Coral restoration works to increase coral cover and to increase the diversity of coral species and genotypes on reefs. This, in turn, makes the reef more resilient to the natural and human-caused stressors that are increasingly affecting coral reefs. These goals are accomplished by collecting coral fragments that have been dislodged from the reef, growing and multiplying them in a nursery, and planting them back onto the reef.
Coral restoration can be divided into four main steps
Broken or dislodged coral fragments are collected and hung on coral ‘trees’.
Fragments are allowed to grow until they have reached a size suitable for out-planting (about one year for staghorn corals).
Some fragments are out-planted onto the reef, while others are cut into smaller pieces and rehung on the trees.
Coral populations grow both on the reef and in the coral tree nurseries.
Successful coral restoration programs have these additional elements
Coral trees must be cleaned at least monthly to avoid overgrowth of algae, sponges, tunicates, barnacles, and other organisms.
Scientific monitoring of coral fragments in the nursery
Coral fragments should be monitored for growth, mortality, and health indicators, including disease, predation, and bleaching. This information can tell coral restoration scientists if the nursery is in an appropriate location, which coral species survive and grow best in that location, and which coral genotypes survive and grow best in that location.
Scientific monitoring of out-planted corals
These corals should also be monitored for growth, mortality, and health indicators. This information can tell coral restoration scientists if out-planting site is appropriate for future out-plants, which coral species survive and grow best in that location, and which coral genotypes survive and grow best in that location.
Community awareness and involvement is an important part of coral restoration. Coral reef ecosystem health affects the people living around it, so feedback from the community should always be sought and considered. Additionally, knowledge about a subject often changes attitudes toward that subject. Members of a community that are knowledgeable about the importance of coral reef ecosystems are more likely to behave as stewards of the ecosystem.
VI Reef Response currently operates two coral nurseries around the island of St. Thomas, USVI, with plans to install a third nursery in the fall of 2018.
Coral Restoration Research
VI Reef Response monitors corals when they are in the nurseries and after they are out-planted. Corals are monitored for growth, partial mortality, presence of bleaching, presence of disease, presence of competitors, and predation. Presence of invertebrates and macrofauna near the corals is also recorded.
The program uses this information to determine which nursery sites and out-planting sites are the most successful in terms of coral survival and growth as well as which coral species and genotypes have the highest survival and growth rates at each location. This knowledge informs management decisions and allows the program to become more effective over time.