Documenting the history of reef restoration is important because it allows us to understand our past and be more informed to take action in the future. The great men and women in our history were innovators who responded to crisis and went against convention. In the early 1900’s there was pioneering research on oyster transplantation in America. The earliest published research on coral transplantation methods we found was from the 1928-29 Great Barrier Reef Expedition. Research on coral farming methods started again in 1974 and became global by 2000. One of the early pioneers of transplanting corals in the 1980s and most prolific scientists in the academic literature was Dr Austin Bowden-Kerby. In the early 2000’s Tom Moore, NOAA, Ken Nedimyer CRF and Caitlin Lustic, were the prime movers developing Acropora nursery techniques. The Mote Marine Laboratory pioneered new methods including micro fragmentation with claims coral growth up to 50 times natural rates. The early leader in management of reef restoration was NOAA who developed legislation in 1973 to protect and restore habitats. This led to small and large-scale repair of coral reefs damaged by ship accidents. Reef restoration communicators are authors of books, manuals, scientific papers as well as photographs, films, TED talks and underwater art. The notable people in this field include Margos (1974), Jaap (2000), Precht (2006) and Edwards (2010) who wrote manuals for practictioners and scientists. There are several popular (over 1 million views) TED talks by scientists such as Kristen Marhaven and artist Jason deCaires Taylor. The business of reef restoration originated in aquaculture and has also covers insurance, conservation and tourism. The Nature Conservancy, Coral Restoration Foundation and Mars Foundation are international leaders in coral restoration. In 2017 the Reef Restoration Foundation deployed Australia’s first coral nursery at Fitzroy Island. The cumulative global area of reef restoration is unknown and difficult to measure. The costs of reef restoration are estimated at $1.6-6.4M per hectare. The participation, number, area, scale and diversity of reef restoration projects appear to be increasing rapidly.

Coral reefs are increasingly under threat from anthropogenic disturbances, and live coral cover has been declining around the globe for the past decades. Halting this trend will require a multi-faceted approach across several scales using a wide variety of responses. Large-scale solutions like curbing climate change, improving water quality and reducing pollutants in oceans are critical for the persistence of coral reefs. However, these tend to be slow to implement and require large-scale commitment at the government level. This has led to a growing interest in direct interventions on coral reefs, in particular outside the scientific community. Citizen scientists, tourism operators and NGO’s have implemented hundreds of small-scale coral restoration projects around the world’s coral reefs, often with very little financial backing or scientific support. This disconnect between the scientific community and coral restoration practitioners represents a lost opportunity for both groups. To mitigate this, we reviewed the current scientific literature describing coral restoration methods, surveyed coral restoration practitioners and scoured the internet for descriptions of methods published in non-traditional channels. Here, we present the results from this comprehensive review of methods, and share technical lessons learned and key issues to look out for concerning each of the main methods. In this talk, we use the online interactive visualisation and database we developed to share that information in a layered approach with scientists, managers and practitioners.

The environmental crisis faced by scientists and policy makers today is complex, and relentless. Deconstructing these intractable problems into smaller design questions is a common, yet powerful, tool in solving many contemporary, interdisciplinary hurdles. While technological innovation is beneficial, development done in isolation often leads to inoperational or ineffective solutions. Rather, understanding the crossover between stakeholder input and ecosystem needs is critical in creating a workable design space. Only then can engineering-based approaches allow for rapid development of holistic solutions via step-by-step pipelines to dissect, assess, and solve problems. This presentation aims to guide the audience through the analytical processes and lines of questioning used by engineers to take on highly convoluted socio-technical problems and intelligently define design metrics that ultimately guide technology development and the success of an intervention. Through real-world case examples and discussion, attendees will have the opportunity to learn and adapt these problem solving protocols to their own reef conservation efforts. Presentation authors are practicing mechanical and biomedical engineers who have translated these approaches to ongoing reef restoration technology efforts with the support of the National Oceanographic and Atmospheric Administration (NOAA).

Marine cloud brightening is an intervention which could potentially mitigate bleaching of heat stressed coral reefs. The proposal is that providing additional cloud condensation nuclei (CCN) in the form of nano sized salt crystals derived from evaporated sea water droplets to the marine boundary layer will increase the reflectivity of low lying marine stratocumulus clouds. By increasing the cloud albedo, incoming shortwave solar radiation reaching the sea surface is reduced, with the integrative effect that over some days to months ocean mixed layer temperatures are lowered compared to otherwise. A potential synergistic benefit is decreased irradiance (shading) during times of heat stress. The response of the Great Barrier Reef hydrodynamic heat flux budget and coral biological response to scenarios of various intensities and scales of imposed cloud brightening is considered using the CSIRO developed eReefs biogeochemical ocean model. Reduction to the shortwave radiation input term is partially offset by reductions in longwave radiation, sensible heat flux, and latent heat flux loss terms, resulting in net cooling. The reduction in sea surface temperatures achieved is found to depend on the amount of suitable cloud cover (the first and second indirect aerosol effect), concentration and reflectivity of aerosols (the direct aerosol effect) and is a function of the amount of time a given water parcel spends under ‘brightened cloud’. Thus, there are regional and inter-annual differences in both hydrodynamic and biological response to cloud brightening.

Over thousands of years, corals build complex geological structures that serve as the foundations for a myriad of critical ecosystem services. Ensuring that both ecological and geological reef functions are maintained is, therefore, critical to designing effective coral-reef management and restoration programs. Using the fossil record captured in reef cores collected throughout the Florida Keys reef tract, we provide a geological perspective on the management of Florida’s coral reefs with respect to processes like carbonate production and reef accretion. We show that reef growth has been negligible throughout the region for at least the last 3000 years, leaving Florida’s reefs balanced at a tipping point between reef accretion and erosion. Unfortunately, the modern declines in coral populations have pushed many reefs past that threshold, triggering reef erosion and the structural decline of Florida’s reefs. Most restoration efforts to date in the western Atlantic have focused on Acropora cervicornis, which provides valuable habitat in the short-term, but contributes minimally to carbonate production and reef building in the long-term. We show that over the last 10,000 years, two corals—Acropora palmata and Orbicella spp.—were the primary reef-building species in south Florida, accounting for ~75% of the reef structure built throughout the Florida Keys reef tract. We suggest that focusing coral-restoration on reef-building taxa like A. palmata, Orbicella spp., and other massive corals, will optimize the outcomes of coral-reef management by mitigating reef erosion and promoting the growth of lasting reef structure.

The interfaces between coral and algal holobionts represent the battle front of fierce competition for space on the reef. Growth of one holobiont over another at these interaction interfaces determines the benthic community structure on reefs. Coral-algal interaction zones frequently promote higher microbial respiration rates. This enhanced microbial activity and concomitant depletion of oxygen at interfaces creates a microenvironment that often reaches hypoxic levels known to harm corals. This microbial-mediated oxygen depletion provides a competitive advantage to benthic algae at interaction zones. The organic exudates released by fleshy macroalgae have also been shown to select for potential coral pathogens; further implicating microbial processes in algal competition over coral holobionts. Resolving the connection between coral microbiome structure and distinct algal competitors is critical for effective management and restoration of coral reef systems.

Despite widespread increases in coral outplanting around the globe, few studies focus on the effects of coral restoration on reef communities or important ecosystem functions like herbivory and coral predation. Here, we measured the impact of coral restoration at four reefs in the Florida Keys, USA, ranging from 2-11 years of coral outplanting. To move beyond focusing on outplanted corals, we examined differences in three major criteria: diversity, community structure, and ecological processes, via paired surveys of restored sites where corals had been outplanted and unmanipulated control sites. Coral restoration successfully enhanced coral populations, increasing coral cover 4-fold compared to control sites. Surprisingly, there were few changes in the coral and fish communities with restoration. Some restored sites had higher abundance of herbivorous fish, higher rates of herbivory, or more juvenile-sized corals, but these effects were limited to individual reefs. Higher densities of territorial damselfishes in restored sites emerged as the consistent difference in fish communities. Corallivorous snails were 1.6x more abundant on corals in restored sites compared to control sites, and disease and mortality were more prevalent in restored areas. Thus, despite successfully augmenting target populations, coral restoration at these sites does not appear to have facilitated positive feedbacks that help reinforce coral success. Although coral restoration can successfully boost the cover of corals at degraded sites, additional restoration strategies are likely needed to realize community-level benefits of coral restoration and restore key functions like herbivory. We advocate for harnessing ecological processes that drive community dynamics on coral reefs in a way that facilitates the establishment and growth of restored corals. Drawing on decades of coral reef ecology research and lessons learned from the restoration of other ecosystems, we posit that restoration practitioners can control factors such as the density, diversity, and identity of transplanted corals; site selection; and transplant design to restore positive feedback processes – or to disrupt negative feedback processes – in order to improve restoration success. Ultimately, we argue that coral restoration should explicitly incorporate key natural processes to exploit dynamic ecological forces and drive recovery of coral reef ecosystems.

Conference Theme: Restoration Operations: best practices, techniques and tools for scaling up Scaling up coral production for restoration and lowering the costs for out-planting: New techniques and alternatives Aquaculture production for marine organisms has always evolved using a three step system of a: Hatchery; Nursery and Field out-planting. Hatcheries have always been land-based, but nursery systems have usually utilized both a land-based system or a field-based system or both. The majority of coral restoration systems have evolved starting with only field-based systems using asexual fragmentation and transporting to field based sites for manual out-planting. Recent successes with land-based nurseries have allowed for implementing more of the massive species thru technologies such as “micro-fragmentation” and have also provided a platform for implementing sexual reproduction into the mix. Increases in the overall production numbers also resulted in a drastic lowering of the costs per unit coral. The use of a land facilities provides also for including sexual reproduction to diversify genotypes plus provide new tissue for asexual reproduction with micro-fragmentation. The utilization of both a land nursery for a shorter period coupled with a field nursery also increases the production capacity and lowers labor costs and the time in the land-based nursery. The hybridization of a first field nursery stage next to the final outplanting site for a “double-cutting” could be the exponential expansion of final out-plants with drastically reducing labor costs. By following these standard methods developed for other marine organism aquaculture production, coral propagation for restoration can optimize both costs and labor to enable production at scale.

The Healthy Reefs for Healthy People Initiative (HRI) is an international collaborative program, involving 73 coral reef-focused research, management and conservation organizations, that has developed and implemented a comprehensive framework for evaluating and improving large-scale reef health, through a science-based adaptive management process in the Mesoamerican Reef. Over the last decade, HRI and partners have produced five Report Cards that summarize reef health -which ranks measured values for: coral cover, macroalgal cover, herbivore and commercial fish biomass at over 300 sampling sites. The HRI/AGRRA database has been instrumental in establishing restoration sites and will help evaluate their efficacy. HRI and AGRRA work actively to promote sharing standardized monitoring data and promptly are launching the MAR Data Explorer. The explorer is helping us better understand large scales processes such as benthic community shifts, herbivory, disease dynamics, as well as structural components like coral species diversity and coral cover. In addition, these data provide important insights to help identify the best sites that have potentially resistant or resilient corals, in order to locate healthy donors colonies for restoration programs. The HRI is an active part of the steering committee of the Restoration Network for the Mesoamerican Reef, this network has been formed mainly to strengthen and advance reef restoration efforts in the region, utilizing a collaborative, interdisciplinary approach, following the approach that the HRI has had for the past years. A strategic action plan for 2019-2020 has been finalized with the main goals being to position the network as a regional advisory entity for marine ecosystem restoration, develop an outreach and communication platform and fundraise plan to make the network self-sufficient. The Network is also participating in implementing an insurance model for prioritized reefs in the MAR mainly focusing on hurricane damage. For the model sites are being prioritized based on: ecosystem data (HRI reef indicators), ecosystem services, exposure to hurricanes and environmental threats. Site prioritization is set to finalize in January 2019 and cost and risk assessments have begun.

The widespread decline of coral reefs stems from a variety of local and global stressors affecting reef structure and function. Much attention has been paid to restoring stony corals as the architects of reef structure. However, in the Mesoamerican Reef coral cover has increased over the last decade, while low herbivory and excess nutrients have led to massive proliferation of macroalgae, which threatens to compromise continued coral growth, recruitment and coral restoration efforts. HRI’s Report Cards include recommended management actions - MPAs, fisheries regulations, pollution controls and restoration efforts. Since 2008 HRI has targeted herbivory as a key ecosystem function in need of restoration, given the doubling of fleshy macroalge measured over the last decade. Initially, our focus was on the protection of parrotfish. Belize was the first to protect parrotfish in 2009, followed by the Bay Islands, Honduras in 2010, Guatemala in 2015 and Quintana Roo, Mexico in 2018, completing protection all the MAR with the exception of coastal Honduras. Despite these efforts the proliferation of fleshy macroalgae continues to increase. In order to achieve a more balanced form of herbivory, we also need to increase populations of Diadema urchins and herbivorous crabs. Therefore, two pilot studies to translocate adult Caribbean king crab into no-take zones of MPAs were recently initiated in Belize, along with Fragments of Hope, and in Mexico, along with the Fisheries Institute. The hypothesized results include a reduction of fleshy macroalgae in the patches where crabs were translocated. A collaboration of NGO researchers and local fisher cooperatives could produce viable income generation venture with ecological benefits from reseeding some crabs onto the reef. Similarly we are planning similar experiments with Diadema in Honduras, in partnership with Tela Marine Station, Operation Wallacea and others. Finally, to remove ecologically ‘stuck’ macroalgal dominated communities, we are also testing the efficacy of human manual reduction of macroalgae in Mexico (with Centro Ecológico Akumal) and in Honduras (with CORAL). The ecological results of these pilot interventions, including time, costs and feasibility will be analyzed in terms of their potential for contributing to larger scale restoration of ecosystem structure and function.

The National Institute of Fisheries and Aquaculture of Mexico (INAPESCA) works on a project for development biotechnology to produce coral colonies and implement actions for reef restoration. The project began in 2009; an aquarium system with controlled conditions (SCC) and small modules of marine nursery (SCM) were installed. An annual production of 350 colonies was maintained by clonal propagation and 1,500 sexual recruits settled until 2011. From 2012 to 2016 a Program for Active Restoration in Mexican Caribbean Coral Reefs was implemented in collaboration with Marine Protected Areas, Academy, and Governmental organizations, with a grant from the National Commission for Biodiversity (CONABIO). A marine nursery was installed in a sandy area with capacity for 1,500 colonies. Outdoor semi-controlled open seawater system and natural light (SCE) was installed within facilities. An annual production of 2,000 colonies by clonal propagation from 8 species (Acropora palmata, A. cervicornis, Orbicella annulata, Orbicella faveolata, Montastraea cavernosa, Undaria agaricites, Porites porites, and Dendrogyra cylindrus) and 10,000 settled Acropora palmata sexual recruits was achieved; the first microfragments production of 2,500 colonies was obtained. Four sites have been successfully restored: coral coverage reached 14%, environmental heterogeneity increased, and the number and biomass of fish community doubled. Colonies of Acropora palmata out-planted in 2011 have been spawning massively since August 2016. Current project (2017-2022), with grant by local government, aim to develop new active restoration programs to: scaling up coral production (goal of 260,000 colonies) through micro-fragmentation techniques, identify successful genotypes for reef restoration and maintain genetic banks, hybrid restoration to build coral colonies that reach both, size and sexual maturity, faster than naturally, and to establish a network of functional restored areas to serve as a source of supply. Finally, a specific monitoring program is being tested to evaluate changes in structure and function during the restoration process

We are working in Belize to restore the full suite of coral reef attributes and services on shallow lagoonal reefs and reef crests. Here, acroporid replacement works at otherwise recalcitrant sites, with results similar to nearby natural regeneration. Success is greatest in shallow waters when coolest and corals are sexually less active, minimizing stress and facilitating colony attachment. Experiments can reveal what works best: (1) single species restoration of fast-growing acroporids or (2) replacement of a suite of preexisting species that trend toward the original hard coral community. Reef habitats vary in depth, location and species composition so restoration should vary accordingly. In Florida framework-building species are essentially on life support while in Belize cover is higher and there is some spontaneous regeneration. Nonetheless, Florida could still restore a valuable veneer reef, whereas in Belize it may be possible to restore entire reefs, re-establishing rugosity, carbonate accretion, upward reef growth and shoreline protection. Restoration goals should match the desired suite of ecosystem services for recovery, for example: single species demographic security (as for endangered species), biodiversity maintenance, aesthetic quality, fish habitat quality, carbonate accretion, current shoreline protection, and upward reef growth keeping pace with sea level. Natural patterns of community recovery may differ from current restoration practices depending on site. The implications of this should be examined, as for example in the outplanting of framework-builders on bare reef rock versus degraded reef rich in persistent non-framework builders such as Porites astreoides, because these could possibly contribute to the natural regeneration of framework-builders. Alternative successional pathways, (e.g. toward Acropora palmata versus Agaricia tenuifolia reef crest on Atlantic Mesoamerican reefs) suggest that we might need to guide succession after outplanting. Coral restoration is most practical in shallow, sheltered, well-grazed waters where biophysical and social factors are favorable and values to people are most readily apparent.