Isla Holbox, Mexico — Georgia Aquarium officials want to hold the next international whale shark conference in Atlanta, but some conservationists bristle at the idea because the world's largest indoor aquarium exhibits the huge polka-dotted fish.

Bruce Carlson, the aquarium's chief science officer, traveled to this sweltering, gnat-infested island off the Yucatan Peninsula to invite scientists, eco-tourism officials and conservationists from around the globe who were attending the 2nd International Whale Shark Conference.

Carlson told the six-day conference, which ended Sunday, the aquarium also plans to produce the most comprehensive guide to date on whale shark science, and he invited the 200 attendees from more than 20 countries to participate.

"A lot more hard science and data are needed," he said in an interview after his Holbox presentation. "You cannot go to one place right now and dig up information on these animals. It's scattered all over the place, much of it in obscure journals."

The aquarium's proposal drew mixed reactions, with some conservationists pouring water on the proposed Atlanta conference even before the invitations are mailed. The conference would likely take place in 2011.

"I would never come because that would condone what they are doing," said Lisa Carne, a conservationist from Belize who doesn't think whale sharks should be kept in captivity. "I'm pretty much one of those people who doesn't believe aquariums should exist."

Other scientists, however, applauded the idea of the Atlanta conference and a comprehensive whale shark reference book.

They included Mark Meekan, a scientist from Australia who has spent years researching whale sharks around the world and helped organize the first whale shark conference, held in Perth three years ago.

"This would attract everyone from around the world who has put serious time and effort into studying whale sharks," Meekan said. "I would hope the Atlanta conference would focus more on science than eco-tourism like they did in Holbox because the science is what I'm interested in."

The Georgia Aquarium is the only fish tank outside Asia to exhibit the gentle, giant sharks, which feed on plankton and small marine animals. The fish can grow to the size of a school bus and in the wild sometimes dive down thousands of feet for reasons scientists still cannot explain.

The sharks' size and diving behavior make them unsuited for aquariums, some have argued, even a tank as large at the Georgia Aquarium's 6.3 million gallon Ocean Voyager exhibit, which was specifically designed to house whale sharks.

Two of the aquarium's original whale sharks died after they were treated with a parasite-ridding chemical that apparently caused the big fish to suddenly stop eating. That parasite treatment was discontinued, and the facility's four remaining whale sharks — who were not treated with the chemical — are doing well, growing at about 3 feet a year, Carlson told the conference.

Carlson's presentation sparked a barrage of questions at an otherwise tame event where attendees presented papers on everything from genetic studies to the impact of whale shark eco-tourism on communities like Holbox, a small fishing village north of Cancun where hundreds of whale sharks gather each summer to feast on a massive plankton bloom just offshore.

Belizian whale shark scientist Rachel Graham said studies indicate the big fish sometimes make a series of deep dives during their ocean voyages. Scientists do not know the precise reason, but have speculated the dives could be a way to navigate, find food, cool off or evade predators. Or, Graham said, the dives could be a critical resting period for the big animals.

"How can we possibly allow these animals to rest in 20 to 30 feet of water" in the Ocean Voyager tank? she asked.

Carlson said aquarium scientists do not know if the deep dives are related to the shark's long-term health. He stressed that the aquarium's whale sharks were taken from Taiwan's kill quota, which means they would have ended up as food if they had not been brought to Atlanta.

He also defended a recent aquarium program that lets a few paying visitors swim with the big sharks in the tank, a move that sparked howls of protest from some quarters.

"If we thought the whale sharks were in any danger from this program, we would stop this program," Carlson told the conference.

Robert Hueter, a scientist from Sarasota's Mote Marine Laboratory whose whale shark research off Holbox has been partially funded by the aquarium, said he found some of the conservationists' complaints hypocritical.

"Some of these people claim to be conservationists, and they focus on a few animals in an aquarium," Hueter said in an interview. "But a lot them benefit from eco-tourism in which thousands of animals have their behavior compromised with people swimming with them. It's the dirty little secret of the eco-tourism world."