In anticipation of the construction of the outer marina in 2014 , priority corals in the footprint of the proposed outer marina and breakwater, at the existing sandy beach, were identified for coral relocation as a mitigation strategy.
Initial relocation efforts were implemented in 2016 by Coastal Management Consulting (CMC), where 500+ coral colonies were manually transplanted to adjacent sites. CMC completed a one-year follow-up monitoring period and reported a 79% success rate on colony survivorship.
A subsequent evaluation by Environmental Systems Ltd. (ESL) in 2023, roughly 7 years later, determined that only 10% of those originally photographed colonies were confidently confirmed, with approximately 51% of coral colonies still showing signs of life. ESL’s 2023 findings highlighted two things. Firstly, some of the transplanted corals were still alive and part of an artificial reef thus contributing to the ecology of the marine environment. Secondly, future coral transplants required some type of tags to identify coral transplants for ecological tracking, and effective long-term monitoring.
In April 2024, ESL launched a second coral relocation initiative at Nanny Cay to mitigate coral loss and/or degradation from the construction of the new south marina and extended revetment, which encompasses the existing sandy beach. This relocation effort resulted in the transplantation of 500+ coral and coral fragments, 230 of which were initially tagged and documented using a standardised photographic protocol, with the remainder to be tagged at a later stage.
The corals and fragments were affixed to cleaned rock surfaces on the revetment and nearby boulder-strewn hard-bottom zones, that ranged in depth from approximately 4 to 8 meters (i.e., ~ 13 to 27 ft.). Although the transplant site was previously modified by coastal development from Nanny Cay’s 2016 expansion, the relocation site offered favourable conditions required for coral survival and growth. These conditions included, but are not limited to:
- habitat complexity;
- consistent water movement; and
- adequate sunlight.
ESL completed a brief statistical analysis of the 566 transplanted corals and coral fragments at Nanny Cay that were observed in April 2025.
The coral transplantation exercise at Nanny Cay yielded encouraging results overall as 81% of tagged and reobserved corals and/or coral fragments survived one year post-transplantation (Figure 7). On the other hand, 5% were confirmed dead, and the remaining 4% were partially dead. The majority of transplanted corals/coral fragments remained securely attached one year post-transplantation.
To build on the current findings and improve future transplant outcomes, several key actions were recommended by ESL. Continued long-term monitoring should be prioritised, with particular emphasis on replacing lost or dislodged tags. Although epoxy-backed plastic tags were used in this project, widespread tag loss highlights the limitations of this method under existing environmental conditions. ESL is actively exploring the use of a more secure and scientifically recognised tagging system to improve long-term colony tracking and site monitoring reliability.
Given the observed impact of Coralliophila snail predation, routine surveys should incorporate targeted removal of these corallivores to minimise chronic tissue loss. Algae management is also necessary, especially in areas where Peyssonnelid Algal Crusts (PACs) and turf algae have overgrown stressed or partially dead coral colonies. Manual clearing during monitoring visits, alongside the translocation of herbivorous organisms such as Diadema antillarum, the long-spined sea urchin, from nearby reef zones, may help control algal proliferation and support coral recovery.
While sedimentation was noted as a contributing stressor—particularly in sheltered, low-lying areas, broad-scale mitigation may be unfeasible without hydrodynamic modification. However, future site selection should avoid locations prone to fine sediment accumulation and poor water exchange. Instead, priority should be given to areas with:
- elevated substrate;
- consistent water movement;
- sufficient light availability for photosynthesis; and
- structurally stable surfaces.
Implementing these adaptive strategies will enhance coral survivorship, improve monitoring accuracy, and support the long-term ecological function of the transplant site, as these measures will promote oxygenation, waste removal, and larval recruitment.