The Florida Keys are probably home to more marine fish species than any other coastal region of the mainland United States.

Description: These reefs extend from Miami to the Dry Tortugas, near Key West. Outside of those of the Bahamas and Bermuda, they are the northernmost reefs found within the western Atlantic. The Florida Keys are probably home to more marine fish species than any other coastal region of the mainland United States. [59] Reefs here are a major tourism draw -- over one million divers visit this area each year. Commercial and recreational fisheries are an additional and important source of income for local communities. For example, the spiny lobster catch generated $10 million in 1980 alone.[60]

Threats: The coral reefs of the Florida Keys exemplify the complexity of threats to reef resources. They naturally lie near the temperature limits for reef building. Strong winter cold fronts have episodically killed Acropora thickets throughout the Keys. Florida reefs have been repeatedly stressed in the past 25 years by bleaching events in 1973, 1983, 1987, 1991, and 1997. Disease is an even more serious problem: two of the most important reef-builder species (Acropora palmata and A. cervicornis) are now relatively uncommon due to white-band disease, while others have proved particularly susceptible to black-band disease. New coral diseases are being reported each summer.

The two major threats to these reefs are polluted waters from Florida Bay and anthropogenic nutrients from storm runoff, discharge from sewage-laden groundwaters, and from agricultural sources. Even distant sources are involved: waters from the heavily polluted Mississippi River periodically reach the Keys while Saharan dust has been implicated as an origin of nutrients and possibly disease spores particularly during El Niño years. Finally, direct human activity is damaging reef resources here. Activities such as boating, fishing, and diving individually cause minimal damage, but because of sheer numbers of participants result in chronic stress. The all too frequent groundings of large vessels have resulted in loss of significant percentages of individual reefs. Aside from boating activities and despite years of research, it is difficult to lay blame for damage on specific anthropogenic stresses. However, it is clear that human activity compounds the natural regional vulnerability of Florida's reefs, thereby severely threatening the future integrity of these ecosystems.

Internet Resources
The world's only underwater laboratory, Aquarius, is sitting 50 feet below the ocean's surface in the Florida Keys National Marine Sanctuary. This underwater habitat allows scientists to collect information about the condition of U.S. coral reefs in waters deepr than can be routinely reached using surface-based diving techniques.
Florida Keys National Marine Sanctuary works to manage, protect and preserve the ecologically diverse marine communities and submerged cultural resources of the Florida Keys.