Manta Rays Secrets Revealed Through Satellite Tracking
Researchers don't know much about manta rays, elusive giant fish that can grow up to 25 feet (8 meters) wide, but in an effort to learn more, scientists used satellites to track six manta rays off the coast of Mexico's Yucatan Peninsula over 13 days. The researchers published the results in the journal PLoSONE on Thursday.
"Almost nothing is known about the movements and ecological needs of the manta ray, one of the ocean's largest and least-known species," Dr. Rachel Graham, lead author and director of the Wildlife Conservation Society's Gulf and Caribbean Sharks and Rays Program, said in a statement. "Our real-time data illuminate the previously unseen world of this mythic fish and will help to shape management and conservation strategies for this species."
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Manta rays, also known as the devilfish because of their bat-like appearance, are harmless to humans. They feed on plankton, like many whales do, and lack a stinger like their cousins, the stingray.
The International Union for Conservation of Nature lists manta rays as vulnerable to extinction. Fishermen sometimes inadvertently catch them in their nets, while others intentionally catch them for use as shark bait. Manta ray fins are also used in traditional Chinese medicine.
Researchers found that over the 13-day study period, the manta rays spent only 11 percent of their time in marine protected areas. The majority of their time was spent in shipping lanes, leaving the animals vulnerable to ship strikes, researchers said.
However, what really surprised the team was how far the manta rays travelled in such a short time period.
"The satellite tag data revealed that some of the rays traveled more than 1,100 kilometers [621 miles] during the study period," Matthew Witt, study coauthor and researcher at the University of Exeter's Environment and Sustainability Institute, said in a statement. "The rays spent most of their time traversing coastal areas plentiful in zooplankton and fish eggs from spawning events."
Howard Rosenbaum, director of the Wildlife Conservation Society's Ocean Giant Program, who was not involved in the research, praised the study, saying it can help protect the manta ray population.
"Studies such as this one are critical in developing effective management of manta rays, which appear to be declining worldwide," he told LiveScience.
Researchers said further satellite tracking could give a deeper insight into the elusive species and allow the team to better understand what is threatening the manta ray population.
"While the broader migratory movements of manta rays are still not known," the researchers wrote in the study, "it is clear that satellite tracking technology has the potential to offer great inroads into understanding movements and contextualizing spatially explicit threats to this species."
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