- September 30th, 2010
- in Yachting
After noticing a decline in the reefs in Guana Island's White Bay five years ago, the resort island called on Dr. Lianna Jarecki to determine what could be done about the problem. Dr. Jarecki, along with Dr. Caitlin O’Connell and Dr. Graham Forrester, conceived of a restoration plan which aims to restore the elkhorn population by reattaching coral fragments to the reef.
The project focuses on elkhorn coral because there used to be a large population around Guana Island. Numbers reduced dramatically in the 1980s, however, when an epidemic of white band disease ravaged the coral reefs for three consecutive years. This was particularly devastating because elkhorn coral is one of only two types of coral that create enough limestone for proper reefs to grow. There are now only very small pockets of elkhorn left around Guana.
The study on Guana Island is not the first of its kind. Coral transplantation has been done before in the BVI, but past projects were not under any kind of scientific direction. Dr. Graham Forrester presented the research project at the Royal BVI Yacht Club, during his talk Experimental Gardening with Corals: Testing Simple Methods for Restoring Endangered Corals in the BVI. Volunteers of Reef Check BVI also had the opportunity to attend a practical workshop to get some hands-on experience in coral gardening.
Coral reef gardening is the process of rescuing coral reef fragments that have broken from the reef and reattaching them. Dr. Forrester explained how pieces of elkhorn coral can come away from the reef, often naturally, through storm damage or other disturbances. If undisturbed, and depending on the surface it lands on, coral pieces can reattach to eventually form a new colony, but the natural reattachment process is not typically successful. An alternative process is through intervention, or coral reef gardening. The project has experimented with different ways of fixing the coral back to a reef, colony or firm base, using cable ties, epoxy and cement.
Transplanted, tagged coral fragments are tied to the reefs in the hopes of regrowth.
The study started by monitoring the growth activity of three different samples of elkhorn coral pieces: fallen coral fragments, fallen coral fragments that were tied down, and fallen coral fragments that were transported to another part of the island and tied down. Looking for additional ways to help the transplantation process, the team also tried scraping seaweed away before attaching new pieces of coral, as seaweed can fight the coral for space and quite often end up winning. Ear tags (often used on cattle) were then used to identify the different control groups, by colour and number, and pictures were taken at the point of transplantation and then again after different periods of time elapsed. The team took before and after pictures and traced the area of each coral sample, which they then used to measure the surface area of the coral. Using free computer software they were then able to calculate the change in surface area over time. The results showed whether the corals had either reduced or grown.
The study found that in most cases, the untouched fallen corals had shrunk in size, and after one year most of them had died, whereas coral pieces that were tied down started to grow again within two months of transplantation. The type of fixing method used made no difference; grow back was the same. Transplanting the coral pieces from one location to another also made no difference to the final results. However, removing the seaweed prior to transplantation gave the coral pieces a significant headstart, enabling them to fix themselves to solid ground a lot quicker.
Overall, the coral pieces fared much better when they had a little help rather than being left to their own devices. Next year, Graham hopes to also compare his results with marine biologists’ monitoring growth rates of wild corals in the same area to see if there is any difference in these results.
The strongest message from Dr. Forrester’s talk was how, even with inexpensive tools and no deep scientific knowledge of corals, a little gardening and some common sense can go a long way to really helping the elkhorn corals grow and flourish again. Leaving them to recover without intervention may not be the best thing for their survival.
According to Erinn Muller, an expert coral biologist who surveys Guana Island on a regular basis, there were 230 colonies of elkhorn coral in Muskemelon Bay in 2007. By 2008, that figure was down to 140. Now, with a little intervention by Dr. Forrester and his team, there are 180. Dr. Forrester moved about 400 pieces of coral to White Bay, and about 200 are still alive with approximately 60 of them being big enough to spawn and reproduce baby corals.
Graham Forrester (far left) poses with the group of BVI volunteers.
Dr. Jarecki, Senior Lecturer at H. Lavity Stoutt Community College, who introduced the evening’s speaker, also summed up the significance of Dr. Forrester’s research for those of us who care for the BVI’s marine environment: “This is just what we need to keep the momentum and interest in reef conservation going. I do hope it inspires ARK volunteers to duplicate our restoration project at another site in the BVI.”
If you’re interested in getting involved with Reef Check BVI or the Association of Reef Keepers, send an email to [email protected]
Special thanks to Guana Island and the Royal BVI Yacht Club for hosting the workshop and talk.