Variation in larval properties of the Atlantic brooding coral <Emphasis Type="Italic">Porites astreoides</Emphasis> between different reef sites in Bermuda

Recent research has documented phenotypic differences among larvae released from corals with a brooding reproductive mode, both among species and within broods from a single species. We studied larvae released from the common Atlantic coral Porites astreoides in Bermuda to further evaluate phenotypic variability. Inter-site differences were investigated in larvae from conspecifics at a rim and patch reef site. Larvae were collected daily for one lunar cycle from several colonies per site each year over 5 yr. Larval volume varied with reef site of origin, with colonies from the rim reef site producing larger larvae than colonies from the patch reef site. This inter-site variation in larval size could not be explained by corallite size and may be a response to different environmental conditions at the sites. Larvae from both reef sites also varied in size depending on lunar day of release over 4 yr of study. Regardless of site of origin, smaller larvae were released earlier in the lunar cycle. Over 1 yr of study, lipid and zooxanthellae content and settlement success after 48 h covaried with larval size. However, there may be a trade-off between larger larvae and reduced fecundity. Overall, larvae released from colonies from the rim reef site were larger and had greater settlement success than those from colonies from the patch reef site. This study documents larval phenotypic variability and a distinct inter-site difference in larval ecology among conspecifics within the same geographic area, which may have implications for recruitment success, population dynamics, and resilience.     

High potential for formation and persistence of chimeras following aggregated larval settlement in the broadcast spawning coral, Acropora millepora

In sessile modular marine invertebrates, chimeras can originate from fusions of closely settling larvae or of colonies that come into contact through growth or movement. While it has been shown that juveniles of brooding corals fuse under experimental conditions, chimera formation in broadcast spawning corals, the most abundant group of reef corals, has not been examined. This study explores the capacity of the broadcast spawning coral Acropora millepora to form chimeras under experimental conditions and to persist as chimeras in the field. Under experimental conditions, 1.5-fold more larvae settled in aggregations than solitarily, and analyses of nine microsatellite loci revealed that 50 per cent of juveniles tested harboured different genotypes within the same colony. Significantly, some chimeric colonies persisted for 23 months post-settlement, when the study ended. Genotypes within persisting chimeric colonies all showed a high level of relatedness, whereas rejecting colonies displayed variable levels of relatedness. The nearly threefold greater sizes of chimeras compared with solitary juveniles, from settlement through to at least three months, suggest that chimerism is likely to be an important strategy for maximizing survival of vulnerable early life-history stages of corals, although longer-term studies are required to more fully explore the potential benefits of chimerism.     

Tissue compatibility between colonies and between newly settled larvae of Pocillopora damicornis

Grafting experiments with newly settled larvae and with adult colonies of Pocillopora damicornis were performed. When pairs of newly settled larvae released from different colonies were kept in contact, they fused to form an aggregated colony. Even newly settled larvae derived from colonies belonging to different color morphs fused with each other and no sign of allogeneic rejection was observed. However, when branches of adult colonies belonging to different color morphs were kept in contact, they did not fuse. Fusion was observed only when branches derived from the same colony were paired. The present results suggest that juvenile corals lack the functional histocompatibility system as shown by adult colonies.     

Experimental fragmentation reduces sexual reproductive output by the reef-building coral Pocillopora damicornis

Natural and anthropogenic disturbances may fragment stony reef corals, but few quantitative data exist on the impacts of skeletal fragmentation on sexual reproduction in corals. We experimentally fragmented colonies of the branching coral Pocillopora damicornis and determined the number and size of planula larvae released during one lunar reproductive cycle. Partially fragmented colonies significantly delayed both the onset and peak period of planula release compared with intact control colonies. Most fragments removed from the corals died within 11–18 days, and released few planulae. The total number of planulae released per coral colony varied exponentially with remaining tissue volume, and was significantly lower in damaged versus undamaged colonies. However, the number of planulae produced per unit tissue volume, and planula size, did not vary with damage treatment. We conclude that even partial fragmentation of P. damicornis colonies (<25% of tissue removed) decreases their larval output by reducing reproductive tissue volume. Repeated breakage of corals, such as caused by intensive diving tourism or frequent storms, may lead to substantially reduced sexual reproduction. Therefore, reef management should limit human activities that fracture stony corals and lead to decreases in colony size and reproductive output. Accepted: 2 February 2000     

Competition between scleractinian corals and macroalgae: An experimental investigation of coral growth, survival and reproduction

Macroalgae are a major component of many coral reef flat communities, and are potentially major competitors with corals. The influence of macroalgae on several demographic parameters of four species of scleractinian coral by means of an algal clearance experiment was examined to determine specifically if macroalgae are affecting coral cover, growth, fecundity, fission, survivorship and recruitment. Also investigated were patterns of natural encounters between corals and algae.

Algal cover at the study site ranged from 41 to 56%, and coral cover from 8 to 10%. In total, 92 ± 4 ( )% of coral colonies were in contact with one or more species of macroalgae. Changes in coral cover were significantly affected by the presence of macroalgae, with cover of Acropora species increasing faster in areas from which algae had been cleared compared to control areas where algae had not been removed, although this pattern did not occur for Pocillopora damicornis (Linnaeus). Similarly, growth of individual colonies was faster when macroalgae were absent for three Acropora species but not for P. damicornis. There were no differences detected in rates of fission or survivorship of corals between algal clearance and control treatments, although there were high levels of variability in both of these parameters. Fecundity of Acropora palifera (Lamarck), the only species examined, was approximately double in colonies in cleared plots compared to those in control plots with macroalgae present. As no recruitment occurred throughout the 2-yr study, it remains to be determined how macroalgae effect the settlement of coral larvae. The results show that macroalgae can have a major influence on the demography of scleractinian corals.     

Mixed asexual and sexual reproduction in the Indo‐Pacific reef coral Pocillopora damicornis

Pocillopora damicornis is one of the best studied reef‐building corals, yet it's somewhat unique reproductive strategy remains poorly understood. Genetic studies indicate that P. damicornis larvae are produced almost exclusively parthenogenetically, and yet population genetic surveys suggest frequent sexual reproduction. Using microsatellite data from over 580 larvae from 13 colonies, we demonstrate that P. damicornis displays a mixed reproductive strategy where sexual and asexual larvae are produced simultaneously within the same colony. The majority of larvae were parthenogenetic (94%), but most colonies (10 of the 13) produced a subset of their larvae sexually. Logistic regression indicates that the proportion of sexual larvae varied significantly with colony size, cycle day, and calendar day. In particular, the decrease in sexual larvae with colony size suggests that the mixed reproductive strategy changes across the life of the coral. This unique shift in reproductive strategy leads to increasingly asexual replications of successful genotypes, which (in contrast to exclusive parthenogens) have already contributed to the recombinant gene pool.     

Transportation techniques for massive scleractinian corals

Transportation techniques for scleractinian corals have been described mainly for fragments and small colonies. As part of a recent study on captive sexual reproduction of the Caribbean species Montastrea annularis and Diploria strigosa, we transported relatively large (max. diameter of 21 cm), heavy (max. weight of 9,200 g) colonies of both species from Curaçao, Netherlands Antilles, to Rotterdam, The Netherlands. A new transportation technology was applied whereby the corals were transplanted to specially designed PVC crosses to provide stabilization during transport. In two transports (November 2001 and February 2002), 100 colonies were transported submerged, in a shipping time of >35 hr. The survival rate measured 2 weeks after transport was 100%. Four and 8 months after transport, respectively, two colonies of D. strigosa died without any obvious cause. In November 2002 we observed an outbreak of Dark Spots disease (DSD) affecting two‐thirds of the colonies of M. annularis. Although the colonies did not show any symptoms when they were collected, the disease most probably was transferred when the coral were transported from the field to the laboratory. The presented method is appropriate for transporting large, heavy corals–especially for scientific purposes. In general, species‐specific properties, colony size, and transportation time determine which transportation method should be applied. In the future, there may be a shift toward transports of fragments, coral larvae, and primary polyps to reduce collections in the field. Zoo Biol 23:165–176, 2004. © 2004 Wiley‐Liss, Inc.     

Engineering of coral reef larval supply through transplantation of nursery-farmed gravid colonies

The continuous worldwide degradation of coral reefs raises an urgent need for novel active restoration techniques as traditional conservation practices have failed to impede the incessant reefs' decline. While applying the “gardening coral reefs” methodology in Eilat (Red Sea, Israel), we examined reproductive outputs of naturally-grown and outplanted, nursery-farmed Stylophora pistillata colonies from three coral-transplantation trials (November 2005, May 2007, and September 2008), along three reproductive seasons. Surprisingly, transplanted colonies showed better reproductive capacities than the natal Stylophora colonies during > 4 post-transplantation years. A higher percentage of nursery-farmed colonies released planula larvae as compared to naturally-grown colonies. Gravid transplants also shed more planulae per colony, yielding significantly augmented numbers of total planulae over naturally developed S. pistillata colonies. Our results indicate that nursery-grown corals may be used to enhance reef resilience by contributing to the larval pool, forming an engineered larval dispersal instrument for reef rehabilitation.     

Genetic traces of recent long-distance dispersal in a predominantly self-recruiting coral

Background

Understanding of the magnitude and direction of the exchange of individuals among geographically separated subpopulations that comprise a metapopulation (connectivity) can lead to an improved ability to forecast how fast coral reef organisms are likely to recover from disturbance events that cause extensive mortality. Reef corals that brood their larvae internally and release mature larvae are believed to show little exchange of larvae over ecological times scales and are therefore expected to recover extremely slowly from large-scale perturbations.

Methodology/Principal Findings

Using analysis of ten DNA microsatellite loci, we show that although Great Barrier Reef (GBR) populations of the brooding coral, Seriatopora hystrix, are mostly self-seeded and some populations are highly isolated, a considerable amount of sexual larvae (up to ∼4%) has been exchanged among several reefs 10 s to 100 s km apart over the past few generations. Our results further indicate that S. hystrix is capable of producing asexual propagules with similar long-distance dispersal abilities (∼1.4% of the sampled colonies had a multilocus genotype that also occurred at another sampling location), which may aid in recovery from environmental disturbances.

Conclusions/Significance

Patterns of connectivity in this and probably other GBR corals are complex and need to be resolved in greater detail through genetic characterisation of different cohorts and linkage of genetic data with fine-scale hydrodynamic models.     

Distribution and adaptive strategies of alcyonacean corals in Nanwan Bay,Taiwan

The factors responsible for the abundance and distribution patterns of alcyonacean corals on the fringing reefs in southern Taiwan have been investigated. Transplantation studies have shown that the lack of alcyonacean corals in current- and storm-protected areas is possibly due to smothering by heavy sedimentation and with interactions with the alga Codium sp. Studies on the changes of alcyonacean-dominated communities revealed that alcyonacean corals are susceptible to storms but colonies often suffer only partial damage, even in severe storms. The remnants of these colonies can undergo rapid regeneration after storms which enables them to occupy space effectively, and may account for their dominance in storm-swept reefs.     

Chemical signals in gametogenesis, spawning, and larval settlement and defense of the soft coral Sinularia polydactyla

 Mass spawning strategies of hard and soft corals on the Great Barrier Reef, Australia have been described in recent years. Nonetheless, the applicability of those studies to corals on other reef systems has not been well documented. Here we describe the mass spawning behavior of the soft coral Sinularia polydactyla on coral reefs surrounding Guam; specifically we describe the events in an annual gametogenic cycle including steroidogenesis, spawning, settlement and early life history defense. The gametogenic cycle of female colonies lasted 12 months while male colonies produced viable sperm within 9 months. Sinularia polydactyla exhibited a split spawn between March and June that correlated with a significant reduction in tissue concentrations of progesterone and testosterone. Estradiol was released into the water column, apparently by female colonies, just prior to spawning. There was a trend for preferential larval settlement in the presence of the crustose coralline algae Hydrolithon reinboldii rather than coral rubble, a natural biofilm, or filtered seawater. The defensive compounds pukalide and 11β-acetoxypukalide were found in eggs and larvae at adult level and three-fold lower than adult-level concentrations, respectively. These compounds provided some predator deterrent and antimicrobial protection against an ecologically relevant omnivorous fish Canthigaster solandri and a sympatric microbe Vibrio sp. Accepted: 10 September 1998     

From parent to gamete: vertical transmission of Symbiodinium (Dinophyceae) ITS2 sequence assemblages in the reef building coral Montipora capitata

Parental effects are ubiquitous in nature and in many organisms play a particularly critical role in the transfer of symbionts across generations; however, their influence and relative importance in the marine environment has rarely been considered. Coral reefs are biologically diverse and productive marine ecosystems, whose success is framed by symbiosis between reef-building corals and unicellular dinoflagellates in the genus Symbiodinium. Many corals produce aposymbiotic larvae that are infected by Symbiodinium from the environment (horizontal transmission), which allows for the acquisition of new endosymbionts (different from their parents) each generation. In the remaining species, Symbiodinium are transmitted directly from parent to offspring via eggs (vertical transmission), a mechanism that perpetuates the relationship between some or all of the Symbiodinium diversity found in the parent through multiple generations. Here we examine vertical transmission in the Hawaiian coral Montipora capitata by comparing the Symbiodinium ITS2 sequence assemblages in parent colonies and the eggs they produce. Parental effects on sequence assemblages in eggs are explored in the context of the coral genotype, colony morphology, and the environment of parent colonies. Our results indicate that ITS2 sequence assemblages in eggs are generally similar to their parents, and patterns in parental assemblages are different, and reflect environmental conditions, but not colony morphology or coral genotype. We conclude that eggs released by parent colonies during mass spawning events are seeded with different ITS2 sequence assemblages, which encompass phylogenetic variability that may have profound implications for the development, settlement and survival of coral offspring.     

Responses of the Metabolism of the Larvae of Pocillopora damicornis to Ocean Acidification and Warming

Ocean acidification and warming are expected to threaten the persistence of tropical coral reef ecosystems. As coral reefs face multiple stressors, the distribution and abundance of corals will depend on the successful dispersal and settlement of coral larvae under changing environmental conditions. To explore this scenario, we used metabolic rate, at holobiont and molecular levels, as an index for assessing the physiological plasticity of Pocillopora damicornis larvae from this site to conditions of ocean acidity and warming. Larvae were incubated for 6 hours in seawater containing combinations of CO₂ concentration (450 and 950 µatm) and temperature (28 and 30°C). Rates of larval oxygen consumption were higher at elevated temperatures. In contrast, high CO₂ levels elicited depressed metabolic rates, especially for larvae released later in the spawning period. Rates of citrate synthase, a rate-limiting enzyme in aerobic metabolism, suggested a biochemical limit for increasing oxidative capacity in coral larvae in a warming, acidifying ocean. Biological responses were also compared between larvae released from adult colonies on the same day (cohorts). The metabolic physiology of Pocillopora damicornis larvae varied significantly by day of release. Additionally, we used environmental data collected on a reef in Moorea, French Polynesia to provide information about what adult corals and larvae may currently experience in the field. An autonomous pH sensor provided a continuous time series of pH on the natal fringing reef. In February/March, 2011, pH values averaged 8.075±0.023. Our results suggest that without adaptation or acclimatization, only a portion of naïve Pocillopora damicornis larvae may have suitable metabolic phenotypes for maintaining function and fitness in an end-of-the century ocean.     

Effects of juvenile coral-feeding butterflyfishes on host corals

Corals provide critical settlement habitat for a wide range of coral reef fishes, particularly corallivorous butterflyfishes, which not only settle directly into live corals but also use this coral as an exclusive food source. This study examines the consequences of chronic predation by juvenile coral-feeding butterflyfishes on their specific host corals. Juvenile butterflyfishes had high levels of site fidelity for host corals with 88% (38/43) of small (<30 mm) juveniles of Chaetodon plebeius feeding exclusively from a single host colony. This highly concentrated predation had negative effects on the condition of these colonies, with tissue biomass declining with increasing predation intensity. Declines were consistent across both field observations and a controlled experiment. Coral tissue biomass declined by 26.7, 44.5 and 53.4% in low, medium and high predation intensity treatments. Similarly, a 41.7% difference in coral tissue biomass was observed between colonies that were naturally inhabited by juvenile butterflyfish compared to uninhabited control colonies. Total lipid content of host corals declined by 29–38% across all treatments including controls and was not related to predation intensity; rather, this decline coincided with the mass spawning of corals and the loss of lipid-rich eggs. Although the speed at which lost coral tissue is regenerated and the long-term consequences for growth and reproduction remain unknown, our findings indicate that predation by juvenile butterflyfishes represents a chronic stress to these coral colonies and will have negative energetic consequences for the corals used as settlement habitat.     

Chronic low-level nutrient enrichment benefits coral thermal performance in a fore reef habitat

Global- and local-scale anthropogenic stressors have been the main drivers of coral reef decline, causing shifts in coral reef community composition and ecosystem functioning. Excess nutrient enrichment can make corals more vulnerable to ocean warming by suppressing calcification and reducing photosynthetic performance. However, in some environments, corals can exhibit higher growth rates and thermal performance in response to nutrient enrichment. In this study, we measured how chronic nutrient enrichment at low concentrations affected coral physiology, including endosymbiont and coral host response variables, and holobiont metabolic responses of Pocillopora spp. colonies in Mo'orea, French Polynesia. We experimentally enriched corals with dissolved inorganic nitrogen and phosphate for 15 months on an oligotrophic fore reef in Mo'orea. We first characterized symbiont and coral physiological traits due to enrichment and then used thermal performance curves to quantify the relationship between metabolic rates and temperature for experimentally enriched and control coral colonies. We found that endosymbiont densities and total tissue biomass were 54% and 22% higher in nutrient-enriched corals, respectively, relative to controls. Algal endosymbiont nitrogen content cell⁻¹ was 44% lower in enriched corals relative to the control colonies. In addition, thermal performance metrics indicated that the maximal rate of performance for gross photosynthesis was 29% higher and the rate of oxygen evolution at a reference temperature (26.8 °C) for gross photosynthesis was 33% higher in enriched colonies compared to the control colonies. These differences were not attributed to symbiont community composition between corals in different treatments, as C42, a symbiont type in the Cladocopium genus, was the dominant endosymbiont type found in all corals. Together, our results show that in an oligotrophic fore reef environment, nutrient enrichment can cause changes in coral endosymbiont physiology that increase the performance of the coral holobiont.

     

Sperm dispersal distances estimated by parentage analysis in a brooding scleractinian coral

Within populations of brooding sessile corals, sperm dispersal constitutes the mechanism by which gametes interact and mating occurs, and forms the first link in the network of processes that determine specieswide connectivity patterns. However, almost nothing is known about sperm dispersal for any internally fertilizing coral. In this study, we conducted a parentage analysis on coral larvae collected from an area of mapped colonies, to measure the distance sperm disperses for the first time in a reef‐building coral and estimated the mating system characteristics of a recently identified putative cryptic species within the Seriatopora hystrix complex (ShA; Warner et al. 2015). We defined consensus criteria among several replicated methods (colony 2.0, cervus 3.0, mltr v3.2) to maximize accuracy in paternity assignments. Thirteen progeny arrays indicated that this putative species produces exclusively sexually derived, primarily outcrossed larvae (mean t_m = 0.999) in multiple paternity broods (mean r_p = 0.119). Self‐fertilization was directly detected at low frequency for all broods combined (2.8%), but comprised 23% of matings in one brood. Although over 82% of mating occurred between colonies within 10 m of each other (mean sperm dispersal = 5.5 m ± 4.37 SD), we found no evidence of inbreeding in the established population. Restricted dispersal of sperm compared to slightly greater larval dispersal appears to limit inbreeding among close relatives in this cryptic species. Our findings establish a good basis for further work on sperm dispersal in brooding corals and provide the first information about the mating system of a newly identified and abundant cryptic species.     

Changes in gametogenesis and fecundity of acroporid corals that were exposed to elevated nitrogen and phosphorus during the ENCORE experiment

Colonies of two scleractinian reef coral species, Acropora longicyathus and Acropora aspera were transplanted into patch reefs at One Tree Reef, Great Barrier Reef, Australia as part of the ENCORE experiment. These corals and colonies of A. aspera which were naturally present in the patch reefs were exposed to four treatments over two years: controls with normal seawater, elevated levels of nitrogen only, phosphorus only, or nitrogen plus phosphorus. These corals were sampled and used to determine whether gametogenic cycles and fecundity were affected by nutrient enrichment. Acropora longicyathus had a single annual gametogenic cycle. Corals exposed to elevated nitrogen produced significantly smaller and fewer eggs and contained less testes material than those which were not exposed to nitrogen. Exposure to elevated phosphorus only resulted in corals producing more but smaller eggs, and more testes material. Egg numbers of colonies from other treatments decreased as the gametogenic cycles continued, but those of the phosphorus colonies showed almost no reduction in egg numbers between the early and late stages of the gametogenic cycles. These results have important management implications for coral reefs as they demonstrate that small increases in concentrations of nitrogen and phosphorus can have severe effects on reproductive activity in these species of scleractinian corals.     

The effects of prolonged “bleaching” on the tissue biomass and reproduction of the reef coral Montastrea annularis

Colonies of Montastrea annularis from Carysfort Reef, Florida, that remained bleached seven months after the 1987 Caribbean bleaching event were studied to determine the long term effects of bleaching on coral physiology. Two types of bleached colonies were found: colonies with low numbers of zooxanthellae with normal pigment content, and a colony with high densities of lowpigment zooxanthellae. In both types, the zooxanthellae had an abnormal distribution within polyp tissues: highest densities were observed in basal endoderm and in mesenteries where zooxanthellae are not normally found. Bleached corals had 30% less tissue carbon and 44% less tissue nitrogen biomass per skeletal surface area, but the same tissue C:N ratio as other colonies that either did not bleach (normal) or that bleached and regained their zooxanthellae (recovered). Bleached corals were not able to complete gametogenesis during the reproductive season following the bleaching, while recovered corals were able to follow a normal gametogenic cycle. It appears that bleached corals were able to survive the prolonged period without nutritional contribution from their zooxanthellae by consuming their own structural materials for maintenance, but then, did not have the resources necessary for reproduction. The recovered corals, on the other hand, must have regained their zooxanthellae soon after the bleaching event since neither their tissue biomass nor their ability to reproduce were impaired.     

Fungi in Porites lutea: association with healthy and diseased corals.

Healthy and diseased scleractinian corals have been reported to harbour fungi. However, the species of fungi occurring in them and their prevalence in terms of biomass have not been determined and their role in coral diseases is not clear. We have found fungi to occur regularly in healthy, partially dead, bleached and pink-line syndrome (PLS)-affected scleractinian coral, Porites lutea, in the reefs of Lakshadweep Islands in the Arabian Sea. Mostly terrestrial species of fungi were isolated in culture from these corals. Hyaline and dark, non-sporulating fungi were the most dominant forms. Fungal hyphae extended up to 3 cm within the corals. Immunofluorescence detection using polyclonal immunological probes for a dark, initially non-sporulating isolate (isolate # 98-N28) and for a hyaline, non-sporulating fungus (isolate # 98-N18) revealed high frequencies of these in PLS-affected, dead and healthy colonies of P. lutea. Total fungal biomass accounted for 0.04 to 0.05% of the weight of corals in bleached corals and was higher than in PLS-affected and healthy colonies. Scanning electron microscopy revealed the presence of fungi within the carbonate skeleton and around polyps. Fungi appear to be a regular component of healthy, partially dead and diseased coral skeleton.     

Population structure is not a simple function of reproductive mode and larval type: insights from tropical corals

1. For a wide range of organisms, heritable variation in life-history characteristics has been shown to be strongly subject to selection, reflecting the impact that variation in characters such as genotypic diversity, duration of larval development and adaptations for dispersal can have on the fitness of offspring and the make-up of populations. Indeed, variation in life-history characteristics, especially reproduction and larval type, have often been used to predict patterns of dispersal and resultant population structures in marine invertebrates. 2. Scleractinian corals are excellent models with which to test this relationship, as they exhibit almost every possible combination of reproductive mode and larval type. Some general patterns are emerging but, contrary to expectations, genetic data suggest that while populations of broadcast spawning species may be genotypically diverse they may be heavily reliant on localized recruitment rather than widespread dispersal of larvae. 3. Here we use microsatellites to test the importance of localized recruitment by comparing the genetic structure of populations of two broadcast spawning corals with contrasting modes of reproduction and larval development; Goniastrea favulus is self-compatible, has sticky, negatively buoyant eggs and larvae and is expected to have restricted dispersal of gametes and larvae. In contrast, Platygyra daedalea is self-incompatibile, spawns positively buoyant egg-sperm bundles and has planktonic development. 4. Surprisingly, spatial-autocorrelation revealed no fine-scale clustering of similar genotypes within sites for G. favulus, but showed a non-random distribution of genotypes in P. daedalea. Both species showed similar levels of genetic subdivision among sites separated by 50-100 m (F(ST) = 0.03), suggesting that larval dispersal may be equivalent in both species. 5. Interestingly, as fragmentation has been considered rare in massive corals, our sample of 284 P. daedalea colonies included 28 replicated genotypes that were each unlikely (P < 0.05) to have been derived independently from sexual reproduction. 6. We conclude that the extreme life history of G. favulus does not produce unusually fine-scale genetic structure and subsequently, that reproductive mode and larval type may not be not good predictors of population structure or dispersal ability.