Tracking whale sharks in Peru: New friends and new partners

It was time to take stock once more. We had two seasons under our belts, successfully locating and tagging whale sharks in southern Galapagos. As usual, the shark movements were not what we expected, and we were still some tracks away from figuring out the drivers of their behaviour. Our ultralight would never fly again, so our next challenge in Galapagos was to locate the sharks without aerial support. While we evaluated the use of kites, drones and other ways to get us visuals from the air, we could not lose sight of the fact that our work along coastal Ecuador seemed irremediably stalled: we had no aircraft, and safety had become a huge issue – we couldn’t find anyone willing to take us out in boats, for fear of piracy.

The solution would come via a serendipitous virtual workshop where I coincided with Alejandra Mendoza, a Peruvian marine biologist who had spent the past few years developing a whale shark monitoring program with the NGO Ecoceánica, in northern Peru. She works closely with artisanal fishers at Cancas, near the port of Máncora, and they carry out abundance surveys and photo-identification work during the whale shark season, which seems to peak from October through December. Her team were keen to understand the movement patterns of their sharks, and open to collaboration, so Sofi and I programmed our tags and made our way to northern Peru.

When we arrived, we were greeted by a hot, arid environment, calm seas… but very green waters. We wondered what Alejandra’s technique to find the sharks would be. As we walked along the pier to meet the team, blue-footed boobies danced around us: a reminder perhaps that sharks do not have the monopoly on Galapagos connectivity! We recognised a group of folks from our flight, juggling cameras and mikes. Another coincidence – it turned out this was another National Geographic-sponsored team, making a documentary about Ever, the 12-year old younger brother of our fisherman, and how he swims with whale sharks and dreams of becoming a marine biologist.

We hit it off immediately: Ale is a firm but fun leader to work with. Ever and I discovered that we shared a guilty urge for chocolate ice cream as soon as we got back to shore each day, and Chía and the film team were a blast: the Nat Geo Explorer family coming together at its finest! On the last evening, they screened the teaser trailer for us and Ever’s family on the beach.

But what about the whale sharks? Turns out, it’s all about time on the water. Each day, we spent 6-8 hours in our boat, staring out across the water, looking for a subsurface shadow or (if we were really lucky) a fin breaking the surface. I never would have thought it, but it worked.

We had 11 whale shark encounters over five days on the water, and we were able to approach and tag six of them. The sharks were all much smaller than the Galapagos whale sharks – between 2 and 6 metres. They were also incredibly skittish. Once we got into the water and approached them with our mask and fins, we had to be very quick getting the tags on. The results were interesting, but a mixed bag. As the clamps were designed for adults, they sat a bit loosely on the sharks, so our tracks only lasted between 9 and 48 days. However, they gave us some great insights into the movements of these animals.

First – with one exception, they kept to within 20 km of the shoreline. Several moved north and crossed into Ecuadorian waters, and our smallest individual, a 2-metre shark we nicknamed Ever, decided to brave the open ocean. After traveling north into Ecuador, it made a 500km movement in the direction of the Galapagos Islands, before looping round back towards the coast. Ever’s last position was 350km offshore.

So what are our next steps? In 2025 we hope to continue working in southern Galapagos, and to investigate a potential aggregation site out in the western islands. We want to build our collaboration, not only with Alejandra and her team in Peru, but with our newly-found NatGeo film crew friends. We may try to explore the Colombian coast… and we really, really hope that the situation in Ecuador will improve so that subsistence and artisanal fishers can feed their families without fear of having their engines stolen and being left to drift at sea by pirates.

One last thing: we’ve given a lot of thought about how to support Ever. There aren’t a lot of opportunities for kids in his village. We decided to start a crowdfunder so that we can get an English teacher to give him and a small group private lessons. If you want to help us support him, please click here.