Coral reef restoration efforts in Latin American countries and territories

Coral reefs worldwide are degrading due to climate change, overfishing, pollution, coastal development, coral bleaching, and diseases. In areas where the natural recovery of an ecosystem is negligible or protection through management interventions insufficient, active restoration becomes critical. The Reef Futures symposium in 2018 brought together over 400 reef restoration experts, businesses, and civil organizations, and galvanized them to save coral reefs through restoration or identify alternative solutions. The symposium highlighted that solutions and discoveries from long-term and ongoing coral reef restoration projects in Spanish-speaking countries in the Caribbean and Eastern Tropical Pacific were not well known internationally. Therefore, a meeting of scientists and practitioners working in these locations was held to compile the data on the extent of coral reef restoration efforts, advances and challenges. Here, we present unpublished data from 12 coral reef restoration case studies from five Latin American countries, describe their motivations and techniques used, and provide estimates on total annual project cost per unit area of reef intervened, spatial extent as well as project duration. We found that most projects used direct transplantation, the coral gardening method, micro-fragmentation or larval propagation, and aimed to optimize or scale-up restoration approaches (51%) or provide alternative, sustainable livelihood opportunities (15%) followed by promoting coral reef conservation stewardship and re-establishing a self-sustaining, functioning reef ecosystems (both 13%). Reasons for restoring coral reefs were mainly biotic and experimental (both 42%), followed by idealistic and pragmatic motivations (both 8%). The median annual total cost from all projects was $93,000 USD (range: $10,000 USD—$331,802 USD) (2018 dollars) and intervened a median spatial area of 1 ha (range: 0.06 ha—8.39 ha). The median project duration was 3 years; however, projects have lasted up to 17 years. Project feasibility was high with a median of 0.7 (range: 0.5–0.8). This study closes the knowledge gap between academia and practitioners and overcomes the language barrier by providing the first comprehensive compilation of data from ongoing coral reef restoration efforts in Latin America.


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Introduction 64
Active restoration, the process of assisting the recovery of an ecosystem that has been degraded, 65 damaged, or destroyed [1], may be increasingly necessary on coral reefs, once it has been determined 66 that the natural recovery of corals is hindered [2]. The goal of any restoration action is to eventually 67 establish self-sustaining, sexually reproducing populations with enough genetic variation enabling 68 them to adapt to a changing environment [3][4][5]. 69 Coral reef restoration may play a particularly important role where coral species are threatened with 70 extinction. The Caribbean Elkhorn coral, Acropora palmata, and Staghorn coral, A. cervicornis, were 71 once widely distributed and among the major reef-building species in the region [6]. Both species are 72 now listed as Critically Endangered on the International Union for Conservation of Nature (IUCN) Red 73 List [7] as a result of major losses in cover of both species throughout the Caribbean since the 1970s 74 [8]. Management programmes have not aided in the recovery of A. palmata [9]. In this context, active 75 restoration of these species is essential to recover their ecosystem functions in the Caribbean region. 76 Several techniques are used for the restoration of coral reefs. The most common techniques are based 77 on asexual methods such as direct transplantation, coral gardening, and micro-fragmentation [10]. An 78 alternative technique, larval propagation, is based on the collection of gametes and the consequent 79 culturing of embryos and larvae, after which the coral spat are either grown in ex situ aquaria to larger-80 sized colonies or are outplanted onto degraded reefs at approximately one month old [11]. While the 81 techniques used to restore coral reefs are reviewed elsewhere (e.g. [10,[12][13][14]), here we focus on 82 direct transplantation, coral gardening, micro-fragmentation, and larval propagation as the 83 techniques most-commonly employed by the case studies in the study area. One of the oldest 84 techniques used in coral reef restoration is direct transplantation of corals [15], which involves the 85 harvesting of coral colonies from a donor site and their immediate transplantation to a restoration 86 site or re-attaching colonies that have been dislodged by a ship grounding, storm or hurricane [16]. 87 The coral gardening approach was developed to scale-up restoration while reducing the stress on 88 donor colonies. Fragments of corals are harvested from donor colonies, grown in nurseries to a 89 threshold size [17] before being transplanted onto a degraded reef [18,19]. Nurseries can be ocean-90 based (in situ) or land-based (ex situ). In situ nurseries are typically located at well-lit sites safe from 91 predation, storm surges, and wave energy, and are regularly maintained and cleaned by physical 92 removal of algal growth [20]. However, strategic siting of ocean nurseries can promote the 93 recruitment of fish assemblages that eat biofouling, thus may significantly reduce person-hours spent 94 in nursery cleaning [21]. In situ nurseries can have many shapes and sizes. For example, they can 95 consist of floating mid-water structures built using ropes, mesh or cages [21][22][23][24] fragmentation is an approach especially useful for slow-growing massive corals. This technique 100 involves the fragmentation of parts of a massive coral donor to yield multiple ~1 cm 2 fragments. The 101 fragments are placed close to each other on either artificial substrates or on the surface of dead coral 102 colonies. The micro-fragments, as they recognize neighbouring fragments as kin, grow towards each 103 other and fuse [29]. Ideally, they are outplanted to the degraded reef at a size of ~6 cm 2 [29,30]. Larval 104 propagation involves the breeding of corals from eggs and sperm. Studies describing this technique 105 typically report the use of raceways with seawater flow-through systems where coral spawn is 106 collected from the wild, fertilization is assisted, embryos are cultured to larvae, which are settled onto 107 substrates and then transported and seeded onto a degraded coral reef [31][32][33]. This process has also 108 been referred to as larval enhancement, sexual propagation, sexual coral cultivation or larval 109 reseeding [12]. As an emerging larval propagation technique, larval restoration concentrates coral 110 larvae over enhancement plots on the degraded reef to facilitate coral larvae settlement directly to 111 the substrate, without the need of laboratory facilities [34]. The main advantages of the larval 112 propagation techniques are that they increase the genetic diversity among restored coral populations 113 thus enabling increased rates of adaptation and improved resilience in the context of climate change 114 [35], and they have the potential to be used over large scales while reducing the cost [31]. Also, they 115 do not cause damage to the parent colonies. 116 While efforts in the USA, Australia or places where European scientists conduct their research are well 117 described in the published literature and disseminated at conferences, there is a paucity of 118 documentation on coral reef restoration projects carried out by practitioners in the Caribbean and 119 Eastern Tropical Pacific. Reasons for this lack of exchange may be the language barrier, lack of interest 120 in knowledge transfer between higher and lower income countries or cultural differences as well as 121 lack of funding. In 2018, the Reef Futures symposium was held in the Florida Keys, USA and attended 122 by over 400 delegates. The aim of this international meeting was to 'bring together experts from 123 around the world to share the latest science and techniques for coral reef restoration while kicking off 124 a global effort to dramatically scale-up the impact and reach of restoration as a major tool for coral 125 reef conservation and management'. The conference was organized by the Coral Restoration 126 Consortium, which is 'a community of practice comprised of scientists, managers, coral restoration 127 practitioners, and educators dedicated to enabling coral reef ecosystems to survive the 21 st century 128 and beyond' [36]. Within the Reef Futures conference, we convened a meeting of scientists and 129 practitioners involved in active coral reef restoration in the Latin-and Centro-American Caribbean as 130 well as the Eastern Tropical Pacific to fill the knowledge gap between academia and practitioners in 131 the region and overcome the language barriers in coral reef restoration. Here, we showcase the 132 advances and share the lessons learned from 12 restoration case studies from the Caribbean and 133 Eastern Tropical Pacific. We provide a comprehensive compilation of unpublished data from coral reef 134 restoration efforts where we outline the techniques that were employed, the motivations and 135 objectives of each project, total project cost per unit area per year, spatial extent of intervention, and 136 project duration. This work provides the most complete data set on total project cost and feasibility 137 of coral reef restoration from practical cases that may guide decisions required to establish new 138 restoration projects in the future. 139 Approach 140

Data collection 141
The co-authors of this work contributed data and descriptions of their restoration projects which 142 constitute the case studies used here. The coral reef restoration projects were carried out in Latin 143 American countries and territories in the Caribbean and Eastern Tropical Pacific (Fig. 1). The data 144 obtained included estimates on total annual project cost, spatial extent of area intervened, project 145 duration, and an estimate on the project reaching specific objectives within a fixed period of time. The 146 motivations for each restoration project were adopted from [10, 37, 38] and classified as biotic, 147 experimental, idealistic, legislative, and pragmatic ( Table 1). 148 Pragmatic Enhance ecosystem services (e.g., fisheries production) Enhance ecosystem services (e.g., water quality improvement, pollution prevention) Enhance ecosystem services (e.g., coastal protection, erosion control, bank stabilisation) Enhance ecosystem services (e.g., carbon sequestration, carbon offsets) The objectives of coral reef restoration projects can be highly diverse and dependent on the specific 151 project as well as its location. In this study, the restoration practitioners were asked to provide the 152 objectives for their restoration projects, which were specific, measurable, achievable, repeatable and 153 time-bound (SMART; [3]). We modified the six primary objectives observed by Hein et al. [39] into the 154 following categories: 1) enhance ecosystem services for the future; 2) optimize/scale-up restoration 155 approaches; 3) promote coral reef conservation stewardship; 4) provide alternative, sustainable 156 livelihood opportunities; 5) reduce coral population declines and ecosystem degradation; and 6) re-157 establish a self-sustaining, functioning reef ecosystem. 158 The total estimated project cost includes both capital and operating costs. Capital costs are those used 159 for planning, land acquisition, construction, and financing [40]. These may also include costs for 160 laboratory/infrastructure, boats and dive equipment. Operating costs are those used for maintenance, 161 monitoring, equipment repair and replacement [40] and may include salaries, housing for 162 scientific/implementation teams, air for SCUBA tanks, gasoline for boat engines, and replacement of 163 computers. Coral reef practitioners were asked to estimate the total cost for restoration interventions 164 The project spatial extent is the coral reef area intervened by the restoration project and is reported 168 in hectares. Spatial extent is not provided for each project since not all restoration case studies have 169 an objective to increase the area of restored habitat. For instance, some projects are aimed at 170 developing new restoration techniques, using coral nurseries as a tool to stimulate public awareness 171 and engagement, for educational purposes, or as a tourist attraction. 172 The project duration is the time during which the restoration project has existed until the present, or 173 the time during which the restoration cost was budgeted for and is provided in years. All projects 174 described here are ongoing and active throughout 2019. 175 The feasibility is the likelihood that each specific project objective can be reached successfully with 176 the interventions at hand and within the outlined project duration. It is ideally measured as the 177 likelihood of success in returning the ecosystem function and resilience of an ecosystem through 178 restoration [42]. This overall restoration project feasibility is rarely reported in the published literature 179 because a standardised method to measure restoration success is largely missing [40]. Here, 180 restoration practitioners estimated the feasibility of the restoration interventions they employed to 181 achieve their specific project objectives. Feasibility is given as a ratio between 0 and 1 and can be 182 interpreted as the likelihood of success to reach a specific objective within the duration of the 183 restoration project. Practitioners provided a minimum, maximum and the best guess for the project 184 feasibility. 185 186

187
Data from a total of 12 coral reef restoration projects carried out by practitioners in the Spanish-188 speaking Caribbean and Eastern Tropical Pacific were compiled and are summarised in Table 2. The 189 supplementary material contains more detailed information about each restoration case study.  Table S1). 199 The primary motivation is idealistic following social reasons such as community education and engagement. The secondary motivation is experimental i.e., to improve management and develop standardized restoration protocols.
1) to develop a training centre for the sustainable use of marine resources and ecological restoration; 2) to establish a community-based coral reef monitoring system for Taganga Bay and coral nurseries therein with the possible expansion of monitoring to other areas; 3) to develop a management plan for Taganga Bay as a marine reserve, which is governed by the local community; and 4) to create a financed organization, which aims to facilitate long-term ecological reef restoration and research in Taganga Bay Corals grown in the midwater nursery will be outplanted by drilling holes in the natural substrate with a pneumatic drill and inserting the plastic nails of the cement cookies carrying the coral fragments into the holes (supported by epoxy glue where necessary). All outplanted corals at the restoration site will be monitored at least once per month while they reattach to the natural substrate.
The spatial extent of the project is currently a matter of negotiation that depends on the capacity to recruit coral gardeners from the local community and to obtain a permit to carry out the ecological restoration work in Taganga Bay.
An estimated budget for the project is $500,000 USD over the next two years. Forty percent of this budget is self-funded by local stakeholders to accelerate the capacity of coral growth and maintenance of coral outplanting through local capacity building. A large proportion of the estimated project budget will be directed to activities such as education, community engagement and training while a minor part will be focused on growing and outplanting corals to the restoration site. Members from the local community are trained as coral gardeners to identify corals of opportunity, carry out coral micro-fragmentation and maintain the nursery.
best guess = 0.5; minimum = 0.2; maximum = 0.9 Colombia, San Andres and Providencia Islands, Caribbean Sea, Corales de Paz The project employs the coral gardening technique. Rope nurseries are floating at 4 to 6 m below the water surface ( Fig. 2a). Microfragmentation is also The primary project motivation is biotic i.e., to enhance coral reef biodiversity, while the secondary motivation is pragmatic i.e., to enhance the ecosystem 1) to generate an annual stock of > 5,000 coral fragments from four reef-building species per island; 2) to transplant 5,000 coral colonies per ha -1 yr -1 per island from year two of the project, for a total of 30,000 coral transplants over six Nursery-grown corals as well as micro-fragments will be outplanted to the reef using a unique mix of marine cement and a colloid adjuvant to improve fluidity and The total spatial extent is six hectares (area of outplant) by year four distributed over three hectares at each of the two islands.
The total estimated budget is $900,000 USD resulting in an annual expenditure of $37,500 USD ha -1 yr -1 . The primary motivation of the project is experimental with the rationale to improve coral propagation techniques for growing corals in the Eastern Tropical Pacific, with an emphasis on answering questions of ecological concern. The secondary motivation is biotic i.e., to enhance biodiversity, ecosystem connectivity, and ecological resilience.
1) to define the best coral propagation and restoration techniques; 2) to establish a coral restoration program in Costa Rica; 3) to facilitate coral reef research to improve restoration work; and 4) to integrate local communities into coral restoration projects Branching corals grown in the nursery are outplanted onto the substrate with cable ties attached to large nails. Future endeavours will attach corals grown on ropes in rope-nurseries directly to the substrate without separating them from the ropes. Massive and encrusting corals, which are grown on ceramic plugs, are outplanted by drilling holes into the substrate and inserting the stem of the plug with a small amount of marine epoxy or cement.
The project aims to restore 10 reef patches of 200-500 m 2 each within the next three years equalling a maximum intervened area of 0.5 ha.
The total project cost over the last 2.5 years was $120,000 USD. If in kind support (such as accommodation, university technical support, volunteer time, etc.) is included, these costs would be 100% higher, i.e., a total of $240,000 USD. The annual project budget was $35,000 USD for 2018, which was mostly composed of salaries ($15,000 USD) and logistics such as travel and boat rental ($15,000 USD  . 2b) and larval propagation (seeding coral recruits after cultivation using in situ SECORE Int.-designed floating pools (Fig. 2c)) and ex situ in a wet lab) are used to restore local coral populations. The primary motivation of this project program is biotic (biodiversity enhancement), while the secondary is experimental (improve restoration approach, technology and methods). A tertiary motivation is idealistic (environmental education and outreach for the local community and tourists).
As above Micro-fragments will be outplanted using established protocols.
By the end of the third phase, an estimate of 5,000 micro-fragments will be outplanted annually covering up to 200 m 2 per year.
The total budget for 2018 was around $30,000 USD. The project duration is three years and the total estimated budget is $850,000 USD (pending grant approvals).
Funding bodies/partners are as above.
best guess = 0. are rescued from donor areas and grown in the nurseries. Small concrete bases are attached to the reef and then corals from the nurseries are fixed to these structures (Fig. 2d).
To increase the diversity at the restoration sites and promote natural resilience to climate change and local stressors, the program identifies the genetic material ( of one coral colony per square meter. Therefore, the annual budget was estimated at $150,000 USD ha -1 yr -1 . The restoration work of Oceanus A.C. is mainly artisanal and requires intensive maintenance to achieve results. Therefore, restoration efforts can only be sustained if the local community is involved to guarantee restoration success. The restoration program has initiated the formation of local restoration groups mainly consisting of members of the local fishing communities and other local organizations as well as the private sector (e.g., hotels) to support the restoration efforts. The program also seeks to engage local communities, service providers such as diving shops, hoteliers and managers to build local restoration groups and form a restoration network that helps increase restoration efforts along the Mesoamerican Reef. Establishing this network and applying different restoration strategies depending on the local stakeholder involved is envisioned to allow the program to become self-sustainable in the long term. annularis; 4) to achieve a 25% increase in selected coral reef health indicators (i.e., live coral cover, fish biomass, and rugosity) at intervened sites for A. cervicornis and A. palmata; 5) to design and implement an effective community-based plan for the rehabilitation of intervened reef areas, which encourages conservation and rehabilitation of ecosystem functions, and to contribute to the sustainability of the benefits of coral reefs; 6) to quantify the ecosystem services of intervened reef areas in current and future scenarios of intervention, variability and climate change Overall, in the time span of 2003-2017 approximately 60,000 coral colonies (mostly A. cervicornis) were harvested and outplanted to coral reefs in Culebra Island. Nursery-grown corals, fragments of opportunity of multiple species, as well as micro-fragments and cuttings are directly outplanted to the reef using Portland marine cement mixed with lime to neutralize pH. Cable ties and masonry nails are also used in the case of A. cervicornis. An outplanting schedule with a density of one individual per square meter of reef for A. cervicornis and of one colony per four square meters for other species is often followed.
The project has intervened an area of ca. 6 ha, but many of these corals were lost during the 2017 hurricanes. The projected spatial extent of reef rehabilitation by year 2023 in total will be 8.4 ha, with a potential to increase the area intervened depending on funding and on communitybased volunteer support. The first 4-year sub-project of the post-hurricane long-term phase of the project will be financed through multiple sources, as described above. It will also involve extensive volunteer work, through a combination of best guess = 0.7; minimum = 0.5; maximum = 0.9 activities. Finally, the project is motivated by an idealistic rationale due to cultural reasons (i.e., community-based aim to restore formerly bombarded grounds by the U.S. Navy which used local coral reefs in Culebra Island to support naval training activities between 1901 and 1975, rescue and stewardship of local coral reefs) and due to social reasons (i.e., fostering increased community involvement, job creation, nature education, environmental outreach, hands-on training in coral farming and reef rehabilitation methods). More recently, the project is being motivated by legislative reasons (i.e., restoration of A. palmata and A. cervicornis as part of mitigatory compensation project).
strategies involving students, fishermen, NGOs, and an internship program. SAM also plans to involve the hospitality sector. There will also be a large focus on a combination of outreach, educational and hands on strategies to prepare the next generation of coral farmers and coral reef restoration researchers in Puerto Rico.

Planned work
Colombia, Gorgona National Natural Park, Eastern Tropical Pacific, ECOMARES The project is presently gathering scientific information for future needs on coral restoration in the area.

Pocillopora damicornis; Pavona clavus
The project is motivated by experimental reasons to improve restoration approaches for their use at Gorgona National Natural Park once restoration efforts are necessary.
1) to determine the feasibility of coral nurseries in the area; 2) to determine the minimum coral fragment size of P. damicornis for successful survival and growth in coral nurseries; 3) to find the optimal fragment size for outplanting in terms of survival The group's expertise in outplanting has been focused in the most abundant coral species in the area, P. damicornis. For this coral species, Portland cement mixed with sand N/A The cost for running the projects have been lower than expected because they are mostly experimental and have not carried out formal coral reef restoration activities yet. In 2018 the budget was $10,000 USD. Partners: Universidad del Valle, Universidad best guess = 0.7; minimum = 0.5; maximum = 0.9 and coral growth; 4) to determine the effect of fish predation on P. damicornis during the outplanting; 5) to evaluate the use of enriched substrates for the massive coral species P. clavus and freshwater was used. So far, no information is available to determine the spatial extent (area) of restored habitat that will be obtained.
Javeriana de Cali, and Gorgona National Natural Park.
Mexico, Cozumel National Natural Park, Caribbean Sea, The Iberostar & CINVESTAV Group: The project aims to start with the development of four genotyped coral nurseries, two for Acropora palmata (3 and 5 m water depth) and two for A. cervicornis (10 and 13 m water depth). Each nursery will have 5 structures with a carrying capacity of approximately 40 fragments each enabling growth of 800 corals at a time.

203
The primary motivations to carry out the coral reef restoration projects are biotic and experimental 204 to equal parts (41.7%), followed by idealistic and pragmatic reasons (both 8.3%). Biotic (36.3%) and 205 experimental (27.3%) reasons were important secondary motivations, followed by legislative reasons 206 (18.2%), and pragmatic/idealistic motivations (both 9.1%). All except for one of the projects reported 207 secondary motivations. The tertiary motivations reported by 5 of the 12 projects were mainly 208 pragmatic (80.0%) and idealistic (20.0%). 209 Most projects have specific objectives to optimize/scale-up restoration approaches (51.1%), followed 210 by providing alternative, sustainable livelihood opportunities (14.9%), and then in equal parts to 211 promote coral reef conservation stewardship and re-establish a self-sustaining, functioning reef 212 ecosystem (12.8%). The objectives to enhance ecosystem services for the future and the reduction of 213 population decline and ecosystem degradation accounted for only 4.2% each of the specific project 214

objectives. 215
The median total cost from all projects per year is $93,000 USD (± $32,731 SE) ranging between 216 $10,000 USD and $331,802 USD. The median spatial extent of coral reef restoration intervention is 1.0 217 ha (± 1.3 ha SE) ranging between 0.06 ha and 8.39 ha. Project duration was as short as 1 year and 218 could be as long as 17 years with the median project duration of 3 years (± 1.5 years SE) to reach the 219 project targets. Projects reported a median feasibility of 0.7 (± 0.03 SE) ranging from 0.5 to 0.8 (Table  220 3). 221 222 229

Discussion 230
Here we present the first comprehensive assessment of coral reef restoration projects in Spanish- projects presented here focused on harnessing social or economic benefits from coral reef restoration 264 such as involving the community through inclusion in activities or educational programs to raise 265 awareness or to provide alternative, sustainable livelihood opportunities for local communities. An 266 assessment of social, economic, and cultural benefits derived from the restoration of coral reefs has 267 been largely ignored by the published literature, which has mostly concentrated on outcomes related 268 to the ecology or described endeavours to improve restoration technology [10]. The present work is 269 an attempt to bridge the gap between academics and practitioners. Academics tend to be more 270 focused on small-experimental coral reef restoration attempts to answer questions of ecological 271 concern, whereas practitioners are more focused on optimising and scaling-up restoration. Bridging 272 the gap between academics and practitioners has been identified as critical for many fields of 273 populations and is of major concern to those attempting to restore corals in the Caribbean. Since its running projects (18 years) has plans to restore up to 8.4 ha, requiring outplanting 10,000 corals or up 296 to 8,000 coral settlement bases with coral larvae per year. These interventions were led by pioneering 297 environmental NGOs and foundations, who often procured un-paid volunteers to carry out much of 298 the work. The interventions were also enabled by strong partnerships initiated by the champion 299 organization with universities (e.g. Universidad Nacional Autónoma de México, University of Puerto 300 Rico, Universidad del Valle, Universidad Javeriana de Cali, Universidad de Costa Rica), conservation 301 management bodies and regulators (e.g. Natural Parks administrations, Departments of Natural and 302 Environmental Resources and the United States National Oceanic and Atmospheric Administration), 303 associations (e.g. Fishers Association, Caribbean Hotel and Tourism Association), national and 304 international business partners (e.g. SECORE International), international environmental NGOs (e.g. 305 Conservation International, The Nature Conservancy), tourist service providers (e.g. the Iberostar 306 Group), private donations (e.g. Global Giving), international grant schemes (e.g. from Deutsche 307 Gesellschaft für Internationale Zusammenarbeit, Counterpart International, InterAmerican 308 Development Bank (IDB)) and in large part with local community groups. Coral reef restoration still 309 remains an underfunded area in the Spanish-speaking countries and territories of the Caribbean and 310 ETP despite the ecosystem services restored coral reefs could provide for the regions such as food, 311 tourism income, protection against storms and wave surges [55,56], and reduction in insurance 312 premiums by offering coastal protection [57]. 313 There are a few caveats that need to be considered when assessing the data within the present work. 314 First, this review does not contain an exhaustive list of interventions in the Spanish-speaking countries 315 and territories of the Caribbean and ETP. Additional projects exist or are planned, but were not aware 316 of, or chose to not participate in our open call. Second, the projects presented here varied in their 317 specific objectives, best practice protocols, and monitoring, which hindered their comparison. For 318 example, some projects were designed to improve and optimise the restoration approach 319 (experimental projects), while others were more operational, i.e., aimed to scale-up the restoration 320 of coral reefs by using already established restoration techniques. Furthermore, the projects used 321 different best practice protocols or key indicators of restoration success, such as size of transplant and 322 density of transplants which made a direct comparison between the projects difficult. Some projects lacked monitoring milestones to evaluate the survival, cover and health conditions of outplanted 324 corals beyond year one. Yet, post-restoration monitoring is an imperative method needed to confirm 325 that outplanted corals are self-sustaining which, from an evolutionary perspective, is the ultimate goal 326 of any restoration effort [3][4][5]. Third, evaluation of the overall project feasibility or the likelihood of 327 success to reach specific project objectives is naturally linked to local conditions and circumstances, 328 thus may be a subjective measure directly related to the experience of the practitioner. More 329 quantitative measures of overall project feasibility (e.g., based on measurements) would be a 330 considerable improvement over the qualitative (derived from expert elicitation) approach. 331 Prior to any conservation action, a prioritisation of interventions based on decision-support 332 frameworks is recommended to help practitioners increase their planning rigor, project accountability, 333 stakeholder participation, transparency in decisions, and learning [58]. Cost-effectiveness analysis is 334 such a tool that allows for the evaluation and prioritisation of conservation interventions [59]. This 335 analysis relates the costs of a project to its key outcomes or benefits i.e., the specific measures of 336 project effectiveness [59,60]. Although this work includes all data required for a cost-effectiveness 337 analysis (see Supplementary material), we considered that comparing the different projects against 338 each other will be inappropriate given the variety of their project objectives (e.g. experimental vs. 339 operational) and the lack of standardisation in reporting on cost, feasibility and key outcomes. 340 Future collaborations between academics, local communities and practitioners will be crucial if we 341 want to achieve restoration at meaningful ecological, spatial and social scales [61]. Unfortunately, the 342 language barrier often inhibits such collaborations. For instance, Amano et al. [62] argues that 343 languages are still a major barrier to global science by showing that more than 35% of the knowledge 344 tourism operators, the private sector, associations, and local community groups. While coral reef 356 restoration has been portrayed as too expensive and challenging with regards to spatial scale, 357 duration, and success, the projects presented here have shown that many of these barriers have 358 already been overcome. These pioneering endeavours were often possible by in-kind commitments 359 of staff and volunteers as well as involvement of the local community and tourism operators, thus 360 socio-economic aspects play a substantial role in coral reef restoration in the Caribbean and Eastern 361 Tropical Pacific. Strong national plans for restoration in conjunction with national and international 362 funding are needed to multiply the already existing activities made by Latin-American organisations 363 to improve the health and status of coral reefs in the Caribbean and Eastern Tropical Pacific. From this 364 compilation of data and knowledge, it is apparent that it would be beneficial for coral reef restoration 365 practitioners in this area to coordinate their efforts with each other and make sure they are sharing 366 and implementing their best practices protocols to standardise efforts and track restoration progress 367 by specific, measurable, achievable and repeatable metrics of success through time. We would like to thank Nufar Charuvi, the pioneer driving the Alianza Coralina Taganga project, who, 372 although no longer with us, continues to inspire by his example, dedication, and passion he served 373 over the last decade for Colombian coral reefs and the local community. This manuscript has been 374 developed upon in-kind time of the authors and has not received any financial support. We