Whale Sharks In Mexico

Next time you are in Mexico and someone asks you to play with dominoes, you may be in for a very large surprise.  Due to the many white spots that mark their gray bodies, in Mexico the common nickname for  whale sharks is "dominoes."  Indeed these gentle giants do resemble dominoes - very, very large ones, that is.  At up to 48 feet in length and weighing up to 25 tons, whale sharks, or Rhincodon Typus as they are known to scientists, are the world's largest fish.  Despite their enormous size, comparatively little is known about them.  One of the reasons for this is that there are not large numbers of them left in the oceans and for much of the year they are solitary animals.

Whaleshark0025.jpg Less than ten years ago, marine biologists discovered that during the months of June to September the world's largest aggregation of whale sharks takes place off the coast of Mexico's Yucatan Peninsula.  In recent years they can be found north of Isla Mujeres, a small island just off the coast of Cancun.  A smaller number can also be found off of Holbox Island near the northern tip of the Yucatan Peninsula.  Whale Sharks are listed on the International Union of the Conservation of Nature's (IUCN's) Red List of Vulnerable Species, meaning their future is in danger.

Along with Seacology Fellow Daniel Grunberg, I recently visited Mexico to see how Seacology might help protect these mighty creatures.  Our guide was Rafael de la Parra, who used to work with whale sharks for the conservation arm of the Mexican government.  He has participated in whale shark tagging and research for many years.  There are few people in the world who have had more direct experience with whale sharks than Rafael.  As an added bonus Rafael and his son Emilio are great people and great guides (his email is grampusr@hotmail.com if you are interested in a trip!).

For several weeks before our trip, Rafael was giving me reports on whale shark sightings.  One day 30 would be seen, the next day 100, and the following none.  So we had a mix of excitement and trepidation when Rafael picked us up in his boat from our hotel on Isla Mujeres for the 80 minute ride to the whale shark aggregation area.  Would we see any whale sharks?  If so, could we really observe them closely?

Our worrying was for naught.  When we arrived we counted 170 "dominoes" from our boat.  This blew our minds until we came back the next day and counted over 300 of them.  It took us all of 30 seconds to don our snorkel masks and fins and slide into the water.  We were surrounded by whale sharks in every direction, as you can see in the photo above.  All we had to do was wait until a few swam by us.  This never took very long because whale sharks are filter feeders and must always keep swimming with their very wide mouths open both to eat and force water by their gills so they can utilize the oxygen.  

In proportion to their enormous bodies, whale sharks have very small eyes which would follow us as they swam by.  Other than this subtle movement they seemed oblivious to our presence, often swimming just a few feet away from us.  Occasionally while looking in one direction I would turn around in the water to find a whale shark only inches away from me which was rather startling, as you can see in the photo above.  While several whale sharks were swimming by us, Rafael yelled down from his boat "Welcome to my office!"  It is easy to see why he has one of the most enviable jobs in the world and has a wonderful personality to show for it.  But the most satisfying aspect of his work has to be the knowledge that he is helping to protect whale sharks.   Indeed it would be hard not to spend two days with these fantastic fish and not want to help them survive and flourish.  In the course of our two day trip we had many conversations on how Seacology could best help.  Rafael indicated that several times a week huge cargo ships come by this area which does not contain demarcation buoys warning ship captains to stay clear because of the vulnerable whale shark population in the water.   Rafael would like to deploy a series of large state of the art demarcation buoys complete with GPS transponders, etc., which would warn ships to stay clear.  Once these buoys are deployed official navigation charts would also denote the area as a whale shark reserve.

Rafael suggested that if Seacology could come up with half of the funds required for this project many of the local hotels and whale shark tour operators could match this contribution.  Seacology will give this proposal very serious consideration and hopefully will be able to play a role in protecting these majestic but threatened behemoths.  One doesn't have to be an expert in dominoes to connect the dots and see that this would be a worthwhile effort.



The photos here, and at the top of the page, are taken by Seacology Fellow Bob Heil. Above, the massive size of a whale shark compared to a human; right, the impressive whale shark surrounded by a school of fish. 


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This page contains a single entry by Duane Silverstein published on August 12, 2010 10:35 AM.

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