

When whale shark research goes wrong
In the second of his series of articles on whale shark research in Galapagos, Dr Alex Hearn reveals some of the frustrations and difficulties tracking whale sharks in the south of the Archipelago.
I had decided to focus my research efforts on the theory that the female whale sharks we see in Galapagos migrate seasonally between feeding grounds. I looked back through old reports and found that the first ever whale shark in Galapagos was actually observed in the southern part of the Archipelago, earlier in the year.
I also engaged with dive guides and recreational divers, and it seemed that although whale shark sightings in southern Galapagos were rare, when they did occur, it was usually between the months of March and May. I connected with the Inter-American Tropical Tuna Commission, whose observers report interactions with whale sharks, and saw that these interactions were clustered off mainland South America from December to February, but that there was an area to the southwest of Galapagos where most interactions occurred from March through June.
Then, I got a call from some Galapagos National Park Rangers who had been carrying out an aerial patrol looking for a suspected illegal fishing vessel, and had come across several large whale sharks just at the surface, between Isabela and Floreana. I now had three independent sources of information, all pointing to the same pattern. It was time to move.

However, it’s not very easy to get funding to search for a species over such a large area. Working at Darwin island was a walk in the park (so long as you were careful with the ripping currents!). You could pretty much guarantee one to four whale shark encounters every time you jumped into the water at the dive site. In the south of the Archipelago, it was going to be hit and miss. And it was mostly miss.
I tried the tactic of getting folks to report whale shark sightings on our Shark Count app. (By the way, if you are going to be diving or snorkelling in Galapagos, please download and use the app to report your sightings of megafauna, such as sharks, turtles and rays. It helps us understand their seasonal distribution and abundance, and in the long term it tells us how our marine reserve is performing).
In this case, the sharks were always on the move. We spent a frustrating season turning up to dive sites with a tag in hand the day after a whale shark had been seen. This was not working.
I decided to switch to the air. There was no way I could afford an aircraft, but colleagues at work had a fixed-wing drone that they were willing to send out over a large area between Isabela and Floreana. We secured a small fund for a preliminary study, and took the boat to Puerto Villamil and made a makeshift runway on the beach. It was a disaster. As soon as the drone took off, a little piece of something fell off the engine. The drone team informed me that they had lost the ability to steer the drone, but not to worry… so long as it remained in sight, they could fly it! So they spent the next three days flying the drone up and down the beach in the surf zone, while I imagined hundreds of whale sharks sitting offshore and laughing at us.


A decade of tracking whale sharks
Read the first in Dr Alex Hearn’s series of articles reflecting on the past ten years of work tracking whale sharks in Galapagos.
The following year, we headed out on a fishing vessel and brought a rotor blade drone. We spent almost two weeks out at sea, combing the surface for signs of whale sharks. We pretty much came across all the large planktivores except whale sharks!
We were able to follow and tag a blue whale, and count huge numbers of giant mantas around Isabela. Although we came back empty-handed in terms of whale sharks, our expedition did shed light on the amazing diversity and abundance of marine megafauna in the reserve at that time of year.
Our drone pilot, Julio Vizuete, was so enamored by what he filmed that he offered to bring his ultra-light aircraft the following year. Perhaps if we could combine aerial and boat surveys, we would have better luck…?

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Beyond Darwin's Arch
In this exclusive series, Dr Alex Hearn takes us on a fascinating journey to try and discover the secrets of the enigmatic whale sharks which congregate in Galapagos...
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