Green sea turtles, cascades of glittering reef fish, blooming coral pillars - countless travelers have come nose to nose with a thriving undersea universe while on vacation. But increasingly, divers and snorkelers are swimming over bleached hunks of coral devastated by shore runoff or overfishing.
From the South Pacific to the Caribbean, coral reefs - which are among the most delicate of marine ecosystems - are bearing the brunt of climate change and other human-driven activities - including coastal development, deforestation and unrestricted tourism. Now, many in the tourist industry are trying to halt the damage.
And it is no wonder. The dollars involved in reef-based tourism are significant: Australia's Great Barrier Reef alone draws about 1.9 million visitors a year, supporting a $4.2 billion industry. According to the Nature Conservancy, the annual economic value of coral reefs to world tourism is $9.6 billion.
Growing awareness of environmental issues means that the tourism industry has lately been a partner to conservation efforts in major reef areas. Though the Great Barrier is the most famous reef, it is not the most threatened; its extensive marine management program is widely regarded as a model for conservation. It includes eco-certification programs for tourism operators within the boundaries of the marine park, environmental tourist fees, large no-take zones, species monitoring and tourism industry contributions to the Great Barrier Reef's main research center.
But the world's second-largest barrier reef, the Mesoamerican Reef in the Caribbean, is seriously endangered by coastal development, runoff and pollution. The reef system stretches nearly 700 miles from the Yucatán Peninsula of Mexico to the Bay Islands of Honduras.
And reefs in the Coral Triangle in Southeast Asia - which reaches from Malaysia to the Philippines, Indonesia and the Solomon Islands, encompassing some of the planet's most diverse marine habitats - have been severely damaged by overfishing and destructive practices, including the use of cyanide and dynamite to capture fish.
In 2004, the nonprofit group Conservation International began a program called the Mesoamerican Reef Tourism Initiative, which aims to address the threat that mass tourism poses to the Mesoamerican Reef by engaging hoteliers, developers, cruise lines and local governments in Mexico, Belize and Honduras. There is special emphasis on the Riviera Maya of Mexico, where, less than nine miles offshore, the island of Cozumel is the world's second most-visited cruise destination after Miami, according to the International Council of Cruise Lines.
Last year, as part of the Mesoamerican Reef initiative's efforts, the cruise line council began an effort to avoid wastewater discharge by cruise ships in environmentally sensitive areas.
"This program will ensure that cruise line wastewater is discharged at least four miles from any of the sensitive marine ecosystems within the Mesoamerican Reef system, thereby minimizing the chance such discharges will have negative impact on the long-term health of the reef," said Jamie Sweeting, who oversees Conservation International's work with the travel industry.
The cruise industry is a particular area of concern, since ships regularly disgorge crowds of passengers into fragile coastal areas that strain to absorb the impact. Conservation International estimates that cruise passengers typically make about 2,000 scuba dives in and around Cozumel's surrounding reefs in a single day.
"We're working with the municipal government, the local dive and water sports association, and the cruise lines themselves, because they all have a vested interest to look after this coral reef," Sweeting said.
Areas being addressed include the creation of a dedicated snorkeling zone in Cozumel to limit visitor impact to one section of the reef, and ensuring that park management fees are collected and put toward protection and management of marine areas. The Mesoamerican Reef Tourism Initiative has also begun a program to evaluate and implement good business practices for conserving water and energy, reducing solid waste and managing chemicals at coastal hotels along the Riviera Maya and in southern Belize.
Crucial partnerships between conservation groups and the tourism industry have also taken root in the Coral Triangle. In developing nations like Indonesia, where human and financial resources are slim, the cooperation of private tourism businesses has been instrumental in accomplishing reef conservation goals.
For example, Bunaken National Park, in north Sulawesi, is today managed in large part by a local association of dive operators who saw the declining quality of coral (and their livelihood) in the mid-1990s.
The Nature Conservancy's Coral Triangle Center works at several sites in Indonesia, including the Raja Ampat Islands in Papua and Komodo National Park, a major protected marine area in the Lesser Sunda Islands. Komodo is now run by a nonprofit joint venture between the Nature Conservancy and a local tourism company. The joint venture, PT Putri Naga Komodo, was established in 2005.
Founded in 1980, the park is a World Heritage Site and protects the habitat of the Komodo dragon, as well as important whale migration routes between the Indian and Pacific Oceans. The reefs are rich in coral species and home to up to 1,000 species of fish.
"After a decade supporting conservation in Komodo National Park, the Nature Conservancy recognized the need for self-sufficiency," said Marcus Matthews-Sawyer, director of tourism communications for the joint venture. "The idea was that a joint venture between a well-respected NGO and local tourism company would be able to balance conservation concerns with the need to generate revenues to ensure the long-term sustainability of the park."
Tourism has helped raise awareness of the destination and of the reefs' biological importance. Blast fishing - using explosives to stun or kill fish - is now prohibited within the park. The ban is credited with a 60 percent increase in hard coral coverage between 1996 and 2002, according to the Coral Triangle Center. The collection of conservation fees from tourists, about $15 a stay, is vital to sustaining park management. The partnership plans to have Komodo self-financed by park fees by 2012.
Though Komodo is one of Indonesia's greatest tourism assets - it is one of the most frequently visited nature reserves in the country - conservation work there is also necessary to protect young fish that are a source for surrounding fishing grounds.
Enforcement of the park zoning system, which restricts access to certain parts of the reefs, continues to be a challenge because of limited resources. But a major goal of the tourism partnership is supporting sustainable community use of the reef area, which includes providing alternative livelihoods to destructive fishing.
"Tourism creates jobs and puts much-needed income into the hands of local people, including those who previously might only have made a living from fishing," Matthews-Sawyer said.
All three reef systems - the Great Barrier Reef, the Mesoamerican Reef and the Coral Triangle - are jeopardized by the threat of global warming, which kills coral and leads to a bleaching effect. And while tourism cannot solve the problem of rising sea temperatures, the industry's cooperation to eliminate specific pressures - by establishing a well-enforced no-take zone, or reducing wastewater pollution, for example - helps reefs recover from bleaching and disease. The contribution of conservation fees to support the protected areas, which many businesses have long resisted, is also important.
To keep coral reefs from disappearing as quickly as they have in recent years, people need to be involved and educated on every level from local government to hotel developers to cruise lines, said Sweeting of Conservation International.
"It took Canc´┐Żn 35 years to develop to this massive size, and it took less than a decade for the Riviera Maya," he said. "But nature will not let you get away with it."