Cayman Islands Coral Watch

Since 1997, the Cayman Islands Department of Environment (DOE) has systematically assessed coral health around the Cayman Islands. However, we cannot be everywhere, particularly during bleaching events and as the reef recovers. We need YOUR help to collect valuable data in order to track the progression of the current bleaching event and the impact of future annual bleaching on our reefs. By simply sending us observations and underwater images/videos of unhealthy corals while diving we will be able to monitor the extent of the bleaching outside the DOE’s normal monitoring range.

What is happening to our beloved reefs?

Coral reefs are ocean oases, supporting immense diversity, and they are estimated to contribute $125-145 trillion per year in global ecosystem services (Costanza et al., 2014). These important ecosystems are currently under threat from local impacts and global climate change, including warming and ocean acidification.

Corals exist because of an incredible partnership between animal and plant. Reef corals acquire the majority of their energy and nutrients from single celled algae called zooxanthellae (zoos), which live inside the coral polyps. Like other plants, zoos get their energy from photosynthesis and are the reason why corals are so colourful. When sea temperatures rise beyond their tolerance, stress causes this partnership to break down. As a result, corals expel the zoos out of their system and turn ghostly white. This condition is known as ‘Coral Bleaching’ and is currently threatening Cayman’s coral reefs and other areas around the world. The sad truth is if current trends continue, severe bleaching is predicted to occur every year on 90% of the world’s coral reefs by 2055 (Hooidonk et al., 2014).

What happens next?

This depends on how severe and enduring the high sea surface temperatures are. Zoos are free living in the surrounding water and can return to the coral within a few weeks if the water cools down fast enough. If not, the coral will die from starvation or cumulative stressors such as disease.

The National Oceanic and Atmospheric Administration (NOAA) Coral Reef Watch (CRW) has developed a set of Heat Stress Gauges to reflect the observed and forecasted bleaching alert level surrounding select islands and coral reefs. The graph (below) provides a record of temperature, thermal stress, and bleaching potential and allows for comparisons between years. It seems sea surface temperatures are gradually lowering this month which may be partly due to the stormy weather we have been experiencing. Hopefully this trend continues so Cayman’s coral reefs will stop bleaching and return to health as soon as possible.

Find out more information:

How can you help us?

You do not need to be a scientist to get involved with this programme. By simply sending us underwater images of bleached corals while diving in the Cayman Islands and recording valuable data with the Coral Watch data sheet (linked below), we will be able to monitor the extent of the bleaching outside the DOE’s normal monitoring range. These data will allow us to monitor the recovery of our reefs once sea temperatures return to normal and help influence important management decisions to help protect our reefs in the future.

   Coral Watch data sheet

How to fill in DoE’s Coral Watch data sheet?

From the data sheet we will be able to gather important information about the unhealthy corals you have photographed:

  • District, Dive Site & Position: We will be able to upload your sightings onto a map to show where corals are bleaching most intensively around the islands. This will also allow the DOE to target specific areas to monitor which have not been reached by the public.
  • Temperature, Visibility, Current & Time of Day Photo was taken: We can assess important variables during your dive which may indicate why some areas are bleaching more than others.
  • Image number: This is a very important column which will allow us to match your images to our data spreadsheet. The captions of images attached in email/dropbox/google drive should correspond with the number noted on the spreadsheet e.g. 1, 2, 3.
  • Depth of Coral: We can assess whether bleaching is occurring deep/shallow/both.
  • Coral species, Stages of Bleaching, Disease present: Unfortunately we will not have time to teach coral/bleaching/disease identification but please try to fill in these columns to the best of your ability (photos attached to help). The DOE reef team should be able to fill in gaps in these columns by using your attached photographs.
  • % of Unhealthy Corals: Will give a useful indication of how stressed the total reef area is.

If you are interested in getting involved in the programme or have any questions/concerns please email:

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