The clear waters around the Cayman Islands are home to a remarkable array of marine life. With underwater visibility often exceeding fifty metres, reliably warm sea temperatures and lack of pollution the islands have some of the healthiest reef structures remaining in the entire Caribbean. Deep sea channels and canyons close to shore ensure that a constant supply of fresh, cooler water is constantly upwelling to refresh the reefs with nutrients. The currents also bring plankton to the surface for the reef fish to feed upon.
Strict government regulations have been in place for several decades on all three islands which divide the reef areas into marine park zones, replenishment zones and environmental zones. Many of the dive sites are accessible to boats only if they use the extensive system of mooring buoys provided so as not to damage the coral with anchors.
Around the shores of the islands the seabed is comprised of several different habitats ranging from shallow seagrass covered sand, to tongue and groove reefs, fringing reefs that protect the shoreline from waves, and deep reef walls that plunge vertically into the abyss. Like underwater rainforests the reefs are an important habitat for thousands of marine species which use them as shelter, breeding grounds, as a food resource and a home. Formed by the skeletons of countless generations of tiny animals the reefs are massive, yet fragile ecosystems that are easily damaged. Star Corals, Brain Corals and Sea Fans are some of the hard species found around Cayman as well as dozens of types of sponges including Giant Barrel Sponges which may be over two metres high.
Fish life in these waters is prolific and boasts some large charismatic creatures including perhaps the most famous underwater inhabitant of Cayman, the Southern Stingray (Dasyatis americana). Easily encountered in large numbers at the Sandbar, the stingrays have become Caymanís most popular underwater attraction.
Although they are equipped with a barbed tail the rays are not dangerous unless harassed, or unless someone stands on them by accident. The flattened pectoral fins are used like wings to allow the rays to glide effortlessly along the seabed where they feed on crustaceans and other creatures hiding in the sand. Southern Stingrays can grow as large as two metres from wingtip to wingtip and weigh more than 130 kilograms. Other rays found in Caymanian waters include the Yellow Stingray (Urolophus jamiacensis) and the Electric Ray (Torpedo nobiliana).
Colourful reef fish are a thrill for snorkelers and divers alike, and commonly sighted species include the Stoplight Parrotfish (Sparisoma viride) which when fully mature is a shimmering mixture of green, pink and yellow. With their powerful beak-like mouths they perform an important function in keeping the reefs free from algae, and also contribute to beaches by excreting fine white sand particles after they have eaten. Smaller but also eye-catching are the Spanish Hogfish (Bodianus rufus), with their gold and purple scales, and Schoolmasters (Lutjanus apodus) Ė large bright yellow fish belonging to the snapper family.
Many divers and snorkelers will be thrilled to see some of the larger marine species that visit the reefs including groups of silvery tarpon and perhaps favourite of all with many visitors the Nassau Groupers (Epinephalus striatus). Once common all over the Caribbean they are now much rarer, although on many Cayman dive sites they are accustomed to seeing divers and will even tolerate being stroked. Little Cayman is an important spawning and mating area for groupers where at certain times of year hundreds, sometimes thousands of fish will gather in one spot around the time of the full moon. Very few such sites remain in the Caribbean making Cayman a crucial breeding ground for this large, friendly fish.
Caymanís clear, clean waters have been found to be especially important for preserving a healthy reef system. While most reefs in the region have suffered severe coral death and outbreaks of disease over the past twenty years, the reefs of Little Cayman and Cayman Brac have been shown to be more resilient, with new growth and recruitment of juvenile corals reported.
Ongoing studies of Little Caymanís reef systems and other important reef science has been facilitated by the Little Cayman Research Station
which is run by the Central Caribbean Marine Institute. Studies undertaken at CCMI have included important monitoring of invasive Lionfish populations, possible medical uses for fluorescing proteins found in corals and discoveries of new species of small Gastrotrich Worms.
On some of the deeper diving sites there is a good chance of seeing Caribbean Reef Sharks (Carcharhinus perezi), gilded bronze species which help maintain healthy populations of fish in the ecosystem. Shallower reefs are often home to Nurse Sharks (Ginglymostoma cirratum), which like to sleep under overhangs or in nooks in the reef. On Caymanís walls and occasionally over sandy bottoms you will also find groups of Spotted Eagle Rays (Aetobatus narinari), a beautiful species which are always a pleasure to see at close quarters. Spending time on the shallower reefs is also rewarding, with colourful Wrasses, Squirrelfish, Basslets and Angelfish easy to find. Look out for tiny banded coral shrimps hiding inside Barrel Sponges, and large green Moray Eels poking their heads out from a hole in the reef.
For many snorkelers and divers it is a special treat to see wild turtles and Cayman has a healthy population of Green Turtles (Chelonia mydas). Non-swimmers can also learn more about this species and see them up close by visiting the turtle farm at Boatswainís Beach on Grand Cayman. Caymanís marine world is a special environment and visitors who take the time to experience it add a new dimension to their time in the islands.
Cayman Islands bird watching