Regional Perspectives:

Tropical Americas

Map 1. Tropical Americas

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Coral reef ecosystems in the Tropical Americas (Map 1) are more numerous in the northern than southern Tropical Americas. Development is restricted on Pacific coasts by cold currents and upwellings off southern and central America, and on the Atlantic coast of South America by freshwater run-off of major rivers (Orinoco, Amazon). Reefs are best developed on Caribbean coasts. Coral reef ecosystems have been under increasing pressure from expanding human populations since the late 1900s. Under the jurisdiction of about 40 different countries the coastal resources provide important resources for millions of people. Degradation has outpaced comprehension of the problems and the ability to deal with them. The extent and accessibility of resources and human densities control the level of impacts. Generally, reefs on narrow offshore shelves suffer intense impact from terrestrial runoff and fishing. Where shelf and reef areas are large relative to the number of fishermen (Bahamas, Belize, Cayman), reef fish are larger and more abundant. Mangrove prefer the low-lying Central and South American coasts but are also found on a smaller scale, throughout the Caribbean (Woodley, in press).

While the reefs of Bermuda are in fairly good shape, sedimentation related to the Bermuda Air Terminal construction caused massive coral mortality, and, since 1940, 13 major ship groundings have destroyed about one percent of the outer reefs (Cook et al., 1993).

South Florida and Florida Keys seagrass beds, including those of Florida Bay and along the reef tract, cover an estimated 5,500 km2. In 1987 a massive mortality of seagrasses occurred resulting in the loss of over 40 km2. Seagrass mortality has persisted at a lower pace since 1990. A combination of ambient conditions that inhibited the sustainability of the seagrass community and the susceptibility to increased organic loadings from domestic wastes in artificial waterways and dead-end canals within the Keys are possible explanations. Little is known concerning the recent mortality of mangroves but there appears to be a rough spatial correlation with adjacent areas of high salinity in Florida Bay. Evidence is growing that freshwater management practices as far north as Lake Okeechobee are having serious effects on coral reef health and coral recruitment (Porter, 1995). Unfavorably warm conditions during long-lasting summer doldrums have been linked to coral bleaching. Add to this equation the four-fold increase in local human population since 1930, impacts from land use (sedimentation), water pollution (point, nonpoint and external sources - eutrophication, leaching of land-based septic systems), boating, recreational and commercial fishing, and the activities of over 3 million tourists each year, and you have a coral reef ecosystem struggling for survival. The impacts of fishing are particularly significant because recreational fishing is the area's primary tourist-related boating activity, and commercial fishing is the fourth largest industry in the region. There are well-documented reports of local declines in coral populations from monitoring, but there is uncertainty about the areal extent of these changes (USDOC, 1994).

The Flower Gardens Banks in the Gulf of Mexico have experienced no significant changes in coral cover, population levels, diversity, evenness, or encrusting growth over the last 20 years. The installation of mooring buoys by the Flower Gardens National Marine Sanctuary has greatly reduced anchor damage (Gittings et al., 1993).

Due to rapid development over the last 50 years, most Caribbean reefs are threatened by adjacent densely populated islands. Mangrove depletion has been prominent in the majority of the Caribbean islands including Barbados, British Virgin Islands, Cayman Islands, Dominican Republic, Guadeloupe, Martinique, Netherlands Antilles, Puerto Rico, Trinidad and Tobago, and the U.S. Virgin Islands. Coastal development has had significant environmental impact through increased turbidity on the majority of the Caribbean islands. Tourist-related threats include anchoring, littering, trampling, diver damage, and over-collection of coral. Both commercial and recreational fishing pressure as well as destructive fishing techniques, such as fish traps, poison and blast fishing, and spearfishing have led to significant declines in fish, lobster, and coral populations. Deforestation has led to erosion and increased soil run-off, causing significant siltation of reefs on Dominica, Guadeloupe, Haiti, Martinique, and Puerto Rico. This problem is often aggravated by the input of fertilizers, pesticides, and other agricultural pollutants as is the case in Barbados, Grenada, and Guadeloupe. Less than 10 percent of total domestic waste receives treatment before disposal and much reaches coastal waters, causing eutrophication and accelerated algal growth. Sewage pollution has been reported from Barbados, British Virgin Islands, Cayman Islands, Dominican Republic, Guadeloupe, Jamaica, Martinique, Netherlands Antilles, Puerto Rico, Turks and Caicos, and the U.S. Virgin Islands Oil terminals/refineries (and associated construction activities), tanker traffic, and offshore oil reserves adjacent to the reefs are also of concern in the Caribbean and the threat of related pollution is most serious in the Cayman Islands, Guadeloupe, Jamaica, Netherlands Antilles, Puerto Rico, Turks and Caicos, and the U.S. Virgin Islands. Caribbean coral reef ecosystems also have been afflicted with natural damage due to hurricanes and prolonged algal blooms following the Caribbean-wide mass-mortalities of Diadema antillarum in 1983. The lack of herbivory, due to the loss of Diadema and chronic overfishing, has allowed algae to replace coral in many areas, particularly after the coral has been reduced during recurrent hurricanes (IUCN/UNEP, 1988).

As early as 1959 in Jamaica, for example, fish catches in coral reef waters consisted primarily of juvenile fish. Overfishing has removed the grazers on coral reefs and allowed algae to compete with corals for living space. In Jamaica, coral cover dropped from 50-70 per-cent to under five percent after hurricane damage and after disease reduced grazing sea urchin populations (Hughes, 1994). There is still little sign of recovery after ten years.

Coastal waters of Central and South America receive large influxes of freshwater from extensive mainland river systems, therefore nearshore reef development is generally poor. However, reefs are found on islands off Costa Rica, Colombia, Honduras, and Panama. Coastal development which has coincided with the influx of tourism in Colombia, Costa Rica, Honduras, Mexico, Panama, and Venezuela is a significant threat to coral reef ecosystems and has resulted in mangrove depletion. Development has increased the amount of raw sewage deposited into coastal waters. Siltation from deforestation has occurred in Brazil, Chile, Colombia, Costa Rica, Mexico, Nicaragua, Panama, and Venezuela, and unhealthy water quality has been compounded by herbicide and fertilizer runoff. While reefs play a major role in supporting the artisanal fisheries of Central and South America, recreational spearfishing and over-harvesting of reef resources is of major concern and has led to a decline of fish and coral populations in Belize, Brazil, Colombia, Costa Rica, Ecuador, Mexico, Panama, and Venezuela (IUCN/UNEP, 1988). A combination of natural and human-related effects have produced significant local coral reef ecosystem declines:

Barbados -- hurricane damage and loss of urchins that graze on macroalgae;

Colombia off Santa Maria City -- pollution and run-off;

Costa Rica -- agricultural-related sedimentation; and

San Blas Islands -- coral bleaching, loss of grazing urchins, mining pollution, coral mining, sedimentation and eutrophication (Ginsburg, 1994).

In contrast, the Belize Barrier Reef Complex has the largest, most varied, and luxuriant array of reefs in the western Atlantic.

While a management plan was proposed in 1992 for the marine reserve, it never took effect. This left a confusing array of responsible agencies and policies that contributed to fisheries conflicts in 1994.

Human Consequences

The loss of coral reef resources in this region would have tremendous social impacts relating to loss of work/income and potential problems of loss of an important food source for many artisanal fishing communities. It would also have detrimental effects on the multi-million dollar tourist and fishing industries.

Existing Management and Research Programs

The focus for marine research on Bermuda is the Bermuda Biological Station. Bermuda also has a complete oil spill contingency plan, a fisheries management plan and several marine protected areas (IUCN/UNEP, 1988). NOAA has a management plan in effect for the Flower Gardens National Marine Sanctuary and a draft management plan for the newly designated Florida Keys National Marine Sanctuary (USDOC, 1994). Both sanctuaries also have ongoing monitoring programs.

In the Caribbean, coastal zone management plans in the Virgin Islands and Puerto Rico as well as regional fisheries management plans help guide conservation efforts. Governments have developed an innovative approach to coastal marine ecosystem (including watersheds) protection through the Protocol on Specially Protected Areas and Wildlife (SPAW) of the Cartagena Convention. The SPAW Protocol calls for the establishment of a regional network of protected areas in order to conserve, maintain, and restore ecosystems, in particular to maintain the "ecological and biological processes essential to the functioning of the Wider Caribbean ecosystems." This new framework is an advance in international environmental law. Appropriate protection focuses on the system as a whole, rather than on individual species. It will foster comprehensive national and regional policies for managing these fragile and threatened ecosystems in integrated coastal marine land use strategies, incorporating, but not exclusively based on, protected areas.

The SPAW protocol was opened for signature in January 1990. Although not now in force, UNEP's Caribbean Environment Programme is nevertheless developing a range of regional strategies to support its purpose, including promoting networks of marine protected areas, monitoring of environmental trends for these fragile ecosystems and species, training in coastal zone management/development of management plans, and studies in pollution trends.

The presence of many universities and marine stations and over 80 parks -- more than any other region in the world -- has provided more localized data on the nearby reefs than probably any other part of the world. The United States, Netherlands, France, and Great Britain have sponsored substantial research and management programs in their respective possessions and affiliated islands in the Caribbean. The CARICOMP coral reef monitoring program, a network of about 24 marine laboratories, has collected data since 1992 (Smith and Ogden, 1993). This program is expected to result in a regional acceleration of research and management activities similar to results from the ASEAN-Australian and ASEAN-U.S. programs in Southeast Asia.

Major centers for research and management advice in Central America include the Centro por Investigación en Ciencias del Mary Limnología (CIMAR) of the University of Costa Rica and the Smithsonian Tropical Research Institute and associated laboratories in Panama. Belize has been the site of a substantial amount of research focused on the Smithsonian field station in Carrie Bow Key. Belize is also beginning to establish an integrated coastal zone management program. The Global Environment Facility approved a project to develop the capabilities of Belize's Coastal Zone Management Unit to manage and conserve the country's coastal resources through institutional strengthening, introduction of adequate monitoring and planning techniques, execution of applied research, and enhancement of public awareness about the value of coastal ecosystems.

National research programs are ongoing in most of the countries of South America bordering the Caribbean. Brazilian researchers are initiating similar programs for the western South Atlantic. It is hoped that these initial efforts will grow into the comprehensive research programs necessary for effective, informed management of these complex ecosystems and the diverse societies that depend upon them.

Preliminary Recommendations for Regional Action

In addition to the general global recommendations, we suggest the following:

Integrated Coastal Zone Management

  • Over-fishing in the region needs to be strictly controlled. This major problem is causing a genetic shift to smaller adult sizes and smaller size at maturity. It also is removing breeding stock (larger individuals) and herbivores, which causes small population numbers and reduces the amount of grazing on reefs, which in turn leads to increased algal growth and poor reef development. In some areas population numbers are so small that certain species face local extinction.
  • Steps should be taken to minimize sedimentation and eutrophication in coral reef areas through wise land use practices and integrated coastal zone management.
  • Properly managed and funded marine sanctuaries that incorporate education, research, monitoring, enforcement, and visitor use programs are one way of preserving highly used coral reef ecosystems from tourist impacts and for preserving fish stocks. It should be noted that the level of protection in many existing marine protected areas is minimal due to the lack of adequate funding, management related information, ineffective regulatory structures, lack of public education, inadequate surveillance and enforcement, and minimal research and monitoring (OAS 1988, IUCN 1992).

Capacity Building

  • Programs are needed to build expertise in coral reef management and science. Presently, the shortage of trained personnel on many islands in the region requires the sharing of limited expertise through networking.

Improved Scientific Understanding of Coral Reef Ecosystems

  • The CARICOMP monitoring network should be supported to help discriminate between natural variability and human impact and to assist in sustained regional coral reef management.


State of the Reefs * May 1995

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