Hundreds of sharks seen mysteriously gathering off the coast of Brazil. Take a look
Hundreds of sharks gathered off the coast of Brazil, attracting the attention of divers and scientists. A video shows the mass of ocean predators mysteriously circling.
Free divers plunged into the Alcatrazes Archipelago Wildlife Refuge, a marine park near São Paulo, on June 20 to record a “large aggregation of silky sharks,” according to a study published Nov. 4 in the peer-reviewed Journal of Fish Biology. The gathering had been spotted by chance three days before.
About 130 feet underwater, the divers found the silky sharks circling. Most of the predators stayed at a distance while a few swam relatively close to the divers, the video shows.
Researchers reviewed the footage and counted between 250 and 300 sharks, mostly silky sharks but a “few” hammerhead sharks as well. The animals ranged in size from about 2.5 feet to about 10 feet “with the smaller ones being more numerous.”
The purpose of the shark aggregation remains unknown, but researchers consider the behavior important.
Shark aggregations are a known but poorly understood phenomenon, researchers said. These mass gatherings could be for “reproduction, predator avoidance, improved feeding efficiency” or something else entirely.
The silky shark aggregation in June was a first-of-its-kind sighting for the Alcatrazes Archipelago Wildlife Refuge and “reinforces the importance of the Refuge in protecting different stages of the silky sharks’ life cycle,” the study said.
Silky sharks, scientifically known as Carcharhinus falciformis, are “long and slender” sharks named for their silky-looking skin, according to the Florida Museum. These sharks generally live in warm “open water away from shore and surface” and travel in groups.
Silky sharks are “among the top three species targeted in the global shark fin trade” leading to “population declines worldwide,” researchers said. The species is considered vulnerable by the IUCN and critically endangered by Brazil’s Ministry of the Environment.
The silky shark aggregation lasted for several days before the animals disbanded, the study said. Researchers suggested further surveys and monitoring of the species.
The Alcatrazes Archipelago Wildlife Refuge is off the coast of São Paulo, a city in southeastern Brazil and a roughly 270-mile drive southwest from Rio de Janeiro.
The research team included Ana Laura Tribst Corrêa, Thayná Jeremias Mello and Carolina Ferreira Candido.
This story was originally published November 11, 2024 at 6:10 AM with the headline "Hundreds of sharks seen mysteriously gathering off the coast of Brazil. Take a look."
