Study shows health of Cayman reefs declining

Graphs and statistics help demonstrate a decline in reef health over the last 20 years.

A new report conducted by the Central Caribbean Marine Institute indicates that overall coral health and coral size have significantly decreased in Grand Cayman waters over the last 20 years.

The report, conducted in cooperation with the Department of Environment and the National Trust, is the third study done by CCMI over the last 20 years. Katie Correia, the science education manager at CCMI, shared the findings at a meeting at the South Sound Community Centre on Sunday.

Ms. Correia indicated that the report is awaiting formal publication, but has been approved by the DoE.

CCMI’s first baseline study was conducted in 1998, and it found that 20 percent of coral reefs were healthy. Ms. Correia said that means that they had increased stony coral cover, healthy corals, low disease, low predation, high amounts of herbivores and lots of Apex predators.

Twenty years later, Ms. Correia said, only 17 percent of Cayman’s reefs are healthy. That is a reduction from the previous study, but still well above the global average of stony coral cover, which is less than 10 percent.

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But the study also found an increase in coral of poor health. Twenty years ago, only four percent of reefs were in poor health, but today that number is eight percent.

“If you don’t think four percent is significant,” Ms. Correia said, “Think doubling it.”

The survey also mapped out the average size of coral around Grand Cayman and the Sister Islands, and it found that coral size is reducing all around, but only at a statistically significant rate in Grand Cayman.

Katie Correia, the science education manager at the Central Caribbean Marine Institute, gives a presentation on local coral reef health on Sunday. – PHOTOs: Spencer Fordin

The original baseline study found that the average stony coral size in Grand Cayman was 40 centimeters in diameter in 1999, and today it is 34 centimeters. Smaller stony coral means less places for fish and aquatic animals to hide and more surface area for algae to grow.

“That may not seem like a large proportion of a coral,” said Ms. Correia of the difference in coral sizes, “But when you go out on a survey and you’re surveying thousands of corals and they’re all significantly smaller, it makes a difference in a reef over time.”

Finally, the report found that in 1999 there was 50 percent macroalgae cover. Today, that has increased to 60 percent. That is a 20 percent increase from the first study to the third.

Ms. Correia urged the audience at South Sound Community Center to make a difference in any way they can and to help ensure that future generations have access to Grand Cayman’s pristine waters.

“Everyone has a different story, but everyone can help,” she said. “Small efforts make a huge difference when a community comes together about something that you’re passionate about.”

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  1. As someone who dive this island as much as just about anyone I agree with the above article. There are a number of things that can be done. First of all there should be more protected areas with no fishing. That means NO fishing Not some fishing, Fish travel. It has been proven in numerous places around the world that if fish are allowed to grow in one area they will swim into other areas where they can be fished. If you fish them all out as we have done with the Nassau groupers there will be no fish left. It has also been proven that with less fish there is less coral and with less coral there is less fish. There is also an incredible over growth of grass killing the coral and sponges all over the reefs. If the dive community made an effort to remove the grass as they have with the lion fish the reefs would get a lot healthier. There is work to be done and we should do it