tightly to rough, slimy surfaces. Petra Ditsche
The finger-sized Northern clingfish employs one of the best suction cups in the world. A small disk on its belly can attach to wet, slimy, even rough surfaces and hold up to 230 times its own body weight.
A University of Washington team inspired by the clingfish’s suction power set out to develop an artificial suction cup that borrows from nature’s design. Their prototype, described in a paper published Sept. 9 in the journal Philosophical Transactions of the Royal Society B, actually performed better than the clingfish.
“I like to say, nature is always best,” said lead author Petra Ditsche, who started this work as a postdoctoral researcher at UW Friday Harbor Laboratories on San Juan Island. “In this case, when considering their attachment force, our suction cups are better.”
The team’s suction cup prototype can hold a rock weighing about 11 pounds. Petra Ditsche
The suction cups could be useful across a number of industries that require a strong but reversible sticking force on rough or textured surfaces. These could include tagging whales and other marine animals, attaching sensors to fouled aquatic surfaces or operating underwater vehicles to clean ship hulls. Applications in shower caddy design or industrial processing are other interesting fields of application for the bioinspired suction cups, the researchers said.
Key to their suction cup breakthrough was understanding how the clingfish’s natural suction works so effectively — especially on rough surfaces that normally cause a manufactured suction cup to fail.
Clingfish have a disc on their bellies that allows them to hold on with great tenacity. The rim of the disc is covered with layers of micro-sized, hairlike structures, in many different sizes. This layered effect creates more friction along the rim and helps the fish stick to rough surfaces. The entire disk is flexible and elastic, allowing it to adapt and hold on to coarse, uneven surfaces.
The underside of a clingfish, including the disk that is important for gripping rough surfaces. Petra Ditsche
“These fish are so evocative in what they can do. They can stick to irregular rocks covered in algae, and you cannot buy something that will reversibly stick to those rocks,” said co-author Adam Summers, a professor of biology and of aquatic and fishery sciences based at Friday Harbor Labs. “An awful lot of experimentation and skepticism finally led us to understanding how it worked.”
There are about 110 known species in the clingfish family found all over the world. The population around the San Juan Islands is robust and healthy. They often cling to rocks near the shore, and at low tide they can be seen in tide pools and under rocks.
Many marine animals can stick strongly to underwater surfaces — sea stars, mussels and anemones, to name a few — but few can release as fast as the clingfish, particularly after generating so much sticking power.
A suction cup prototype sticking to a rough surface. Petra Ditsche
After more than five years spent deciphering how the clingfish suction cups work, the researchers began building their own prototype, borrowing from the innovations of nature.
The team discovered after years of lab tests that combining different materials helped give the artificial suction cups a rigid structure that was strong enough to hold tension, while also soft and flexible enough to conform and stick to rough surfaces. They also found a way to increase the friction on the rim of the cup.
“This combination of all these different aspects finally gave us good results and enabled us really to build a suction cup that is able to attach strongly to rough surfaces,” Ditsche said.
Researchers Adam Summers, left, and Petra Ditsche demonstrating the sticking power of their suction cup prototype. The lower cup is holding an 11-pound rock, while an upper cup is affixed to a piece of whale skin. University of Washington
The researchers tested several iterations of their suction cup design by sticking them to a spectrum of rough and smooth surfaces, then pulling until each cup failed using a testing machine. They did the same tests using the natural clingfish suction disk. Each time, the most advanced artificial cup outperformed the clingfish suction across all surfaces.
The prototype is ready to be taken to the next step, ideally in collaboration with engineers who could develop the concept further with specific products and applications in mind, Ditsche said. Depending on how the cups are used, factors like temperature and sun exposure might require fine-tuning of the design.
“There’s understanding of how something works. And then there’s understanding how it works so well that you can actually make one. Biology doesn’t always give you that opportunity,” Summers said. “This is a really unusual situation, where when we looked closely over time, we realized we could mimic what we saw.”
This research was funded by the National Science Foundation and the Seaver Institute.
Sockeye salmon wait to spawn in Alaska’s Lake Iliamna, which helps produce about 20% of Bristol Bay’s salmon. The Pebble Mine would sit in the lake’s headwaters.
It’s hard to think small in Alaska. The largest of the United States is home to North America’s highest mountain range. It’s a place where undammed rivers run more than 1000 kilometers, glaciers collapse into the ocean, and polar bears roam.
Daniel Schindler, however, is here hunting for something the size of a grain of rice. Crouching in tiny Allah Creek, hemmed in by alders and smeared in blood, he grasps a rotting sockeye salmon carcass and nearly decapitates the fish with a stroke of a carving knife. With tweezers, he delves into a cavity of creamy goo tucked behind the brain and plucks out a sliver of what looks like bone. It is an otolith, a bit of calcium carbonate that sits within the inner ear and acts like an internal gyroscope, helping the fish orient its movements.
Schindler, an aquatic ecologist at the University of Washington in Seattle, holds the white fleck up to the sunlight. “For some reason, picking otoliths is a very therapeutic activity,” he says, as a cluster of scarlet-sided sockeye thrashes by in the shin-deep water, frantically searching for their spawning grounds.
Please join us in congratulating Dr. Sarah Converse who will be receiving the Department of the Interior’s Distinguished Service Award in Washington D.C. on September 12th. The award is the highest honorary recognition an employee can receive within the Department of the Interior and is granted for “outstanding contribution to science, outstanding skill or ability in the performance of duty, outstanding contribution made during an eminent career in the Department, or any other exceptional contribution to the public service.”
Converse is honored for her work in whooping crane recovery and research, and the application of decision science as a management tool in support of federal trust agencies.
José grew up in Córdoba (Spain) and received his PhD in Marine Sciences from the University of Cádiz (Spain) in 2010. As a postdoctoral researcher, he joined the Northwest Fisheries Science Center-NOAA in 2011, where he focused on the endocrine mechanisms that regulate the onset of sexual development in fishes.
He started working as an instructor at SAFS in 2015, where he became passionate about effective teaching and the science of education. Besides teaching a series of undergraduate-level courses, José is a coach for the UW Evidence-based Teaching Program, where he trains faculties across campus in evidence-informed pedagogical practices, and assists them in the development of specific strategies based on their teaching needs.
When not working, you can probably find him up in the mountains or exploring the PNW with his husband, friends, and his dog Paco.
SAFS is excited to announce that Camrin Braun will be joining us as our newest Assistant Professor.
Camrin has worked on movement ecology of top predators and biophysical interactions in the ocean for nearly a decade. He recently finished his PhD in the MIT-WHOI Joint Program in Oceanography and has been working as a Postdoctoral Research Scientist in the Air-Sea Interaction and Remote Sensing Department at the Applied Physics Lab (APL-UW).
He plans to continue his close collaborations at APL, MIT-WHOI, and San Diego State University to study the structure and function of a highly dynamic ocean and quantify its influence on pelagic ecosystems. He is particularly excited about coming to SAFS because it will allow him to work closely with our exceptional students, postdocs, and faculty and will bolster his multidisciplinary approach to fisheries management, ecology, and oceanography.
Beyond the lab, Camrin enjoys mountain biking, fly fishing, and spending time with family, friends, and his German shorthaired pointer, Mako.
When you’re hungry, wouldn’t it be nice to just slip into a tunnel that rushes you off to a grand buffet? It sounds like something Elon Musk might dream up, but it turns out, certain species of sharks appear to have this luxury.
Last year, researchers at Woods Hole Oceanographic Institution (WHOI) and the Applied Physics Lab at the University of Washington (UW) discovered that when white sharks are ready to feast, they ride large, swirling ocean currents known as eddies to fast-track their way to the ocean twilight zone—a layer of the ocean between 200 and 1000 meters deep (656 to 3280 feet) containing the largest fish biomass on Earth. Now, according to a new study in Proceedings of the National Academy of Sciences (PNAS), scientists are seeing a similar activity with blue sharks, which dive through these natural, spinning tunnels at mealtime. The eddies draw warm water deep into the twilight zone where temperatures are normally considerably colder, allowing blue sharks to forage across areas of the open ocean that are often characterized by low prey abundance in surface waters.
To track their movements, the researchers tagged more than a dozen blue sharks off the Northeast Coast of the U.S. and monitored them for a period of nine months. According to Simon Thorrold, a senior scientist at WHOI and co-author of the study, each shark was “double tagged” on their dorsal fins; one tag monitored ocean temperatures and depth as the sharks moved through the ocean and the other tag tracked their location. This double-tagging strategy allowed the scientists to reproduce the three-dimensional tracks of the sharks with the resolution and accuracy needed to link their movements to the positions of ocean currents like eddies.
Data relayed from the tags via satellite to labs at WHOI and UW revealed that the sharks spent a good portion of their days diving these warm-water tunnels to the ocean twilight zone hundreds of meters below the surface. There, they’d spend an hour or so foraging before swimming back to the surface to warm up before diving again.
Satellite tags like this one displayed by WHOI biologist Simon Thorrold are giving scientists an unprecedented ability to follow sharks and understand their habitats and behavior. The information is essential for determining management strategies to ensure that the sharks are not overfished. (Photo by Tom Kleindinst)
Dives were less frequent at night, when many twilight zone animals make their daily migration from the ocean’s mid-water to the surface. According to Camrin Braun, an ocean ecologist at UW and lead author of the study, a trip to the twilight zone at night isn’t really worth it for hungry blue sharks since their “deep ocean buffet” isn’t particularly well stocked after dark.
“Sharks are all about opportunity, so with fewer prey items down there at night, they’re just not going to make the trip,” he said. “Going down there is costly for them from an energetic and metabolic standpoint.”
University of Washington ocean ecologist Camrin Braun and his colleagues tagged sharks to track them as they dove warm-water eddies to the ocean twilight zone to forage. (Photo by Tane Sinclair-Taylor, James Cook University)
Braun, who conducted the research as a PhD student in the MIT-WHOI Joint Program in Oceanography before working at UW, says that the behavior of the blue sharks was generally similar to that of the white sharks tracked in the previous study. However, the two species had different preferences when it came to water temperature. White sharks, which are warm-blooded animals, used a combination of warm- and cold-water eddies as a conduit to the twilight zone, while blue sharks—a cold-blooded species—relied exclusively on warm-water eddies.
“Blue sharks can’t regulate their body temperature internally to stay warmer than the ambient seawater like white sharks can, so they need to control it behaviorally,” said Braun. “We think this is why they show a clear preference for the warm-water eddies—it removes a thermal constraint to deep diving.”
In general, when it comes to the secret lives of large apex predators like sharks, scientists know relatively little. This research, according to Thorrold, helps fill important knowledge gaps about where they go and why, which can inform decision making on where to implement marine protected areas to conserve them. And, the work underscores the importance of the ocean twilight zone as a critical biomass resource.
“The twilight zone is vulnerable to overfishing,” he said. “If we’re harvesting low-value fish there at the expense of high-value fish like blue sharks and other pelagic predators, that’s probably not a good tradeoff.”
