Coral ReefsPub Date : 2024-08-31DOI: 10.1007/s00338-024-02546-0
Krista V. Laforest, Chelsea G. Petrik, Ashlee A. Hylton, Rachel L. Ionata, E. Murphy McDonald, Morgan L. Short, Joana Figueiredo
{"title":"Induced sexual reproduction ex situ reveals bidirectional sex change of the coral Montastraea cavernosa","authors":"Krista V. Laforest, Chelsea G. Petrik, Ashlee A. Hylton, Rachel L. Ionata, E. Murphy McDonald, Morgan L. Short, Joana Figueiredo","doi":"10.1007/s00338-024-02546-0","DOIUrl":"https://doi.org/10.1007/s00338-024-02546-0","url":null,"abstract":"<p>Induction of gonad maturation and synchronized spawning of corals ex situ has been mostly used to propagate corals for restoration, but it also provides a unique opportunity to study the reproductive biology of species. We present, for the first time, the induction of gonad maturation and synchronous spawning of the coral <i>Montastraea cavernosa</i> in a laboratory. This was achieved by mimicking the annual temperature, sun and moon cycles experienced in the northern portion of Florida’s Coral Reef. Similarly to field observations, peak spawning of <i>M. cavernosa</i> colonies in the laboratory occurred 5–10 nights after the full moons of July, August, and/or September, 75–125 min after sunset. This coral species was known as gonochoric, meaning colonies are either females (release eggs) or males (release sperm). Yet, three consecutive years observing the same colonies ex situ revealed that these corals are capable of changing sexes annually, and they can do so in both directions. Spawning observations and histology showed corals shifting from male to female, others shifting from female to male, and several changing sex one year and reverting to their original sex in the following year. The sex change was not related to size, nor likely socially driven. A greater number of colonies was observed to shift from female to male when food provision was reduced. Further studies are required to determine if food availability drives sex change in this species.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"31 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coral ReefsPub Date : 2024-08-29DOI: 10.1007/s00338-024-02547-z
Andrew Heyward, Christine Giuliano, Cathie A. Page, Carly J. Randall
{"title":"Rock and roll: experiments on substrate movement and coral settlement","authors":"Andrew Heyward, Christine Giuliano, Cathie A. Page, Carly J. Randall","doi":"10.1007/s00338-024-02547-z","DOIUrl":"https://doi.org/10.1007/s00338-024-02547-z","url":null,"abstract":"<p>Rubble is ubiquitous on coral reefs and can aggregate into fields, forming a significant component of the reef substrate. Rubble fields often remain unconsolidated, with the component rubble pieces subject to movement that is dependent on hydrodynamic forcing, rubble size, shape, and other factors. Settlement of corals to rubble fields has long been assumed, but the dynamic movement of rubble pieces has been presumed to deter settlement and is thought to contribute to high post-settlement mortality. Rubble often forms on coral reefs following severe disturbances, and is predicted to increase under climate change, with the potential to impact settlement and recruitment-dependent recovery processes. Through a series of laboratory and field experiments, we demonstrate that corals from broadcast spawning species on the Great Barrier Reef will settle on unstable substrates, even those in constant motion. We also observed more coral spat on settlement tiles suspended in the water column than those fixed to the reef using a common approach to censusing settlement. Sampling of natural rubble on the reef 50 days after a mass-spawning event confirmed the presence of similar numbers of coral settlers on rubble and on tiles fixed to the reef. These results suggest that rubble fields are places of significant settlement for broadcast spawning corals. Suspended tiles were also surprisingly effective in collecting coral settlers, demonstrating that a change in sampling protocol can produce significant variation in settlement data and strengthening the argument for standardisation of settlement-monitoring protocols, particularly at a time of growing need for reliable metrics. These results also suggest that movement of rubble is not precluding settlement outright, but rather post-settlement processes (i.e. competition, predation, shading or burial by shifting rubble) are limiting recruitment to rubble patches. Consequently, rubble stabilisation may increase the survival of spat that have settled in these environments.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"101 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coral ReefsPub Date : 2024-08-29DOI: 10.1007/s00338-024-02557-x
Phongsathorn Röser, Karin Glaser, Desiree Juchem, John Everett Parkinson, Christian R. Voolstra, Ulf Karsten
{"title":"Species-specific effects of light and temperature on photosynthesis and respiration among Symbiodiniaceae (Dinophyceae)","authors":"Phongsathorn Röser, Karin Glaser, Desiree Juchem, John Everett Parkinson, Christian R. Voolstra, Ulf Karsten","doi":"10.1007/s00338-024-02557-x","DOIUrl":"https://doi.org/10.1007/s00338-024-02557-x","url":null,"abstract":"<p>Coral reefs are exposed to various environmental stressors that cause bleaching events, whereby endosymbiotic microalgae (Symbiodiniaceae) disassociate from coral hosts. Bleached corals are compromised and face mortality. The combination of high-light exposure and elevated seawater temperature often lead to coral bleaching. The physiological properties of the Symbiodiniaceae within the coral tissues contribute to the thermal tolerance of the holobiont (the host and all its symbionts). The present study aimed to investigate the effects of light and temperature stress on four Symbiodiniaceae species from three genera with respect to photosynthetic oxygen production and consumption. Under control conditions, the species displayed predominantly low-to-moderate light requirements for photosynthesis with increased photoinhibition at higher photon flux rates. After 30 days of heat acclimation at 32 °C, maximum photosynthetic activity declined in <i>Effrenium voratum</i>, doubled in <i>Fugacium kawagutii,</i> and remained unchanged in <i>Breviolum psygmophilum</i>. In subsequent acute heating assays, species-specific effects on maximum photosynthetic activity were observed. Photosynthesis in all species declined across a temperature gradient between 25 and 39 °C in the acute heating assays; full inhibition occurred at 37 °C in <i>B. psygmophilum</i> and <i>E. voratum</i> and at 39 °C in <i>B. aenigmaticum</i> and <i>F. kawagutii</i>. In contrast, respiration remained largely constant in all species across temperatures. Our data point to species-specific photophysiological traits that lead to different thermal tolerances among Symbiodiniaceae.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"2 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of the frequency of multi-specific synchronous spawning on genetic introgression among three Acropora species","authors":"Naoko Isomura, Keisuke Inoha, Akifumi Shimura, Nina Yasuda, Taisei Kikuchi, Kenji Iwao, Seiya Kitanobo, Shun Ohki, Masaya Morita, Hironobu Fukami","doi":"10.1007/s00338-024-02554-0","DOIUrl":"https://doi.org/10.1007/s00338-024-02554-0","url":null,"abstract":"<p>Hybridisation is an evolutionary process that generates genetic diversity in organisms. However, the relationship between reproductive features, such as spawning synchronisation and gamete compatibility, and the degree of introgression leading to hybridisation are poorly understood. The reef-building coral <i>Acropora</i> spp. have a complex evolutionary history, and the link between their ecology, life-history traits, and potential to hybridise is disputed. Here, we examined the relationship among the reproductive features involved in the intercrossing of three species, <i>Acropora florida</i>, <i>Acropora gemmifera</i>, and <i>Acropora intermedia</i>, at two sites: Akajima and the Sesoko islands in southern Japan. Although the examined species showed synchronous spawning and high rates of gamete compatibility, spawning synchronisation and gamete compatibility were less strongly associated with high rates of interbreeding among the three species. Model-based genetic clustering and site-pattern frequency-based tests with single nucleotide polymorphisms supported genetic admixture among the three species in each location. Demographic analyses using fastsimcoal implied that the admixture among the three species in each location might have occurred in the past (> 2,000 generations) and recently (< 50 generations). Furthermore, the recent admixture of these three species is potentially associated with heavy bleaching events and population declines. The principal component analysis, structure, and fastsimcoal showed that the extensive admixture of <i>A. intermedia</i> and <i>A. gemmifera</i> on Sesoko Island occurred recently. Therefore, gamete interactions that lead to hybridisation in the field must be clarified. Furthermore, the connectivity between the two locations needs to be identified; however, our results implied that population fluctuations could be associated with introgression.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"63 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coral ReefsPub Date : 2024-08-27DOI: 10.1007/s00338-024-02542-4
Adam T. Downie, Caroline M. Phelps, Björn Illing, Jen Whan, Mark I. McCormick, Jodie L. Rummer
{"title":"Changes in aerobic metabolism associated with the settlement transition for the leopard coral grouper (Plectropomus leopardus)","authors":"Adam T. Downie, Caroline M. Phelps, Björn Illing, Jen Whan, Mark I. McCormick, Jodie L. Rummer","doi":"10.1007/s00338-024-02542-4","DOIUrl":"https://doi.org/10.1007/s00338-024-02542-4","url":null,"abstract":"<p>Metamorphosis is a critical aspect of coral reef fish ecology. This developmental milestone marks changes in form and function that permit successful transition of pelagic larvae to the demersal lifestyle on coral reefs. However, we know very little about the physiological changes that occur during this period, specifically potential changes in energetics associated with swimming. This is critical, as swimming is the mechanism by which pelagic larvae find a suitable reef on which to settle. Coral grouper larvae (Serranidae: <i>Plectropomas leopardus</i>) were collected at night as they came into the vicinity of a fringing reef to settle, and their physiological metamorphosis was characterized. Larvae and 24 h-settled juveniles were exposed to an endurance swimming test at ecologically relevant swimming speeds, and oxygen uptake rates were measured during activity. To describe how aerobic and anaerobic properties of tissues change during metamorphosis, we also measured whole body citrate synthase and lactate dehydrogenase activity, respectively, as well as mitochondrial density in the trunk and pectoral fins. Our approach accurately measures the oxygen uptake rates these life stages need during the recruitment process, with larvae having a 74% higher mass-specific oxygen uptake rate (<i>Ṁ</i>O<sub>2</sub>) than settled juveniles despite swimming at speeds that are only 1.5 body-lengths per second (BLs<sup>−1</sup>) faster. Citrate synthase activity significantly decreased upon settlement; as larvae had 3.7 times higher activities than juveniles, suggesting that rapid changes in aerobic metabolism of tissues may be an important process during metamorphosis in this species. In contrast, lactate dehydrogenase did not significantly differ upon settlement. These findings highlight some physiological modifications that pelagic coral grouper larvae undertake within 24 h that contribute to successfully settling onto a coral reef.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"22 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Differential strategies developed by two light-dependent scleractinian corals to extend their vertical range to mesophotic depths","authors":"Gonzalo Pérez-Rosales, Héloïse Rouzé, Michel Pichon, Pim Bongaerts, Nelly Bregere, Jérémy Carlot, Valeriano Parravicini, Laetitia Hédouin","doi":"10.1007/s00338-024-02544-2","DOIUrl":"https://doi.org/10.1007/s00338-024-02544-2","url":null,"abstract":"<p>Mesophotic coral ecosystems are characterised by the presence of photosynthetic scleractinian corals despite the decreasing amounts of light available with depth. To better understand physiological strategies across a broad depth gradient, we studied the biological trait responses of <i>Pocillopora</i> cf. <i>verrucosa</i> from 6 to 60 m depth and <i>Pachyseris “speciosa”</i> spp. from 20 to 90 m depth at four islands of French Polynesia. Specifically, we characterised associated Symbiodiniaceae communities, photophysiological traits (Symbiodiniaceae density and chlorophyll concentrations), micro-morphology and trophic plasticity (autotrophy vs heterotrophy inferred from stable isotopes). Our results showed that both taxa can live at mesophotic depths without significant genetic structuring in their generic Symbiodiniaceae communities, mainly composed of <i>Cladocopium</i> and <i>Durusdinium</i>. Yet, the prevalence of Symbiodiniaceae ITS2 profiles revealed location-based variations that sometimes interact with depth and highlight putative shallow- or depth-tolerant taxa. For both taxa, symbiont density and chlorophyll pigment concentrations increased with increasing depth. We also found a change in their skeletal micro-morphology with an increase in the inter-corallite distance for <i>Pocillopora</i> cf. <i>verrucosa</i> and a decrease in the height of septa for <i>Pachyseris “speciosa”</i> spp. with depth. Finally, we found no isotopic evidence of switching to a more heterotrophic diet as their primary energy source, although host–tissue δ<sup>13</sup>C ratios became more negative with depth in both corals. Overall, our findings show similarity (across the two species) and species-specific strategies (biological trait patterns with increasing depth) underlying the capacity of symbiotic scleractinian corals to live in low-light environments.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"4 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coral ReefsPub Date : 2024-08-26DOI: 10.1007/s00338-024-02543-3
Andrew A. Shantz, Mark C. Ladd
{"title":"Shifting patterns in parrotfish corallivory after 12 years of decline on coral depauperate reefs in the Florida Keys, USA","authors":"Andrew A. Shantz, Mark C. Ladd","doi":"10.1007/s00338-024-02543-3","DOIUrl":"https://doi.org/10.1007/s00338-024-02543-3","url":null,"abstract":"<p>When coral cover declines, numeric responses of parrotfish can facilitate top-down control of algae and help reefs recover. Yet many parrotfish are facultative corallivores and we know surprisingly little about how their numeric or functional responses to coral decline modify their interactions with coral prey to shape their impacts on surviving corals. Here, we use benthic and fish surveys conducted in the Florida Keys more than a decade apart to assess how coral communities have changed, and how these changes have impacted parrotfish and their predation rates on corals. We found that disturbances and disease have continued to drive declines in coral cover and changes in coral community composition, but that the parrotfish abundance has not changed. In turn, while parrotfish corallivory has remained relatively constant or even declined for some coral taxa, predation on preferred branching Porites species increased 10% in frequency and, when normalized to live tissue area, > 50% in intensity. These coral-mediated shifts in predation correlated with declines in conspecific cover and are indicative of depensatory predation, which can destabilize trophic interactions and drive prey to low densities or even extinction. While coral reefs cannot recover from disturbances without robust parrotfish populations, our study suggests that parrotfish corallivory has important ramifications for coral community structure and, after prolonged degradation, the ability of some diminished coral populations to recover or persist. In a world where corals bleach annually, understanding the functional responses of corallivorous parrotfish to changes in resource abundance will be increasingly important for effective ecosystem-based management.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"55 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coral ReefsPub Date : 2024-08-19DOI: 10.1007/s00338-024-02545-1
Michael P. Lesser
{"title":"Irradiance dependency of oxidative stress and coral bleaching","authors":"Michael P. Lesser","doi":"10.1007/s00338-024-02545-1","DOIUrl":"https://doi.org/10.1007/s00338-024-02545-1","url":null,"abstract":"<p>The degradation of tropical coral reefs continues unabated as global climate change causes mass “coral bleaching” events. At the organismal level, there is significant evidence that the production of reactive oxygen (ROS) and nitrogen (RNS) species, followed by programmed cell death, causes coral bleaching. Additionally, in tropical marine environments exposure to high irradiances of solar radiation contributes to the photooxidative production of ROS in corals. But most thermal stress experiments on corals have not manipulated and tested the direct and interactive effects of solar radiation on coral bleaching, which is further compounded by the ecologically unrealistic low irradiances used in many experiments. Using published data, a direct relationship between excitation pressure (<i>Q</i><sub>m</sub>) on photosystem II for the photosymbionts of corals with irradiance, when exposed to thermal stress, is demonstrated here. Using these results, the photoinhibition model of oxidative stress and coral bleaching is refined for shallow coral reefs; high irradiances increase <i>Q</i><sub>m</sub> and when exposed to thermal stress result in an increase in ROS and coral bleaching, but under low irradiances the production of ROS decreases while the production of RNS increases, leading to coral bleaching. This suggests that irradiance-dependent effector molecules of coral bleaching (i.e., ROS versus RNS) may dominant the oxidative stress landscape in the coral holobiont. Incorporating measurements of irradiance, tissue oxygen concentrations and ROS/RNS levels, in addition to temperature, into experiments and predictive models is required in order to better understand the full range of environmental conditions that cause coral bleaching.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"116 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coral ReefsPub Date : 2024-08-16DOI: 10.1007/s00338-024-02524-6
Matthew L. Doherty, Alex D. Chequer, Tali Mass, Gretchen Goodbody-Gringley
{"title":"Phenotypic variability of Montastraea cavernosa and Porites astreoides along a depth gradient from shallow to mesophotic reefs in the Cayman Islands","authors":"Matthew L. Doherty, Alex D. Chequer, Tali Mass, Gretchen Goodbody-Gringley","doi":"10.1007/s00338-024-02524-6","DOIUrl":"https://doi.org/10.1007/s00338-024-02524-6","url":null,"abstract":"<p>Phenotypic variability is the ability of the same species to express different phenotypes under different environmental conditions. Several coral species that exist along a broad depth distribution have been shown to differ in skeletal morphology and nutrient acquisition at different depths, which has been attributed to variability in response to differing levels of light availability. This study examined the phenotypic variability of two common depth generalist corals, <i>Montastraea cavernosa</i> and <i>Porites astreoides,</i> along a gradient from 10 to 50 m in the Cayman Islands, by examining changes in skeletal morphology, photophysiology, symbiont cell density, and chlorophyll concentration. Skeletal features of <i>M. cavernosa</i> were found to increase in size from 10 to 30 m, but returned to smaller sizes from 30 to 50 m, while <i>P. astreoides</i> skeletal features continued to increase in size from 10 to 40 m. No differences were observed in either symbiont density or chlorophyll concentration across depths for either species. However, all photophysiological parameters exhibited significant depth-dependent variations in both species, revealing adaptive strategies to different light environments. These results suggest that both species have high variability in response to depth. Patterns of skeletal morphology and photophysiology, however, suggest that <i>M. cavernosa</i> may be more variable in regulating photosynthetic efficiency compared to <i>P. astreoides</i>, which likely facilitates the broader depth distribution of this species.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"9 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coral ReefsPub Date : 2024-08-14DOI: 10.1007/s00338-024-02541-5
Deborah Burn, Andrew S. Hoey, Chiara Pisapia, Josie F. Chandler, Cassandra A. Thompson, Morgan S. Pratchett
{"title":"Comparison of juvenile coral assemblages between Australia’s Coral Sea and Great Barrier Reef Marine Parks","authors":"Deborah Burn, Andrew S. Hoey, Chiara Pisapia, Josie F. Chandler, Cassandra A. Thompson, Morgan S. Pratchett","doi":"10.1007/s00338-024-02541-5","DOIUrl":"https://doi.org/10.1007/s00338-024-02541-5","url":null,"abstract":"<p>Densities of juvenile corals (≤ 50 mm diameter) are expected to vary between geographically isolated and more spatially proximate reefs, and may constrain local recovery potential. This study compared juvenile coral densities and their relationships with local abundance of adult congenerics at geographically isolated reefs within Australia’s Coral Sea Marine Park (CSMP) versus highly connected reefs within the Great Barrier Reef Marine Park (GBRMP). Three latitudinal regions and two habitats (reef crest and slope) were examined within both marine parks to test for spatial variation. Densities of juvenile corals in the CSMP (13.99 ± 0.72 juveniles 10 m<sup>−2</sup>) were significantly lower compared to those in the GBRMP (23.72 ± 1.86 juveniles 10 m<sup>−2</sup>). Specifically, there were significantly less <i>Acropora</i> and <i>Pocillopora</i> juveniles on the reef crest in the central CSMP compared to the GBRMP. Relationships between juvenile abundance and percent coral cover were greatest for <i>Acropora</i> and <i>Pocillopora</i> in the GBRMP. This may be due to the low range of coral cover estimates recorded in the CSMP, especially for <i>Acropora</i> (0–15%). Low juvenile coral abundance, and in particular, the lack of fast-growing juvenile corals (e.g., <i>Acropora</i>) in the Central CSMP, in combination with low cover of broodstock (particularly <i>Acropora</i>) on CSMP reefs, poses a significant constraint on post-disturbance recovery capacity, possibly attributable to isolation and limited connectivity among reefs in this region.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"17 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}