Massive influxes of tourists, often to a relatively small area, have a huge impact. They add to the pollution, waste, and water needs of the local population, putting local infrastructure and habitats under enormous pressure. For example, 85% of the 1.8 million people who visit Australia's Great Barrier Reef are concentrated in two small areas, Cairns and the Whitsunday Islands, which together have a human population of just 130,000 or so.
In many areas, massive new tourist developments have been built - including airports, marinas, resorts, and golf courses. Overdevelopment for tourism has the same problems as other coastal developments, but often has a greater impact as the tourist developments are located at or near fragile marine ecosystems. For example:
- tourist developments such as piers and other structures have been built directly on top of coral reefs
Careless resorts, operators, and tourists
- nesting sites for endangered marine turtles have been destroyed and disturbed by large numbers of tourists on the beaches
The damage doesn't end with the construction of tourist facilities.
Some resorts empty their sewage and other wastes directly into water surrounding coral reefs and other sensitive marine habitats.
Recreational activities also have a huge impact. For example, careless boating, diving, snorkeling, and fishing have substantially damaged coral reefs in many parts of the world, through people touching reefs, stirring up sediment, and dropping anchors.
Marine animals such as whale sharks, seals, dugongs, dolphins, whales, and birds are also disturbed by increased numbers of boats, and by people approaching too closely.
Tourism can also add to the consumption of seafood in an area, putting pressure on local fish populations and sometimes contributing to overfishing
Collection of corals, shells, and other marine souvenirs - either by individual tourists, or local people who then sell the souvenirs to tourists - also has a detrimental effect on the local environment.
The increased popularity of cruise ships has also adversely affected the marine environment. Carrying up to 4,000 passengers and crew, these enormous floating towns are a major source of marine pollution through the dumping of garbage and untreated sewage
at sea, and the release of other shipping-related pollutants