Monitoring Mediterranean Monk Seals: Greece, 2019

Latest update July 2, 2019 Started on June 12, 2019

Marine biologists are unanimous: the Mediterranean monk seal is a highly threatened species, yet their numbers seem to be increasing. The development of new tools may be useful to scientists that study this magnificent marine mammal.

June 12, 2019
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In The Field

Is there a better way to finish a field mission ? If there is, please tell us..

As the three autonomous monitoring systems were now working, with almost daily monk seal pictures, we decided to try and collect outstanding footage. To reach this goal, our resourceful photographer imagined a “photo-trap”. Under his underwater camera, on a tripod, he installed a large mirror, with the hope that a curious monk seal would find it interesting. Then, he set up his trap with a specific time lapse designed to last for several hours. Then, it was only a matter of installing the trap in a strategic location, and patiently wait.

Did it work ? Yes… yes it did…

Our work here is now done. It’s time to go back home, and monitor the three different caves to collect valuable data. We will come back here in a few months to share the ongoing results.

Thanks for the support !

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After the exhausting yet gratifying work of yesterday, we took a day off to explore the beautiful surroundings of Kefalonia.

Our diving guide from Fiskardo Divers took us to an undisclosed location, where an underwater amphora field can be visited. This area was probably used as a mooring site hundreds of years ago, as several boats must have sunk to produce such wealth in archaeological remains. The crew was happy to dive on this beautiful site, and have a break from installing autonomous monitoring systems in the harsh Greek sun.

Once back on dry land, we checked our FTP server, only to see that a monk seal had just now visited “our” last cave, less than 24 hours after the camera installation !! What a thrill !

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Today was the most important day of the entire expedition: the plan was to install a camera deep in a marine cave, where sections are completely underwater.

The whole crew was engaged, with specific gear, such a full diving equipment, a ladder, waterproof bags, powerful underwater torches, speleology devices etc.

The “surface team” arrived on location by car and foot and a “cave team” arrived by boat.

Everything was carefully planned over the past few days. The aim was to stay as little as possible in the cave in order to limit the nuisance for the wild animals.

Early in the morning, the “cave team” went for a reconnaissance dive and took pictures and videos that were analysed by the whole crew. There was no room for error. Once in the cave, there was only a little hole through which to communicate with the “surface team". This is also where the camera and cable were sent to the “cave team”.

Inside, in almost complete darkness, it took them hours to collect all of the cable and bring it to the far end of the cave. There the camera was fixed to a support on the rock. Finally, outside, the other end of the 90m long POE cable was plugged into the electronic system. Instantly, we had a live view of the interior !!

Once the camera was firmly in position and correctly angled, the “cave team” collected all the gear, and exited the frigid and dark waters to emerge once again in the Greek sun.

Without the divers’ exceptional competences and experience, this challenging task would have never been accomplished in such a short period of time. We feel very proud of the work done today.

We know have a total of 6 cameras (3 interior and 3 exterior) running 24/7, sending approx. 600 photos daily. The expectations are high !

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Our reparations from yesterday all went well, so that the fully functional solar panels can be once again installed on location.

We thus went hiking to the remote electronic boxes and worked four hours under the strong Greek sun. Luckily, the temperatures aren’t too high this early in the season.

In the evening, we all prepared our gear for tomorrow: we will attempt our most difficult camera installation, and everything needs to be well coordinated !

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This morning, we hiked to the location where we installed our second prototype in 2018. There, we found much more damages than at the first location.
The main problem came from the solar panel’s cable, which was damaged to the point where no electricity could reach the battery. Thus, the latter probably died months ago. We also found that one camera wasn’t responding at all, and it took us ages to figure out that the Raspberry Pi’s SD card also died some time during the winter.

By upgrading the system with the new battery and charge controller, and changing the Pi’s SD card, we were able to relaunch the system. We headed back to the center with the damaged solar panel, and will come back in the following days with a replacement camera.

There are now approximatively 500 photos that are uploaded to our FTP server each day, that’s a lot of data for such a short period of time ! We are working on groundbreaking ways to automatically deal with these monthly gigabytes while extracting the valuable data for scientific studies.

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We’ve got some photos of seals on our autonomous system ! What a surprise, only four days after installation.

With this great news in mind, we left Ithaca and sailed to Fiskardo, on the island of Kefalonia. Upon arrival, we were greeted by Cédric, long time friend and owner of Fiskardo Divers ( This award winning diving school is in part responsible for the incredibly clear waters of the iconic Mediterranean port, organising yearly clean-ups and various eco-friendly programs. Cédric is a biologist who has been in contact with monk seals for many years now, and he helped us install our autonomous monitoring systems in 2018.

In the afternoon, we hiked to one of the locations in order to check how our first prototype had resisted the harsh Ionian winter. The results weren’t too bad ! A bit of rust here and there, and only a few cables were damaged. We upgraded various components such as a bigger battery and better charge controller. Straight away, the system was back online for the first time in many months. The damaged cables were taken back to the center for repair. We now have two operating kits !

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In the morning, the rainy weather forced us to stay mostly inside. We took the opportunity to sort out the hundreds of gigabytes of footage and prepare the gear for the next few days. This will save us some time, as it's now all well organized.

Luckily, in the afternoon, the sky cleared. George took us for a tour of Ithaca that ended at a stunning lookout of the legendary island.

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Beautiful imagery, like always.

On Ithaca, we met with Georges Lilas, founder and owner of “Odyssey Outdoor Activities” ( ).
Through his center for travel adventures, George is in contact with approximately 500 kayakers and 500 more scuba divers each year.

He always takes the opportunity to explain the luck we have to live in such a beautiful location, where dolphins, monk seals and all kinds of animals can be seen. This privileged relationship he develops with people visiting from the whole world makes him one of the strongest advocates of wild species’ protection, and the best practices we all need to adopt when traveling to touristic destinations.

We take the opportunity to thank him for his dedicated job, and are looking forward to working with him in the following years.

During the afternoon, he lend us kayaks in order to explore a small piece of the coast of Ithaca, and check out what could possibly be a cave used by monk seals. Kayaks are great tools to spot wildlife, as they are silent and move quite slowly.

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During the night, a local fisherman anchored next to us. We started talking, and he agreed to take us in the morning to retrieve his nets, and talk a little about the state of the Ionian Sea, the fish stocks, the monk seals etc.
He proved to be quite philosophical, and very photogenic as well !

After photographing and filming more monk seals in the morning, we decided that the hard drives were full enough, and that the autonomous system was performing well enough without our maintenance.

We decided to set sail, and a few hours later, we docked in Vathy, on the mythical island of Ithaca ! Have a look at this great article:

Our evening meal, entirely made from the fresh fish caught by our friend the fisherman in the morning, was absolutely delicious.

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These monk seals are so fast underwater, it’s quite unbelievable !

Thanks to our fleet of aerial drones, we were able to film at least five distinctive individuals today. Most of the time, they peacefully swim around, checking things out. On several occasions though, we were lucky to witness two young ones playing along the coast, very close to rock pools that seem to be a prime location for fooling around.

We also put an underwater action camera in a strategic location, and let it sit for several hours. The result left us speechless.

Regarding our autonomous system, it’s running smoothly. We are still fine tuning several aspects, as it will soon be left on its own for the next months (or years?).

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This video is great. I can't believe how quick they are!

Many success today !

The autonomous prototype is installed and functioning to its full potential. We are already receiving the first inside and outside pictures, and it’s looking promising.

We also saw and photographed many monk seals. We still don’t know if it’s only a couple of very active individuals, or if there are many more who currently navigate in these waters. There is at least one large female that has distinguishable marks on her back, and we are looking forward to seeing if it’s possible to photograph her over several days.

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The real adventure begins at last ! With the help of favorable winds, our faithful sailing boat took us in no time from Lefkas to our undisclosed destination in the Ionian Sea.

Unfortunately, we are not at liberty to indicate where the monk seals are. There is a real risk that with this information, tourist operators will begin sending too many boats with people eager to see the animals with their own eyes. The truth is that this threatened marine mammal has been hunted to the brink of extinction, and therefore is fearful of man’s presence. Too much hassle can cause many problems, such as mother’s abandoning their pups, animals panicking or simply leaving the zone, never to be seen again. It’s not a surprise that for the past decades, the remaining individuals have chosen secluded and hidden marine caves to rest and give birth. They certainly don’t enjoy all of this sudden attention.

That being said, there are currently sailing charters and tour operators that play a very important role in raising awareness about the monk seal’s dire situation. Even though the boats packed with snorkelers regularly come to this location, the owners ask the tourists not to approach the caves and stay in a well defined area for a short period of time. This ensures that the animals are not disturbed. We witnessed with our own eyes that with this sort of practice, the animals don’t seem to mind the presence of man. Hopefully, most of the tour operators will adopt these kinds of best practices, and not only with monk seals, but with all of the marine and terrestrial ecosystems.

Let’s all fight for better touristic future, with less impacts on the places we love to visit !

Now, back to our expedition: we were lucky to experience calm weather for our first day on location. This allowed us to start installing the autonomous monitoring system. We also spotted our first monk seals, and there seems to be more individuals than last year at the same period. It all looks very promising for the next few days.

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After visiting the Ionian Dolphin Project in Vonitsa, the whole crew headed to Lefkas marina to prepare for the field mission ahead.

The whole day was dedicated to prepare and stock the 40 feet sailing boat, in order to welcome a crew of 7 with diving equipment, filming gear, water and food for several days.

We also spend several hours building the wood box where all of the electronic devices will spend the following months (or years?), hopefully sheltered by the scorching Greek summer sun and violent winter storms.

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For our first day in the field in Greece, we met with Joan Gonzalvo, Project manager and Science coordinator of the Ionian Dolphin Project (IDP)

This Greek NGO, based in the lovely and calm little town of Vonitsa, is our scientific partner for our 2019 Monachus monachus project.

Joan will be in charge of building, installing and supervising our third autonomous monitoring prototype. We were received in the IDP’s field station, where eco-volunteers come every summer (April to September) to help survey coastal dolphins and monk seals in the Inner Ionian Sea archipelago (more info here: )

Starting from scratch, and with the help of our detailed manual, Joan managed to assemble the various components in order to test the fully functioning prototype.

The next step will be to install it on location !

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For this new mission in the Ionian Sea, the Octopus Foundation took all the lessons learned during last year’s project (see: Working all winter in Lausanne, Switzerland, we greatly improved our autonomous and open-source prototype.

We also developed a strong partnership with the Ionian Dolphin Project, whose scientists have regularly been in contact with monk seals over the past decade.

Together, we decided to install our upgraded monitoring system on an isolated islet.

In 2018, our goal was to have a system running for 6 months. Encouraged by this success we chose new components in 2019 that should allow us to have a functioning system all year round. That’s the theory. We very well know that in practice, things don’t usually go as planned.

We’ll keep you updated all along our 2019 mission to Greece, on the tracks of the marvelous Mediterranean monk seal. Stay tuned !

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Expedition Background

The monk seal is an emblem of the Mediterranean Sea.

Hunted to the brink of extinction, these intelligent and sociable marine mammals are today getting a second breath. Their numbers seem to be growing, and individuals are once again seen in places where they were thought to have completely vanished.

The Octopus Foundation develops and tests new tools that could help scientist gather precious data on this elusive animal, still considered to be the most threatened marine mammal in the world (according to the IUCN's red list).

In the Ionian Sea, the crew will sail to remote places where monk seals are known to gather in calm months. The aim is to test and validate the use of cutting-edge open-source and affordable tools for the study of these animals.


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