Stingrays living in the Cayman Islands' Stingray City, one of the world's most famous and heavily-visited
ecotourism sites, have profoundly changed their ways, raising questions about the impact of so-called "interactive
ecotourism" on marine wildlife.
Researchers from Nova Southeastern University's Guy Harvey Research Institute and the University of
Rhode Island studied the southern stingray population of Stingray City -- which draws nearly a million visitors
each year to feed, pet and swim with its stingrays -- to assess how the intensive ecotourism has affected the
animals' behavior. "Measuring that impact is important because there's a lot of interest in creating more of these
interactive ecotourism operations, but we know little about the life histories of the animals involved or how they
might change," said study co-author Guy Harvey, who initiated the project.
The results, published last month in the journal PLOS ONE, found that Stingray City's stingrays show distinctly
different patterns of activity than their wild counterparts, who don't enjoy daily feedings or close human
contact. "We saw some very clear and very prominent behavioral changes, and were surprised by how these
large animals had essentially become homebodies in a tiny area," says study co-author Mahmood Shivji, director
of the Guy Harvey Research Institute.
Wild stingrays are active at night and solitary; they forage through the night over large distances to find
food, and rarely cross paths with other stingrays. To see if Stingray City's residents stray from this behavior, the
research team tagged and monitored both wild and fed stingrays for two years and compared their patterns of
movement. They found that fed stingrays swapped their normal nighttime foraging for daytime feeding, and in
contrast to their wild counterparts, began to rest at night. They also didn't mind rubbing shoulders with their
neighbors. At least 164 stingrays abandoned the species' normal solitary behavior, crowding together in less than
a quarter-square-mile of space at Stingray City. They even formed schools and fed together. The fed stingrays
mated and became pregnant year-round, instead of during a specific mating season, and also showed signs of
unusual aggression, biting each other more frequently than their wild counterparts.
These results suggest that human-provided food can dramatically change how even large, highly mobile
ocean animals behave, with potentially serious consequences. "There are likely to be some health costs that
come with these behavior changes, and they could be detrimental to the animals' well-being in the long term,"
Shivji said.
Stingray City means big business in the Cayman Islands, where each stingray generates as much as
$500,000 annually in tourism income. The team plans to continue to monitor Stingray City's population to
track its health -- and the industry's impact -- over time. "Right now, these animals have no protection at all,"
Harvey said. "Without more studies like these, we won't know what that means for the wildlife or if we need
to take action. It's unclear how much of the stingray's daily diet comes from tourism provided food, but the
good news is we have seen the animals forage when tourists are absent, suggesting that these animal are not
completely dependent on these handouts."