Coming down to the Mexican Caribbean this summer? Have your own National Geographic experience, a memory to treasure for a lifetime and something special to tell your family and friends about, swim with the whale sharks, the world’s largest fish. True ocean wanderers, these gentle giants are found in a handful of spots around the world such as Fiji, Australia, Indonesia, Honduras and Baja California Sur, and in the summer it’s the turn of the Mexican Caribbean to welcome them as they gather here to feed.
From mid-May to mid-September, whale sharks (Rhincodon typus), gather in the northern waters of the Mexican Caribbean off the island of Holbox and in the ocean deeps to the east of Contoy and Isla Mujeres. What draws the world’s largest fish –they can measure up to 40 feet long– here? The answer is food! They are filter feeders and swim on the surface with their jaws open swallowing the plankton that is plentiful in the summer as the water heats up, rather like mammoth vacuum cleaners. But local marine biologists have also discovered that these gentle giants are rather partial to fish roe, in this case to the eggs of the little tunny which spawns here during the summer.
Sightings of over 200 whale sharks have been recorded in one day in the area and scientists believe that the Mexican Caribbean hosts the largest whale shark feeding aggregation or gathering in the world. The largest whale shark gathering here to date was registered in 2009, a staggering 420 of these creatures in one place on one day!
Known as the tiburón ballena in Spanish, local fishermen also refer to the whale shark to the pez domino or domino fish due to its dappled grey or dark blue skin. Biologists working in the Mexican Caribbean use the distinctive markings to compile catalogs of individual fish sightings. When divers encounter a whale shark they take a photo of a patch of skin behind the gills and above the left pectoral fin. The pattern of dots and stripes recorded does not change or fade with age and can be used to identify individual fish, almost like a fingerprint. These photos are uploaded to an international data bank to help track the shark. The location of the fish is recorded with a GPS reading and the findings are used to monitor whale shark movements. Some whale sharks are even being marked with a satellite sensor to study migration patterns.
Whale shark movements are still wrapped in mystery and scientists have much to learn about this enigmatic species. They are known to move from the Gulf of Mexico into the Mexican Caribbean and south to Belize and the Bay Islands in the Gulf of Honduras during the year, and some have even been tracked to Brazil. Other whale shark aggregation zones are Ningaloo Reef off the coast of Australia, Fiji, the Seychelles, Madagascar, the coast of Mozambique and Tanzania, India, Philippines, Belize and the Sea of Cortez, Baja California Sur.
For nature lovers, divers and seafarers, a whale shark sighting is the highlight of a summer vacation in the Mexican Caribbean. From the moment you spot fins on the surface of the water and watch as a whale shark glides serenely past the boat to the emotion as you enter the water and watch a creature the size of a bus approaching you, culminating in a feeling of peace as you swim beside these beautiful creatures and share their watery world, the whole experience is unforgettable.
Your knowledgeable eco guide will tell you about whale shark feeding habits and behavior during the boat trip out to the whale shark area and point out other marine creatures. You might spot dolphins, sea turtles, manta rays leaping from the water, flying fish and a variety of seabirds.
There are two whale shark feeding grounds in the northern Mexican Caribbean: the sea between Holbox and Cabo Catoche where the Gulf of Mexico meets the Caribbean, and la zona de afuera, a stretch of deeper “blue water” to the east of Contoy and Isla Mujeres where boats will venture on calm days. Part of the area has been declared a marine biosphere reserve by the Mexican government.
Thomas More Travel offers whale shark trips during the season, for more information and reservations check www.thomasmoretravel.com or ask at the tour desk at your resort.
Whale Shark Conservation
As with all sharks, the whale shark is threatened with extinction. In other parts of the world it is hunted for its fins and at risk from boat collisions, pollution and the impact that climate and ocean changes may have on its food sources. In the Mexican Caribbean, the number of boats taking visitors out to the whale shark feeding grounds is strictly limited to protect them. Biologists are concerned that the presence of too many boats may stress the fish, interrupt their feeding patterns and cause them to move elsewhere. They have noticed that they tend to dive deep when several boats gather in the same place.
If you swim with the whale sharks help protect them by following these rules:
• Keep a distance of 16 feet between you and the whale sharks as you swim alongside them
• Do not touch them
• You will only be permitted to enter the water with your guide, two people at a time. Follow the guide’s instructions carefully
• Enter the water slowly and carefully, do not jump
• No flash photography when taking pictures of whale sharks
• Do not apply sunscreen, oil or any kind of lotion the day you are due to swim with the whale sharks. Use a t-shirt to protect you from the sun instead. This rule also applies whenever you go snorkeling or diving, as the chemicals on your skin are harmful to corals and marine life.
• Don’t forget your camera, take water and a hat
A tip for visitors who are prone to seasickness, Dramamine or ginger tablets are recommended, as there may be a swell especially en route to the “blue water” east of Contoy.
Whale Shark Festival, Isla Mujeres
If you are interested in learning more about whale sharks, the latest research findings and conservation initiatives underway around the world, don’t miss the Isla Mujeres Whale Shark Festival, July 18-24.