Brazil-based NGO Associação de Pesquisa e Preservação de Ecossistemas Aquáticos (Aquasis) nursed a West Indian manatee named Tico back to health over the course of eight years. Specialists prepared him to release to nearby shallow waters, and in July 2022, he was tagged and released. But what happened after surprised everyone following him. Tico traveled nearly 2,500 miles over 62 days from Icapuí, Ceará, Brazil, to La Blanquilla Island in Venezuela. While some manatees are known to travel hundreds and even thousands of miles, the speed and distance of Tico’s journey were anything but normal.
Aquasis reached out to Woods Hole Oceanographic Institution (WHOI) Physical Oceanographer Iury Simoes-Sousa to help analyze and study Tico’s unusual route. Simoes-Sousa studies ocean currents, and he was able to identify a probable cause for the manatee’s concerning speed and direction: Tico was caught in the North Brazil Current (NBC), a fast-moving, warm ocean current that flows along the coast of South America and is a key feature of the tropical Atlantic circulation.
“Studying his path, we can assume that Tico had a very tiresome journey,” Simoes-Sousa said. “Based on simulations of past sea-state conditions and satellite data, it’s likely he encountered multiple violent storms. The two probable sources of freshwater available to him were the storms themselves and the diluted Amazon River plumes intersecting with the ocean currents.”
At one point, the team tracking Tico began receiving more accurate coordinates from the middle of the journey, leading them to believe that the transmitter remained exposed for a longer period. This could indicate that the transmitter detached from the animal, the animal started spending more time at the surface, or that it was a floating carcass. Throughout Tico’s journey, Aquasis team members were in contact with researchers from different countries, including Trinidad and Tobago, who helped get eyes on Tico utilizing their own resources and networks.
“We received an unexpected email from two fishers near Tobago saying they had spotted a manatee with a tag; we thought it may have been Tico, and we were able to confirm it was, in fact, Tico. We were so happy, some of us cried,” said Aquasis Senior Veterinarian Vitor Luz Carvalho. “By the time Tico reached the Margaritas Islands in Venezuela, he was in poor physical condition. A crew was able to transport him to a local aquarium for the intensive care and rehabilitation he required.”
Tico had lost significant weight and showed signs of dehydration. Technicians in Venezuela administered an enema to address a suspected obstruction, successfully removing a plastic bag from Tico’s digestive tract, which was crucial for his survival. Aquasis experts proposed he be brought back to Brazil for a second round of rehabilitation, incorporating lessons learned from the first release. However, understanding the factors that influenced Tico’s movements was important in making the decision about his fate.
Aquasis leaned heavily on Sousa’s expertise in ocean currents in the months following Tico’s rescue. Sousa analyzed several computer simulations, overlaying playback of Tico’s journey with meteorological and oceanographic data from satellite missions. Everything from the manatee’s breakneck speed to his meanders aligned perfectly with the movement of the NBC and its giant vortices. Because of this detailed report and the expert perspective of an oceanographer, Brazil’s environmental ministry approved an import license to bring Tico home.
It’s a heartwarming victory for Sousa, who says he’s grown attached to the manatee. “This work was really important for me,” says Sousa. “In the beginning, I had the perspective that I was bringing something to Aquasis and Tico, but with time, I’ve realized how much I got from them.”
‘Without the additional perspective of Iury, I am not sure we would have gotten permission to bring Tico home,” said Aquasis monitoring coordinator Camila Carvalho de Carvalho. “The data provided by an oceanographer was critical in being able to tell the full story of Tico’s incredible, and long, journey.”
Sousa is a co-author of the study now running in the Journal of Marine Biological Association.
Not only does the study shed light on Tico’s journey, but it also provides guidance on the importance of ocean conditions for the future release of rehabilitated marine mammals, specifically the West Indian manatee.
