Coral cover on many Caribbean reefs has declined up to 80 percent over the past three decades. Southeast Florida’s reefs, which are a
part of the greater Caribbean/Western Atlantic reef province, are being monitored for diseases, bleaching and other problems
associated with human activities. Monitoring data from 105 stations in the Florida Keys has revealed a 44
percent decline in coral
cover from 1996-2005. Because corals are very slow-growing, this loss represents a serious and significant threat to local
coral ecosystems. While reefs can withstand varying levels of natural disturbance, they may not be as resilient to
human-induced stresses. In southeast Florida, coastal resources are under intense stress resulting from high population
densities and coastal development.
Large coastal infrastructure projects, such as the installation of pipes, cables and wastewater outfalls for public utilities,
can contribute to shoreline erosion and can damage coral habitat through mechanical impacts or degradation of water quality.
Beach nourishment projects, in which large volumes of sand are re-located from offshore to onshore, can cause severe impacts to
reefs. Coral reef organisms may be smothered by sediments and reduced water clarity deprives corals of the light they require
for photosynthesis by their symbiotic algae.
A large brain coral, crushed by a grounded vessel off Port Everglades, Florida
Photo: Dave Gilliam, National Coral Reef Institute
Dredge and fill projects and construction of seawalls and docks can negatively impact seagrasses, mangroves and other benthic
communities that are inter-connected with the coral reef ecosystem. These projects can directly impact corals by destroying
them during construction, or they can result in indirect impacts, such as reducing the amount of available light when a new
dock shades the seafloor.
Runoff from residential, industrial, and agricultural areas containing fertilizers, silt, chemicals, debris, and other
contaminants are carried through storm drains to Florida’s waterways. Sewage discharges from waste treatment facilities,
boats, and developed land areas contribute to coral diseases and death. Even treated sewage contains high nutrient levels
which trigger algal blooms that smother reefs, and may also contain bacteria and viruses which threaten the health of both the
marine environment and humans. Pollution from people who live many miles from the coast can destroy corals as liquids and
solids eventually make their way downstream to the ocean through our numerous inland canals and waterways, and through
Physical contact from fins, hands, or equipment of boaters, divers, snorkelers and fishermen can damage delicate corals.
Abandoned, improperly discarded, or lost fishing gear like line, nets and traps cause physical damage to reef systems. Ships
and other vessels that run aground or drop anchor on reefs can dislodge, overturn and crush corals.
Overfishing has depleted many fishery resources. A 2001 scientific assessment of fisheries and marine habitats in Biscayne
National Park, Florida indicated that 77 percent of the 35 fish stocks studied (including groupers, snappers, grunts, and barracudas)
were overfished according to federal designations. Recreational fishing in south Florida increased 444
percent from 1964 to 1998.
In southeast Florida, the number of registered recreational vessels has increased 329
percent and the size of the commercial fleet
has doubled since 1945.
Two species of coral (Acropora cervicornis and Acropora palmata) that are found in south Florida waters and
throughout the Caribbean were listed as Threatened Species under the federal Endangered Species Act in 2006. On geologic time
scales, Acroporids were the dominant reef building corals off the southeast Florida coast. Pillar coral (Dendrogyra
cylindrus), which also occurs offshore southeast Florida, was placed on the State of Florida’s Endangered Species List by
the Florida Fish and Wildlife Conservation Commission in 1985. All species of stony corals (Order Scleractinia), including
fire corals (Genus Millepora), as well as sea fans of the species Gorgonia flabellum and Gorgonia ventalina, are
protected from take, attempted take, destruction, sale, attempted sale or possession under Florida Administrative Code Rule
A lack of public awareness and appreciation regarding the significance of coral reef communities and how they can be harmed is
another threat to reefs. Increased public knowledge and community involvement in the protection of coral reefs will help to
decrease the threats to this valuable natural resource.