August 30, 2012
Provided by: Dr. Al Dove
Director of Research and Conservation at Georgia Aquarium
People: It’s time to celebrate the stipple, marvel at the maculate and party for polkadots, because August 30th is International Whale Shark Day! What, you didn’t know there was an official day on the calendar dedicated entirely to Rhincodon typus? Well now you do, so let’s get the party started…
Why have a Whale Shark Day? Why NOT, I ask you? Because it's spectacular spotted behemoths. Because it's peaceful proof that sharks are not lethal predators. Because it has the thickest skin of any animal. Because they are filter feeding SHARKS. Because they are ten times bigger than the biggest bony fish. Because they are the largest fish In. The. World. Because whale sharks, that’s why!
OK, maybe I get a bit carried away, but I hope you’ll indulge me one day out of 365. For a marine biologist like me, the opportunity to work with whale sharks in the Georgia Aquarium collection and in our main field location in Mexico has been the privilege of a career. Just 20 years ago we knew almost nothing about the world’s largest shark, largest fish of any kind, and in the relatively short history of Georgia Aquarium we’ve been able to contribute significantly to a veritable explosion of new research about this amazing animal. Here’s some highlights:
The 300. With our colleagues from Project Domino, we’ve documented the largest aggregation of whale sharks anywhere in the world, by far. The afuera aggregation east of Isla Contoy in Yucatan Mexico can sometimes have over 300 whale sharks gathered in one place at one time, dispelling the notion that whale sharks are solitary species. We published the description of this incredible natural phenomenon here and I wrote more about it here. It blows my mind to think that whale sharks may have been gathering there since T. rex was roaming the Yucatan jungles, not tourists.
Nom nom. The Aquarium’s staff nutritionists have worked with researchers from Mote Marine Lab and the University of South Florida to describe the diet of whale sharks in two sites in Yucatan Mexico, as well as the anatomy of the amazing filtration pads they use to separate their food from the water in that giant mouth of theirs. The efficiency of that filtration leaves the great baleen whales in the dust, but then, they’ve had tens of millions of years longer for evolution to perfect it (whale sharks were around at least 60 million years ago, whereas baleen whales came along less than 20 million years ago).
It’s in the blood. I wrote a paper with one of the aquarium’s veterinarians and a colleague from National Aquarium in Baltimore, describing the blood cells of whale sharks. They’re big cells to be sure, but it doesn’t have much to do with the size of whale sharks. Instead, it seems to be a feature of the group to which they belong, most of which are slow metabolism bottom dwellers.
ACTG. Emory University researchers are helping sequence the genome of the whale shark. That is, all the letters in the DNA code that lies in the nucleus of every cell. There’s probably 7 billion of them (letters that is, not cells), so it’s going to take a little while. When we’re finished, we’ll understand more about how the human immune system works. That’s because sharks were the first group of animals to evolve antibodies. If you want to know where you are, it helps to know where you came from.
We’ve got chemistry. I’ve worked with chemists and physicists at Georgia Tech to work out what chemicals are in whale shark blood. Knowing this helps us to look after them better, by telling us what to look for in order to monitor their health. It’s also a chance to use cool tools like Nuclear Magnetic Resonance Spectroscopy (magnets, how do THEY work??)
Best behavior. When people think of behaviour research, they usually picture monkeys, apes or maybe dolphins doing complex cognitive tasks, but we’ve been asking scientific questions about whale shark behaviour with our colleagues from Georgia State University. Whale sharks won’t be playing chess with us anytime soon, but we have been learning that perhaps they are smarter than we’ve given them credit for, and certainly capable of marked individualism (“personalities” so to speak). To appreciate this, you just have to slow down and watch them quietly for much longer than you would with one of those high-strung mammals.
What’s the point of all this research, you may ask? Fair question, to which I have two responses, one for the Descartes fans and one for the Bacon fans (in other words, pure science and applied science, respectively). In terms of pure science, we’ve really started to build a nice and diverse body of knowledge about the world’s biggest fish. We’re learning new things every day and when you do that, you can’t help but appreciate the subject more with every new discovery. Whale sharks are incredible animals and they deserve our attention and respect. They are true ambassadors for the ocean, majestic and peaceful and capable of inspiring wonder, curiosity and awe in young and old alike. In terms of applied science, we’re delighted to contribute our research results towards better conservation efforts for whale sharks, and all species with which they share the pelagic zone, like manta rays, mobula, tuna and dolphins. The Mexican Government used our data to help establish the Whale Shark Biosphere Reserve, a sanctuary for whale sharks in the northern Yucatan. We’re not finished either. After all, isn’t that what it’s all about? Understanding and caring for our oceans and the spectacular diversity of life that makes them home.
If you live in the Atlanta area or can get here easily, I invite you to come by and see the whale sharks in Ocean Voyager. If you can’t make it, just grab some dominoes (the official game of whale sharks, naturally) and play a round or two dedicated to our giant spotty cousins on this, International Whale Shark Day.