Although some resilient coral reefs are being monitored in the past decades and still present signs of health and integrity, most of the coral reefs close to unustainable development areas are being exposed to high stress and degradation. The coral reefs scientists should inform industrial developers top decision makers and society, the great difficulty in time scales to bring back the original healthy integrity, structure, function and composition of coral reefs after provoking degradation. The ecological, social and economic values are very high and non comparable to the low benefit of any unsustainable project. Restoration is natural when stopping local and global stresses. In Colombia we have two cases studies, that are not yet officially protected by the Colombian Government but recently declared as Hope Spots by Mission Blue through a bottom-up process. Both protection frameworks were presented by scientists to the Fishers community who were requesting intervention and nomination according to the Colombian Law 70 from 1993, they expressed their disagreement with unsustainable development projects that affect them. The first case study is in the boundaries between Panama and Colombia in the Caribbean Sea. These coral reefs of Capurganá-cabo Tiburón have 70% Coral Healthy Cover. The second one is in the South of Cartagena Bay where there is 80% Coral Healthy Cover Hope. Fishermen Communities have been empowered in the last ten years to avoid the threats to their coral reefs from industrial fishing, oil / gal extraction and dredging. As result their coral reefs show indicators of good ecological integrity. Artisanal fisheries are thriving sustainably and even lionfish catches by the fishers have controlled the invasive species successfully in the past 10 Years. Even though the future (40 years of global warming and possible extinction of coral reef species) seems far away, it is actually beginning right now. Breaking coral colonies with funding of enterprises that develop dredging projects, oil extraction, pollution, amd more threats to coral reefs. Depend on the empowered scientific community, how well its advice is given to top decision makers in coherence to the real total value of the coral reef ecosystem

The spatial context in which species interactions occur strongly influences an ecosystem’s resilience and ability to recover after disturbance events. Therefore, understanding how spatial interactions impact coral growth, recruitment, and diversity is of paramount importance when restoring a degraded coral reef ecosystem. On Palmyra, a remote atoll in the equatorial Pacific, the corallimorpharian Rhodactis howesii has dramatically increased in abundance and now dominates >3 km2 of reef, displacing hard corals and other dominant biota in the process. To curtail further ecosystem degradation, a restoration experiment was established at the epicenter of the corallimorph outbreak. Restoration was initiated by removing corallimorph to create a bare CaCO3 substrate, which was accomplished by tenting and application of granulated bleach for 48-hours followed by manual removal of remaining corallimorph tissue fragments. Of the 12 9m2 treatment plots created, 9 plots received coral transplants and the remaining 3 were designated as treatment controls. Coral fragments of Acropora acuminata (n = 27), Pocillopora damicornis (n = 27), and Montipora capitata (n= 27) were collected from nearby regions of reef unaffected by the corallimorph outbreak and transplanted with non-toxic two-part epoxy. Fragments were transplanted in same-species aggregations, aggregations consisting of all three species, and non-aggregated arrangements to determine how spatial distribution impacts growth among corals with varying competitive abilities and life history strategies. Four years post establishment, the restoration site has experienced nearly a 300% increase in coral cover due to growth of original transplants. Plots in which corals were transplanted in aggregations consisting of three different coral species had the highest amount of coral recruitment and an additional 100% increase in coral cover due to prolific A. acuminata growth. Corallimorph reinvasion in treatment plots has been negligible. The methods used to produce this restoration experiment can be applied to other locations around Palmyra to effectively mitigate further expansion of the corallimorph throughout the atoll. Moreover, aspects of these methods, such as multi-species coral transplant aggregation and substrate preparation, could benefit coral reef restoration programs aiming to limit biological invasions, enhance coral cover and diversity, and improve branching Acropora growth rates.

Ocean acidification (OA) can lead to dissolution of coral skeletons as well as impacting general health and physiology. This can be detrimental to ongoing coral restoration efforts. Seagrass meadows, sometimes found adjacent to coral reefs, are mostly net autotrophic as a carbon sink and use excess bicarbonate for growth. This presents the possibility of locally mediating OA effects on corals downstream of seagrass meadows and may help determine new locations for coral restoration efforts. We performed land-based and in situ studies to understand if seagrass could improve coral physiological performance under ambient and OA conditions.

A progressive decline in seawater pH known as ocean acidification (OA) will result in the reduced growth of numerous species of coral. The threatened staghorn coral Acropora cervicornis was once an ecologically important contributor to reef framework production throughout the Caribbean. Recent widespread mortality has decimated populations of this species and has provided the impetus for extensive nursery, restoration, and outplanting efforts. Here we synthesize the current state of knowledge concerning the impacts of OA on A. cervicornis. We explore new data that reveals that dynamic diel pH oscillations may enhance calcification at contemporary CO2 levels, and discuss how these findings may help to explain the differences in calcification responses observed among prior studies. We expand on these data to investigate the importance of co-occurring environmental conditions, such as light, temperature, and heterotrophy, as well as the contribution of host genotype. Finally, we address the impacts of OA on skeletal structure in order to examine how future conditions may interact with different nursery techniques to impact skeletal fragility, mortality, and asexual reproduction.

Scleractinian corals secrete calcium carbonate skeleton to form the solid foundation of the reef matrix. This process of calcification both captures (at geological time scales) and releases (at annual time scales) CO2 at a rate of 0.6 moles for each mole of CaCO3 deposited. Due to the small amount of carbon released, reefs are not included in blue carbon calculations, however, reefs have high rates of primary production, and it is likely that the carbon released by calcification is consumed in other biological processes on the reef, such as photosynthesis by associated macrophytes, and is stored within the reef system. Corals also contribute to the ocean carbon cycle through photosynthesis and respiration. They recycle their nutrients efficiently, so that carbon sequestered into the coral reef stays within the reef system, and organic matter is converted to inorganic carbon stores in coral skeletons and reef sediments. Reef crevices house organic debris, with high organic carbon content, and herbivores produce faecal pellets which sift down into long-term sediments where the carbon processed from algal tissues can be stored for millennia. Loss of hard coral results in the large-scale release of long-term carbon stores. The cycling of carbon on reefs is more complex than that of other shallow coastal ecosystems and their actual role as blue carbon repositories has not been clarified. The balance between organic carbon release and storage on modern coral reefs has not been assessed. This study evaluates the key functional groups for carbon sequestration and storage on Caribbean reefs, and measures their physiological processes to calculate a 'carbon budget' for degraded reefs vs. high-coral cover reefs. Using water sampling and in-situ incubation to measure metabolic rates of reef organisms, we demonstrate the amount of carbon captured within a small area of reef, and by sampling at degraded areas of reef we can project how this will change under future climate conditions. Demonstration of the carbon storage properties of healthy reefs will support restoration of critical reef habitat and structure, and guide protection measures as part of the Blue Carbon Initiative regulations.

Invertebrate corallivores can negatively impact the survival of coral species through direct predation and by serving as a vector for diseases. While outbreaks of Acanthaster and Drupella are known to rapidly devastate entire reef systems, other corallivores such as Culcita, Coralliophila and Hermodice also degrade resilience and prevent recovery of coral populations following disturbance from bleaching, hurricanes and disease outbreaks as they tend to form feeding aggregations on remnant wild colonies. Furthermore, chronic predation on nursery-propagated corals has been shown to cause partial and total colony mortality, reduced growth rates and increased algal colonization. Predator control efforts for Acanthaster were first initiated in the early 1960s, with intensive removal efforts undertaken to date in 48 countries, resulting in the elimination of 18 million starfish. Although large scale, multi-year efforts have been considered inefficient and unsuccessful, smaller scale programs have successfully eradicated starfish, prevented declines in coral cover, and improved recovery prospects, especially when control efforts are implemented after first detection and outbreaks are confined to a restricted area. Furthermore, removal efforts for Acanthaster and other Pacific corallivores are being recommended to improve survival, growth and recovery of remnant coral populations following the catastrophic bleaching between 2014-2017. In the Caribbean, removal of Coralliophila abbreviata has mitigated losses to endangered acroporids and has reduced bleaching severity in boulder corals. Extensive mortality among outplanted and wild acroporids during recent hurricanes and increased prevalence of aggregations of C. abbreviata on surviving storm generated fragments and colony remnants, along with recent emergence of coral diseases, emphasizes the need for direct efforts to control corallivore predators, as this will prevent further decline, enhance recovery, and improve coral restoration outplanting success.

Coral reef ecosystems are under increasing pressure by multiple stressors that degrade reef condition and function. Although improved management systems have yielded benefits in many regions, broad-scale declines continue and additional practical and effective solutions for reef conservation and management are urgently needed. Ecological interventions to assist or enhance ecosystem recovery are standard practice in many terrestrial management regimes, and they are now increasingly being implemented in the marine environment. Intervention activities in coral reef systems include the control of coral predators (e.g. crown-of-thorns starfish), substrate modification, the creation of artificial habitats and the cultivation, transplantation and assisted recruitment of corals. On many coastal reefs, corals face competition and overgrowth by fleshy macroalgae whose abundance may be elevated due to acute disturbance events, chronic nutrient enrichment and reduced herbivory. Active macroalgae removal has been proposed and trialled as a management tool to reduce competition between algae and corals and provide space for coral recruitment, in the hope of restoring the spatial dominance of habitat-forming corals. However, macroalgae removal has received little formal attention as a method of reef restoration. This review synthesises available knowledge of the ecological role of macroalgae on coral reefs and the potential benefits and risks associated with their active removal.

Grazing rates of Caribbean reef ecosystems have been in decline for the better part of a century. Top-down trophic cascades driven by a long history of overfishing, disease, and mortality of key herbivore and foundation species, and strong bottom-up eutrophication have been synergistic in shifting Caribbean reefs from a system typified by a taxonomic dominance of corals in the benthic community to one devoid of corals and often dominated by sponges, octocorals, and algae. These radical shifts in the character of the benthic community have been accompanied or even preceded at times by massive declines in fish communities. As such, restoration programs have sought to reverse these phase shifts through both algal removal/management and direct enhancement of hard corals. A great deal of emphasis has been placed on the recovery of the long spined sea urchin, Diadema antillarum, as a means of mediating the proliferation of benthic algae. The failure of D. antillarum to recover throughout the region as well as the rareity of large herbivorous fishes has left the grazing functional niche largely vacant on many Caribbean reefs. Here, we present evidence of an alternative grazer, the Caribbean King Crab, Maguimithrax spinosissimus, which may, through density-enhancement, offer restoration practitioners and resource managers a substantial tool for algal management efforts on Caribbean reefs. Additionally, we present evidence that M. spinosissimus grazing results in a series of cascading effects which may improve conditions for community-level coral reef recovery.

Coral restoration projects have been established to facilitate the recovery of coral throughout the Florida Keys. To optimize coral restoration success, identifying the ecological conditions and habitats that promote coral survival need to be identified. Since herbivory is one of the most important ecological factors effecting coral settlement, recruitment, and survival, it is necessary to determine factors controlling herbivore populations. Therefore, the purpose of this study was to identify reef habitat features that facilitate and influence herbivorous fish assemblages. We quantitatively evaluated herbivorous fish assemblages among different reef habitats throughout the Florida Keys using data from the Reef Visual Census monitoring program. This program collects abundance and size data for fish species and the associated benthic coverage information throughout the Keys. The assessment of these data provided an overview of herbivorous fish species composition for various reef habitats, a correlation between trophic and benthic composition (i.e. algal versus coral dominated reef), and a “baseline” of herbivore communities found in natural habitats and available to restoration programs in the Keys. This analysis demonstrates the importance of long term monitoring to understand the spatial variation in herbivorous fish assemblages available to coral restoration sites. Future work will review the extent to which these baseline patterns can be used to predict the relationship between the recruitment of herbivore fish to restoration sites and to restoration sites influenced by the addition of artificial habitat. These analyses will provide managers with information to increase the success of restoration efforts to rebuild coral reefs in the Florida Keys.

The long-spined sea urchin (Diadema antillarum) was once an abundant reef grazing herbivore throughout the Caribbean. Benthic surveys in the Florida Keys during the 1960-70s revealed average densities of five to ten individuals per square meter. During the early 1980s, 98-99% of Diadema antillarum populations disappeared due to an unknown disease outbreak that appeared to originate at the Panama Canal. Sudden and considerable population reduction from this event resulted in lack of reef herbivory, and contributed to ongoing ecological shifts from coral dominated systems to macroalgae-dominated systems throughout the Caribbean. Diadema antillarum populations have remained very low throughout this region since the substantial reduction in the early 1980s. Currently, depressed populations of this ecologically important herbivore necessitate exploring Diadema antillarum restoration as part of an overall reef restoration initiative. Investigations into Diadema antillarum aquaculture have been occurring for over fifteen years. The purpose of this study is to refine methodology for reliable ex situ reproduction and larval rearing of Diadema antillarum in closed recirculating aquaculture systems (RAS). The intention of this work is to improve the viability of large scale aquaculture for experimental population enhancement. Adult broodstock from the Florida Keys are being conditioned for spawning. A novel RAS incorporating vessel design elements developed by Martin Moe has been constructed. Replicated experiments in 40-L recirculating vessels will be used to investigate larval development in Diadema antillarum. Initial culture parameters tested will include cell density and species composition of microalgae diets. Microalgae species used will include Rhodomonas lens, Isochrysis galbana (T-Iso), and Chaetoceros gracilis. To assess larval development, morphometric features will be examined including larval appendage length and symmetry, body condition, and presence or absence of rudiments. Larval survival and feeding condition will also be assessed. Data collected will be presented. Future studies will test strategies for larval settlement.

The mass mortality of Diadema antillarum throughout the Caribbean in 1983-4 resulted in decreased herbivory and an increase in abundance of macroalgae on coral reefs in the region. This project intends to increase population densities of Diadema antillarum on reefs in Puerto Rico by releasing lab cultured urchins to enhance herbivory and coral recovery (recruitment rates, survival, and growth). During the summer months (May to October), Diadema settlers are collected on settlement plates set along the shelf edge in La Parguera, Puerto Rico. Settlers (0.4 mm to 1.0 mm test diameter) are brought back to the lab and grown out in aquaria and raceways. Once the urchins reach a size sufficient to reduce mortality (2.0 cm to 4.0 cm test diameter), they are then transplanted to reefs in Puerto Rico. The restocking of the urchins will increase herbivory to reduce algal cover, especially Ramicrusta, and promote coral recruitment and recovery.

The die-off of the long-spined sea urchin (Diadema antillarum) in the early 1980s is a well-studied event in the Caribbean. The loss of this important herbivore lead to significant increases in algal abundance, and consequently, coral reef degradation. Recently, D. antillarum populations have been increasing throughout the Caribbean basin. The potential effects of the return of this species on coral recruitment, however, remain unclear. While the return of D. antillarum is expected to increase the availability of suitable habitat for settling larvae and young settlers, dense urchin populations may also cause high settler mortality due to incidental grazing. On Curaçao, early algal community succession and subsequent coral recruitment are currently studied on ceramic tiles that were deployed on June 1st 2018 in areas where populations of D. antillarum are naturally recovering (≥ 1 urchin m-2), and in areas where they are virtually absent. In August 2018, settling larvae of the critically endangered coral species Acropora palmata will be exposed to tiles harboring these algal communities to track their settlement success. The tiles harboring settlers will be returned to their original location so their long-term survival and growth can be monitored. At present, two-month-old algal communities grown in the presence of dense urchin populations comprise 1.6 times more CCA and 2.1 times less turf algae compared to tiles conditioned in areas where D. antillarum are absent, confirming the role of D. antillarum in aiding the formation of benthic communities beneficial to recruiting corals. We thus expect D. antillarum to promote A. palmata settlement. If the latter hypothesis is confirmed, restoration techniques using sexually reared Caribbean corals may be significantly improved by conditioning and outplanting artificial settlement substrates in areas where D. antillarum is naturally occurring or recovering.

Corals are dying at an unprecedented rate and concurrently natural ecosystem processes on reefs are being degraded. Many restoration efforts focus on increasing the abundance of corals and fish, but fail to restore some of the processes necessary for the persistence of reefs. Coral recruitment is a key process that can promote the recovery of coral abundance and diversity after a disturbance event. While there is ample evidence that crustose coralline algae (CCA) are key facilitators for coral recruitment, very little is known about these algae on reefs. Understanding the diversity of CCA has been limited by a taxonomy that relies on an understanding of specialized morphological features that are difficult to see in live plants. We have developed a multi-faceted research program to better understand the diversity of CCA living on Caribbean reefs, how these CCA facilitate or inhibit coral recruitment, and what conditions are necessary to enable the growth and proliferation of CCA. To advance research and restoration of CCA we have built a database of genetic barcodes to identify Caribbean species of CCA. We have also designed a guide book that is available to help researchers identify CCA using the morphology of live plants in situ. These resources should facilitate the study of CCA in an effort to restore the processes that are critical for coral reef persistence.

Crown-of-thorns starfish (CoTS) cause widespread loss of hard coral cover on reefs across the Indo-Pacific. CoTS outbreaks are considered to be one of the major threats facing the Great Barrier Reef (GBR) and might be expected to have a significant influence on the success of coral restoration programs. Despite a long history of CoTS management and research on the GBR there has been only slow improvement in CoTS control programs since the 1960s. Other than the development of the single-injection culling method and the deployment of a dedicated control program, there has been no significant advance in how control activities are implemented or in their effectiveness. In response to this, we developed a linked management and research strategy that was firmly focussed on improving the design and performance of the CoTS control program. In developing the strategy we applied an integrated pest management approach. We started by asking how CoTS outbreaks arise and spread, what management responses were possible, how they might operate, and from this, what objectives were realistic. The resultant management strategy allowed us to identify key areas where research could best contribute to management by identifying realistic management objectives and providing recommendations to ensure that operations were efficient and effective. This process identified five clear management domains and associated research needs: 1) Control at sites, individual reefs, and local areas and its optimization; 2) Control at regional scales and its optimization; 3) Identifying appropriate management objectives for existing and new outbreaks; 4) developing new control and monitoring approaches; and 5) addressing ultimate causes. In this talk we describe the development of the management and research strategy, the process through which it is being implemented on the GBR, and analysis of the effectiveness of manual control to date relative to other management options.

Crown-of-Thorns Starfish (CoTS) population outbreaks are one of the major threats to the Great Barrier Reef (GBR). They are also the threat that is most directly and immediately manageable in the short term through active control. The scale of the CoTS problem, however, threatens to dwarf the resources available to combat it. It is therefore vitally important that CoTS control activities are conducted as efficiently and effectively as possible. The effectiveness of current CoTS control activities can be maximised by ensuring that CoTS are removed efficiently from areas of ecological or economic importance, or areas which foster the growth and spread of the population. Identifying and prioritising the areas where the greatest impact can be achieved requires knowledge of the current distribution of CoTS from control and surveillance activities, and a detailed understanding of the ecology that drives the spread of their population. At the same time, it is vital that the effectiveness of control actions is monitored to ensure the desired outcomes are being achieved, and to know when the CoTS population at a site has been successfully controlled and resources can be redirected to another site. The CoTS Control Centre is a tablet-based, ecologically-informed, on-water decision support system. It uses the cull and surveillance data collected by the control program, coupled with detailed ecological and management models, to recommend which sites control program staff should survey and which they should dive at, how often, and at what point they should move to the next priority site in order to achieve the greatest improvement in coral health and resilience on the GBR. It leverages advanced decision science techniques to compartmentalise the data and decisions that need to be made on-water on a daily basis from those made by program managers each month. It uses robust hierarchical decision trees to make optimal decisions under uncertainty and intermittent connectivity. It coordinates decisions across the fleet of control program vessels to optimise control strategies given current knowledge, while also generating the data required to improve our knowledge and decisions in the future.