Queen Of Mantas

MY LIFE IN THE BLUE

You Gotta Be Kidding Me – A Third Species of Manta?

September 8, 2010
By Andrea Marshall
Manta-Breach-Holbox_630_465_70

As I write this, I am sitting at the airport in Cancun, Mexico. I have this surreal feeling that something huge just happened to me, but I still cannot overcome the feeling that I am in a dream. Everything just seems a little too bizarre, a little too out of the ordinary.

A little over a week ago, I touched down in Mexico and was given a warm welcome by a fabulous team of Mexican biologists and conservationists. Considering the rural location, I was impressed at both the size of their strong and dedicated team and what they have been able to accomplish out here with respect to their marine protected areas. My heart swelled with hope as I thought about the future possibilities in Mozambique.

Almost immediately, I headed out to the tiny island of Holbox, a world-renowned aggregation site for whale sharks, to meet up with Silvia Hinojosa, the manta research team leader. It was early and I was battered, bruised and a little deflated from the Brazilian leg of my journey, not to mention a week behind schedule. While the scenery surrounding me was breathtaking, I have to admit that my fatigue was starting to get the better of me. But then she uttered four little magic words and my determination was instantly restored, “The mantas are here.”

The next three days passed in a whirlwind. There were mantas, there were tags, there was joy and there was guacamole.  What was this place and why had I never been here before? It seemed like utopia.

After literally months of travel and struggle I had reached payday. Day 1, Mexico, probably the single best day I have spent in the field in two years. If I tell you about it, it will probably seem like fiction, but I will give it a go anyway…

Research kicks off early in the morning in Holbox. The team likes to get out on the water early to avoid competition with tourist boats, which suited me just fine. As we approached the dock at dawn, we were greeted by one of the most spectacular sunrises in recent memory. We may have the best sunsets in Africa…but surly Mexico has the best sunrises. The ocean that day was dam flat. Dam flat. I cannot reiterate this point enough. It was one of the most unusual things I have ever seen, and not because I have never seen the ocean like that before, but because as we started to drive out to sea, the water became flatter and flatter until there was not so much as a ripple on the surface (and we were a good hour offshore at this point). Incredible stuff. I looked at my watch, it was only 7:45 am and I was already overcome with a sense of good fortune.

Holbox-2010_629_469_70Holbox is the manta ray and whale shark capital of the Gulf. Photo © Andrea Marshall

And sure enough, it continued… A few minutes later, like we were in some kind or zoo or game park, Silvia drove straight up to a massive group of feeding mantas, parking the boat a few meters off to the side of them. Imagine that! All over the world I’m diving at specific reefs or offshore rocks, waiting and waiting for mantas to arrive or spending countless hours searching, and we just zoom straight out to sea, with zero reference points, and just park next to 20 feeding mantas. I am still in disbelief.

Fearing my luck would fade, I quickly jumped in. The water was warm and inviting and I felt weightless after diving for weeks in heavy suits and diving equipment in Brazil. Invigorated by the freedom, I swiftly swam over to the pack of feeding mantas. At a distance, my first observation was of the water itself. While crystal clear, the water was swarming with endless varieties of zooplankton (from chaetognaths to copepods) making it slightly difficult to see properly. However, even from a distance, I could see the determination of the mantas trying to siphon up all of the wriggling and zooming animals into their enormous mouths.

I am always awe-struck when I see manta rays feed. It seems so effortless, their technique so efficient, their bodies so well designed. Today the sea was so calm that the plankton reflected off the surface like glass, doubling the appearance of food particles in the water. I could almost hear the manta’s stomachs grumbling. Interestingly enough, much of the plankton was concentrated at the surface and the split vision of my dive mask allowed me to watch the tiny copepods jump clear into the air whenever the water was disturbed (an obvious technique to avoid predators).

While dramatically arching their backs, the mantas propelled themselves forward skimming the upper edge of their elongated mouths across the surface of the water. Their cephalic fins, held wide like enormous paddles on either side of their face, blocked the escape routes of the fleeing plankton. For hours I watched as these manta rays literally gorged themselves on this plankton feast.

And there were whale sharks too! True to Holbox’s reputation, dozens of whale sharks were spotted slowly patrolling beneath the surface of the ocean, their enormous dorsal fins weaving trails in the still surface water.

Amazingly the tourist only appeared interested in the sharks. Dozens and dozens of tourist boats dotted the horizon, each patiently awaiting their turn. Marine park law prohibits more than three people in the water at a time, which helps to reduce the stress on these massive animals while they are feeding in the park. Although most of the boats adhered to this and many of the other rules and regulation for swimming with these animals, I still saw several whale sharks and manta rays with fresh propeller marks, suggesting that, despite their best efforts to protect these gentle giants, there are still a fair amount of boat strikes occurring in the area.

But as amazing as all of this action was, it did not compare to the elation that overcame me as I swam into that first pack of feeding manta rays. For those of you that have been following our work, you may distinctly remember the discovery of a second species of Manta in 2009. If you have heard my lectures or have read our Manta taxonomy paper, you may also recall my proposal of a third species of Manta in the Atlantic.

I initially made this suggestion after a dissection I preformed on an odd looking specimen in a museum archive. This suspicion continued to strengthen after sourcing many photos from Caribbean and North American waters. Something was just not adding up; what I was seeing was neither Manta birostris (the giant manta) or Manta alfredi (the reef manta), it was something else. It was hard to put my finger on the differences at the time, but something was definitely different. I was sure of it.

As I swam into that cloud of feeding mantas on Day 1 in Holbox all of my doubts melted away. I was looking smack into the face of the mystery ray. I had not imagined it, I was not grasping at straws, it was real, it was alive, and it was coming right towards me. It is not often in the life of a scientist that you get a Eureka moment. I have been fortunate enough to have had a few so far in my short career. It is an amazing feeling, a totally indescribable moment (kind of a feeling of peace washing over you mixed with smug contentment, as the elated screams of your internal self claims its righteous victory).

When I finally snapped out of it, I realized I was laughing with delight into my snorkel and the mantas were well behind me. Although I wanted to savour the moment, the scientist in me immediately kicked into gear and I knew that I had to get to work. I had a job to do…and with this newest bit of information I now had a lot more to do than I had initially bargained for…

Despite knowing that I was only meant to satellite tag giant mantas (Manta birostris) on my current worldwide expedition, I could not resist the temptation to put a few tags on this mysterious new ray as well. So, I made a snap decision, and in what felt like an instant, two tags went on. The two rays that I tagged could not have looked more unlike Manta birostris if they tried, both epitomizing the visual appearance of this foreign looking Manta.

I tagged one mature female and one mature male. As with the other mantas in the study, I named them after famous ocean explorers, Streeter (after Tanya Streeter-the no limits free diving champion) and Columbus. Columbus was feisty and did not hang around for long, but Streeter was very tolerant and allowed me to additionally take a genetics sample as well as many photos of her newly attached scientific jewelry!

Meet-Streeter_629_472_70Meet Streeter! Photo © Andrea Marshall

As I inspected her, I marveled at how unusual these mantas were and started to pick up on some of the subtle differences, like their soft skin and their atypical colouration. After spending almost a decade of my life working on these amazing creatures all over the world, it was such a shock, as well as a very pleasant surprise, to be in the water with such a different looking manta. It was a strange feeling, like looking at an old and new friend at the same time.

While it will be still be awhile before we can confirm the presence of a third species of Manta, we are definitely dealing with something unique along the western side of the Atlantic and into the Caribbean. To me this is where the real science and the real fun begin. Are we looking a new species? A new sub-species? A hybrid? Only time and a lot of investigation will tell and I look forward to getting started.

As the days passed in Mexico, I only got more excited about this location and these unusual mantas. They really were very different than any other manta rays that I have ever encountered, both behaviourally and physically. During my time in Holbox, we even came across a few melanistic mantas (the black colour form), which at this location were more charcoal grey than black. Rather than looking like the sleek stealth fighters that I was used to, these black mantas looked more like they had fallen down a chimney than anything else! Even the parasites on the mantas in Holbox were unusual. Instead of the normal clear to white caligid copepods that I was familiar with, they were often riddled with blood red or dark grey parasites. Their skin was literally crawling with hundreds and hundreds of these parasites and with no proper reef systems or cleaning stations in sight, it appeared (due to the scratches all over their skin) as if the manta rays were forced to scrape themselves on the sand itself to remove these annoying stowaways.

But there were some similarities too. I enjoyed watching the Holbox mantas breaching during their feeding bouts just like both Manta alfredi and Manta birostris. No matter how many times I witness manta rays breaching, I never get over how impressive this feat of acrobatics really is… At this location, the mantas seem to always breach twice in a row, usually landing on their backs. The reason for this is unclear, but the resulting splash could be heard from quite a distance and I was reminded of how this behaviour could really be a form of communication between the rays. Again, something else to investigate further in the future.

Amazingly, a few days after my arrival, the manta rays all but disappeared from Holbox. I imagine that both Columbus and Streeter left with the group and are on their way to exploit another plankton bloom down the coast. For the secrets of their journey, we will have to wait patiently for the tags to detach. I, for one, can hardly wait.

Sample-7-Boca-Negra_628_379_70Holbox’s black manta or ‘Boca Negra’ locally! Photo © Andrea Marshall

My entire experience in Mexico was so interesting and overwhelming. As always, I am grateful for the opportunity to have come out to this location and thank the entire team on the ground in Holbox for their invaluable assistance. Once again, I am reminded how important it is to keep an open mind in the field. Anything, I mean anything, is possible and with manta rays I have gotten use to expecting the unexpected!

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