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Caribbean Coral Reefs

The biogeographic region containing Caribbean coral reefs extends from The Bahamas in the north through the northeast coast of Venezuela, and eastward through the lesser Antilles.

These reefs provide critical habitat to thousands of species - some of which are of very high commercial value. They also provide numerous benefits to nearby human communities, not the least of which is a measure of shoreline protection from the hurricanes that regularly ravage these waters.

Nonetheless, Caribbean coral reefs comprise only about 8% (by surface area) of the world's coral reefs. This is no surprise, considering the overall size of the wider Caribbean compared with that of the vast Indo-Pacific region.

Caribbean Reef Types

Most of the coral reefs of the Greater Caribbean region are fringing reef complexes. In many cases these are quite extensive and well developed, such as those that parallel much of the coast of Cuba, and the east coasts of Andros Island and Eleuthera in The Bahamas.

Fringing reefs also encircle most of the smaller islands of the Caribbean region including those of The Bahamas, Aruba, Bonaire, Antigua, and the Cayman Islands.

These shallow reefs provide some of the best Caribbean scuba diving and snorkeling opportunities to be had anywhere.

The entire Caribbean region is home to only two true barrier reefs. The largest (Belize Barrier Reef) is about 220 km in length and runs from the Yucatan (southern Mexico) to the Gulf of Honduras. A smaller barrier reef lies north of Providencia Island (Colombia) in the southwest Caribbean.

There are also only a few true atolls (between about 10-20) in the Caribbean region. Most of these lie offshore Central America from the Yucatan to Nicaragua, and most (if not all) appear to have developed in ways other than volcanic island subsidence as is typical of Indo-Pacific atolls. The best developed Caribbean atoll is Glover's Reef, which lies about 50 miles off shore the coast of southern Belize.

Caribbean Reef Structure

Along with the overwhelming predominance of fringing reefs as the major reef type, Caribbean coral reefs tend to differ structurally from those of the Indo-Pacific region in a number of other ways.

One such marked difference is the rarity of a prominent algal ridge on Caribbean reef crests, a feature far more prevalent on Indo-Pacific reefs.

A Caribbeaan coral reef with abundant octocorals
Numerous octocorals adorn a Caribbean coral reef. ©

Another distinguishing structural feature of many shallow Caribbean reefs is that they often support an abundant mixture of sponges and octocorals that grow from the hard coral base of the reef (see photo; left).

These additions afford Caribbean coral reef surfaces substantial added biodiversity and topographic complexity.

Well developed reef systems of the Caribbean region also generally contain numerous patch reefs. Usually, the dominate corals of Caribbean patch reefs are Porites porites, Montastrea annularis, along with several Diploria spp. and Porites spp.

Biodiversity Of Caribbean Reefs

The Greater Caribbean became completely isolated from the Pacific Ocean some 3-4 million years ago by the closing of the Isthmus of Panama, and has since developed its own unique coral reef biota. The diversity of Caribbean coral reef life is poorer than that of the Indo-Pacific region. Nonetheless, it is far richer than of any other marine habitat of the region with about 65 species of hard corals recognized, and perhaps 500-700 reef-associated fish species.

The center of marine biodiversity for the region lies in the west-central Caribbean Sea, in the neighborhood of the Jamaica - Belize Barrier Reef area. Reef biodiversity generally decreases with distance from this center.

For example, about 40-50 species of stony corals have been recorded from The Bahamas, whereas 62 species were recorded at a single reef complex in Jamaica back in the 1960's - when reef health there was exceptional. Likewise, the number of reef-associated fish species recorded from all of The Bahamas is "only" about 480, less than 80% of the total reef fish species recorded in the entire Greater Caribbean.

Current Status of Caribbean Coral Reefs

Over the last 30 years, Caribbean coral reefs have suffered enormous declines both in terms of overall coral reef ecosystem "health" and the productivity of reef fisheries.

Caribbean reef overgrown with algae
Caribbean reef with heavy algal growth. Credit: NOAA

Overdevelopment of coastal areas, overfishing, direct tourism impacts such as overuse of particular reefs for recreational diving and snorkeling, and declines in water quality have in many cases led to dire consequences for coral reefs, leaving devastated underwater seascapes where thriving hard coral colonies once stood (see photo, above).

In recognition of the intrinsic value and vulnerability of coral reef ecosystems, many Caribbean nations are now actively engaged in developing more Marine Protected Areas (MPAs) along with increasingly stringent regulations aimed at better protecting these resources.

WEBMASTER'S NOTE: Our newly released eBook entitled "Caribbean Coral Reefs: An Introduction" provides much more information on these fascinating ecosystems!

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