They want to know why whale sharks, the largest shark species, gather each year by the hundreds in the teal-blue waters off this Yucatan Peninsula barrier island.
"It's like a fishbowl full of whale sharks," said Robert Hueter, director of the shark research center at the Mote Marine Laboratory in Sarasota, Fla. "We are witnessing a spectacle of nature down there that we don't fully understand."
Hueter, Mexican biologist Rafael de la Parra and a group of other marine scientists are trying to make sense of the big shark reunion, an event dubbed the "afuera." The word means "outside" in Spanish, and it was the name de la Parra initially used to describe to the phenomenon.
"They are showing up in an area outside the area the Mexican government set up for their protection and outside the area we had normally studied them," de la Parra said.