THREATS

Healthy coral reef habitats need clear, clean water...

Top threats to coral reefs

• Coastal Development
• Habitat Loss
• Over fishing and destructive fishing

• Coral Reefs
• Mangrove Shorelines
• Sandy Beaches

Polyps extend their tentacles from the coral skeleton to filter particles of food from the sea, mostly during the night. During the day, tiny single celled plants (algae) living inside the polyp gather energy from the sun, and through photosynthesis, make food. Working together, polyps and algae create a mutually beneficial (symbiotic) arrangement to produce a highly efficient biological mechanism to generate a healthy coral.

This life style is finely balanced: add pollution, excess organic material, or even extra sediment from dredging or coastal erosion and corals begin to suffer because the particles clog the tiny polyps and prevent them from eating.

When the corals die, the reef system begins to collapse. A whole chain of marine life begins to starve, to lose its breeding grounds and its home. Eventually, even the islands behind the reefs begin to suffer: people living on them lose a food resource and in extreme cases the islands themselves will be washed away by the ocean.

Our healthy coral reef habitat needs clear, clean sea water.

Stony corals are the framework for reefs because as they grow, each generation leaves behind a limestone exoskeleton that over thousands of years builds the coral reef. It is strong enough to sink ships and to reduce wave energy along our shoreline by 90%.

Warm water corals are not the only animals that live on the reef but without corals our shallow environment would be deserted. The coral reef habitat is a Mecca for sharks, rays, angel fish, lobsters, conch, sea cucumbers, sponges, with a diversity that surpasses any other marine environment on earth.

Corals do not create the integrity of the reef alone. Reef structures are like houses built with bricks and mortar cemented together by all of the encrusting sponges, algae, and corals.

This tapestry of life creates the splendor of our coral reefs that attracts divers, yachtsmen and anglers to the Cayman Islands. Our beautiful marine environment is famous throughout the world.

Our reefs are thousands of years old. It may take one coral head 250 years to grow to be the size of your living room couch. What might be damaged in a matter of minutes will take three human generations to restore.

 

Growing healthy coral reefs, maintaining healthy corals
Over the last 25 years, coral reefs in the Caribbean region have declined by 80%.

What are the threats toour clean clear water?
Our beautiful sandy beaches, and healthy coral reef, our mangrove and lagoon habitats are all interdependent. Mangroves, with their interlocking root systems along our shorelines act like a wall to incoming waves. They protect the island from erosion, protect our homes, and may even protect our lives during a major storm.

Scientists completed a study of coastal areas after the catastrophic 2004 Indonesian tsunami and showed that areas with intact mangroves had the lowest loss of life and property. Intact mangroves also filter sand and mud which helps keep the water in the nearby lagoons crystal clear.

The major threat to water quality is the partial and complete removal of mangroves in coastal zones and coastal erosion. Little by little our coastline is eroding. Coastal erosion is a complex issue for the Cayman Islands that we plan to discuss in detail in our upcoming publications.

What is being done?
The Central Caribbean Marine Institute provides leadership in undergraduate, graduate and professional education through marine ecology and conservation field-oriented courses so that students gain a better understanding of critical issues facing tropical marine environments. The Caribbean Sea Camp program is designed to engage local high school students in active learning about the local marine protection laws and to empower them to make the best choices for the local environment. CCMI offers generous scholarships for local students to participate in this program.

At CCMI’s marine facility, the Little Cayman Research Center, scientists are working to better understand what is causing the declines in the health of our reefs and what we could do to contribute to a more resilient reef. The goal is to reduce the major threats by humans so that our reefs can be more resilient to the stresses caused by global warming and climate change.

In 2005, CCMI began tagging juvenile corals to measure their rate of growth. The idea was to measure any decline in the amount of coral on the reef and to see how long it might take to regenerate the reef.

This work shows that Cayman coral species grow at highly variable rates from year to year. Corals take an extremely long time to grow, the fastest species at 15 cm/year, with many growing less than 1 cm/year. A large head of star coral might take 300 years to grow to 3 meters.  

THREATENED SPECIES

Corals
Two corals that were once remarkably abundant are now rare in Cayman and have just been listed by the US Endangered Species Act (May 6, 2006). The corals are the Staghorn coral (Acropora cervicornis) and the Elkhorn coral (Acropora palmata).

In the 2007 reef survey, CCMI scientists reported these endangered species in the Cayman Islands have increased over the previous 10 years, but more work needs to be done.

Why they are threatened
Both coral species have succumbed to disease, have been destroyed by major storms, and some have been broken by divers and snorkelers. One of the most dramatic declines in regional coral reefs in the past 30 years has been the demise of these two species.

These species provided an important baffling structure along the fringing reef – absorbing the force of the breaking waves – so that other organisms could become established. These species are the equivalent of a pioneering species in a forest and they still provide protection for our shoreline.

Elkhorn coral and rubble is responsible for the whitecaps that you see offshore on the north, south and east sides of all three islands.

Ever since the last ice age some 18,000 years ago, sea level has continued to rise and corals developed at the edge of what was the islands. These corals could grow so rapidly that they kept pace with the sea level. As they grew, they created a barrier for lagoons to develop all around the Cayman Islands several thousand years ago.

Will the demise of these species result in higher wave energy along our shore as this baffling system breaks down? Yes.

Don’t touch!
Divers and snorkelers must hover well above the reef. For the best experience, keep your eyes open & your hands to yourself. The coral structure may be limestone but remember that the tiny polyps are as soft as delicate flowers or sea anemones, and they are easily damaged. In fact, when corals are broken by boat anchors, storms, or a diver’s fins they rarely survive. Many corals also have a protective mucus layer that can be ruptured by the touch of a human finger – if the mucus is disturbed the coral may be prone to infections.

Turtles
Today, all of the turtles that you will find around the Cayman Islands, Loggerheads, Hawksbills, and Green turtles are listed as endangered species. This is largely due to the turtles being an exclusive source of food and income to the early settlers of the islands and continued hunting even today. Over time, the turtles around the islands began to disappear, and the turtle industry began to suffer.

A limited license from the Marine Conservation Board is granted during the open season that allows turtles to still be caught for food around the Cayman Islands. Turtles h ave played an important functional role on reefs. Hawksbills eat sponges which could potentially out compete corals for space on the reef. Green turtles eat sea grass and they are important for maintaining healthy stands of sea grass communities.

Extinctions are forever
Some other Endangered or Highly Threatened Marine Species:

• Nassau grouper
• Queen Conch
• Caribbean Spiny Lobster
• West Indian Whelk