An unusual project taking place in the waters of the Brac is producing some encouraging results.
The Cayman Brac Coral Nursery is part of an initiative that the Department of Environment started in May 2015. Permits were issued to dive shops willing to participate in the project, four on Grand Cayman, one on Little Cayman, and one on Cayman Brac, and the nurseries began in early 2016.
“Coral Nurseries were started in the hopes of establishing new thickets of sexually reproducing Acropora corals,” said Department of Environment senior research officer John Bothwell.
“However this alone will not save coral reefs in Cayman or anywhere else. The best hope of that is enhanced protected areas, as other countries have recently been initiating and as the Department of Environment, after carrying out several years of public consultation, has proposed and had accepted by the National Conservation Council a system of enhanced Marine Parks for the Cayman Islands. These proposals now rest with the Cabinet and the public to decide how to move forward.”
The Brac coral growing project is overseen by Roxane Boonstra and her fiancé Philip Kravitz. According to Ms. Boonstra, the nursery will likely belong to Brac Scuba Shack in the near future.
“Ideally a nursery and outplant site would be near a wild colony of the same species [in order] to encourage genetic recombination during future spawning events.”
“My fiancé and I are currently the main keepers of the nursery, which involved weekly cleaning of the PVC trees and monitoring of the corals,” said Ms. Boonstra, who holds a research-based graduate degree from the University of Miami’s Rosenstiel School for Marine and Atmospheric Science.
“Although I originally planned on studying fish and larval distributions, I wound up staying in a coral lab I was initially working as a lab technician for,” she said of her journey to her role of coral steward on the Brac.
“Corals turned out to be so much tougher than I ever expected, with a complexity I didn’t realize they had – corals get involved in chemical warfare with one another at night, they have a surprisingly complex immune system that responds to disease and bleaching, and their methods of sexual reproduction are diverse and beautiful to see. Yet they are so very fragile, and are essential to the backbone of fish populations, of human fishing populations and of tourism.”
She explained that all coral strives to catch its own food, but not all corals are very good at it. To make up for this difficulty, corals have developed a mutually beneficial symbiotic relationship with a single-celled algae known as a zooxanthella.
“My research was to study the different communities of coral-algal symbionts of Madagascar,” said Ms. Boonstra.
She explained that there are many different kinds of symbionts all over the world, and they are what give corals their typically golden color. When a coral is stressed out, such as during a period of excessive warming, this coral-algal relationship breaks down.
“Without the algae, all you can see is the clear ‘body’ of the coral and the white skeleton below,” she said.
“This is a state called bleaching; the coral is still very much alive, but in a state of extreme stress.”
Ms. Boonstra noted that if the environmental stressor is relieved, the coral-algal relationship will resume and the coral will recover, but if not, the coral animal will ultimately die.
Coral nurseries like the one Ms. Boonstra is supervising aren’t meant to bring dead reefs “back to life,” but are instead meant to strengthen weakening systems or enhance already healthy reefs.
“The first goal of the coral nursery projects is not to harm the wild corals,” said Mr. Bothwell, underscoring that it is important that only people who have experience or training collect the wild corals and put them into the nurseries, and that the amount of coral taken be limited and monitored.
He said the second goal will be growth of the corals in the nurseries resulting in outplantings that live for at least a few years.
“Stony corals like Staghorn and Elkhorn are important to a reef’s growth and structural support, not to mention providing crucial habitat for fish,” said Ms. Boonstra.
“Ideally, a nursery and outplant site would be near a wild colony of the same species [in order] to encourage genetic recombination during future spawning events.”
She said the idea of coral nurseries has been around for a considerable period of time, but the practice only recently started gaining momentum and popularity.
“Staghorn and Elkhorn corals [Acropora cervicornis and Acropora palmata] are the most popular species of coral to use, since they grow quickly, but some nurseries are experimenting with other species of corals as well,” she said.
“The basic method is to sample a wild population by taking a few small 2-3 inch fragments of coral and then moving these pieces to a structure on which they can grow. The structure can vary – cinder blocks, PVC ‘trees,’ nets and metal structures have all been used with varying pros and cons,” she said.
Once big enough, the corals can be outplanted to the reef or to another structure that would serve as the corals’ permanent new home. Once transplanted, monitoring of the coral is necessary to ensure that it’s doing well.
Providing diversity may help Cayman’s reefs in coming years.
“Research in the Cayman Islands has shown that the genetic material of staghorn coral colonies between the islands is quite different, but even the colonies on a single island are genetically different,” said Ms. Boonstra.
“Just as mixed-breed dogs are said to have a lower incidence of genetically inherited disease, perhaps a mixed coral can result from the spawning of genetically different individuals of a same species that will be more resilient to future climate change.”
So far, the results have been encouraging.
“Last May, we transplanted six big beautiful colonies of staghorn to new permanent homes, and we are thrilled to see them growing well and overgrowing their zip-tie attachments, which indicates they are cementing themselves to their new structure,” said Ms. Boonstra.
“Although our immediate goal is to see them through this unusually warm post-summer temperature, our vision is to see them grow big enough to spawn with the nearby wild colonies,” she continued.
“Phil and I talk sometimes about making an underwater art sculpture, but that would be far into the future.”