Key takeaways
- Drone footage revealed constant violations of Mexico's whale shark tourism rules, even when far fewer boats were on the water than regulations allow.
- Surprisingly, infractions increased when many whale sharks were present, as boats spread out and accountability broke down.
- The findings raise broader questions about whether popular wildlife encounters - from manta rays and sea turtles to whales and even elephants - are truly "ecotourism" and highlight the need for stronger monitoring and community-led stewardship.
By John Dudley, University Communications and Marketing
A new study led by University of South Florida biologist Lucas Griffin has found that tour boats and swimmers routinely violate Mexico's whale shark tourism rules - even when the waters are far less crowded than the law allows.
The research, based on drone footage from 2016 and 2022, suggests that one of the world's busiest whale-shark destinations is struggling to manage the boom in demand, and that the world's biggest fish may be paying the price.
Despite their size - adults can reach nearly 60 feet long - whale sharks are known as gentle filter-feeders and are vulnerable to human distractions that could disrupt their feeding patterns.
Whale shark off Mexico's Yucatán coast [Photo courtesy of Jessie Bujouves]
Boats circling whale sharks off off Mexico's Yucatán coast [Photo courtesy of Kim Ovitz]
The findings are newly published online in the Journal of Sustainable Tourism.
Griffin, the study's senior author, first recognized the scale of the problem several years ago during a family trip to Mexico with his father, Curtice, a biologist at the University of Massachusetts Amherst and a co-author on the paper.
"We were on a whale shark tour and watched multiple groups of snorkelers converging on a single whale shark," he said. "It was chaotic, and it was clear something wasn't working."
USF biologist Lucas Griffin
That experience led to a formal study of what happens during peak tourism weeks at El Azul, a 400-square-kilometer aggregation site off Mexico's Yucatán coast.
Using drones to observe boat behavior, swimmer interactions and the number of whale sharks feeding at the surface, the team documented hundreds of rule violations - from boats maneuvering too close to the animals to swimmers touching sharks or crowding within prohibited distances.
At the time of the study, Mexican regulations limited each whale shark to a single boat at a time and allowed only two swimmers and one guide in the water, all of whom must stay at least five meters from the shark's head and tail.
"We knew it was already pretty hectic, so we knew that our results were going to come back showing that," Griffin said.
What they expected held true: More boats and more tourists led to more infractions. But one finding surprised them.
"What we weren't expecting was that when there were a lot of whale sharks, infractions actually continued to increase," he said. "That's a bit counter to what we would think."
The team found that when dozens of whale sharks were present, boats tended to spread out and pursue individual animals rather than following an orderly rotation. In theory, this should relieve pressure. In practice, it reduced accountability.
"When there are a lot of whale sharks around, no one is really watching one another," Griffin said. "Every boat ends up with its own shark to do as it pleases, and any sense of peer pressure or mutual enforcement just breaks down."
Boat among whale sharks off Mexico's Yucatán coast [Photo courtesy of Andy Danylchuk]
Even more striking, violations were widespread even when boat numbers were far below the regulatory cap of 120 vessels. The study recorded a maximum of 82 boats in 2016 and 68 in 2022 - yet drones still captured constant rule-breaking.
The presence of a patrol boat also made little difference. With so many vessels spread across a large area, effective oversight was difficult, and swimmers often had no idea that enforcement was nearby.
"If we're disturbing them from their feeding behaviors, that could be energetically expensive," Griffin said. "You'll also see a handful of prop scars on these whale sharks from being run over."
Large shipping vessels passing through the region can also strike sharks, he said, though the extent of this impact is still being studied.
For local communities, whale sharks are more than wildlife - they're a cultural touchstone and an important economic driver. Tourist demand has skyrocketed since the early 2000s, and giant murals, sculptures and even community nicknames celebrate the species.
That's why the researchers stress that while government oversight is important, top-down rules are only part of the answer.
"Certainly more enforcement, and more continuous enforcement, would help," Griffin said. "But it really comes down to self-regulation within the guiding community."
While tour guides and boat captains already receive training, he added, "Clearly maybe some more involvement needs to be taking place."
The findings also matter beyond whale sharks. Griffin argues that the study reveals a broader blind spot in wildlife tourism, which is often marketed as environmentally friendly.
"When you really break it down, is it actually harming the species and can it be called ecotourism?" he asked.
He added that similar questions apply across wildlife tourism worldwide, from manta ray and sea turtle encounters to whale-watching and even elephant attractions. He emphasized that any solution must also support the local communities that rely on whale shark tourism, both economically and culturally.
Rafael de la Parra, a conservation scientist and local whale shark guide who is a co-author on the paper, says the study's findings underscore the need for both tour operators and tourists seeking a once-in-a-lifetime whale shark encounter to recognize their roles in keeping the animals safe.
Rules for how to safely and responsibly view whale sharks are commonly found on tour operators' websites. The operators are required to complete a government-approved training workshop that covers not only regulations but also the biology and ecology of the animals. Operators are also expected to verbally communicate guidelines to tourists on their boats.
"The key is choosing responsible operators who clearly explain and actively enforce current guidelines," de la Parra said. "More broadly, tourists should think of themselves as stewards of these animals. Maintaining your distance and respecting their space ensures these encounters remain sustainable for future generations."
He suggests asking operators upfront about group sizes and how they maintain proper distances from whale sharks.
Like de la Parra, Griffin sees promise in approaches that combine better monitoring tools - such as drones - with deeper community collaboration. He pointed to other Mexican regions where co-developed codes of conduct and operator-driven data collection have improved compliance, noting that progress is underway within local whale shark tourism.
But such solutions require resources and long-term investment. Local agencies already "are doing all the right steps and working towards that, including drones to help monitor activity," Griffin said. "But it's challenging because they simply don't have the financial resources to fully support these initiatives."
Griffin said the team is now turning to accelerometer-based tags - tools that record fine-scale movement - to measure how tourism disturbances affect sharks' energy use and long-term health.
"Can we quantify those actual disturbance metrics now?" Griffin said. "We haven't solved that piece yet."
The research was conducted in partnership with the University of Massachusetts Amherst and Rafael de la Parra, a conservation scientist with Ch'ooj Ajuail AC and local whale shark guide. Other co-authors include Hoa T.T. Ninh, Curtice R. Griffin and Andy J. Danylchuk (University of Massachusetts Amherst); and Kimberly L. Ovitz (University of Manitoba).
