Nairobi, Kenya - Kenya is famous for sightings of the "Big Five" safari animals: lions, elephants, leopards, buffaloes and the thick-skinned rhino.
Next month, that could become the "Big Six", thanks to a new marine enclosure that will allow holidaymakers to snorkel with live whale sharks.
Organisers of the Indian Ocean sea park say the €100 ticket price ($134 USD) will fund schemes to stop the docile fish from being wiped out.
But a vocal group of conservationists says it is cruel and unnecessary to catch and exhibit animals, and wants to stop the scheme, saying it puts money before animal welfare. Organisers have dismissed critics as "over-emotional eco-zealots".
The heated debate raises a question that splits conservationists: whether showcasing captive animals advances or hinders their efforts.
Volker Bassen, founder of the Waa Whale Shark Sanctuary near Mombasa, Kenya's second city, said it will be a boon for tourism and conservation.
"If you ever have a chance to swim with whale sharks, you will never forget the magical experience," he said. "You will become an ambassador for the protection of these majestic animals for the rest of your life."
An underwater polyethylene net measuring 2,000 metres by 600 metres will give the juvenile male occupants plenty of room to shake their fins, he said.
Whale shark enclosures are rare. Opportunities to swim with captive animals are limited to the Georgia Aquarium in the US and Okinawa Island in Japan.
The spotted filter-feeders grow to more than 10 metres in length and weigh more than 20 tonnes, making them the biggest fish in the sea.
"They plan to attach ropes and buoys to the tail fins and tire the animals out. This method has been banned in India because it is cruel and has been known to kill sharks in the process."
- Raabia Hawa, animal rights advocate
Bassen, who hails from Germany, said they also have one of the smallest brains relative to their size, meaning they care about little else than mating and scooping algae into their leviathan jaws.
Visitors to the planned sea park will learn about whale shark conservation before taking a dip with two massive beasts.
Snorkelers must wear life vests, keep at least three metres away from the animals and avoid using startling flash photography.
The German has tracked whale shark numbers off Kenya's coast for the past seven years and said he has noticed a steep decline. Monitors spotted at least four whale sharks every day during the 2006 migratory season. Last year, they counted only one animal every five days.
Bassen blames Bajuni islanders for hunting whale sharks, whom he says boil down their livers, using the oil to coat their wooden fishing boats. He said that about half the profits from his €1 million ($1.33m) enclosure will be spent on discouraging locals from hunting the grey-brown animals to extinction.
"It's about giving fishermen an alternative," he explained. "By importing machinery and know-how from India we can extract oils from cashew nut shells, and use it to protect their boats instead of whale shark oil."
Some ecologists have blasted the scheme at public meetings and in heated debates on a Facebook page dedicated to eco-tourism.
Raabia Hawa, a media personality and animal rights advocate in Kenya, is a vocal critic of capturing the slow-moving plankton-eaters. "They plan to attach ropes and buoys to the tail fins and tire the animals out," she said. "This method has been banned in India because it is cruel and has been known to kill sharks in the process."
Whale sharks are too big to be hunted by fishermen, she said, adding that putting migratory animals in an enclosure is unfair and unnecessary. "It's possible to track the animals using tags and aircraft and bring snorkelers to them when they are in the wild, out at sea. There's no reason to put them in what is effectively a cage."
The enclosure currently faces its final hurdle. Its environmental impact assessment is being evaluated by the National Environment Management Authority before a license is granted.
The marine biologist David Obura, from the Indian Ocean research body Cordio, said the conservation gains of tourism ventures are often overblown.
"High-end projects like these are very good at marketing and publicity," Obura said. "But if you assess the total benefits of the project then I doubt it will be very positive."
Tourism is central to Kenya's economy, but the industry has been shaken by kidnappings, attacks, and fears of violence during next month's elections.
Many travellers avoided the palm-fringed coast last August following the killing of radical cleric Sheikh Aboud Rogo, and the port city of Mombasa erupted in riots.
Jake Grieves-Cook, director of Gamewatchers Safaris, said critics should consider the economy before a potentially lucrative scheme is "shot down in flames".
"An attraction that brings in visitors while meeting the right ethical standards is positive for tourism," he said. "Kenya is in a good position to do it right. We are experienced in conserving wildlife and showcasing animals to huge numbers of tourists every year."
But Mohamed Hersi, chairman of the Mombasa and Coast Tourist Association, said that keeping sharks and other animals in captivity is never a good idea - even if it raises money.
"Keeping animals in captivity and showcasing them raises awareness and finances conservation efforts."
- Volker Bassen, sanctuary founder
"The beauty of visiting Kenya and other African countries is that you see wildlife in its natural habitat," he said. "Looking for elephants and lions on safari or going deep-sea diving for marine wildlife is part of the adventure."
Ecologists have argued for decades about whether showcasing wildlife to fee-paying punters advances or impedes the goal of animal protection.
Advocates say visitors to zoos and game parks are better educated about wildlife, and ticket sales can fund breeding programmes and animal protection. But critics say that keeping animals in captivity turns them into circus-like entertainment. They also warn that commercial interests tend to trump animal welfare.
Arthur Tuda, from the government-run Kenya Wildlife Service (KWS), cites "positive examples" of animals being showcased in East Africa's biggest economy.
He praises a giraffe centre and orphanage for young elephants in western Nairobi, which win squeals of approval from tourists and schoolchildren daily. "A non-financially driven model for conservation works in many cases, particularly for endangered species," he said. "But the objective is to conserve them with a breeding programme. The whale shark scenario is different because it is driven more by tourism than conservation."
But Bassen said his enclosure will do more good than harm, and plans to ply the ocean next month to catch the supersize stars of his marine spectacular.
"Keeping animals in captivity and showcasing them raises awareness and finances conservation efforts," he said. "It can prevent the extinction of a species. If this is possible, then it would be unethical not to do so."