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.
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
firstname.lastname@example.org 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.
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.