23 September 2005

Scientists document unusual gathering of whale sharks in the Gulf of Mexico

Scientists document unusual gathering of whale sharks in the Gulf of MexicoThe biggest shark in the sea comes here for an all-you-can eat buffet. Just off this remote speck of land three hours north of Cancun, whale sharks mass by the hundreds each summer in a spectacle only recently discovered by scientists.

This is where the fish that inspired the Georgia Aquarium — the world’s biggest fish — swims wild, stuffing itself with tons of olive-green plankton, which blooms profusely in the bathtub-warm waters between Cuba and the Yucatan Peninsula.

"The numbers of animals that gather here could be astounding," said Robert Hueter, director of the Center for Shark Research at Sarasota's Mote Marine Laboratory. "This could be the largest gathering of these sharks in the world."

Just last week, 53-year-old Hueter was swimming with the gentle filter-feeders as part of a research effort partially funded by the Georgia Aquarium, which opens November 23 in downtown Atlanta. The Georgia Aquarium will be the only fish tank outside of Asia to display the huge fish, which feed by straining plankton through a mesh-like layer in the throat. They can grow to the size of a rail car. The two Atlanta whale sharks, which were imported from Taiwan and dubbed Ralph and Norton, are young and still growing, measuring about 16.5 and 15 feet, respectively.

The aquarium was specifically designed for whale sharks. Their football-field-size tank holds 6 million gallons of water and is the largest man-made fish tank on the planet. Marcus, as part of the aquarium's research mission, is funneling about $50,000 a year to Mote and Mexican conservation officials to study and protect the sharks in the wild off Holbox (pronounced hole-bosh) Island.

The aquarium is touting research and education as part of its mission. A piece of that research began before sunrise three days last week as Hueter, National Geographic explorer-in-residence Sylvia Earle and a few assistants loaded their gear into a boat and headed northeast to the vast plankton beds where the big sharks feed.

Scientists did not even know the sharks — usually solitary animals — massed off Holbox until a local fisherman casually mentioned it to Hueter three years ago. He described hundreds of giant fish that the locals call tiburon ballena, or domino sharks (because of their spots), that congregate in the waters off the island from May to September. They had come when the fisherman's father was a boy and when his father’s father was a boy. Hueter was speechless.

Before Holbox, researchers knew of a few other documented gathering spots in the world — western Australia, Belize, Honduras, the Indian Ocean. But these areas attract far fewer whale sharks than Holbox.

"And in all these other places around the world where they gather, it's almost all males," Hueter said. "Off Holbox, about 25 percent of the animals are females. Something very special is going on out here."

Source: www.indianexpress.com


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