Tagged whale sharks traveled nearly 10,000 miles since summer

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WhaleShark - credit George Schellenger

Whale sharks are known to be nomadic, but the recent travels of two tagged whale sharks raises questions about the lifestyle of the world’s largest shark species.

Male whale sharks Milo and Lucho were tagged last summer near Isla Mujeres, Mexico, by marine biologist Rafael de la Parra, director of the Ch'ooj Ajauil AC.

The sharks have made nomadic journeys of nearly 10,000 miles and are both now swimming in the same place where they were originally tagged nearly eight months ago. Both sharks were tagged with fin mounted satellite SPOT tags in an unprecedented feat – while de la Parra swam with them underwater.

This study of whale shark migrations is being undertaken in collaboration with Nova Southeastern University’s Guy Harvey Research Institute. The ongoing journeys of these and other whale sharks can be followed online in real-time here.

Milo’s journey is the longer of the two, first swimming east deep into the Atlantic Ocean past Bermuda and returning near the tagging site in February. Then he took a month-long excursion into the Gulf of Mexico, returning close to the tagging site once again, logging more than 7,000 miles.

Lucho left in late August on a 2,713-mile swim through the waters surrounding the Cayman Islands, Cuba, Jamaica, Haiti and the Turks and Caicos Islands before turning around and travelling to the coast of Honduras. From there, he made his way home to the tagging site by Isla Mujeres in late December. Three months later, he’s still there.

“Tagging these whale sharks on their fins with SPOT tags was a scientific coup,” said Mahmood Shivji, Ph.D., the director of NSU’s GHRI and a professor in the university’s Halmos College of Natural Sciences and Oceanography, in a statement. “Rafael did an incredible job getting this done. The direct satellite communicating technology of these SPOT tags provide much more accurate tracks of the shark migrations compared to the traditionally used, data archival satellite tags, which have a lot more positional error associated with them.”

A whale shark study by the GHRI and collaborators from the Maldives Whale Shark Research Programme made news in 2018 when the data showed that whale sharks can live as long as 130 years and may grow as large as 61.7 feet on average — nearly 17 feet longer than a school bus and three times the length of a Great White Shark.

“Unfortunately, whale sharks are currently on the endangered species list, so revealing their migration behavior allows us to better understand, conserve, monitor and effectively manage shark populations,” said Greg Jacoski, executive director of the Guy Harvey Ocean Foundation, which is helping fund this research.

A new documentary chronicling whale sharks will be released this month by Dr. Guy Harvey. Available on Amazon.com, "This is Their Ocean: Sea of Life" is hosted by Dr. Harvey’s daughter Jessica and follows the adventures of two students as they swim with whale sharks off the coast of Mexico.

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