The shallow, warm, crystal clear waterssurrounding the Cayman Islands have provided us with some of nature's most spectacular marine life, none more noteworthy than our breathtaking coral reefs. For hundreds of years, Caymanians depended on healthy coral reefs to provide food, building materials, medicines and even decorative objects. To this day, our coral reefs are integral to our island economy thanks to their contribution to tourism and fisheries. In addition, they play a critical role in protecting the shore from storms and hurricanes.

Although sometimes viewed as a separate entity, coral reefs are a vital part of a vast inter-connected marine ecosystem that also includes seagrass beds and mangrove wetlands. Each system depends heavily on the others, resulting in a tightly integrated and finely balanced marine environment. Changes in one area of a system may have 'knock on' effects through all of the other systems. It is hard to imagine the massive reef structures and reef walls as fragile, living entities, but coral reefs are extremely sensitive to external pressures and over-exploitation. The mucus, or 'skin', that forms a layer over corals can be damaged simply by the touch of a hand or contact with a snorkeller's fin. Once damaged, the living layer of tissue is exposed to bacteria, which can prove fatal to coral.

Coral reef structures are actually built from the skeletons of tiny creatures living in colonies. A closer look at the colourful colonies will reveal thousands of tiny bumps, called polyps. Each of these polyps is an individual coral animal, all of which join together to form a coral colony. Most coral colonies start life as a single polyp, no bigger than a pinhead, that drifts with the ocean currents to settle on a suitable surface, such as a bare rock bottom. Once settled, the newly established coral polyp begins to grow, laying down a skeleton by extracting calcium carbonate from the surrounding water and budding off a new, individual polyp identical to itself. Continued budding is the mechanism for increasing the size of the colony but not, in general, producing new colonies. As this process repeats itself, time and time again, over many thousands of years, so the tremendous reef formations that can be found in Cayman, have been formed.

As well as budding, coral can reproduce sexually. This results in the formation of a free-floating larva, which, when settled, starts developing as a new colony. In the Caribbean, the main spawning period is long, lasting from July through September. During this period, corals release sperm and eggs at night using the moon as their cue to ensure they spawn together. Fortunate night divers can sometimes witness the milky white releases.

Corals feed at night by stretching out their tentacles to capture tiny animals suspended in the water column. Coral tentacles contain specialised cells called nematocysts, which act like poison darts to paralyse the prey which is then passed to the coral's central mouth. During the day, they withdraw their tentacles into a cup-like skeleton and are fed by algae (single cell plants) residing within their tissue. The algae use sunlight along with the coral waste products to make food for themselves and the corals. The corals, in turn, give the algae nutrients they need to survive and provide a home. This type of mutually beneficial relationship is called symbiosis. This relationship is especially important for coral growth around the Cayman Islands as tropical waters are typically nutrient poor and food for corals is scarce. Without the algae, corals would not survive. Interestingly, it is the algae that are responsible for giving each coral its beautiful colours.

In addition to hard corals, horny corals (sometimes called soft corals) can also be found on Cayman's coral reefs. Sea fans or gorgonians do not produce a hard skeleton. Instead, their skeletons are formed within their bodies as a horny substance. The skeletons of these corals are flexible so that their branches wave back and forth in the currents.

Anyone visiting the reef will quickly notice that corals are not the only inhabitants; indeed, the diversity of life on Cayman's reefs is outstanding. Wherever one looks, there is always something different to see; every available nook and cranny is occupied by different kinds of animals, and it is this closeness of community that makes reef systems so remarkable. Everything on a reef has a function, and no matter how small, that function will be vital to other creatures, making the whole system an extremely well balanced and tightly integrated living unit. Coral reefs provide Cayman with immeasurable benefits ranging from the rich and diverse resources that can be harvested, to our safe-harbours, tranquil lagoons and the sand which makes up our idyllic beaches. In more recent times, Cayman's coral reefs and marine environment have helped attract a multitude of visitors from around the world who have come to enjoy the natural beauty and majesty of our underwater realm.

In 1996, the Cayman Islands' Department of Environment began a long term reef monitoring programme encompassing all three islands. The study is designed to assess and monitor the living coral cover of our reefs and document any changes over time. This information can then be used to guide management decisions. Additionally, the Marine Conservation Laws act to protect our reefs and allow for the establishment of our Marine Parks. No marine life may be taken on scuba or removed by excavation without prior written approval of the Governor-in-Council. Furthermore, no vessel is allowed to anchor in coral. It is hoped that with these laws and a new awareness of the importance of our coral reefs, Cayman's marine environment will be preserved for future generations of the Cayman Islands.

Last Updated: 23 Nov 2011