﻿Do whale sharks go to cleaning stations? Coming up, the Blue World team travels to
the Galapagos to investigate! Welcome to Jonathan Bird’s Blue World!
The Galapagos are an exotic place. Of course almost everyone has heard of the
endemic land tortoises, perhaps the most famous resident of the Galapagos. But in my opinion,
the most amazing Galapagos residents live in the ocean.
There are marine iguanas, that dive down to feed on submerged algae.
There are vast schools of fish that thrive in the nutrient-rich waters. And in the
northern Galapagos, where the water is warmer, schools of hammerhead sharks and
really big whale sharks—the largest fish in the world.
Today, the Blue World team is heading north towards Darwin Island, probably the single
greatest place to see really big whale sharks. MAP/ANIMATION The Galapagos
are located 600 miles off the coast of Ecuador, practically right on the equator. We fly to the
main airport on San Cristobal Island and then sail 150 miles north to reach Darwin Island.
Darwin is completely uninhabited by people, and in fact we’re not even allowed to go ashore.
We will eat, sleep and dive from a live-aboard boat. A
few hundred meters from the island stands a structure formerly known as Darwin’s Arch. In
2021, erosion took its toll and the arch collapsed. Now we call it Darwin’s Pillars.
The dive site lies just this pile of rocks. My favorite ocean dive site in the world!
With our home base parked in the lee of the island,
we take the inflatable boat over to the pillars for the dive. Julia and I discuss the plan.
Underwater: a plateau of rocks, with a drop-off into deeper water.
There’s a tiny patch of coral here and there, but mostly the rocks are just covered in barnacles.
We settle down on the plateau, with a good view out over the blue,
and wait. We need to relax and go easy on our air supply.
It’s easy to get distracted by marine life. A sea
turtle comes by. There are a ton of sea turtles in the Galapagos.
And the aptly-named Heiroglyphic hawkfish stands its ground as I go in for a close-up. But we try
not to be too distracted because if we want to see the big stuff, we need to keep an eye on the blue.
If we relax and watch carefully, we’ll be ready when a big school of scalloped hammerheads passes
by. The trick with hammerheads is to stay on the wall, keep low, and breathe gently,
trying not to scare them. It’s hard to believe, but scalloped hammerheads are afraid of scuba
bubbles. If you swim out into the blue to get closer, they vanish in a flash. After the
school of hammerheads passes by, we go back to waiting and watching. If nothing shows up
by the time our tanks are getting down to about half pressure, we may elect to swim out into the
blue to see if there is anything just beyond our visibility. And while we are out there
swimming around, we are drifting with the current, either out to sea, or back towards the island,
depending which way the current is running. Every once in a while we get lucky when a
shape emerges from the distance—and that shape takes the form of a whale shark!
By whale shark standards, she is barely swimming, her tail gently swishing back and forth. But for
us humans, it’s all we can do to keep up, with our fins flailing furiously in hot pursuit. We
often see absolutely mammoth whale sharks in the Galapagos. In this encounter, I ask Zach to swim
over and get in the shot, swimming directly above the shark so he could illustrate the
scale of the animal at the same distance from the camera. The huge distended belly of this female
shows that she is pregnant. In fact, most of the whale sharks we see at Darwin Island are large,
pregnant females. It seems like they might come here to give birth, but nobody really knows.
What an encounter! In another
crazy encounter, we’re following one large animal just off the wall by the pillars,
when a second whale shark comes in to see what we’re up to!
After excitement like that, you just can’t help but scream: Whale sharks!
The next day, we hit the water, head down the wall,
and immediately catch a glimpse of a whale shark deep down below.
As I swim down the rocks at the base of the wall, I can see that the shark is swimming in place,
like she is on some kind of an aquatic treadmill. She is swimming into the
current at the exact same speed the water is moving, so she stays in place over the rocks,
but the water goes through her gills so she can breathe.
I stop at about 80 feet. She is still at least 30 feet deeper, but I don’t want to
frighten her off. I’ll observe from a distance to see if I can figure out what she is doing.
Todd is hanging back a little further, so he can film the encounter.
From my vantage point close to the shark, it almost looks like she is hovering over the
rocks to attract the attention of cleaner fish. Hammerheads do it all the time here,
but I don’t know of anyone ever witnessing a whale shark at a cleaning station. Unfortunately,
I am just too far away to see. I need to sneak up a little closer.
So down I go. Just to be clear, I’m not actually sneaking up on a whale shark. She can see me, and
she certainly can hear my noisy bubbles, so she is well aware of my presence. But if I approach
very slowly, maybe she won’t swim away. Now only perhaps 20 feet from the shark, I can see that she
is in fact another very large pregnant female, and she is absolutely holding her place on the reef.
The current is strong. I need to hang on to the rocks. But she is
casually swimming exactly the right speed to stay in place.
I move even closer. I still don’t see any sign of
cleaning going on. But I am getting an amazing view of a huge whale shark!
Then the shark starts to rise up above me. I’m below the thermocline,
in cooler water and the shark has risen up above it, into warmer water, so my view of the shark
becomes distorted. Light gets bent when it goes through water at different temperatures--which
have a different index of refraction. It’s the same thing we see with haloclines in caves.
As I’m now at more than 100 feet and my air is getting low, I need to start thinking about
heading up. So I decide to ascend to the depth of the shark, and try for a close-up view. I
swim up to the massive pectoral fin and settle in behind it. Now I’m kicking hard to stay in
place. But I’m amazed by the size of her gill slits. They’re as tall as me! She’s huge!
It’s hard to describe what it’s like to swim with an animal this large.
But it’s also just incredible that these enormous fish are completely harmless to
people--absolutely gentle animals. Who can resist a selfie with a whale shark?
At last however, with all that kicking combined with my depth, I need to head back up to the
surface. So I relax and begin to fall back. The shark isn’t swimming away, I’m being carried away
by the current. Back at the surface, I am ready for pick up in the inflatable. What a dive!
The Galapagos are a magical place, and Darwin Island is one of my favorite dive sites in the
whole world. Every time I visit, I see something new and mysterious. This trip was no exception.
Was the whale shark actually being cleaned? I will never know, but the behavior certainly
looked like it. It’s just another wonder in the Blue World for a guy with such a cool job.
Hey you guys! Check out that video! It’s a really good one!
Also this one’s pretty good too! Oh and don’t forget to subscribe!