Employing a highly fragmented,weedy coral species in reef restoration

A major determinant in reef restoration programs is the choice of species employed. In this paper, we concentrate on the potential use of Montipora digitata (Dana, 1846), a highly fragmented and weedy coral species, for reef restoration and for recreation of reef physiognomy in Bolinao, The Philippines, under the ‘gardening concept’. Coral ramets (n = 1960) were reared in a shallow lagoon nursery for 1 year and then, the resulting nursery-grown colonies were transplanted onto denuded reef knolls at two different sites and according to three transplantation designs (grid design with high or low density and patch design). The nursery grown ramets, which had initially exhibited a 99% survivorship, were reduced to 87% by a super typhoon. Low detachment rates, low mortality (<1% both) and low bleaching (<3% over most months), have been indicating good nursery conditions for corals. Monitoring transplanted colonies for over 15 months showed no significant differences between the sites or among the three different transplantation designs. The major events of mortality and detachment were documented during the first 3 months post-transplantation and in the wake of a bleaching event. M. digitata transplants exhibited rapid growth (a 384% increase in ecological volume) and frequent fragmentation. Some fragments remained by their colonies of origin entangled in the attached branches, while other fragments fell onto the surrounding sandy substrate, forming M. digitata ‘beds’ around the knolls. In both, nursery and transplanted corals, creation of complex 3D structures was followed by recruitment of juvenile fishes into aggregations. Above results reveal that employing fast growing, weedy and easily fragmenting branching species, which are also considered as ‘modifier species’, in reef restoration may result in a fast regeneration of reef physiognomy. Instead of ‘copying’ natural processes, reef managers should therefore concentrate on recovering the reef's ability for self-maintenance.     

Coral reef restoration in the Eastern Tropical Pacific: feasibility of the coral nursery approach

Due to the worldwide degradation of coral reefs, the active restoration of these ecosystems has received considerable attention in recent decades. This study investigated (1) the feasibility of using coral nurseries for restoration projects, (2) the minimum size required for a Pocillopora damicornis (Pocilloporidae) coral fragment to survive and grow in a nursery, and (3) the optimal transplant size of a fragment when transplanted to a degraded reef at Gorgona Island (Colombian Pacific). For this investigation, 230 fragments were transplanted directly to El Remanso reef, and another 150 fragments were maintained in in situ nurseries. Every 2 months, the length, weight, and survival of the fragments were recorded. After growing for 134 days in the nurseries, the 52 surviving fragments were transplanted to El Remanso reef, and after 5 months, the same variables were measured. Among the nursery‐reared fragments, the largest (4 to <8 cm) had the highest survival and growth rates, whereas among the directly transplanted fragments, the smallest fragments (<2 cm) had the highest survival and growth rates. However, the nursery‐reared fragments acquired greater structural complexity (arborescent morphology), and they were all alive 156 days after transplantation and presented a maximum linear growth rate of over 2 cm, which was higher than that of the directly transplanted fragments. Apparently, the arborescent morphology acquired during the nursery period provides advantages to the colonies that favor greater success when transplanted. Therefore, nursery‐reared fragments of P. damicornis between 2 and 4 cm are the most appropriate for use in restoration projects.     

Testing the first phase of the ‘gardening concept’ as an applicable tool in restoring denuded reefs in Tanzania

Studies on coral reef restoration through a two-step coral gardening protocol have lately proved it to be a viable solution for future reef restoration. This involves a first step of gardening small colonies in mid-water nurseries and a second step, their transplantation, upon reaching suitable size, onto the pre-surveyed damaged areas. We established in September 2007 two mid-water nurseries, each holding 10,000 fragments measuring 2 cm average initial size, at 4 m depths (high tide) in Zanzibar and Mafia Islands, Tanzania. Each nursery comprised six species, each of which was represented by three genotypes. During 9 months, we followed developments by analyzing and comparing survivorship and growth rates of fragments between the different nurseries, species and genotypes. A significant difference between species survival and growth rates was observed in acroporid species, in Pocillopora verrucosa and Millepora sp., which showed better success than Porites cylindrica. In both sites, Millepora suffered no mortality and other species exhibited low mortality, ranging (per coral genotype) between 3% and 24% in Zanzibar (most cases below 10%) and between 13% and 44% (mostly below 25%) in Mafia Island. Most of fragments’ mortality occurred during the first two nursery months. Coral species in Zanzibar nursery also performed better in growth rates than those in Mafia, but in both sites, farmed corals were ready for transplantation just 9 months after the nursery was set up. Economic evaluations involved in the overall nursery set-up and the results indicated that the coral gardening approach could be used in Tanzania to generate large quantities of coral colonies for the restoration of damaged reefs at relatively low cost.     

Closing the circle: is it feasible to rehabilitate reefs with sexually propagated corals?

Sexual propagation of corals specifically for reef rehabilitation remains largely experimental. In this study, we refined low technology culture and transplantation approaches and assessed the role of colony size and age, at time of transfer from nursery to reef, on subsequent survival. Larvae from Acropora millepora were reared from gametes and settled on engineered substrates, called coral plug-ins, that were designed to simplify transplantation to areas of degraded reef. Plug-ins, with laboratory spawned and settled coral recruits attached, were maintained in nurseries until they were at least 7 months old before being transplanted to replicate coral limestone outcrops within a marine protected area until they were 31 months old. Survival rates of transplanted corals that remained at the protected in situ nursery the longest were 3.9–5.6 times higher than corals transplanted to the reef earlier, demonstrating that an intermediate ocean nursery stage is critical in the sexual propagation of corals for reef rehabilitation. 3 years post-settlement, colonies were reproductively mature, making this one of few published studies to date to rear a broadcasting scleractinian from eggs to spawning adults. While our data show that it is technically feasible to transplant sexually propagated corals and rear them until maturity, producing a single 2.5-year-old coral on the reef cost at least US$60. ‘What if’ scenarios indicate that the cost per transplantable coral could be reduced by almost 80 %, nevertheless, it is likely that the high cost per coral using sexual propagation methods would constrain delivery of new corals to relatively small scales in many countries with coral reefs.     

Improved sustainable maintenance for mid-water coral nursery by the application of an anti-fouling agent

The ‘gardening concept’ for reef restoration focuses on coral colonies farming in mid-water nurseries before their transplantation onto denuded reef areas. Nurseries situated in a nutrient-enriched environment significantly curtail nursery time, but extend labor, as nursery construction and farmed corals must be frequently cleaned from competing fouling organisms. Mass farming of corals calls, therefore, for efficient and cheap maintenance methodologies, which we here tested by employing Aqua-guard M250, an anti-fouling agent used in the fish farming industry. We found that this anti-fouling paint, while reducing fouling organisms on nursery components during the crucial phase of coral ramets' development from nubbins and small fragments sizes to colony sizes suitable for transplantation, is not toxic to maricultured coral fragments that staged more than 2 cm away from the paint. Applying small quantities of such antifouling paint to coral nurseries, while restricting its use to nursery components that are not in direct contact with farmed coral material, reduces fouling coverage and cleaning procedures by 90%.     

Poor Performance of Corals Transplanted onto Substrates of Short Durability

Worldwide, coral reefs are degrading due to increasing anthropogenic pressures. Yet, management of reefs still falls short of effectively addressing these threats, and active restoration methods are increasingly being called for. Coral transplantation is frequently advocated as a possible means of coral reef rehabilitation. Fragments produced in coral nurseries or farms have been proposed as a potential source for transplantation, and culture media (inexpensive but non‐durable materials such as wood or bamboo) may serve as transplantation substrate if placed directly in the reef. However, the performance of coral transplants attached to such substrates has not been examined yet. Here, the long‐term survival of transplants attached to bamboo substrates is reported. A total of 6,164 fragments of 4 coral species (Acroporids and Pocilloporids) were monitored for up to 20 months at three sites in North Sulawesi/Indonesia. Bamboo failed as a suitable inexpensive substrate in at least two of the three sites examined. Mortality of transplants 2 years after transplantation was high in three of the four species (67–95%) and was partially linked to substrate disintegration. The results show that, in places were currents or waves threaten to dislocate transplants, a higher effort needs to be directed at a strong and durable attachment of transplanted corals.     

Direct and indirect effects of nursery habitats on coral‐reef fish assemblages,grazing pressure and benthic dynamics

Migrating species are common within seascapes, but the potential for these movements to alter the populations and functional roles of non‐migrating species (e.g. by increasing predation) is rarely investigated. This study considers whether the presence of nursery habitats (mangroves and seagrass) simply enhances the abundance of nursery‐using parrotfishes and piscivores on nearby coral reefs, or also affects other parrotfishes. Data from 131 reef sites and multiple seascape configurations across 13 degrees of latitude were used to model correlations between biophysical variables, including nursery habitat connectivity, and the abundance and grazing pressure of both nursery‐using species and other parrotfishes and piscivore biomass. Connectivity to mangroves and dense seagrass was positively correlated with the biomass of nursery‐using species, but was also negatively correlated with non‐nursery parrotfish populations. This reduction may be caused indirectly by nursery habitats increasing confamilial competition and predation by nursery‐using piscivores, particularly affecting small parrotfishes settling directly onto reefs. As key reef grazers, parrotfishes affect coral demographics. Consequently, a spatial simulation model predicted the impacts after five years of changes in grazing pressure because of nursery habitat connectivity. The model demonstrated that high nursery connectivity was correlated to changes in grazing pressure on nearby reefs that could potentially lead to differences in coral cover of ～3–4% when compared to low connectivity reefs. However, the direction of this change depended on the seascapes’ characteristics. Historically, large‐bodied, nursery‐using parrotfish would have increased grazing in all nursery‐rich seascapes. Overfishing means that nursery availability may have spatially variable impacts on coral cover, influencing reserve design. This study suggests that nursery availability may directly and indirectly modify an ecological process, and alter an ecological cascade (migrating species increase predator and competitor abundances, affecting other grazers and consequently corals). Therefore, elucidating the multi‐species impacts of animal movements is required to better understand ecosystem functioning.     

Optimizing industrial‐scale coral reef restoration: comparing harvesting wild coral spawn slicks and transplanting gravid adult colonies

Accelerating coral reef restoration is a global challenge that has been attempted around the world. Previous attempts show varying levels of success at localized scales, but comparisons of cost and benefits to evaluate large‐scale reef restoration approaches are lacking. Here, we compare two large‐scale restoration approaches: the harvesting, development, and release of wild coral spawn slicks onto a target reef, with the transplantation of gravid coral colonies to provide a seed population and local source of larvae. Comparisons incorporate the best available information on demographic rates to estimate population growth, beginning at embryo production to colony maturity 4 years following deployment. Cost‐effectiveness is considered in a coarse manner. The harvesting, development, and controlled release of coral spawn slicks is anticipated to achieve large‐scale restoration of coral communities with low‐impact technology at low cost per colony. Harvesting wild spawn slicks has the potential to (1) transport billions of larvae up to thousands of kilometers that (2) are relevant to coral restoration efforts at vast geographical scales while (3) benefitting from the use of technology with extremely low impact on wild populations and (4) retaining natural genetic and species diversity needed to enhance the resilience of restored communities. Transplanting colonies is most useful from reefs designated to be impacted by infrastructural development by providing an opportunity for transfer to high value zones, from dedicated nurseries, and for brooding species. Our contribution provides insights into critical elements of both concepts, and we highlight information gaps in parameter uncertainties.     

Evaluating Methods for Transplanting Endangered Elkhorn Corals in the Virgin Islands

Restoration of rare corals is desirable and restoration projects are fairly common, but scientific evaluation of this approach is limited. We tested several techniques for transplant and restabilization of Acropora palmata (the elkhorn coral), an ecologically important Caribbean coral whose populations have suffered severe declines. In rough weather, fragments break‐off colonies of branching corals like A. palmata as a normal form of asexual reproduction. We transplanted naturally produced coral fragments from remnant populations to nearby restoration sites. Untouched control fragments at the donor site died faster and grew slower than fragments attached to the reef, so attaching fragments to the reef is beneficial. Transplanted fragments grew and died at a rate similar to fragments left at the donor site (both groups were attached to the reef), so there were no effects of moving fragments or differences in habitat quality between donor and restoration sites. Growth and survival were similar using four methods of attaching fragments to the reef: cable ties, two types of epoxy resin, and hydrostatic cement. Corals sometimes compete with the macroalgae that dominate degraded reefs, and clearing surrounding algae improved the growth of fragments. After 4 years, transplanted fragments grew to 1,450 cm² in area and so were potentially sexually active. Because the methods tested are simple and cheap, they could be used by volunteer recreational divers to restore locally extirpated A. palmata populations or to enhance reefs where natural recovery is slow.     

In situ nurseries enhance coral transplant growth in sedimented waters

In situ nurseries have been a crucial part of coral reef restoration initiatives for the past two decades. However, the advantages over direct transplantation in sedimented waters has yet to be examined. In the present study, we showed that Pachyseris speciosa and Pocillopora damicornis fragments reared in in situ nurseries (NR) in Singapore’s sedimented waters grew significantly faster (by three to five times) than those which were directly transplanted (DT) onto the substrates. The increased growth rate during the nursery phase augmented the size of NR transplants, and had a flow-on effect on their performance during the post-transplantation phase. Overall, the maximum diameter of the NR transplants was 1.8–2.7 times larger than DT transplants after 11 months. The growth enhancement of the nursery-reared transplants improved the cost-effectiveness of our restoration effort: the estimated cost per centimetre growth of NR transplants was one-fifth of the DT corals despite the additional costs incurred to construct the nurseries. These results highlight that coral nurseries are beneficial to reef restoration in chronically sedimented waters.     

Macroalgae reduces survival of nursery‐reared Acropora corals in the Florida reef tract

Recent declines in coral populations along the Florida reef tract have prompted the establishment of coral restoration programs which raise coral species, such as the threatened Acropora cervicornis, in nurseries ready for outplanting. Large numbers of nursery‐reared coral colonies have been outplanted along the Florida reef tract in recent years, yet few studies have characterized benthic habitats that are considered optimal for colony survival. In 2016, we surveyed 23 A. cervicornis restoration sites, located at six different reefs in the upper Florida Keys. We examined the condition of the outplanted corals and quantified the benthic assemblages adjacent to the outplanted coral colonies. We found that where A. cervicornis survived for more than 1 year, the substrate significantly supported less brown macroalgae of the genus Dictyota than at sites where A. cervicornis had died. Coral survival was highest at sites with less than 15% Dictyota cover. These results suggest that the habitat conditions that supported Dictyota spp. were not conducive to A. cervicornis growth and survival. Restoration practitioners should avoid attaching nursery‐raised corals to substrate with Dictyota spp. cover greater than 15%.     

Motivations,success, and cost of coral reef restoration

Coral reef restoration is an increasingly important part of tropical marine conservation. Information about what motivates coral reef restoration as well as its success and cost is not well understood but is needed to inform restoration decisions. We systematically review and synthesize data from mostly scientific studies published in peer‐reviewed and gray literature on the motivations for coral reef restoration, the variables measured, outcomes reported, the cost per hectare of the restoration project, the survival of restored corals, the duration of the project, and its overall spatial extent depending on the restoration technique employed. The main motivation to restore coral reefs for the projects assessed was to further our ecological knowledge and improve restoration techniques, with coral growth, productivity, and survival being the main variables measured. The median project cost was 400,000 US$/ha (2010 US$), ranging from 6,000 US$/ha for the nursery phase of coral gardening to 4,000,000 US$/ha for substrate addition to build an artificial reef. Restoration projects were mostly of short duration (1–2 years) and over small spatial extents (0.01 ha or 108 m²). Median reported survival of restored corals was 60.9%. Future research to survey practitioners who do not publish their discoveries would complement this work. Our findings and database provide critical data to inform future research in coral reef restoration.     

Mid-water rope nursery—Testing design and performance of a novel reef restoration instrument

Fast degradation of coral reefs worldwide has promoted the exploitation of active restoration instruments, one of which is the ‘gardening concept’. This concept comprises two phases: (1) establishing in situ coral nurseries for rearing large numbers of coral fragments; (2) their transplantation onto denuded reefs. This study tested the design and performance of a novel mid-water floating nursery instrument, a ‘rope nursery’. This nursery accommodated small coral fragments attached to a rope, creating an easily constructed nursery bed that is rapid and inexpensive. Two sets of experiments were conducted: the first tested two mid-water rope nursery prototypes in small-scale trials that tested depth, coral genotypes and construction stability, whereas the second set incorporated lessons learned from the first set, and was designed to carry larger numbers of colonies. These highly economical nurseries (US$ 0.11/fragment) revealed high survivorship low detachment and fast growth rates compared to previous coral-nursery types. Moreover, the coiling force of the ropes adequately held fragments without adhesives, and the minimal surface area of rope nursery beds provided not only improved water flux around farmed corals, but also reduced proliferation of fouling organisms. The rope nursery prototypes studied here attest to the diversity of their potential uses under various conditions and demands, making the construction of large scale nurseries a very feasible target. This restoration instrument was proven to be an effective coral reef rehabilitation tool.     

How Quickly do Fragments of Coral “Self‐Attach” after Transplantation?

Transplantation of coral fragments is seen as a potential method to rapidly restore coral cover to areas of degraded reef; however, considerable research is still needed to assess the effectiveness of coral transplantation as a viable reef restoration tool. Initially, during restoration efforts, coral transplants are attached artificially. Self‐attachment (i.e., growth of coral tissue onto the substrate) provides a more secure and lasting bond, thus knowledge about self‐attachment times for corals is of importance to reef restoration. While it is known that coral fragments may generate new tissue and bond to substrata within a few weeks of transplantation, surprisingly little is known about the speed of self‐attachment for most species. Two independent experiments were carried out to examine the self‐attachment times of 12 scleractinian and one non‐scleractinian coral species to a natural calcium carbonate substrate. The first experiment examined times to self‐attachment in 11 species of differing morphologies from seven families over approximately 7 months, whereas the second experiment examined three fast‐attaching Acropora species over approximately 1 month. In the first experiment, the branching species Acropora muricata had a significantly faster self‐attachment time compared to all other species, while Echinopora lamellosa had the slowest self‐attachment time. For the second experiment, A. muricata was significantly slower to self‐attach than Acropora hyacinthus (tabular) and Acropora digitifera (corymbose‐digitate). The results suggest that a combination of factors including growth rates, growth form and life history may determine how quickly fragments of coral species self‐attach after fragmentation and transplantation.     

Performance of single versus mixed coral species for transplantation to restore degraded reefs

Coral transplantation has become a potential tool for the restoration of coral cover in degraded reef habitats. Yet, very few investigations have attempted to determine whether there is an advantage for at least two species to be used together in coral transplantation. It is hypothesized that corals would perform better in terms of survival and growth when transplanted in mixed‐ than in single‐species plots. Single‐species plots were compared with combinations of two species at several reef sites, using three separate coral species, namely, Porites cylindrica, Pavona frondifera, and Hydnophora rigida. P. cylindrica performed consistently well in terms of survival whether alone or in the presence of another species. In a stressful environment with strong wave action, P. frondifera performed better when mixed with P. cylindrica than when alone. However, this difference was not evident where wave action was weak. The influence of mixing on the growth rates of H. rigida and P. frondifera transplants could not be examined completely because of high mortality because of predation by the starfish Acanthaster planci and the gastropod Drupella sp. Interestingly, the presence of P. cylindrica appeared to minimize the impact of predation on P. frondifera transplants. The setback caused by predation stresses the importance of other factors that influence the outcome of restoration interventions. Future initiatives should take into consideration management measures when selecting sites in relation to wave action and predators, control predator outbreaks, and use coral species, e.g. P. cylindrica that are less susceptible to predation.     

Fixed and suspended coral nurseries in the Philippines: Establishing the first step in the “gardening concept” of reef restoration

The worldwide degradation of reef ecosystems has promoted the advocators of restoration acts to the foreground. Here, we describe the results of the first step of large-scale restoration based on the “gardening with corals” concept. During June-September 2005, two coral nurseries were established in Bolinao, the Philippines, in front of Silaqui Island, in a shallow (2 m depth) sandy lagoon. Two types of nurseries were employed: (1) suspended nursery; (2) leg-fixed nursery. The nursery held a total number of 6824 ramets, from seven coral species representing different growth forms (branching, leaf-like and sub-massive forms) and different growth rates (fast and slow growing species). Each species was represented by several genotypes. During one year, we analyzed and compared survivorship, bleaching and growth rates of fragments between the different nurseries, species and genotypes. Survivorship, which was high in both nurseries, > 85%, fluctuated between the different species indicating that different species require different rearing methodologies. Mortality and detachment was subjected to environmental conditions, especially affected by the typhoons prevailing in this part of the world. The one-year nursery phase produced sizeable colonies, especially of branching forms, suitable for transplantation.     

Effect of severe hurricanes on biorock coral reef restoration projects in Grand Turk, Turks and Caicos Islands

Artificial reefs are often discouraged in shallow waters over concerns of storm damage to structures and surrounding habitat. Biorock coral reef restoration projects were initiated in waters around 5 m deep in Grand Turk, at Oasis (October 2006) and at Governor's Beach (November 2007). Hemi-cylindrical steel modules, 6m long were used, four modules at Oasis and six at Governor's Beach. Each project has over 1200 corals transplanted from sites with high sedimentation damage, and are regularly monitored for coral growth, mortality and fish populations. Corals show immediate growth over wires used to attach corals. Growth has been measured from photographs using a software program and is faster at Governor's Beach. After hurricanes Hanna and Ike (September 2008) the Governor's Beach structure was fully standing since the waves passed straight through with little damage, the Oasis structures which were tie-wired rather than welded had one module collapse (since been replaced with a new, welded structure). Hurricane Ike was the strongest hurricane on record to hit Grand Turk. Most cables were replaced following the hurricanes due to damage from debris and high wave action. The projects lost about a third of the corals due to hurricanes. Most of those lost had only been wired a few days before and had not yet attached themselves firmly. These projects have regenerated corals and fish populations in areas of barren sand or bedrock and are now attractive to snorkelers. High coral survival and low structural damage after hurricanes indicate that Biorock reef restoration can be effective in storm-impacted areas.     

Effects of nursery table slope orientation on coral survival and growth

Transplanting nursery-reared corals is among one of the most common approaches to assist the recovery of degraded reefs. The nursery phase is considered essential for providing a favourable environment for coral fragments to grow into suitable sizes before transplantation to natural reef substrates. Several types of coral nursery designs have been used, but the effect of nursery table slope orientation on survival and growth of coral fragments has not been fully evaluated. Survival and growth of coral fragments from four species (Pectinia paeonia, Podabacia crustacea, Pocillopora acuta, Merulina ampliata) on three inclinations of nursery table top (horizontal (0°), diagonal (45°) and vertical (90°)) were monitored over six months. The effects of slope orientation on survival and growth of fragments were not significant among species except P. acuta, for which survivorship and growth decreased significantly only on vertical nursery tables. The conditions required for coral propagation, such as slope orientation of nursery tables and the initial size of fragments, clearly differ among species due to their inherent attributes and restoration success will greatly benefit from empirical studies derived from a wider range of species.     

Long-term heightened larval production in nursery-bred coral transplants

The ‘gardening coral reefs’ method is part of the approaches proposed for counteracting the substantial impacts of global climate change on the survival of coral reefs. It incorporates ecosystem engineering strategies for coral nursery farming and coral colonies out-planting. This study explores the reproductive output of three sets of nursery-grown Stylophora pistillata colonies along eight reproductive seasons following transplantation, as compared to that of native corals. When native and transplanted corals grew side by side in a disturbed environment, the nursery-grown transplants showed enhanced larval release (2.6–22.5 times more planulae/colony; multiyear average: 11.6±1.8 planulae/transplant vs. 1.5±0.3 planulae/native colony) with higher percentages of gravid colonies (91±2.1% transplants vs. 34±7.6% native colonies). The inherently enhanced larval production of transplants, maintained for such a long period of time post-transplantation, reveals a possible enduring impact of the nursery conditions on future fitness and ecological traits of transplants. This is further supported by the emerging documentation regarding the enhanced growth of corals under nursery conditions, which continues to be detected even years after transplantation was conducted on the natural reef. The above enhancement of coral reproduction can be harnessed as a human intervention tool for countering global climate change impacts.     

Implications of coral harvest and transplantation on reefs in northwestern Dominica

In June, 2002, the government of Dominica requested assistance in evaluating the coral culture and transplantation activities being undertaken by Oceanographic Institute of Dominica (OID), a coral farm culturing both western Atlantic and Indo-Pacific corals for restoration and commercial sales. We assessed the culture facilities of OID, the condition of reefs, potential impacts of coral collection and benefits of coral transplantation. Coral reefs (9 reefs, 3-20 m depth) were characterized by 35 species of scleractinian corals and a live coral cover of 8-35%. Early colonizing, brooders such as Porites astreoides (14.8% of all corals), P. porites (14.8%), Meandrina meandrites (14.7%) and Agaricia agaricites (9.1%) were the most abundant corals, but colonies were mostly small (mean = 25 cm diameter). Montastraea annularis (complex) was the other dominant taxa (20.8% of all corals) and colonies were larger (mean = 70 cm). Corals (pooled species) were missing an average of 20% of their tissue, with a mean of 1.4% recent mortality. Coral diseases affected 6.4% of all colonies, with the highest prevalence at Cabrits West (11.0%), Douglas Bay (12.2%) and Coconut Outer reef (20.7%). White plague and yellow band disease were causing the greatest loss of tissue, especially among M. annularis (complex), with localized impacts from corallivores, overgrowth by macroalgae, storm damage and sedimentation. While the reefs appeared to be undergoing substantial decline, restoration efforts by OlD were unlikely to promote recovery. No Pacific species were identified at OID restoration sites, yet species chosen for transplantation with highest survival included short-lived brooders (Agaricia and Porites) that were abundant in restoration sites, as well as non-reef builders (Palythoa and Erythropodium) that monopolize substrates and overgrow corals. The species of highest value for restoration (massive broadcast spawners) showed low survivorship and unrestored populations of these species were most affected by biotic stressors and human impacts, all of which need to be addressed to enhance survival of outplants. Problems with culture practices at OID, such as high water temperature, adequate light levels and persistent overgrowth by macroalgae could be addressed through simple modifications. Nevertheless, coral disease and other stressors are of major concern to the most important reef builders, as these species are less amenable to restoration, collection could threaten their survival and losses require decades to centuries to replace.