Massive arrivals of tourists, often to a small area, have a substantial impact. They add to the pollution, waste, and water requirements of the local population, putting local infrastructure and habitats under huge pressure. For example, 85% of the 1.8 million people who went to see Australia's Great Barrier Reef are focused in two small areas, Cairns and the Whitsunday Islands, which together have a human population of only 130,000.
In many places, huge new tourist developments have been constructed - including airports, marinas and golf courses. Overdevelopment for tourism has the same issues as other maritime developments, but often it has a much greater impact as the tourist developments are focused at or near fragile marine ecosystems. For example:
mangrove forests and seagrass meadows have been eradicated to create open beaches
tourist developments like piers and other structures have been created directly over coral reefs
nesting sites for endangered marine turtles have been ruined and disturbed by large numbers of tourists on the beaches
Careless resorts, operators, and tourists
The damage does not end with the building of tourist facilities.
Some resorts empty their sewage and other wastes straight into water around coral reefs and other sensitive marine habitats.
Recreational activities also have a considerable impact. For example, boating, diving, snorkelling, and fishing have hugely damaged coral reefs in several parts of the world, through people touching reefs, stirring up sediment, and dropping anchors.