54,700 Kilometers: Whale Shark Completes Record-Breaking Journey

A whale shark roaming the waters of the Caribbean and the Gulf of Mexico logged more than 50,000 kilometers in ten years, the longest journey ever documented for a shark.

Oceanic Odyssey

Named Milo, this 8-meter-long male Rhincodon typus has been closely tracked by researchers since 2017. In the following year, the shark vastly surpassed Bermuda Island, and in 2020 pushed its Atlantic exploration much farther north, even beyond the latitude of New York.

In 2019, 2021 and 2022, Milo favored the Gulf of Mexico, moving along the coasts of Mississippi, Louisiana and Texas, before heading, as each year, toward the Yucatán Peninsula.

While whale sharks are reputed to be rather solitary creatures, they do gather off the coast of Cancún, in what scientists regard as one of the largest seasonal aggregations known for R. typus. In 2009, an aerial survey revealed the presence of around 420 individuals in a zone of barely 18 square kilometers.

Taking advantage of the upwelling of nutrient-rich tropical waters, they can spend months feeding on zooplankton, small crustaceans and fish eggs, and are often joined by other giants of the seas, such as manta rays.

Flexible Whale Sharks

To precisely document Milo’s peregrinations, researchers relied on both the data from his satellite tags, changed five times, and on his unique arrangement of skin blotches, comparable to our fingerprints. The roughly 54,700 kilometers traveled provide a remarkable glimpse into the species’ flexibility, alternating between long migrations and extended stays in the same regions.

« They are evidently as at home in the ocean depths as in coastal waters », notes Guy Harvey, of Nova Southeastern University. « Long-term studies like this are essential to understand the life cycle of these animals with such remarkable longevity. »

As whale sharks are currently listed as Endangered by the International Union for Conservation of Nature, these data also prove valuable for guiding conservation efforts.

Previously, a study had revealed that whale sharks were able to regrow damaged tissues identically.