Rio Lady had no idea the valuable legacy she left in her path as she glided through the cold upwells of the Caribbean Sea on her 150-day journey to the mid-Atlantic Ocean, just south of the equator, in what scientists believed was to give birth.
"When we saw her, she had a thick mid-section, so we had an idea that she was pregnant," John Tyminski, a Mote Marine Laboratories biologist and co-author of nine-year study of the behavior of whale sharks, said Thursday from his Sarasota office.
When the team of international scientists started the collaborative study in 2003 to record the behaviors of the largest fish in the world, they had no idea of the broad migration of the whale shark, Tyminski said.
The study has not only garnered valuable insights into the whale shark's behavior, but also has cemented a respect between several countries, including Cuba, Mexico and the United States.
"(Working on this study) has crossed political boundaries with a main goal of learning more about the gentle giants of the ocean," he said. "We all worked together because the whale shark doesn't abide by state or local boundaries. In a sense, they are ambassadors for all of us."
This Mote-led study shows that whale sharks found at a major feeding hotspot near Mexico's Yucatan Peninsula traveled to many places throughout the Gulf of Mexico, the northwestern Caribbean Sea and the Straits of Florida, just north of Cuba. Tyminski said on occasion the sharks have made their way into the waters surrounding the Florida Keys, despite the shallow depths.
"There have been several sightings in Marathon over the years," he said.
The study also documented the second-longest whale shark migration ever confirmed -- a trail that may help researchers discover where the female sharks give birth.
The project was centered off the Mexican state of Quintana Roo, on the northeastern Yucatan Peninsula. Coastal waters there host rich plankton blooms -- a feast for the filter-feeding whale sharks, which frequent the area from May through September, Mote explained in a press release.
As many as 420 whale sharks were observed during a single airplane survey, making this the largest known feeding aggregation of whale sharks on Earth.
From 2003-2012, project scientists studied these big eaters by fitting 813 sharks with ID tags and examining underwater photographs of 956 sharks to document their unique spot patterns, which serve as fingerprints and allow them to be individually identified.
Both methods allowed scientists to recognize the sharks if they were found in other areas. The researchers also attached electronic satellite tags to 35 whale sharks -- the most ever outfitted with satellite tags in one study, scientists said.
They were able to track the sharks' movements beyond the feeding site, recording the temperatures and depths of the places the animals traveled. These tags automatically released from the sharks anywhere from two to 190 days later, floating to the surface, sending data to the Mote scientists via satellite.
The results were amazing, Mote scientists said.
"They went all over the place," said study leader Robert Hueter, director of the Center for Shark Research at Mote Marine Laboratory in Sarasota. There is also a Mote office in Summerland Key, but it was not involved in this study, Tyminski said.
A large number of the sharks moved from the Yucatan Peninsula to other parts of the Gulf of Mexico, as far north as the Mississippi coast, and at least three satellite-tagged sharks visited waters off Cuba, the study found.
"Rio Lady's trek was a huge finding for us," Hueter said. "She undertook the second-longest migration ever confirmed for a whale shark, and she moved into an extremely remote area of open ocean where, we suspect, she gave birth to her young."
One thing's for sure: These fish are international travelers -- a fact that matters for conservation.
"Considering that these whale sharks wander in the Gulf of Mexico, the Caribbean and the Atlantic Ocean, it is fundamental to have regional collaboration in order to establish proper regional management," said Rafael de la Parra, who co-authored the study while working with Mexico's Proyecto Domino of the federal agency CONANP, and who now leads the nonprofit organization Ch'ooj Ajauil AC to continue his work on whale sharks.
Whale sharks are classified as "vulnerable" by the International Union for Conservation of Nature's Red List of Threatened Species. This list is recognized as the most comprehensive, objective global approach for evaluating the conservation status of plant and animal species.
Like many oceangoing animals, whale sharks worldwide face threats including boat strikes, net entanglement, habitat alterations and even too much pressure from well-intended ecotourism.
Moving forward, Mote scientists and collaborators in the U.S. are beginning work with Mexican and Cuban colleagues to help establish a linked network of areas to protect whale sharks throughout the Gulf and Caribbean.
At home in Florida, for Tyminski and his colleagues, there is so much more to learn.
"We need to study the 'big girls' pupping ground," he said. "It is very intriguing as to why the older females go off to different parts of the oceans than their male counterparts and younger females. We know they eat about seven to eight hours a day, but we don't know why the females go to remote areas and the males congregate together somewhere else."