French Polynesia – Mystery of the Atoll Passes
A fascinating explanation about ocean tides and currents and how they affect the marine life in the remote atolls in the Tuamotu islands.
Video by: Adam Alpert
Bad Romance – Shark Canyon
The south pass of Fakarava Island atoll, Passe Tumakohua, provides for one of the best examples of natural marine habitat facilitated by the exchange of seawater with slightly fresher water from inside a lagoon. It is the freshwater runoff (rain) that carves a path through the coral. (Corals cannot tolerate fresh water.) But beyond the formation curiosity, these passes are where the action is. The tidal currents that form both in and out of the lagoon 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.
While there are many fish species to behold, this place hosts an amazing density of gray reef sharks. Further, these animals are largely oblivious to the presence of divers. So, an up-close view is possible most days. Important to note, the danger from the gray reef sharks and most shark animals is minimal. To the extent there are attacks on humans the incidents are rare, usually caused by the shark confusing a human swimmer/surfer with normal prey during feeding times. Certain sounds including those similar to crushing an empty plastic water bottle can trigger aggressive behavior, too. Still, more people die from eating hots dogs than shark attacks.
Written by: Adam Alpert
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.
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.
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.
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.
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.
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.
French Polynesia – Makemo Arikitamiro Primary School Computer Learning Project
As Seahawk’s 2024 exploration of French Polynesia comes to a close it should be noted that the archipelago is much more than a beautiful natural wonder. Our time here has indeed been magical due to the splendor of so many lush tropical atolls, each offering its own amazing and often unique underwater vista. But the charm of the Tuamotu and other island groups we have visited here in French Polynesia is also reflected in its people, especially the children. Despite the challenges of island life, and there are many, the generosity and warmth extended to visitors enjoy few equals.
Seahawk’s repurposing for community outreach and the advancement of science affords many interesting and rewarding experiences. The shark migration work in particular has delivered a unique insight into the amazing biodiversity of the world’s oceans. The hope, of course, is that beyond satisfying curiosity these new understandings will lead to better management of fish stocks and other ocean resources. But science by itself cannot address the impending collapse of the marine ecosystem. As custodians of seas what happens next will depend on what people, especially the next generation, decide to do. The sobering fact is that children in primary school today will likely determine the fate of world, at least in terms of climate and other life-giving resources. Hence the reason to do everything possible to give this new generation the tools needed to make good choices.
Seahawk has supported many island communities as part of an effort to better equip this next generation with the knowledge to be careful and prudent custodians. While the ultimate outcome is not known, the hope is that an improved skillset will lead to both greater personal success and better decision making for the local communities and beyond. The idea roots to an assumption that everything begins locally before transcending to something bigger. In essence a collective wisdom is born once local concerns are addressed.
In this spirit, and in combination with Yacht Aid Global, Tahiti Private Expeditions, the Government of French Polynesia, and Seahawk Enterprises, I present Seahawk’s latest endeavor, the Makemo Arikitamiro Primary School computer learning project. If successful, primary students attending Arikitamiro school will acquire a practical understanding of modern PC and Apple based technology. More is more when it comes to being both aware and expert in the subject. Those in command of the information, able to communicate that knowledge effectively, will determine the final outcome.
Written by: Adam Alpert
To learn more about projects like this, and how you can get involved, please visit: https://yachtaidglobal.org/
French Polynesia – Plastic Odyssey
“If we do nothing there will be more plastic in the ocean than fish by 2050.” This is the problem/scary prospect the Plastic Odyssey expedition is trying to address. Specifically, there is a need for a practical solution to the plastic waste problem that is both economically viable and self-sustaining. The idea at its heart is to develop a recycling technology that is simple to implement and easy to operate in places where plastic waste accumulation is most severe. Think third world countries that have few regulations and much consumption of plastic contained products. Senegal, a country experiencing extreme plastic pollution of its coastline already has a facility in place. Key to success, however, is that the recycling enterprise must be profitable to work. Hence the focus on recycling manufacturing designs that are inexpensive to produce and maintain. And this is not just about cleaning up beaches. The result is an economically viable product, e.g., beams, roofing tiles, specialty molded parts, that can be sold on a competitive basis to local consumers.
S/Y Seahawk was introduced to the Plastic Odyssey team in Monaco coincident with the Royal Yacht Club of Monaco La Belle Class Superyacht Awards. S/Y Seahawk won in the category of “Adventure and Environmental Ethics”. It was at this event that Nicola Watton, Chief Stewardess, receiving the award on Seahawk’s behalf, met Plastic Odyssey’s CEO, Simon Bernard. Her introduction led to the tour of Plastic Odyssey during our visit to Hao French Polynesia.
The Plastic Odyssey team acknowledges that reduction/elimination of plastic waste entering the environment is an existential challenge. In the interim, boutique recycling systems like those demonstrated on the vessel could serve to mitigate until a more proactive solution is adopted.
To learn more about Plastic Odyssey, visit their website at: https://plasticodyssey.org/en/
Written by: Adam Alpert
French Polynesia, Part III – Last days in the Tuamotus
We end our trip in the Tuamotus, excited for the path ahead, and yet aware of the uniqueness of this side of the world. A future nostalgia will accompany us every time we remember the experiences lived here on board Seahawk.
We’ve spent the last few days exploring new atolls and visiting previous ones in the Palliser group, northwest of the Tuamotus.
We finished our science trip back in Rangiroa, where we also conducted crew changeovers and provisions. In the days that followed, crew and guests from Seahawk got trained as PADI Rescue Divers by Righardt, the diver instructor on board.
Also, we made use of the windier days that followed by doing some Tiwal Regattas and land excursions to the local vineyard. As it turns out, Rangiroa is the only atoll in the world where wine is produced. With vines growing in limestone and coral soils, the wine produced in the region is a unique one.
It was interesting to learn about the history of the vineyard and the particular challenges it faced since the first grape variety was imported to French Polynesia in 1992. Years of research to find the best area ended up with the creation of Vin de Tahiti in this atoll. On our visit we did some wine tasting and, delighted by some of the flavors (especially the rosé nacarat), we bought some wines for Seahawk’s collection.
The final Tuamotus cruising aimed to complete our visit to all the atolls that Seahawk could fit into. Some of the pass entrances started to get quite tight; in Tikehau, the pass had an indicated charted depth of 3.6m, but Seahawk needs 4.5m to float. Calculating pass entrance time is a complex task. Normal astronomical tides are only part of it, and swell height affects the amount of water passing over the rim of the atoll, as does wind direction. Getting this right for Tikehau was vital and very much comes down to the experience of the local guide. Our entry was successful, using the tender to mark the shallowest point for us to follow, with around 0.3m below us.
On another note, the diving has been excellent. A clear highlight was the manta cleaning station we came across on a dive in Toau, where 6 mantas could be found relaxing, and even showing curiosity and approaching us several times. But this is just one of many sightings one could encounter while on this side of the world, along with the large amounts of fish and incredibly rich biodiversity.
The thriving underwater world of the Tuamotus serves as an example of what healthy reefs can look like if taken care of. Facing their own share of environmental challenges, these areas are critical for the stability of many species. A realization that keeps Seahawk focused on its mission to support scientific research that will aid in the protection and conservation of these fundamental marine hotspots.
Also in Toau, we went on a mission to find the bizarre coconut crabs; these crabs are known to be the largest terrestrial arthropods on earth, weighing up to 4kg in some cases. Practically extinct in areas with a human population (they have been a food source for many pacific islanders over the years), they can still be found in remote places across the Indian and Pacific Ocean.
With Rodolphe being a professional coconut crab whisperer (among his many other occupations), one night he lead us on an expedition to find these creatures, as they are nocturnal feeders. We followed along with some flashlights and ready to investigate this mystic animal with a taste for ripe fruit and a pair of tweezers one wouldn’t want to get in between. Our mission was successful, and we found several of them that night climbing coconut trees and foraging for some food.
On a more extreme side, in the atoll of Apataki, we had some fun dives with currents hitting 4 knots while dragging us towards the lagoon. What made these dives particularly thrilling was the amount of grey reef sharks in the canyon as we drifted through.
But, without a doubt, it’s the final marine encounter as we were heading back to Tahiti that leaves us with a good memory of our time in the Archipelago.
As shared in their ongoing newsletter, the owners of Seahawk couldn’t have said it better:
“So ends our exploration of the Tuamotu Islands (for now). An amazing six weeks of science and discovery. Many firsts for us including the rare witnessing of a family of Orcas late during the passage to Tahiti. The experience reminds me that dreams realized begin by having dreams and embracing them. In many ways, this is what the “Mighty Hawk” adventure is all about.”
