t some point every scuba diver dreams of diving with a whale shark (Rhiniodon Typus), the biggest fish in the sea! Like many divers, I traveled the globe for years searching for them but to no avail. I always seemed to hear the same old thing – “you should have been here last week.” In my mind, whale sharks were the “unicorns of the sea.” This all changed this past summer with a trip to Isla Mujeres, Mexico – a place recognized as having the world’s largest aggregation of whale sharks.
Whale Sharks of Isla Mujeres
Story & Photos by Douglas Ebersole
Pg 21 www.UnderwaterJournal.com
Issue 21 - 2011
Isla Mujeres is a small island located due east of off the Yucatan peninsula in Mexico. It is about 8 miles across the Bay of Women (Bahia Mujeres) and still within sight of its neighbor to the west, Cancun. The island is approximately five miles long and one half mile wide at it’s widest point. Legend has it that the island was once recognized by the Mayan people as a sanctuary, dedicated to Ixchel, the goddess of love and fertility. Supposedly, when the Spanish arrived they found a large number of women statues carved in stone in honor of the goddess, and it is from here that the island gets its name “Isla Mujeres,” the island of women. Pg 22 www.UnderwaterJournal.com Issue 21 - 2011
Long famous for fishing, especially for sailfish in the winter months, the island is now promoting ecotourism with whale shark trips each summer. These gentle giants grow to 50 feet (15 meters) in length and can weigh upwards of 27,000 pounds (12,500 kilograms). Local fisherman have known for many years about the whale shark aggregation but ignored them in favor of trying to catch other species of fish. The island’s whale shark eco-tourism began slowly around 2001 with a few local boats taking a handful of researchers and tourists to visit Pg 23 www.UnderwaterJournal.com
the animals. Within two years, the demand to see these beautiful creatures had increased to the point that the Mexican government, along with scientists and tour boat operators, had to put together a set of protocols. The current guidelines are basically that the experience is limited to snorkeling (no scuba); all boat operators must have a permit; only two guests and a guide are allowed in the water at a time; no touching of the animals is allowed; no flash photography and only biodegradable sunblock can be used. Issue 21 - 2011
Meanwhile, scientists from all over the world have also converged on the region to conduct various studies on the animals. There are lots of areas across the globe known for whale sharks such as western Australia, the Maldives, Galapagos and Honduras, but none have the large predictable aggregation found in Isla Mujeres each summer. From June Pg 24 www.UnderwaterJournal.com
through September hundreds of whale sharks gather just north of Isla Mujeres in a sevenmile radius to take advantage of the plankton rich waters created by the joining of the Gulf of Mexico and the Caribbean Sea. Additionally, in July and August there is a bonito spawn, which brings in masses of whale sharks to feed on these eggs at the surface. Issue 21 - 2011
Whale shark tagging data shows the sharks disperse widely after leaving the area – some to the western Gulf of Mexico, others to the northern Gulf near the Deepwater Horizon oil spill site, others to the Florida Straits, and still others to Central America. Bob Hueter, director of the Center for Shark Research at Sarasota, Florida’s Mote Marine Laboratory, has been traveling to Isla Mujeres for several years and has implanted 28 whale sharks with satellite tags.
These tags pinpoint the animal’s movements for a preset period of time until the tags are released and float to the surface. The data is then downloaded via satellite. According to Hueter, tagging data shows the sharks disperse widely after leaving the area – some to the western Gulf of Mexico, others to the...