Montbrun, A.

Coral reef protection is the process of modifying human activities to avoid damage to healthy coral reefs and to help damaged reefs recover. The key strategies used in reef protection include defining measurable goals and introducing active management and community involvement to reduce stressors that damage reef health. It is difficult to create a substantial plan for the protection of coral reefs due to their location out in open water; there is no distinct ownership over certain parts of the ocean, which creates difficulty in delegating responsibility. Private and government groups whose purpose is to help the environment have made steps towards the restoration of coral reefs [wikipedia, retrieved Ferbruary 2018]. Today, coral restoration is recognized as a promising strategy for preserving the genetic diversity of endangered coral species, enhancing coral populations and increasing the likelihood of successful sexual reproduction in short timeframes (National Marine Fisheries Service, 2015).

Since 2012, Coral Restoration Foundation Bonaire (CRFB) has developed a large scale reef restoration program, promoting awareness and engaging tourists and local volunteers. To date 50 different genotypes of A. cervicornis and A. palmata are growing in the nurseries and more than 15,000 coral colonies have been already transplanted back to the reef. The restoration of Acropora corals as practiced by CRFB is shown to be highly successful in terms of growth and survival of new colonies in both nurseries and transplant sites. Coral restoration is expected to contribute to ecosystem services and increase coastal protection, biodiversity, fish biomass, and tourism (Meesters et al. 2015).

The above figure shows a sequence of pictures taken at one of the restoration locations at Klein Bonaire. The corals were selected after having grown 6-8 months in off-shore nurseries and then “glued” onto the substrate. The pictures show one coral cluster, which consists of 10 A. cervicornis coral colonies of the same genotype, transplanted on March 2016. Different clusters are strategically placed in the same general area, in order to promote genetic diversity and enhance the chances of having successful sexual reproductions between different strains.

Please contact the DCBD administrator for access to the photographs or find them at Project baseline. 

The Coral restoration of Staghorn (Acropora cervicornis) and Elkhorn (A. palmata) as practiced by the Coral Restoration Foundation Bonaire (CRFB) is shown to be highly successful in terms of growth and survival of new colonies, in both nurseries and transplant locations. Coral restoration is expected to contribute to ecosystem services and increase coastal protection, biodiversity, fish biomass, and tourism.

Staghorn fields once covered the bottom of the shallow reefs of Bonaire for up to 70%. Most of Bonaire’s Staghorn and Elkhorn populations have been decimated by white band disease (WBD), leaving the shallow terraces around this popular diving destination as biologically barren sandy plains. The CRFB restoration project attempts to restore these populations by actively (with help from volunteers) rebuilding the once so attractive Staghorn fields. The coral restoration project of CRF Bonaire needed scientific assessment of important aspects of the restoration methodology such as growth, regeneration and survival of CRFB’s corals recruits.

Fragments are created from mother colonies by cutting and these cuts are short‐term wounds that need to be regenerated by the living tissue on both the ‘parent’ and the fragment. Results of a series of field experiments in the CRFB coral nurseries indicated that recovery of cut fragments was 99.6% (n=234). Time until recovery of tissue was extremely fast within approximately 1 week. Full pigmentation and apical polyp formation was generally achieved within two weeks and depended on the origin of parental colonies and the current growing location.

Over 200 colonies were transplanted from the nurseries on to attachment structures at different locations on the reef to determine growth rates and potential effects of location, attachment structure, and parental origin (genetic identity). Transplant sites (several kms apart) differing in environmental conditions and type of attachment structure were not found to impact transplant growth which was exceptionally high (almost 14 cm per year per branch tip and). An average fragment of 25 gram will grow to approximately 12 times its weight within one year. Nursery grown Staghorn fragments developed more side branches compared to their wild counterparts. While the exact mechanism behind side branch formation is not yet understood, several possible explanations are provided. The results of this research generate many follow‐up suggestions and exciting ideas for future coral restoration practices.

Results show clearly that current restoration practices by CRFB of transplanting Staghorn colonies to different locations is likely to be an excellent way to restore the Staghorn fields of Bonaire and probably in the wider Caribbean. Parental origin of the transplanted fragments significantly affected damage regeneration and growth rate, opening up the possibilities for active selection of specific genotypes to increase transplantation success. However, genetic diversity of the population should be studied and safeguarded. The measured survival, regeneration, and growth rates indicate that current restoration practices of CRFB are highly sustainable and may create viable clusters of Staghorn colonies which may initiate the regrow of Staghorn corals into thick fields. Coral restoration through fragmentation can create a very large number of viable fragments in a very short time (one fragment can be cut into two fragments within 6 months without influencing survival rate). It is recommended to also monitor the long‐term development of these restored Staghorn colonies in order to determine the recovery of the total community associated with these colonies.