The warm, crystal clear waters surrounding 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.
Coral reefs are the most diverse and beautiful of all marine habitats. Large wave resistant structures have accumulated from the slow growth of corals. The coral may look like rock but it is alive.
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.
The development of these structures is aided by algae that are symbiotic with reef-building corals, known as zooxanthellae. Coralline algae, sponges, and other organisms, combined with a number of cementation processes also contribute to reef growth.
Star Coral (Montastrea cavernosa) inhabits all reef environments, but is often the main coral in deeper zones.
This coral is often green, brown, or reddish-orange and colonies form massive boulders or flat plates important for reef framework. Visiting the reef at night gives us a better idea of what these animals look like as they feed on passing prey. Star Coral captures and feeds on zooplankton through the use of tentacles, which extend from the polyp during feeding. Polyp expansion occurs during day and night, however it is more frequent at night when there is a greater amount of zooplankton moving in the water. Each animal reaches out into the water hoping to catch food as it floats or swims by.
The tentacles are lined with tiny white dots that are stinging cells called nematocysts.
The stinging nematocysts will kill or paralyze the prey, and then the polyp drags its prey into its mouth. Consumption of zooplankton provides nitrogen, phosphorus, and other essential nutrients.
These tentacles are also very important to this coral for defense against competing corals; space is limited on the reef!
Tentacle movement allows for a potentially deadly attack on their neighbors which allows Star Coral colonies to expand over the reef.
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.
Protect Cayman’s Marine Wildlife and Celebrate the International Year of the Reef! For more information, to share your knowledge or if you would like to get involved with the many activities in the National Trust’s Know Your Islands Program, please visit www.nationaltrust.org.ky or call 949-0121.
Last week’s answer: The Velvety Free-tailed Bat eats insects. It may be our most important species because it is so numerous and has enormous impact upon insect populations.
Trivia question: What coral is actually closer on the family tree to jellyfish and other stinging anemones?
Look for the answer in next week’s feature!