What is a coral?
Corals are in a very special group of animals. Each coral polyp has a soft, gelatinous structure covered by a rigid calcium carbonate external skeleton. Each polyp has a ring of tentacles surrounding a central mouth. The tentacles are used to catch food from the water. Coral polyp have unicellular algae in their tissues called zooxanthellae.
The zooxanthellae (plant) and the polyp (animal) have established a symbiotic relationship through evolutionary pathways. Zooxanthellae provide the polyps with oxygen and other nutrients. Zooxanthellae, in turn, receive carbon dioxide and nitrates produced as wastes by the coral polyp which are used for growth by the algae.
The external calcium carbonate skeletons produced by the coral polyps form what is called the coral reef. Even though, the individual polyps are small, colonial growth can cover extensive areas and produce a great variety of shapes and sizes. Some coral colonies are cylindrical, others are branched (like elkhorn coral) and others are plate-like or dome-shaped.
There are other types of corals in the coral reef. The soft corals are flexible in the form of fans, whips or bushes. They also have many different colors and carry zooxanthellae in their tissues.
Why are coral reefs important?
Coral reefs are very important natural ecosystems. They grow best around the equator of the Earth which covers nearly 3,000 miles of ocean. In the oceans, coral reefs support the largest diversity of living organisms. They are the first to receive the energy of the waves, protecting the shore from erosion. Skeletal remains of plants and animals from coral reefs form the the sand on many of the sparkling white Caribbean beaches.
Humans benefit from the ecological services that coral reefs offer. There are many natural products obtained from reef organisms, such as the sponges and gorgonians that are used by pharmaceutical industries to produce medicines. Many of the fishes and seafood forming the Caribbean fishing industry come from coral reef.
In the U.S. Virgin Islands and Puerto Rico, coral reefs constitute one of the most importantattractions for tourists. Peripheral services to tourists, related to the recreational use of coral reefs include dive shops, marinas, use of recreational vessels and other tourist services. In addition, the tourism industry and recreational activities depend on the beaches, which are protected and maintained by healthy coral reefs and associated seagrass beds, as well as mangroves that help stabilize the coast and retain sediments. In addition to coral reefs, which are formed by coral themselves, there are other reef systems where corals grow on the rocks and other hard bottom areas.
The waters around the Virgin Islands are home to an abundance of corals, fishes, sharks, dolphins, turtles, crustaceans and a multitude of other marine life. In the U.S. Virgin Islands there are over 400 reef associated or near shore ranging fish. Some of these fish include:
Spotted Butterfly fish
For more information on the coral reef and marine life in the U.S. Virgin Islands and the actions that are taking place to protect these environments, see:
Marine Protected Areas as tools for conservation
One of the most important actions to protect the marine ecosystems in the Caribbean is the designation of marine protected areas (MPAs). The term marine protected area refers to:
“Any areas of intertidal or subtidal terrain, together with its overlying water and associated flora, fauna, historical and cultural features, which has been reserved by law or other effective means to protect part or all of the enclosed environment”.
Besides the overall objective of environmental protection through the establishment of MPAs, these have proven to be effective management strategies for the recovery of populations of overfished species, improvement of fisheries, habitat restoration, promotion of non-extractive activities, and protection of nesting areas for birds and sea turtles. Some MPAs may contain no-take areas where fishing is strictly prohibited, as well as areas where a variety of activities are allowed.
Actions to protect marine-habitats
Restoration: Actions such as mangrove reforestation in Salt River Bay National Historical Park and Ecological Preserve in St. Croix and coral farming and transplanting being done by The Nature Conservancy in the Virgin Islands have the objective of bringing back plant and animal species to the mangrove and reef systems.
Signage: Cays and shallow patch reefs are difficult for non-local boaters to detect resulting in groundings that damage the reefs. Placing adequate signs and markers can protect these areas and is a positive action.
Education: Lack of awareness on part of the public about the functions and important ecological processes in marine habitats in the U.S. Caribbean has been identified by the Coral Reef Task Force as one of the main causes for the loss of coral reefs and associated resources. It is important that partnerships between government agencies and non-governmental organizations such as The Nature Conservancy, St. Croix Environmental Association, and the Coral Bay Community Council, for example, be established to promote public education at all levels.
Here are some examples of a collaborative efforts between local and federal government agencies and others to improve community awareness: