March 19, 2013
Socialized Stingrays Develop Unnatural Habits Compared To Wild Counterparts
Brett Smith for redOrbit.com - Your Universe Online
Interactive ecotourism where people can mingle with traditionally wild animals can be big business, sometimes bringing millions of dollars to a local economy. Yet despite the educational and financial opportunities that ecotourism provides, very little study has gone into the long-term impacts on the animals that inhabit these attractions.
A team of American biologists has decided to see how Stingray City, an ecotourism site in the Cayman Islands where tourists can feed and swim with stingrays, is affecting the habits of its main aquatic attraction.
"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 Guy Harvey, a marine biologist from Nova Southeastern University who initiated the study.
According to the report by Harvey and his colleagues in the open access journal PLOS ONE, the feeding and social habits of the stingrays are being greatly affected by their interactions with tourists. Wild stingrays are typically nocturnal and solitary, often traveling long distances to forage for food.
"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," said study co-author Mahmood Shivji, a professor at the Nova Southeastern University´s Oceanographic Center.
To better understand how Stingray City affects the animals´ behavior, the research team tagged and tracked the approximately 164 stingrays that are allowed to swim freely at the tourism site. The researchers also tracked and collected data on several wild stingrays to use for comparison.
An analysis of the data showed the fed stingrays had almost completely foregone their natural nighttime foraging for the daytime food offered by the tourists. Instead, the animals at Stingray City began to rest at night during the times when they would normally be feeding in the wild.
The tourist-fed stingrays were also more social, bunching closely together in a square quarter-mile of space at Stingray City. Some stingrays were even seen forming schools and feeding together. As familiarity often breeds contempt, these socializing stingrays also demonstrated an unusual amount of aggression, biting each other far more frequently than their wild counterparts.
The researchers also noticed a shift in the animals´ reproductive habits, as they mated and became pregnant year-round. By comparison, wild stingrays typically only breed during a specific mating season.
The team concluded the unnatural socialization and feeding regimen of Stingray City was having a profound impact on their behavior, one that could have long-term 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.
Any proposed changes to Stingray City´s operations will likely be met with heavy resistance, as the park brings in about $500,000 per animal each year, according to Harvey. The team does plan to continue monitoring the fed animals to continue studying the impacts of interactions with human visitors.
"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."