UP CLOSE: A snorkeller gives a kick of the flippers right in front of the nose of a whale shark off the Yucatan Peninsula of Mexico.
By Franz Smets
A unique spectacle of nature takes place every the summer off the Yucatan Peninsula in south-eastern Mexico. Every morning, hungry whale sharks numbering into the hundreds rise to the water’s surface in search of food.
Meanwhile, thousands of adventure-hungry tourists board more than 200 boats heading for the teeming feeding grounds off the islands of Holbox, Contoy and Mujeres near the Mexican resort of Cancun.
Equipped with snorkelling gear, they go into the water to swim with the whale sharks, the largest fish in the sea at a length of up to 16 metres.
The health consequences for the whale sharks are unknown. As for the swimmers, they have nothing to fear. Whale sharks are docile, slow-moving filter feeders that scoop up plankton with their colossal gaping mouths.
The Yucatan Peninsula separates the Gulf of Mexico from the Caribbean Sea. Where their waters mingle is one of the world’s most bountiful feeding grounds, according to Mexican marine biologist Francesco Molina.
Upwellings of cold, nutrient-rich water lead to plankton blooms that attract all with a taste for the tiny plants and animals: whale sharks as well as sardines, tuna, marlins, dolphins, sharks and manta rays.
While whale shark tourism is fairly new to Mexico, the whale sharks aren’t newcomers.
“Fisherman have long known about the whale sharks, but didn’t catch them because they used them as orientation in casting their nets,” said Nacho Peon, a whale shark tourism pioneer on Isla Mujeres. “They knew that where there are whale sharks, there are also plankton and lots of other fish.”
The first tourist boats set out in 2002 for the gentle giants north of the islands of Holbox and Contoy off the northern tip of the Yucatan Peninsula. Conditions then were heavenly, with just three or four boats and no more than 40 tourists daily. But the days when more or less professional divers could be alone with the amiable whale sharks are gone.
Today, there’s an armada of more than 200 boats, packed most days with up to 2,300 tourists in all. On a good day, the tours bring in revenues of as much as 400,000 dollars for the boat firms. According to Mexico’s Environment, Natural Resources and Fisheries Ministry, whale shark tourism has directly created about 750 jobs.
Trips to the “dominoes” — the fishermen’s name for the whale sharks because of the light spots on their back — have become one of the biggest attractions in the Mexican Caribbean from May to September. The sharks are easy to locate, because their dorsal fins and tails stick out of the water.
Generally solitary creatures that feed mainly on plankton and fish eggs, whale sharks live in tropical seas around the globe. In other parts of the world they are lured with food so that tourists can see a few. This isn’t necessary off the Yucatan Peninsula, where Mexican marine biologist Rafael de la Parra counted 420 of them in a single aerial survey in 2009.
“It’s the biggest aggregation ever sighted worldwide,” he said, adding that the biggest aggregation of manta rays he had seen there was about 350. But he is concerned about the effects of tourism.
“Having too many boats there is disturbing the whale sharks,” de la Parra said. On some days, the sharks are veritably mobbed. “The fish are good-natured. They don’t let individual snorkellers stop them from feeding. Basically they’re gigantic suction machines that filter the tiny plankton.”
If people touch the animals or a boat bumps into them, however, they descend into deeper water, he said. This reduces their feeding time.
“An insufficient diet impairs the animals’ ability to grow and to multiply,” warned Francisco Remolina, former director of Isla Contoy National Park, where swimming with whale sharks is part of the tourist programme. “This endangers both the whale shark and manta ray populations.”
Mexican authorities are considering ways to organise whale shark tourism so that the animals aren’t harmed, fishermen earn a good living and the tourism industry flourishes.
“That’s the challenge,” said Mari Carmen Garcia Rivas, the national park’s current director.
The likely solution is a reduction in the number of licences for whale boat captains — and consequently in the number of boats and swimmers — as well as strict enforcement of rules of conduct on the open sea.
“When the maximum number of licences have been handed out, that will be it,” said Garcia, adding she hoped this could be implemented.
Remolina has his doubts, as the licences are issued by various agencies “and the decision-makers are in Mexico City.” The Mexican government, he said, bears a great responsibility.
“If we fail to protect the animals and their unique ecosystem, it would be a world-class disgrace.”
