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Four-year-old Caribbean Acropora colonies reared from field-collected gametes are sexually mature

  • SECORE International
  • SECORE International
  • Ripley's Aquarium of Canada
BULLETIN OF MARINE SCIENCE. 00(0):000–000. 0000
Bullen of Marine Science
© 2011 Rosensel School of Marine and Atmospheric Science
of the University of Miami
Bulletin of Marine Science
© 2016 Rosenstiel School of Marine & Atmospheric Science of
the University of Miami Portraits of Marine Science
Bull Mar Sci. 92(2):000–000. 2016
Four-year-old Caribbean Acropora colonies reared
from eld-collected gametes are sexually mature
VF Chamberland 1, 3, 4 *, D Petersen 1, 2, KRW Latijnhouwers 4,
S Snowden 1, 5, B Mueller 3, MJA Vermeij 3, 4
1 SECORE Intern ational, c/o Colu mbus Zoo and Aquar ium, 9990 Riversid e Drive, Powell, Ohi o 43065.
2 SECORE International, Arensburgstraße 40, Bremen, Germany.
3 Carmabi Foundation, Piscaderabaai z/n, Willemstad, Curaçao.
4 Aquatic Mi crobiology, Inst itute for Biodive rsity and Ecosyst em Dynamics, U niversity of Amst erdam, Science Par k 700,
1098 XH Amster dam, Netherla nds.
5 Pittsbu rgh Zoo & PPG Aquarium , One Wild Place, Pi ttsburgh, Penn sylvania 15206.
* Corresponding author email: <>.
Rehabilitating populations of Caribbean coral species that have declined in recent
decades has become a management priority throughout the region, stimulating the
development of new methodologies to artificially reseed degraded reefs. Rearing lar-
vae of ecologically important coral species appears a particularly attractive method
to aid the recovery of degraded populations because genetic recombination could
yield new genotypes better capable of coping with the altered conditions on modern
Caribbean reefs. Well-developed elkhorn coral (Acropora palmata Lamarck, 1816)
populations form dense thickets that contribute to the maintenance of healthy and
productive reefs by providing shelter to a variety of other reef organisms (Gladfelter
and Gladfelter 1978). After >95% of A. palmata populations were decimated by a
disease beginning in the mid-1970s, this species was listed as critically endangered
under the Red List of reatened Species (IUCN 2013) and restoration efforts were
initiated throughout the region to assist its recovery (Young et al. 2012). In 2011, we
collected gametes from eight A. palmata colonies in situ off Curaçao, which were
subsequently cross-fertilized to generate larvae. Competent larvae were settled on
clay tiles (Panel A) and reared in a flow-through land-based nursery for one year
(Panels B–C), after which they were outplanted to a breakwater at 2–5 m depth
Fas t Track
BULLETIN OF MARINE SCIENCE. VOL 00, NO 0. 0000106 Bulletin of Marine Science. Vol 92, No 2. 2016
(Panel D) [refer to Chamberland et al. (2015) for details on methodology]. Seven out
of nine outplanted colonies survived and continued to grow in situ (Panels D–E),
reaching a size of 30–40 cm diameter and 20–30 cm height after 4 yrs (Panel F). On
8 and 10 September, 2015, nine and 11 d after the full moon, two colonies were ob-
served releasing gametes between 155 and 175 min after sunset (Panels G–H). is is
the first time that an endangered Caribbean Acropora coral species was raised from
larvae and grown to sexual maturity in the field. Indeed, only one other study has
documented age and colony size at reproductive onset in a broadcast spawning scler-
actinian coral reared from larvae (Baria et al. 2012). e relatively short time until
onset of spawning (≤4 yrs) observed for A. palmata shows that recovery of degraded
coral populations by enhancing natural recruitment rates may be practicable if out-
planted colonies are able to rapidly contribute to the natural pool of larvae.
is research was supported by the European Union Seventh Framework Programme
(FP7/2007-2013) under grant agreement no 244161 (Future of Reefs in a Changing Environ-
ment), the National Oceanic and Atmospheric Administration (NOAA), the Green Founda-
tion, the Walton Family Foundation, TUI Cruises/ Futouris e.V., the Clyde and Connie Wood-
burn Foundation, and the Montei Foundation. We are grateful to the Curaçao Sea Aquarium
staff and all participants from the 2011 and 2012 editions of the SECORE workshop for their
assistance in the field.
L C
Baria MVB, Villanueva RD, Guest JR. 2012. Spawning of three year-old Acropora millepora cor-
als reared from larvae in northwestern Philippines. Bull Mar Sci. 88:61–62. http://dx.doi.
Chamberland VF, Vermeij MJA, Brittsan M, Carl M, Schick M, Snowden S, Schrier A, Petersen
D. 2015. Restoration of critically endangered elkhorn coral (Acropora palmata) popula-
tions using larvae reared from wild-caught gametes. Glob Ecol Cons. 4:526–553. http://
Gladfelter WB, Gladfelter EH. 1978. Fish community structure as a function of habitat struc-
ture on West Indian patch reefs. Rev Biol Trop. 26(1):65–84.
International Union for Conservation of Nature (IUCN). 2013. IUCN Red List of reatened
Species. Version 2013.2. Accessed August 2015. Available from:
Young CN, Schopmeyer SA, Lirman D. 2012. A review of reef restoration and coral propaga-
tion using the threatened genus Acropora in the Caribbean and western Atlantic. Bull Mar
Sci. 88(4):1075–1098.
Date Submitted: 23 October, 2015.
Date Accepted: 4 January, 2016.
Available Online: 28 January, 2016.
... In the Caribbean Diploria labyrinthiformis is a common and frequently encountered coral species. Depending on its location, this species can spawn from April to October before sunset, having a wider and earlier spawning window compared to most broadcast spawning corals in the region (Weil and Vargas, 2010;Chamberland et al., 2016). D. labyrinthiformis was selected for this study due to its ability to build 3D structures in reefs, its early and multiple spawning events throughout the year, its high spawning predictability, and the contribution to recent and ongoing research regarding its reproductive potential and early life history stages (Chamberland et al., 2016). ...
... Depending on its location, this species can spawn from April to October before sunset, having a wider and earlier spawning window compared to most broadcast spawning corals in the region (Weil and Vargas, 2010;Chamberland et al., 2016). D. labyrinthiformis was selected for this study due to its ability to build 3D structures in reefs, its early and multiple spawning events throughout the year, its high spawning predictability, and the contribution to recent and ongoing research regarding its reproductive potential and early life history stages (Chamberland et al., 2016). FUNDEMAR has been monitoring and documenting spawning events of this species at the Playita reef site since May 2017, producing a spawning prediction calendar for 2020 including this and 7 other coral species (Sellares-Blasco et al., 2021). ...
... To date, published observations of spawning in outplanted Atlantic acroporid species have only been reported in the Caribbean (Carne et al., 2016;Chamberland et al., 2016;Calle-Triviño et al., 2018). However, there have been no reports in Florida of spawning activity by outplanted A. palmata. ...
... In 2022, we observed spawning activity among A. palmata colonies outplanted in March 2018, indicating that nursery-raised fragments outplanted to Florida reefs can become reproductively mature in as little as four years and four months (52 months) after outplanting. This is consistent with the observation of A. palmata outplants spawning~60 months post outplanting in Belize (Carne et al., 2016) and four-year-old (48 months) sexual recruits of A. palmata being reproductively mature in Curacao (Chamberland et al., 2016) and other species of acroporids spawning at 4-5 years old (Calle-Triviño et al., 2018;Ligson and Cabaitan, 2021). ...
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Here, we provide the first reports of spawning activity by Acropora palmata colonies outplanted to reefs in Florida, USA. In 2020, we observed light spawning from A. palmata colonies five years after they had been outplanted on two Florida reefs. In 2021 and 2022, we observed outplanted A. palmata colonies spawning synchronously with other nearby (<3 m) outplants and wild colonies more than 100 m away. During the 2022 spawning event, some colonies spawned in as few as four years after they had been outplanted. Among all spawning seasons, gametes collected from the outplanted colonies yielded high fertilization rates and viable larvae. These observations are promising for A. palmata restoration as they indicate fragments of A. palmata can spawn four years after outplanting and that efforts to restore A. palmata may be close to achieving the first step towards self-sustaining populations that can produce viable larvae, resulting in an increase in the population’s genotypic diversity upon successful recruitment to the reef.
... Subsequent culturing within facilities may facilitate larger scale production of larvae for restoration in the future. Despite demonstrated success in producing breeding Acropora corals with these methods (Baria et al., 2012;Chamberland et al., 2016;Harrison et al., 2021) there remains a dearth of long-term data that demonstrates the overall efficacy of these techniques in contributing to self-sustaining populations for most coral species. We recommend immediate investments to determine the rate of recruitment, post-recruitment survival, and demographic effects on local populations resulting from large-scale, multiple species techniques including larval slick relocation, as these data are critical in evaluating the return on these efforts. ...
... Coral larval propagation may involve seeding competent larvae directly to reef substratum (Heyward et al. 2002;Edwards et al. 2015;dela Cruz and Harrison 2017) or settling larvae onto appropriate substrates for rearing and subsequent outplant (Nakamura et al. 2011;Villanueva et al. 2012;Guest et al. 2014;Chamberland et al. 2017). The feasibility of producing a first filial generation (F1) and rearing these until maturity in situ has been demonstrated for several competitive coral taxa (e.g., Iwao et al. 2010;Baria et al. 2012;Chamberland et al. 2016;Ligson and Cabaitan 2021). While research is ongoing to develop coral larval propagation for other life history groups (e.g., Marhaver et al. 2015;O'Neil et al. 2021), only one study to date has reported long-term outcomes of sexual propagation for a massive coral (Bonilla et al. 2021). ...
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Efforts to restore coral reefs usually involve transplanting asexually propagated fast-growing corals. However, this approach can lead to outplanted populations with low genotypic diversity, composed of taxa susceptible to stressors such as marine heatwaves. Sexual coral propagation leads to greater genotypic diversity, and using slow-growing, stress-tolerant taxa may provide a longer-term return on restoration efforts due to higher outplant survival. However, there have been no reports to date detailing the full cycle of rearing stress-tolerant, slow-growing corals from eggs until sexual maturity. Here, we sexually propagated and transplanted two massive slow-growing coral species to examine long-term success as part of reef restoration efforts. Coral spat were settled on artificial substrates and reared in nurseries for approximately two years, before being outplanted and monitored for survivorship and growth for a further four years. More than half of initially settled substrates supported a living coral following nursery rearing, and survivorship was also high following outplantation with yields declining by just 10 to 14% over four years. At 6-years post-fertilisation over 90% of outplanted corals were reproductively mature, demonstrating the feasibility of restoring populations of sexually mature massive corals in under a decade. Although use of slower growing, stress tolerant corals for reef restoration may provide a longer-term return on investment due to high post-transplantation survival rates, considerable time is required to achieve even modest gains in coral cover due to their relatively slow rates of growth. This highlights the need to use a mix of species with a range of life-history traits in reef restoration and to improve survivorship of susceptible fast-growing taxa that can generate rapid increases in coral cover.
... Subsequent culturing within facilities may facilitate larger scale production of larvae for restoration in the future. Despite demonstrated success in producing breeding Acropora corals with these methods (Baria et al., 2012;Chamberland et al., 2016;Harrison et al., 2021) there remains a dearth of long-term data that demonstrates the overall efficacy of these techniques in contributing to self-sustaining populations for most coral species. We recommend immediate investments to determine the rate of recruitment, post-recruitment survival, and demographic effects on local populations resulting from large-scale, multiple species techniques including larval slick relocation, as these data are critical in evaluating the return on these efforts. ...
Full-text available
Temperate oyster and tropical coral reefs are analogous systems that create habitat for economically, ecologically, and culturally important species, and they provide countless ecosystem services to human coastal communities. Globally, reefs are imperiled by multiple anthropogenic stressors, particularly climate impacts. Using aquaculture to support conservation goals - known as conservation aquaculture - is a relatively new approach for many reef building species, but it shows great promise for promoting species recovery and bolstering resilience to stressors. Concerns about aquaculture-associated risks, both known and potential, have often restricted the implementation of this tool to an emergency intervention following dramatic declines on reefs, when species or systems were unlikely to recover. Here, we combine expertise from coral and oyster reef ecosystems to consider the role of aquaculture as a conservation intervention for reefs, and provide recommendations for its timely development and targeted implementation. We highlight the importance of evaluating reef systems - alongside local stakeholders and Indigenous communities - to determine where and when the benefits of using aquaculture are most likely to outweigh the risks. We spotlight the importance of proactive monitoring to detect reef population declines, and the value of early aquaculture interventions to increase efficacy. Novel aquaculture approaches and technologies specifically designed for reef builders are considered, including techniques for building complex, multi-generational and multi-species reefs. We address the need for scaling up aquaculture-assisted reef recovery, particularly of corals, using high volume methods like those that have been successfully employed for oysters. We also recommend the immediate assessment and development of techniques to increase climate resilience of reef builders and we identify the challenges and trade-offs of these approaches. We highlight the use of proof-of-concept projects to test these promising methods, and we advise tracking of all interventions over time to determine their long-term efficacy. Finally, we outline opportunities to leverage novel partnerships among conservation, industry, and community interests that utilize aquaculture to facilitate the conservation of reefs. Developing conservation aquaculture approaches now is critical to position managers, scientists, and restoration practitioners to implement this intervention in timely and effective ways to support resilient reef and human communities worldwide.
... All sites that did not match presence data were changed to seed zero reefs in a new connectivity matrix for each species (CM Acer Mean; CM Apal Mean). Since habitat reefs could be seeded, and to account for asexual growth on reefs that reaches reproductive maturity, polyps generated by the model at any site can contribute larvae ("spawn") in the model after they are four years old (Chamberland et al., 2016). Thus, after four years of the simulation, the reefs that were barren at t-3 and had received larvae, would then use the connectivity data from CM Mean to then be able to "spawn" and see other reefs. ...
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Since the 1980s, populations of Acropora cervicornis and A. palmata have experienced severe declines due to disease and anthropogenic stressors; resulting in their listing as threatened, and their need for restoration. In this study, larval survival and competency data were collected and used to calibrate a very high-resolution hydrodynamic model (up to 100m) to determine the dispersal patterns of Acropora species along the Florida’s Coral Reef. The resulting connectivity matrices was incorporated into a metapopulation model to compare strategies for restoring Acropora populations. This study found that Florida’s Coral Reef was historically a well-connected system, and that spatially selective restoration may be able to stimulate natural recovery. Acropora larvae are predominantly transported northward along the Florida’s Coral Reef, however southward transport also occurs, driven by tides and baroclinic eddies. Local retention and self-recruitment processes were strong for a broadcast spawner with a long pelagic larval duration. Model simulations demonstrate that it is beneficial to spread restoration effort across more reefs, rather than focusing on a few reefs. Differences in population patchiness between the Acropora cervicornis and A. palmata drive the need for different approaches to their management plans. This model can be used as a tool to address the species-specific management to restore genotypically diverse Acropora populations on the Florida’s Coral Reef, and its methods could be expanded to other vulnerable populations.
... Losses of genetic diversity over the course of larval development in ex situ cultures are well illustrated in a lab-bred Acropora palmata cohort on the Caribbean island of Curaçao. This now 10-year-old restored and sexually mature (Chamberland et al. 2015;Chamberland et al. 2016) population of 11 colonies is partially composed of half-siblings and full siblings (Kitchen et al. 2020, Conn et al., unpublished data, Fig. 3.1). That is despite the initial mixing of hundreds of thousands of wild-caught gametes spawned by at least seven colonies on three different nights and on two reefs. ...
As natural coral populations decline, thousands of outplanted corals are poised to dominate reefs in the hardest-hit areas, such as the Florida Keys. Genetic management plans are urgently needed to prevent unintended erosion of genetic diversity in managed populations. Drivers of genetic diversity loss include limited nursery genets available for outplanting or that these genets were reared from crosses among a limited number of parent genets. Existing data indicate that captive rearing of coral larvae can impose substantial genetic bottlenecks that result in closely related cohorts. Thus, questions arise about how to safeguard genetic diversity and optimize the adaptation potential of restored populations. What is the optimal ratio of asexually propagated colonies to sexually produced coral recruits at each site? What breeding scheme should be used if a limited number of donor genets are available? Should breeding be selective to achieve a shift in phenotypes such as thermotolerance at the risk of losing genetic diversity? Population viability analyses (PVA) can answer some of these questions, but current models need to be modified to resolve the most pressing issues. This chapter discusses omics methods to determine genetic diversity of corals and their symbionts and outlines strategies to achieve genetic diversity goals.KeywordsGenetic diversityCoral restorationCoral breedingInbreedingEvolutionary potentialPopulation viability model
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Acropora palmata is a foundational yet endangered Caribbean reef-building coral species. The lack of recovery after a disease outbreak and low recruitment has led to widespread use of fragmentation to restore populations. Another option is the production of sexual recruits (settlers) via assisted reproduction to improve the genetic diversity of depleted populations; however, the viability of this approach has not been tested over the long term. In 2011 and 2012, A. palmata larvae were cultured, settled, and the sexual recruits raised in an ex-situ nursery. Survival and growth were monitored over time. In 2014, these two F1 cohorts were moved to an in-situ nursery and after one year, a subset (29 colonies) was outplanted onto Cuevones Reef in the Mexican Caribbean. Growth and survival of these colonies were monitored periodically and compared to colonies that remained in the in-situ nursery. In 2019, samples were collected and analyzed for fertility and fecundity. 53% of the colonies were gravid and fecundity was 5.61 ± 1.91 oocytes and 3.04 ± 0.26 spermaries per polyp. A further 14 colonies from these two cohorts were outplanted in 2020 onto Picudas Reef and monitored during the subsequent spawning seasons. Two years after outplanting onto Picudas Reef, all colonies were alive and spawning of three of these colonies was recorded in 2022 in synchrony with the wild population. Gametes were collected from two colonies and crossed, with 15% fertilization success. Spermatozoa from wild colonies were then added and fertilization success increased to 95%. The resultant larvae followed normal development and symbiont uptake was visible within two weeks. The F2 generation was settled, maintained in an ex-situ nursery, and monitored for survival and growth. Both F1 and F2 generations followed a Type III survival curve with high initial mortality while in the ex-situ nursery and low later-stage mortality. The growth rates of these colonies increased three-fold after outplanting when compared to their growth rates in the ex-situ and in-situ nurseries. All colonies survived while in the in-situ nursery and for an additional nine years after outplanting onto Cuevones Reef. Overall, our results show that colonies produced by assisted breeding, once outplanted, may contribute to the genetic diversity and establishment of self-sustaining sexually-reproducing populations, which is an overarching goal of coral restoration programs.
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Reproductive traits such as fecundity (i.e., the number of gametes produced) and the size and age of coral colonies at reproductive onset can vary in predictable ways among life history strategies. However, most studies on the onset of reproductive maturity in corals only report the presence or absence of oocytes with little known about variation in fecundity across size and age classes. This study aimed to determine the colony size and fecundity at the onset of reproductive maturity across size classes of two scleractinian corals with contrasting life history strategies, Acropora millepora (competitive) and Favites colemani (stress-tolerant). Colonies at a site in northwestern Philippines were sampled to determine the smallest colony size class with mature oocytes and to estimate fecundity across size classes. Histological slides were also prepared to verify the presence of mature gametes. Colonies were able to produce mature oocytes when they had attained colony diameters of 4.7 cm for A. millepora and 1.5 cm for F. colemani. A. millepora had lower fecundity, but larger oocytes compared to F. colemani. Although small colonies can contribute to the larval pool, the proportion of mature colonies increased for larger size classes, suggesting that larger colonies make a disproportionately greater contribution to population reproductive output. These findings contribute to our understanding of coral population dynamics, particularly in parameterizing population and demographic models for different coral life histories.
The sensitivity of reef-building coral to elevated temperature is a function of their symbiosis with dinoflagellate algae in the family Symbiodiniaceae. Changes in the composition of the endosymbiont community in response to thermal stress can increase coral thermal tolerance. Consequently, this mechanism is being investigated as a human-assisted intervention for rapid acclimation of coral in the face of climate change. Successful establishment of novel symbioses that increase coral thermal tolerance have been demonstrated in laboratory conditions; however, it is unclear how long these heterologous relationships persist in nature. Here, we test the persistence of a novel symbiosis between Acropora palmata and Durusdinium spp. from Mote Marine Laboratory’s ex situ nursery by outplanting clonal replicates (ramets) of five A. palmata host genotypes to natural reefs in the lower Florida Keys. Amplicon sequencing analysis of ITS2-type profiles revealed that the majority of surviving ramets remained dominated by Durusdinium spp. two years after transplantation. However, 15% of ramets, including representatives of all genotypes, exhibited some degree of symbiont shuffling or switching at six of eight sites, including complete takeover by site-specific strains of the native symbiont, Symbiodinium fitti. The predominant long-term stability of the novel symbiosis supports the potential effectiveness of symbiont modification as a management tool. Although, the finding that 6–7 year-old coral can alter symbiont community composition in the absence of bleaching indicates that Symbiodiniaceae communities are indeed capable of great flexibility under ambient conditions.
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Elkhorn coral (Acropora palmata) populations provide important ecological functions on shallow Caribbean reefs, many of which were lost when a disease reduced their abundance by more than 95% beginning in the mid-1970s. Since then, a lack of significant recovery has prompted rehabilitation initiatives throughout the Caribbean. Here, we report the first successful outplanting and long-term survival of A. palmata settlers reared from gametes collected in the field. A. palmata larvae were settled on clay substrates (substrate units) and either outplanted on the reef two weeks after settlement or kept in a land-based nursery. After 2.5 years, the survival rate of A. palmata settlers outplanted two weeks after settlement was 6.8 times higher (3.4%) than that of settlers kept in a land-based nursery (0.5%). Furthermore, 32% of the substrate units on the reef still harbored one or more well-developed recruit compared to 3% for substrate units kept in the nursery. In addition to increasing survival, outplanting A. palmata settlers shortly after settlement reduced the costs to produce at least one 2.5-year-old A. palmata individual from $325 to $13 USD. Thus, this study not only highlights the first successful long-term rearing of this critically endangered coral species, but also shows that early outplanting of sexually reared coral settlers can be more cost-effective than the traditional approach of nursery rearing for restoration efforts aimed at rehabilitating coral populations.
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Coral reef restoration has gained recent popularity in response to the steady decline of corals and the recognition that coral reefs may not be able to recover naturally without human intervention. To synthesize collective knowledge about reef restoration focused particularly on the threatened genus Acropora in the Caribbean and western Atlantic, we conducted a literature review combined with personal communications with restoration practitioners and an online questionnaire to identify the most effective reef restoration methods and the major obstacles hindering restoration success. Most participants (90%) strongly believe that Acropora populations are severely degraded, continue to decline, and may not recover without human intervention. Low-cost methods such as coral gardening and fragment stabilization were ranked as the most effective restoration activities for this genus. High financial costs, the small footprint of restoration activities, and the potential damage to wild populations were identified as major concerns, while increased public awareness and education were ranked as the highest benefits of coral reef restoration. This study highlights the advantages and outlines the concerns associated with coral reef restoration and creates a unique synthesis of coral restoration activities as a complementary management tool to help guide “best-practices” for future restoration efforts throughout the region.
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Polyp age and colony size determine the onset of sexual maturity in scleractinian corals (Hall and Hughes 1996), and this has important ecological and evolutionary implications as it influences rates of adaptation and trade-offs between growth and reproduction. Colony age is normally estimated based on size (e.g., Wallace 1985); however, corals have highly variable growth rates and may undergo fission and fusion, making it difficult to accurately determine age based on size alone (Hughes and Jackson 1985). Here we examined sexual maturity in a single cohort of 3-yr-old colonies of Acropora millepora (Ehrenberg, 1834) that had been reared at Bolinao Marine Laboratory from larvae (A, arrows: newly settled spat reared in 2008) settled to artificial substrates in an outdoor hatchery, and subsequently transferred to an in situ nursery. By 2011, three out of 12 colonies transplanted to natural reef after 6 mo of rearing in the nursery and 17 out of 19 colonies that remained in the nursery (B) were sexually mature (C, arrow: mature pigmented oocytes visible in fractured branches). Gravid colonies had mean diameters ranging from 14.4 to 28.3 cm in the nursery and from 12.3 to 13.7 cm on the reef, whereas colony mean diameters in non-gravid colonies ranged from 11.8 to 13.5 cm in the nursery and 7.8 to 11.0 cm on the reef, indicating that spawning can occur at 3 yrs of age provided colony mean diameter is ≥ 14.4 cm in the nursery and ≥ 12.3 cm on the reef. Four gravid colonies were collected from the nursery and observed to spawn synchronously on the night of the full moon (20 March, 2011) between 20:30 and 21:30 hrs at the land based hatchery (D). This is the first report to confirm Wallace's (1985) estimate of onset of sexual maturity in Acropora at 3 yrs of age, 1 yr sooner than the previous observation for Acropora tenuis (Dana, 1846) colonies reared from gametes (Iwao et al. 2010). Our finding further demonstrates the potential for relatively short generation times in Acropora and highlights the difficulties in estimating age from