Last week I was in Mexico for my project Giants of the Caribbean. From late May to early September, off the coast of Yucatan, hundreds of whale sharks feed on zooplankton that consists mostly of the spawn of the bonito. This frenzy also attracts underwater photographers from all over the world; during my stay I had the pleasure of meeting Howard & Michele Hall (renowned IMAX film makers), Louie Psihoyos (director of The Cove), Greg Sweeney, Jim Abernethy, Shawn Heinrichs, Eric Cheng, Douglas Seifert, Adam Hanlon, Marty Snyderman and many others. Both underwater and on land I had an amazing time.
The annual migration of Whale Sharks was discovered by Robert Heuter around 2003, who later described it in his paper ‘An Unprecedented Aggregation of Whale Sharks, Rhincodon typus, in Mexican Coastal Waters of the Caribbean Sea‘. Today, there are around 800 whale sharks in the Yucatan with conventional tags and another 35 are equipped with satellite tags that precisely track their movements. Researchers have compiled a photo database of more than 950 whale sharks that identifies each individual. They have also found that the whale sharks that participate spread out all over the western and northern Gulf of Mexico, and great Caribbean. Some whale sharks where even found to swim all the way down to Brazil!
This year for the first time there were also large groups of Manta Rays present in the feedings. This was particularly exciting for me as I had no expectations seeing any Manta’s (they are one of my favorite animals). It has been suggested by researchers that the Manta’s in Isla Mujeres are actually a third, putative species, the. Manta birostris, that are distinct from the Giant Manta Ray. However, at present there is not enough empirical evidence to warrant the separation of a third species of Manta.
This annual gathering of Whale Sharks and Manta Rays has become a magnet for tourist – as a result during rush hour there can be as much as a 100 boats on the water with a maximum of 2 people per boat allowed in the water at a time. The impacts of these crowds on the feeding behavior of Whale Sharks and Manta’s remains unknown, however tourism may be the only way that these species will survive. After visiting Mozambique in 2003, I have learned that the majority of Manta’s and Whale Sharks are now gone. I am hopeful that the countries surrounding the Caribbean will do a better job at protecting their Ocean treasures, because when managed properly this is a huge asset for tourism and the local economy.