Reflections on Operation Swimway: Tahanea 2025

Reflections on Operation Swimway: Tahanea 2025

Please enjoy this video about Seahawk’s Operation Swimway expedition in French Polynesia in April 2025

I have adored sharks from a young age, diving with species worldwide and always feeling they are misunderstood. Sharks have populated our oceans for 450 million years, surviving five mass extinctions and becoming one of nature’s most successful predators. Yet we are losing around 100 million each year, through overfishing, finning, bycatch, and habitat destruction. Their loss destabilises ecosystems, as prey populations boom and food chains unravel, ultimately affecting fish stocks humans choose to harvest.

Grey Reef Shark and divers

Operation Swimway, managed by YachtAid Global with support from yachts such as Seahawk, works to protect critical migration corridors for sharks, rays, turtles, whales, and billfish. By studying where these animals travel, the aim is to establish more marine protected areas (MPAs). Seahawk has been involved since 2022, focusing largely on French Polynesia.

Research is complex, combining transmitter tags, passive receivers, and baited remote underwater video devices (BRUVs). These methods reduce human interference while capturing valuable behavioural and migration data. For this mission, BRUVs were deployed as deep as 70 metres using closed-circuit rebreathers. Tahanea Atoll was chosen for its three distinct passes, thought to offer unique habitats. Our primary focus was the Tiger Shark, classified as ‘Near Threatened’ on the IUCN Red List.

BRUV

The 2025 expedition carried great anticipation, it was the first chance to see results from three years of work. Seahawk’s crew supported four IREMP scientists led by Dr. Clementine Seguine, diving up to four times daily despite bad weather, illness, technical setbacks, and even sharks destroying equipment.

Early in the week, the Tiger Shark we tagged in 2022 reappeared, recorded 191 times passing through Tahanea. This confirmed the atoll’s importance and lifted morale. Each evening the scientists shared updates, reinforcing the sense of shared purpose across Seahawk.

Science team in stormy weather

On the final day, after an exhausting push to complete the study, the biggest breakthrough came: BRUVs recorded seven threatened shark species, including two three-month-old male Tiger Shark pups. Whether they were the offspring of our 2022 tagged Tiger Shark, we cannot be sure, but the discovery confirmed Tahanea as a pupping ground, an emotional moment for us all.

3 passes at Tahanea atoll

Back on the dock in Tahiti, I reflected on Tahanea’s raw beauty: pristine reefs, manta rays, hammerheads, and endless schools of fish. It feels untouched, alive, and strangely, happy.

In the months ahead, we hope the data will strengthen the case to protect Tahanea and other atolls. As Adam Alpert once said, we are “custodians of the planet”. Never have I felt that more strongly than during this mission.

Grey Reef sharks in Fakarava

“We all come from the sea, but we are not all of the sea. Those of us who are… must return to it again and again, until the day we don’t come back, leaving behind only that which was touched along the way.” -Chasing Mavericks

Written by Adam Cowley

Written by Adam Cowley

Chief Officer

Indonesia – Walking Sharks

Indonesia – Walking Sharks

Walking Sharks and the Fight for Ocean Biodiversity in Raja Ampat:

The global abundance of oceanic sharks and rays has plummeted by nearly three-quarters (71%) over the past 50 years, primarily due to overfishing  A quarter of all shark species are currently at risk of extinction.

Each year, approximately 100 million sharks are killed globally, either intentionally for their fins, meat, oil, and cartilage, or unintentionally as by-catch of the fishing industry. In stark contrast, sharks are responsible for just five to six human fatalities annually. Statistically, in the US you’re over 7 times more likely to die from eating a hot dog than from a shark attack 

Seahawk in New Caledonia

What We Saw on the Way to Indonesia:

Most people will never witness what we saw while navigating toward Indonesia: a forest of fishing vessels appearing on AIS (Automatic Identification System—a marine navigation tool) choking and overexploiting marine life. Seahawk was forced to weave and meander between countless boats and avoid hundreds of miles of fishing nets stretching across the ocean.

AIS Screen of fishing vessels

Overfishing of this scale has undoubtedly taken a toll on Indonesia’s marine biodiversity. Even in areas where coral reefs looked healthy, our dives revealed fewer large fish. A stark reminder of the invisible damage taking place. Demand fuels destruction, and the myth of “sustainable fishing” unravels quickly when faced with the reality of indiscriminate netting. These massive nets scoop up all species (known as by-catch), destroy habitats, and operate under poor regulation.

Change will only come when consumers reject these destructive practices. Among the countless vessels we passed a Singapore-flagged 250-meter bulk carrier ironically named Eternal Resource (insert eye roll here).

Epaulette Shark in shallow reef

Raja Ampat’s Secret Shark:

One of the ocean’s lesser-known yet fascinating shark species is the Epaulette Shark (Hemiscyllium freycineti) also known as the “walking shark.” Endemic to the coral-rich waters of Raja Ampat, this shark is not your typical apex predator. It grows only about 60 to 76 cm (24 to 30 inches) long and has the unique ability to “walk” across the seafloor using its pectoral and pelvic fins.

These nocturnal creatures favour shallow reef environments, seagrass beds, and coral flats. Emerging under cover of night, they feed on small invertebrates like molluscs and crustaceans. They reproduce by laying eggs, typically placing them in rock crevices or coral outcroppings for protection until hatching.

Kayaking in the mangroves in Bouraké Lagoon

Science at Sea: A Collaborative Mission:

To better understand and protect this unique species, Seahawk colaborated with Yacht Aid Global to support Indonesian marine scientists from the Elasmobranch Institute of Indonesia. Dr. Edy Setyawan, Dr. Danang Ambar Prabowo, Abdy Hasan and their team, have been conducting a groundbreaking study in Raja Ampat. Their efforts include tagging and tracking walking sharks to establish a population baseline and understand movement patterns.

Their research revealed highly restricted ranges for the sharks and a reliance on specific habitat types, making them particularly vulnerable to threats like:

     · Artisanal fishing

     · Habitat loss from coastal development

     · Climate change and coral bleaching

Armed with this data, the team aims to implement local conservation strategies to ensure the long-term survival of the species.

Innovative Conservation: eDNA and Biologging

The research team is also pioneering the use of environmental DNA (eDNA) to detect the presence of walking sharks through water samples – an innovative, non-invasive method that allows scientists to track species even in hard-to-reach habitats.

In tandem, biologgers are being deployed to gather data on temperature and depth preferences, helping scientists understand how the species may adapt, or struggle, in response to climate variability.

These combined methods are offering a richer, more accurate picture of the species’ life cycle and habitat needs, contributing to science-based policy and management decisions.

Tiger Shark swimming in clear blue water with sunbeams coming from above

Why Should We Care About a Walking Shark?

It’s easy to dismiss the plight of a small, strange-looking shark as inconsequential in the grand scheme of ocean conservation. But the truth is: we don’t fully understand the ecological role of many marine species until their absence causes cascading, devastating effects.

Just as a skyscraper depends on hidden structural supports, our oceans rely on species big and small. Remove enough, and the whole system begins to crumble. Biodiversity is not a luxury, it’s the foundation of ocean health.

 

Colourful Coral Reef in Indonesia

The story of the walking shark is more than a curiosity, it’s a call to action. In Raja Ampat, where marine life clings to fragile reef systems, the survival of this small, remarkable species reflects the health of the broader ocean. Through cutting-edge science and cross-border collaboration, we have a rare opportunity to protect not just a single shark, but an entire ecosystem. The choices we make, what we eat, how we travel, what we support, ripple outwards. If we want thriving oceans tomorrow, we must act today – with awareness, intention, and a deep respect for even the smallest creatures that “walk” the seafloor. 

diver making heart shape with hands over a red fan coral

Article written by Nicola Watton

Sources:

Marine Megafauna Foundation

Rodolphe Holler – Tahiti Private Expeditions

French Polynesia – Operation Swimway

French Polynesia – Operation Swimway

Much of what the S/Y Seahawk mission is about involves developing a better understanding of the marine environment, especially pelagic species. The focus is on migration patterns, Tiger and Grey Reef sharks of special interest because it is suspected that the travel itineraries in play are key to sustainability. Understanding reproduction strategies for these animals is also important. Knowing where the pupping areas are located could be the key to protecting the threatened population without having to make the sometimes-controversial Marine Protection Areas (MPAs) excessively large.  For this, we mostly lean on our visiting scientists including Clémentine Séguigne who joined S/Y Seahawk for its most recent exploration of the Tuamotu Islands, French Polynesia during the months of March and April. The work itself is awe inspiring just because of the magnificence the laboratory affords. Of course, the science that follows is exceedingly important, too. What is learned may be the key to not only saving a species but the ecosystem as a whole. 

Seahawk in New Caledonia

The Tuamotu Island chain of French Polynesia is known for its stunning beauty both below and above the water. There is much complexity here to unravel because these atolls all revert to a volcanic history. Similar to the present-day younger islands of Moorea and Bora Bora, the Tuamotu islands once enjoyed some relief. Now, where there was land forming, e.g., domes and plateaus, there are luxurious lagoons, in most cases surrounded by the remanence of vast coral colonies. There are also one or more natural passes that exit these lagoons. In some cases, the passes through the coral reefs were formed because of the geology in play. More often it is the freshwater runoff (rain) that carves a path through the coral, (coral does not like fresh water.) But beyond the formation curiosity, these passes are where the action is. The currents that form both in and out of the lagoons attract a wide variety of species. Some come to these places to breed. Others, prototypically a variety of shark species, enjoy feeding and the luxury of resting on the bottom while the current effortlessly pumps oxygen through their gills. 

Noumea beaches were closed due to recent shark attacks

Sharks are a keystone species in the marine ecosystem. As an apex predator, they keep the ecosystem in balance, and without them, the entire food web will collapse. Sharks are vital to the health of the oceans and to our existence on this planet. We must protect them. 

Seahawk is on a mission to help researchers and advance the protection of sharks. In 2021 we  began our involvement with Operation Swimway and partnered with researchers to tag 4 Tiger sharks and deploy 10 electronic receivers underwater to detect the transmission of the tagged sharks. Each receiver is an electronic device capable of detecting acoustic signals from the tags; it is encased in a waterproof canister that is about the size of a 1 litre water bottle, and affixed to the ocean floor by a rope attached to a chain at the base and a buoy at the top to keep it upright in the water column. To learn more about this endeavour,  check out our mission log  from our last trip in 2022 to French Polynesia.

Diver removes shark tag reciever

Fast forward 2 years and Seahawk is back cruising around the stunning Tuamotu Islands, French Polynesia in March 2024. Along with our excellent guides Rodolphe and Sébastien, Tahiti Private Expeditions, the dive team followed the GPS coordinates of the receivers and set out to retrieve them. The team strategically planned each dive to navigate strong currents, shifting tides, and depths up to 35 meters to dismantle the chains, buoys, and collect the receivers with 2 years of crucial data about the sharks’ movements.  

Kayaking in the mangroves in Bouraké Lagoon

After the retrieval mission was complete, Seahawk sailed back to Tahiti and returned the canisters to the research team at IREMP so that they could analyse the sharks’ movements over the past 2 years. They learned some fascinating information about the local tiger sharks, which atolls they tend to prefer, which ones they didn’t visit, and which passes they frequented. Because of this information learned, the research team decided to focus their next data collecting mission on one unique atoll called Tahania atoll. This spot was chosen because tiger shark activity was detected here, and it is uncommon for an atoll to have 3 separate passes that allow water and marine life to flow in and out of the lagoon with each changing tide.  

Along with researcher Clémentine Séguigne, and our experienced local guides, Seahawk helped deploy 6 new receivers at Tahania atoll. The receivers were strategically placed on the outside corners of each of the 3 passes to get the best chance of detecting a ping from a tagged tiger shark. Clementine found that the best chance for data collection would be at a deeper depth, so we deployed each receiver at a depth of 30-40 meters. The team had to work quickly at these depths and pay careful consideration to their no decompression time limits, but once the receiver was successfully installed, and the GPS coordinate marked, there were high fives and celebration all around! We look forward to learning more about the tiger shark movements around Tahania Atoll. 

Tiger Shark swimming in clear blue water with sunbeams coming from above

Through all these efforts, the ultimate goal is to better understand the tiger shark movements and ecology so that the researchers can propose MPAs to the local government and protect the crucial habitats for the species. Seahawk is one vessel able to provide support to researchers conducting field work in these remote locations. Through nonprofits like Yacht Aid Global, the hope is that other vessels will become involved in similar projects, all part of the greater effort to preserve the world’s oceans.  

Galapagos – A Science Trip to Darwin and Wolf

Galapagos – A Science Trip to Darwin and Wolf

Seahawk arrived to Darwin in July 2021, the northernmost island in the Galapagos archipelago, after previously cruising the southern parts of the province and formally launching YachtAid Global’s Swimming and Sailing program in San Cristobal.

Much excitement could be felt on the boat as the inaugural science mission was about to begin. In a joint effort led by YachtAid Global, Seahawk became an active participant in Operation Swimway; a project dedicated to lending support to science and marine conservation NGOs conducting state-of-the-art research around the world.

Operation Swimway’s focus is to determine patterns of migratory animals, such as sharks, mantas, and turtles. Understanding the movements of these animals and the corridors they use to feed and breed is key for protecting all marine life, especially so for sharks who have to take increasingly dangerous journeys due to unsustainable fishing practices and other hazards including water pollution. High on the list of Operation Swimway’s priorities is to precisely define endangered species migratory patterns. The data collected and analyzed is then used to help define candidate Marine Protected Areas (MPAs) with the goal of seeking and obtaining approval from the responsible governing agencies.

While visiting Darwin, Seahawk was joined by scientists from the conservation group Migramar, a well-known organization that operates in the Eastern Pacific Ocean dedicated to studying the movement of threatened marine species. Dr. Alex Hearn led the effort on this expedition, which focused on studying whale sharks, known to visit Darwin Island during the July, August, and September timeframe. Adult female whale sharks congregate annually in the Galapagos, a phenomenon that is one of the subjects of Migramar’s research. Most of the females are pregnant when visiting the islands, suggesting the archipelago could serve as a nursery for these sharks. The mission’s objective was to attach GPS tags to individual whale sharks in order to provide tracking data based on a representative sample for determining the overall nature of species’ movements. Very little is known about where the whale sharks go, their pupping grounds, or their feeding habits.

During our cruising of Darwin and Wolf, we were lucky to have several encounters with some of the whale sharks. As stewardess Thea remembers:make

“It was a crazy experience. I suddenly saw this 12-meter fish swimming very fast past us. You could feel the water moving around you as she swam past. The scientists tried to tag her, but failed to do so as she was at full speed. The sighting lasted a few seconds, but it was incredible.”

Some of the attempts at tagging these sharks were successful, but the process is far from perfect. The sheer size, speed, and strength of whale sharks make the attachment of transmitters very challenging.

But not all was focused on GPS tracking. Dr. Diana Alexandra Pazmiño Jaramillo was part of the science team leading Operation Swimway. Her work at the Galapagos Science Center focuses on a more evolutionary approach; research designed to trace the migration patterns of various shark genotypes by using genomics, a special kind of DNA fingerprinting used to identify individual species without actually tagging them. Dr. Diana Alexandra’s work involves analyzing the secretions and tissues of the animals at a molecular level, which is crucial to revealing their behavior and patterns of movement. 

Miguel Herrero, Marine Biologist and Project director at Mantas Ecuador, was also on board Seahawk. His research revolves around developing an understanding of both the reproductive processes and migration patterns of giant manta rays. But Miguel is also interested in the role of cleaning stations and the special fishes that symbiotically bond to keep the rays healthy and free of parasites. Like many symbiotic relationships in the ocean, there is much specialization. In the case of the giant mantas, there are only a few specific types of cleaning fish suitable for servicing this shark family species. 

During our days at Darwin and Wolf, owners, guests, and crew were fortunate to experience the outstanding marine life that the famous Galapagos islands hold, while also witnessing how research on marine animals is conducted by professional scientists; an inspiring and educational experience.

However, not all was fieldwork. The Seahawk team also attended presentations held by the Migramar scientists, in which they discussed the experimental design needed to further improve the understanding of the mechanisms in play. Much was about how to better track the animals, sharks and mantas, but also important to the cause was developing a comprehensive understanding of the ecosystem; the Galapagos islands in particular are complicated because of the byzantine matrix of converging currents, some very warm, some very cold. It is acknowledged that a more holistic approach to science is likely the right answer in order to secure the outcome desired.

Prototypically, developing MPAs in isolation will not solve the problem unless other environmental hazards are addressed. Migramar and other similar NGOs realize the problem is multifaceted and are working to establish more comprehensive understandings and solutions. As for the Seahawk team, the boat is exceedingly proud to have played a small role in this most important effort.

If you’d like to know more, you can watch the video below. It includes interviews with the Migramar team on board, as well as footage of our days cruising the islands. Not to be missed!

Fiji, Part II – Lau and the Seascape Initiative Project

Fiji, Part II – Lau and the Seascape Initiative Project

While our exploration of Fiji during the first part of the trip delivered much to celebrate, not all is well in paradise. In particular, underwater exploration of Fiji revealed much stress on the coral and fish life there; a bittersweet realization given the many goodnesses characteristic of the country. Arriving within the Lau Group, Fiji’s least visited hidden jewel to the east, we hoped to find a natural world largely untouched.

It is now August, about half way through our Fijian itinerary. Here, in Vanua Balavu, Seahawk and her crew stood ready to support a new scientific mission, again organized by our partners at YachtAid Global. This is where the sponsored scientist, Kristian Miles, working with the NGO Conservation International (CI), joined us to survey the remote islet of Duff Reef, a recently declared turtle sanctuary.

Sadly, many of our dives, including those conducted with Kristian, showed the coral reefs were struggling. Many colonies were bleached or suffering from other stressors such as cyanobacteria blooms and destruction by cyclones. And other marine life, especially larger pelagic fish species, were suspiciously lacking, 

All signs point to what is now a common problem around the world; overfishing, bad agricultural practices, and climate change. Over the course of our trip, we learned about Fiji’s struggles with overfishing, unsustainable fishing practices (catching of undersized, juvenile fish), and a growing population that increasingly turns to the sea for subsistence. Recent cyclones to hit the islands have also been problematic, some causing serious damage across coral reefs and devastation on land.

We wanted to know more about Fiji’s underwater world, the challenges faced and the organizations and individuals working towards solving them.

Behind the recently protected Duff Reef was the Lau Seascape Initiative; a plan launched in 2019 to protect Lau’s marine and terrestrial life from the current challenges while preparing the region’s communities to develop sustainably. It was launched by regional leaders with Conservation International and partners, with the support of the Fijian government. 

Duff reef is a community-based marine managed area and is now a no-take zone where sea turtles can find refuge as they visit the site to breed.

The mission was going to be highly constructive. Kris gave the crew and owners a presentation explaining the Duff Reef environment and the many species found there. The introduction was fortuitous because it facilitated both owners and crew playing a role in surveying the area for key species of marine life. Much to take in and learn to be able to properly identify the different turtles species and other resident fish like groupers, jacks, and barracuda targeted for the survey. It was an intensive course that had some of the team members studying the fish identification book all night prior to next day’s planned dive.

Unfortunately, due to rough weather conditions that included 40-knot winds and heavy rains, Duff Reef’s expedition had to be canceled; located in a very exposed area (the islet is a small sandbank in the ocean) and surrounded by coral reefs, the risk of dragging anchor in such a delicate environment was too high. Seahawk got there and had to turn around straight away, back to the sheltered waters of the Bay of Islands.

On the bright side, Kristian and the Seahawk team were able to deploy a remote underwater temperature monitoring system in the northwestern pass of Vanua Balavu, to collect data on the inputs of ocean temperature. This unit is part of a greater effort by the University of the South Pacific to understand the impacts of climate change. The device will record temperatures over short intervals for up to a year. The annual retrieval/replacement of these devices will aid in the collection of data on ocean sea temperature changes. A similar system has already been installed in the southern Lau Group reef system.

During the days Kris  was with us he was able to conduct several surveys of marine life in the various Vanua Balavu passes Seahawk visited. These surveys are about determining the density of populations of benthopelagic and pelagic animals along with turtles & sharks within scientifically important areas of the Lau group.

The dive sites we explored were some of the best of the trip. The reefs were healthy, like busy cities, filled with fish, and diving alongside the reef wall we encountered big schools of barracuda and other pelagic fish. A thriving environment that benefits from the remote nature of the region. 

Still, cyanobacteria blooms were also present there. As Valu and Kris showed us how to identify the red algae covering the reef, it was difficult to unsee it. Another sign of how nutrient runoffs from agriculture are having an impact everywhere.

It is hoped that the Lau Seascape Initiative accomplishes its conservation goals and that the dependent communities in the area enjoy a sustainable future. There is much damage done, but also a lot to be saved within the pristine waters of the Lau islands.

The weeks that followed in Lau were marked by an immersion into the Fijian culture and a deeper understanding of the way of life and traditions of Fiji, as Seahawk made her way south of the group and visited some of the country’s most remote corners.

References used on this blog:

Sheldon Chanel, Shailendra Singh (2021, February 3rd). Fishing in Fiji Under Strain [Blog post]. Retrieved from https://earthjournalism.net/stories/fishing-in-fiji-under-strain#:~:text=According%20to%20a%202009%20University,fishing%20practices%2C%22%20says%20Dr.

Andrew Freedman (2020, December 17th). Fierce Cyclone Yasa strikes Fiji as one of the countrys most powerful storms [Washington Post]. Retrieved from https://www.washingtonpost.com/weather/2020/12/17/cyclone-yasa-hits-fiji/