A photo post from field work in Mexico

Sorry things have been a bit quiet on the blog lately.  Our field work season has reached a crescendo, with several back-to-back trips to Mexico where I and others from Georgia Aquarium are studying whale sharks that aggregate annually in the coastal waters of the Yucatan, and thats left little time for writing.  To learn more about the whale shark project, go here.  Its been a real treat lately, with hundreds of sharks feeding in the area east of Isla Contoy and Isla Mujeres.  Between the boat work, which focuses on photo cataloguing and ecological sampling, and aerial surveys, which focus on counting and distribution, we’ve been gathering a ton of data that will help shed light on why these aggregations form, and how to better protect them in the future.  Rather than write about it, I figured I’d let the pictures do some talking.  Required legalese: all these images are copyright 2010 Alistair Dove/Georgia Aquarium and may not be reproduced without permission.

Flating mats of Sargassum are home to all sorts of things. These baby jacks were seeking shelter from me and caught a red reflection off my rashguardThis is what we came for: a whale shark feeding east of the Yucatan.Any port in a storm: this tiny 2 inch barracuda was hitching a ride with a moon jelly

Most filefish live on rocky and coral reefs, but this one was vigorously defending a little bit of SargassumIts hard not to feel like the whale sharks are checking you out sometimes

Georgia Aquarium senior aquarist Marj Awai wielding the 7D and housing: stills AND HD video *drool*People are the biggest threat to whale sharks. This male had a close encounter with a boat but luckily came away with only shallow scrapes. We see deeper cuts from propellers sometimes, and utmost caution is warranted when moving among the animals.The most common view of a whale shark. Even though they seem to swim effortlessly, keeping up with them is only possible for short distances. This is the last one we’ll see until next years field work season. Adios amigo!

Dancing with a Giant - the reprise

You might remember an earlier post about Dancing with a Giant, in which I was pretty emotional about an amazing swim I had just done with a whale shark in Mexico.  Well I can now share the video of that animal.  There’s a good bit at around 0:50 where you can see right into his mouth, and see the filter pads they use for sieving their planktonic food from the water. In this case, he’s filtering fish eggs, which you can’t see because they are too small and are also transparent; thats good for us though, because it gives us a nice clear view.  Without further ado then, here he is, MXA-181:

Shark Week is here

In the past I've had mixed feelings about Discovery Channel's "shark week".  Its great for raising the   profile of our toothy friends, but it has tended to dwell on the gory or sensationalist stuff in the past.  This year, though, they seem to be pushing the conservation and science end of things a bit more, which of course makes me happy.  Georgia Aquarium (my employer) is their partner this year on the website, and they are featuring the web cam from our Ocean Voyager exhibit, which houses manta rays, whale sharks, lots of other sharks and a great teleost (finfish) collection too.  They're also hosting website Q&A with aquarium shark experts (tonights is at 10PM) after each premier on the TV channel, and vignettes from life working with sharks at the aquarium, including a couple of my lab-coated self.

So if you're into sharks, check it out.  And if you don't totally dig sharks - well, what's wrong with ya? 

If you have to go, go big!

When you want to learn about the biology of a charismatic species, any species really, sometimes you end up learning about the grosser side of life too.  Thats kind of how I came to take this picture last week in Mexico, where I and several others from the team at Georgia Aquarium have been doing research on whale sharks lately (see several other blog posts heareabouts).  It was taken during an aerial survey we did from an altitude of 1,500 ft in a Cessna 206 and shows a whale shark that has just defecated.  Now, whale sharks tend to do everything on a giant scale, so perhaps we shouldn't be too surprised, but I estimate the animal to be between 8 and 11m (25-35ft) in length and so, based on that estimate, thats a cloud of poo behind him thats over 30ft in diameter!  Its unusual to see wild sharks in the act of pooping, but this group of animals was so numerous and feeding so heavily, that you could actually see several clouds like this at any given time.  Whats feeding heavily got to do with it?  Well, unlike mammals, which tend to have a relatively fixed gut passage time for food, a lot of cold-blooded critters can, well, sort of push it out the back end, simply by pushing more in the front end.

Far from being a trivial observation of one of life's less savoury moments, it could actually become a really important research opportunity if we can manage to catch some of that magical egesta in a container of some sort, for analysis back at the lab.   Scientists can do all sorts of stuff with poo, like looking for parasite eggs or other pathogens, sequencing the DNA of both the shark and its prey species, or comparing nutrient values of food (from plankton tows) and comparing them to values from faeces to work out how much nutrition they are gaining from their food.  Its a great way to learn a lot in a short time and do it in a totally non-invasive way.

Mostly though, its a cool photo to gross people out at parties...

Dancing with a Giant

A lot of people think science is soulless, sterile or austere in its objectivity; there’s a prevalent stereotype of the scientist as a lab nerd in a white coat, out of touch with the “real world” and with the more emotive aspects of life. That couldn’t be further from the truth, of course. Most scientists I know – me included - are motivated precisely by a profound wonder and amazement for the natural world around them; its usually why they get into science in the first place. When biologists go into the field, they often end up reconnecting with those feelings, established during their formative years, and end up resorting to a sort of childish state of pure joy over whatever biological phenomenon that they happen to be studying. I just had such an experience, one that was so extraordinary that it may well have changed the way I think about biology forever.

As part of the research program at Georgia Aquarium, we are in Mexico to study the biology of whale sharks, which gather annually in the coastal waters of Quintana Roo, from Isla Mujeres north and west to Isla Holbox. Its bliss just to be out on the water again (its been a while), admiring the everchanging seascape, marveling at the myriad forms of life that make their home in the ocean, and reminding yourself that the endless stream of doom and gloom news about “the environment” isn’t really the full picture. Flying fish skip from wave crest to wave crest, pursued by sinister-looking frigate birds that swoop in to grab them on the wing, while turtles lazily periscope their heads above the surface to spy on pods of spotted dolphins that race around as if there were somewhere important that they really needed to be.

In due time, we found our objective, a group of whale sharks feeding at the surface, attended by a flotilla of ecotourist boats. Each of our team had a chance to swim alongside these spectacular behemoths as they were cruising effortlessly among the boats and patches of food, at speeds that exhausted a mere human to match.  We also photographed many of them for an identification database.  Then we took some time to gather data on the physical and chemical properties of the water, during which the ecotour boats petered away, returning their cargo of tourists to their respective all-inclusives in time for lunch and leaving us with the whale sharks mostly to ourselves. They continued to feed, constantly inhaling bathtubs of plankton from the surface tension, their gills flapping loosely on the rejected water current like flags in a gentle breeze.

It was at this point that I got in the water a second time. Rafael, our captain and colleague from Project Domino, had put us on a large animal that was feeding below the surface in a more vertical pose than their normal surface “ram filtering” style. This more upright type of feeding, which they use when food is especially dense, sees their tail sink down towards the bottom and cease its rhythmic swinging and, hanging suspended like this, the animal begins to actively suck in enormous gulps of water. In this state I was able to approach the animal much more closely, a large male, and to see how each pulse of that fantastic mouth was pulling in not only water but tiny silver vortices of air down from the surface, such was the force of suction. He was suspended like this for what seemed like an eternity, but was realistically perhaps 15 or 20 minutes, during which he continued to feed and appeared completely indifferent to my presence. I was able to swim over every part of his massive frame and inspect every detail, from his tremendous girth to the creamy white belly distended with food, and from the remoras that pestered his every fin to the tiny copepod parasites grazing across his skin like herds of hoofstock might roam a savannah.  His body was home to a veritable community of hangers-on. I watched his eye roll carelessly over me while he continued to inhale vast amounts of water and plankton, all of which disappeared into that cavernous mouth with its 20 jet-black filtering pads. We continued to dance together like this – or rather I danced around him - close enough that I could have reached out to touch him at any point, until with a tiny shake of his head and a hefty sweep of his tail he was done with the meal and headed off in search of another patch to vacuum, leaving me breathless from a cocktail equal parts exertion and exhilaration.

Back on the boat I did my best to relay to the others what I had just experienced. Despite apparently talking “a mile a minute”, I struggled to find the right words, but they were probably unnecessary anyway. Certainly everyone who had been in the water with the animals that day had experienced many of the same feelings, and I am sure they were writ large on my face (in big black and white spotted letters!). In swimming with this one particular animal, I experienced a profound connection with a truly spectacular natural phenomenon, one that will provide ample motivation to continue the search for a better understanding of the nature of such things, for long into the future.  These are the moments that launch and tie together a career in biology, and that was the best one I have ever had.

The latest from the Whale Shark Festival in Isla Mujeres

I am down here with other folks from the aquarium as well as other scientists, government folks and ecotour operators for the 3rd annual Whale Shark Festival in the beautiful Yucatan location of Isla Mujeres.  Here's some short videos that might give you the flavour of whats been going on.

Here's Beatrix and Rafael de la Parra from Proyecto Domino explaining the importance to Isla Mujeres of whale shark movements to and from Utila in Honduras.  The audience is mostly ecotour operators and members of the public.  Bob Hueter from Mote spoke about threats to whale sharks, while Darcy Bradley from ECOCEAN talked about their program and I chimed in for a talk on whale shark research at Georgia Aquarium

Check out this inflatable whale shark from the festival parade - that thing is made of awesome!  Later that night they illuminated it from the inside and it watched over the stage show and the Ms Whale Shark awards, where they elected a grandma as queen of the festival!

This is Teatro del Mar, and educational puppet show that Amigos de Isla Contoy have shown to thousands of school kids to improve ocean literacy.  The kids were completely rapt!

And I couldn't resist putting in this clip of turtle hatchlings at the state run hatchery in Isla Mujeres.  There's a lot of problems there with beach erosion and disturbance, so when turtles nest, they excavate the eggs and bring them to the hatchery, where they have a cool fenced off area where the eggs are reburied and incubated until they hatch.  Warning, cuteness overload a distinct possibility...

You can follow along on Twitter too

Fieldwork here we come!

Things will probably get a little irregular around here over the next couple of weeks.  I'm part of a group of Aquarium folks leaving for Mexico tomorrow to participate in the Whale Shark Festival on Isla Mujeres, just near Cancun, followed by some intensive field work with colleague Rafael de la Parra, who you may remember from previous posts.  We'll be tagging animals, photographing their spot patterns for the ECOCEAN project (their spots are like fingerprints!), collecting plankton samples and sampling the chemistry of the water to look for differences where they are feeding and where they are not.  I'll try to post some stuff as we go along, even if its only a picture or a video here and there (there wont be much time for writing, unless the weather closes us out)

All of this is part of our partnership called Project Domino, which aims to understand and protect whale sharks in Mexican waters.  Its bigger than that, however, because many of those same animals travel from the Yucatan to the Caribbean, the West Atlantic and the Gulf of Mexico; sharks dont pay attention to sovereign borders.  Obviously concerns are running high for any animals that travel into the GoM, due to the Deepwater Horizon disaster.  Keep your fingers crossed that those animals avoid the affected area and that this latest attempt to cap the wellhead is successful.

Whale shark news roundup

Photo: Bruce Carlson/Marj Awai

There’s a heck of a lot going on in the world of whale sharks right now, so I thought a news roundup was in order.

Blogger GrrlScientist has a nice blog post up about whale sharks right now, over at Scientist Interrupted

Sad news about a whale shark that was trapped in fishing nets in Pakistan and died. I have no idea what the scientist is talking about when he describes them as “inefficient swimmers”; as far as we know they are paragons of efficiency. I also have my suspicions about whether this animal was actually dead when it was brought back to shore. In a different story about the same event, it described the animal as being alive when the fisherman found it, tail-looped it and dragged it back to the beach, and how its illegal to fish for them, but legal to use them as you like if they die accidentally, hmmm....  Without witnesses, I guess we'll never know.

Our collaborator Bob Hueter from the Shark Research Lab at Mote Marine Laboratory is following an animal dubbed Sara in the Gulf of Mexico, who has been affixed with a real-time satellite tag. So far she is avoiding the worst affected area of the BP oil spill, which is a relief. Follow her movements here.

Unfortunately, other whale sharks don’t appear to be avoiding the pollution. NOAA scientists last week observed whale sharks among ribbons of surface oil, not 4 miles from the Deepwater Horizon wellhead. If whale sharks are unable to avoid the oil, it’s a potential disaster because the anatomy of their gills and filter-feeding apparatus are superbly susceptible to fouling, as I discussed in a recent blog post.

One of my projects is getting a bit of press this week. Georgia Aquarium has entered into a collaboration with the Core Sequencing Facility at Emory University to start sequencing the genome of the whale shark. It’s a huge job, but the lab at Emory, led by Dr. Tim Read, are up to the task! They’re using Roche 454 pyrosequencers to generate a survey sequence right now, from DNA we isolated in the lab at the aquarium. Its exciting stuff and was picked up on the AP wire. Read an example here, or just google “whale shark genome emory”

University of Southern Mississippi research Eric Hoffmayer was lucky enough to observe an aggregation of about 100 whale sharks off the coast of Louisiana last week, accompanied by legendary marine explorer and Nat Geo guru Sylvia Earle.  Eric has been working with that population for some time, but as far as I know thats the most he's ever seen in one place.  Lets hope they are animals avoiding the oil spill.

And, finally, the 3rd annual Whale Shark Festival is scheduled to get underway in Isla Mujeres, Mexico, next Friday the 16th.  I'll be there with other scientists including Bob Hueter and Rafael de la Parra, talking publically about whale sharks in the Gulf and the other amazing marine biology of the Yucatan.  There's also going to be a film festival and cultural activities highlighting Quintana Roo.  Did you know that "shark" is one of the only English words with a Yucatec Indian origin?  Its comes from the Mayan "Xoc".  Hope you can join us!

The water is ALIVE!

Its easy to get discouraged about the plight of marine ecosystems and the future of all those incredible marine species that we love so much. This is especially so of late, with all the bad news about the oil spill in the northern Gulf of Mexico and the impacts that it may well have on several habitats. Consider this post, then, as your good news story for the week. I am here to tell you that there is still amazing stuff to see in the ocean. Incredible stuff. Stuff that will blow your mind. I can tell you this with supreme confidence, because for the last two days, that’s exactly what I have been seeing. As part of the research program at Georgia Aquarium, I am with colleagues in Quintana Roo, Mexico, studying whale sharks and other species that live in the azure waters of the Yucatan peninsula. Jeff Reid, who is the aquarium’s dive safety officer, is here and our main colleague in Mexico is Rafael de la Parra of Project Domino, who has been working on whale sharks and other marine species in the area for many years. This is a remarkable part of the world, with a lot of great terrestrial activities (can you say Cenotes, anyone? No? How about Mayan ruins?), exceeded only by the marine life, which is truly spectacular.

Yesterday Jeff and Raffa and I spent the day boating around the northeastern tip of the Yucatan along with videographer Jeronimo. Now, when you’re on a boat, you can only see a small strip of ocean either side of the vessel, and yet over the course of the day we saw lots of mobula (devil rays), turtles, flying fish, manta rays, spotted dolphins and whale sharks. We snorkeled alongside some of these animals and, in the case of whale sharks and mantas, took samples of their food for later analysis. They dine on the rich plankton soup of this tropical upwelling area, much of which consisted of fish eggs, which hints at other fish species – yet unseen – taking advantage of the plankton to start their next generation by spawning in the surface waters. Snorkeling next to a whale shark in the natural setting was a special thrill; I’ve been lucky enough to work with the animals in the collection at Georgia Aquarium since 2006, but this was my first encounter with them in the wild. Except for the slightly different “faces” (we do get to know our animals pretty well) and the parasitic copepods visible on the fins of the wild animal, it could have easily been the very same sharks Jeff and I have been working with in Atlanta.

Today, Jeff and Raffa and I joined Lilia (from the Mexican department of protected areas CONANP) and pilot Diego for an aerial survey of the waters around the northeastern tip of the Yucatan. In contrast to the boat, you can’t get in the water from a plane (its not advisable anyway), but you can see a whole lot more at once and cover a much greater area in a relatively shorter time. From the air, lots of sharks, cownosed rays, manta, dolphins, fish schools and whale sharks were all visible, and I am told that flamingos and manatees can be seen at other times too. The manta rays, which numbered in the hundreds, were especially impressive and included at least two species (see my post about taxonomy of mantas). The sheer number of cownosed rays, called chuchas in the local slang, was staggering (muchas chuchas, if you will). They formed huge schools that looked for all the world like the rafts of sargassum weed that accumulate on the wind-lines at the water’s surface offshore. Many of the turtles and mobula seemed to be in the mood for love; most turtles were in pairs (or a pair being followed by other hopeful males), whereas the mobula followed each other in lazy tandems, their wingtips breaking the surface with every stroke. Whale sharks were also there – lots of them – with their attendant flotilla of tourist boats and tiny orange specks of snorkelers in life-vests, doing their best (and largely failing) to keep up with the gentle giants.

When you have experiences such as those I have shared with my colleagues over the last two days, you are reminded why we do this stuff in the first place. Its not just for the papers, or the salary or the glory of new discovery (yeah, right!), its for those moments working with animals when you and a colleague become friends because you shared an experience of the oceans that most folks will never have. We should seek to share and recreate those moments with everyone we can, whether its in an aquarium or on the open ocean. I am pretty sure that if we could all do that, then public empathy for the plight of the oceans would skyrocket, and many of the threats that face them would be addressed quick smart.

Whale sharks start to give up their secrets

Whale sharks are the largest fish in the oceans; they can grow to 20m in length and weigh many tons, although 7-9m is closer to the common average these days.  Despite their tremendous size, scientists don't know that much about them.  We know that they eat plankton and that they live in the tropical oceans throughout the world and there have been quite a few papers reporting their presence in different waters, but these represent only the most basic foray into the biology of a species.  More recently, there's been a few more including one that explores genetics (Castro et al., see below) and some that have started to explore behaviour (see Brunnschweiler et al.).  Up to this point, the focus has all been external; that is, only the biology that can be observed from the outside.  That's no surprise really; its a logical place to start and there are some huge logistic challenges to working with whale sharks, as you can probably imagine.

There are 4 whale sharks in the collection at Georgia Aquarium in Atlanta and I have been lucky enough to work with these amazing animals since 2006.  Part of that work has involved veterinary examinations, which has allowed us, for the first time, to look at aspects of the internal biology of whale sharks. The first part of that work is now in print: a paper I co-authored with the aquarium's principal clinical vet, Dr. Tonya Clauss, and a colleague from National Aquarium in Baltimore, Jill Arnold (Jill is an expert in medical techniques, especially blood work), which is in the latest issue of Aquatic Biology.  Our paper is a discovery-based one (i.e. not testing a specific hypothesis) about the nature of the blood of whale sharks, both the cells and the chemistry of the blood serum.  Its open access, so you can get it at the journal web page here

In it, we show that whale sharks have blood that is fundamentally similar to that of some other sharks, specifically the bottom dwelling ones like nurse sharks and wobbegongs, but pretty different from the toothy predatory sharks like great whites.  They have very large red cells, actually white cells too, but this is something they share with the bottom dwellers, so it appears to be a feature of the group rather than a function of the size of the whale shark as such.  Whale sharks are the only pelagic members of that group, the order Orectolobiformes.  Why such large cells, then?  Our study didn't answer that question, but my best guess is that they have relatively low metabolism compared to the carcharhinids, which may need the high relative surface area of smaller red cells to improve the movement of oxygen in and out of cells.  This is the first of several hypotheses that we can only begin to pose because of these first discovery-based efforts.

I can't tell you how excited I am that we can begin to share what we've been learning at the Aquarium.  The chance to work with whale sharks is a real gift for a fish nerd like me, and the opportunity afforded by having access to them in the more controlled environment of an aquarium makes it possible to do safely and effectively research that has been prohibitively difficult with free-ranging whale sharks up to this point.  Of course, the ultimate goal is to extend that work to compliment the field research, and I look forward to telling you more about that in future posts.

Brunnschweiler, J., Baensch, H., Pierce, S., & Sims, D. (2009). Deep-diving behaviour of a whale shark during long-distance movement in the western Indian Ocean. Journal of Fish Biology, 74 (3), 706-714 DOI: 10.1111/j.1095-8649.2008.02155.x 

Castro, A., et al. (2007). Population genetic structure of Earth's largest fish, the whale shark ( )
Molecular Ecology, 16 (24), 5183-5192 DOI: 10.1111/j.1365-294X.2007.03597.x 

Dove, A., Arnold, J., & Clauss, T. (2010). Blood cells and serum chemistry in the world’s largest fish: the whale shark Rhincodon typus Aquatic Biology, 9 (2), 177-183 DOI: 10.3354/ab00252