Habitat degradation disrupts neophobia in juvenile coral reef fish

Habitat degradation not only disrupts habitat‐forming species, but alters the sensory landscape within which most species must balance behavioural activities against predation risk. Rapidly developing a cautious behavioural phenotype, a condition known as neophobia, is advantageous when entering a novel risky habitat. Many aquatic organisms rely on damage‐released conspecific cues (i.e. alarm cues) as an indicator of impending danger and use them to assess general risk and develop neophobia. This study tested whether settlement‐stage damselfish associated with degraded coral reef habitats were able to use alarm cues as an indicator of risk and, in turn, develop a neophobic response at the end of their larval phase. Our results indicate that fish in live coral habitats that were exposed to alarm cues developed neophobia, and, in situ, were found to be more cautious, more closely associated with their coral shelters and survived four‐times better than non‐neophobic control fish. In contrast, fish that settled onto degraded coral habitats did not exhibit neophobia and consequently suffered much greater mortality on the reef, regardless of their history of exposure to alarm cues. Our results show that habitat degradation alters the efficacy of alarm cues with phenotypic and survival consequences for newly settled recruits.     

Enhancing coral larval supply and seedling production using a special bundle collection system “coral larval cradle” for large‐scale coral restoration

Larval recruitment is essential for sustaining coral communities and a fundamental tool in some interventions for reef restoration. To improve larval supply and post‐settlement survival in sexually assisted coral restoration efforts, an integrated in situ collector system, the larval cradle, was designed to collect spawned gametes then culture the resulting larvae until settled on artificial substrates. The final design of the larval cradle was cylindrical, a nylon mesh structure with a volume of 9 m³, suspended in the sea and extending vertically toward the seabed. We found three key design features that improved the efficiency of the apparatus: (1) an open area of sea surface and mesh size of less than 100 μm produced high fertilization and optimal survival (>90%), (2) a special skirt‐shaped net (3 m in diameter) with a connection hose for attaching the cradle to collect bundles from many adult colonies over a wide area and at various depths, and (3) adding short square tube pieces, called square hollow sections, as a substrate for enhancing larval settlement and survival, to a larval cradle at 4 days after spawning was optimal for uniform settlement. This system allowed not only the collection of several million eggs, but also subsequent production of several thousand settled juvenile corals, without land facilities. Our design achieved several hundred times higher survival for early life stages of Acropora tenuis compared to nature.     

Interactive effects of interspecific competition and microhabitat on early post-settlement survival in a coral reef fish

Microhabitat type and the competition for microhabitats can each influence patterns of abundance and mortality in coral reef fish communities; however, the effect of microhabitat on the intensity and outcome of competition is not well understood. In Kimbe Bay, Papua New Guinea, surveys were used to quantify microhabitat use and selectivity in two live-coral specialist damselfishes (Pomacentridae), Chrysiptera parasema, and Dascyllus melanurus. A patch reef experiment was then conducted to test how intra- and interspecific competition interacts with two types of microhabitat to influence survival of recently settled C. parasema. Surveys demonstrated that C. parasema and D. melanurus recruits utilized similar coral microhabitats; 72% of C. parasema and 85% of D. melanurus used corymbose and bottlebrush growth forms of Acropora. One microhabitat type, Pocillopora sp. coral, was commonly used by D. melanurus but rarely by C. parasema. The patch reef experiment revealed that both microhabitat and interspecific competition influence abundance of recently settled C. parasema. Microhabitat had the strongest influence on survival of C. parasema. In the absence of interspecific competitors, ~85% of C. parasema survived for 5 days after transplantation to high-complexity bottlebrush Acropora reefs when compared to only 25% survival of Pocillopora reefs. In both microhabitats, interspecific competition with D. melanurus, but not intraspecific competition, significantly decreased the survival of C. parasema. Taken together, these results suggest that the observed distribution of C. parasema results from specialized microhabitat requirements and competition for space in those microhabitats. This study demonstrates that interspecific competition and microhabitat type can interact to influence early post-settlement survival in coral reef fishes, though, whether and how these factors influence survival will depend on the behavioural attributes and strength of habitat associations among potential competitors. Communicated by Environment Editor Prof. Rob van Woesik     

In situ observation of coral recruitment using fluorescence census techniques

A novel method for the observation of recruitment of fluorescent taxa was developed combining fluorescence census techniques with conventional microscopic examination. The new technique was used to observe coral recruitment on natural limestone plates over a period of 4 months on Meras reef, North Sulawesi, Indonesia. During this period, fluorescence photos were taken of each plate on a weekly basis. This allowed for the detailed observation of fluorescent coral recruitment in-situ. After specific time periods, the plates were sampled and the detected recruits were categorized to family level using their skeletal structure. The fluorescence census technique detected 97.6% of all coral recruits bigger than one millimetre in diameter. The diameter measurements of the recruit's skeletons were used to estimate growth rates at family level. Using the photo series method, the time of settlement of fluorescent recruits on the plates was determined. The results showed roughly linear diameter growth of recruits in the first two months. Acroporidae-polyps were 1.14 mm in diameter when they settled and grew at rate of approximately 0.18 mm in diameter per week. Pocilloporidae-polyps settled at approximately 1.14 mm and showed a growth rate of approximately 0.23 mm in diameter per week. Recruits of three families were observed in detail over time on the artificial plates using this method. While recruitment was fairly continuous, an increase in pocilloporid recruits was observed during the month of September. Similar increases were observed for acroporid recruits during the middle of November and the second quarter of December. This method identifies the limits of detection for the fluorescence census technique used and represents a useful method for the temporal fine scale observation of recruitment in situ.     

Successful sexual reproduction of the scleractinian coral Porites panamensis: Evidence of planktonic larvae and recruitment

Porites panamensis is a hermatypic brooder coral endemic to, and distributed along, the Eastern Tropical Pacific, and is considered a species vulnerable to local effects because it has limited capacity for long‐distance dispersal (and low genetic diversity). Although larvae of P. panamensis have been previously shown to recruit to artificial settlement platforms, they have never been observed in the water column. The present study describes the reproductive behavior of P. panamensis, with a focus on using molecular tools to document evidence for a larval planktonic stage and for successful recruitment. Larvae collected from the water column, and recruitment on natural and artificial substrata were documented. Phylogenetic analysis of two ribosomal markers, 18s rRNA and ITS (ITS1‐5.8‐ITS2), and one mitochondrial marker, cytochrome oxidase subunit 1 (cox1), confirmed the taxonomic identity of larvae, and showed that larvae and recruits have genotypes similar to adults of P. panamensis. Lipid vacuoles and Symbiodinium sp. were present in the gastrodermis of all larvae. A total of 12 and 371 recruits settled on artificial and natural substrates, respectively, and the recruitment rate differed significantly over time. By documenting the reproductive success of the species, we show the potential for existing individuals both to maintain the population in the study area and to contribute to maintenance of the coral reef community in the coming decades.     

Coral reef restoration in the Eastern Tropical Pacific: feasibility of the coral nursery approach

Due to the worldwide degradation of coral reefs, the active restoration of these ecosystems has received considerable attention in recent decades. This study investigated (1) the feasibility of using coral nurseries for restoration projects, (2) the minimum size required for a Pocillopora damicornis (Pocilloporidae) coral fragment to survive and grow in a nursery, and (3) the optimal transplant size of a fragment when transplanted to a degraded reef at Gorgona Island (Colombian Pacific). For this investigation, 230 fragments were transplanted directly to El Remanso reef, and another 150 fragments were maintained in in situ nurseries. Every 2 months, the length, weight, and survival of the fragments were recorded. After growing for 134 days in the nurseries, the 52 surviving fragments were transplanted to El Remanso reef, and after 5 months, the same variables were measured. Among the nursery‐reared fragments, the largest (4 to <8 cm) had the highest survival and growth rates, whereas among the directly transplanted fragments, the smallest fragments (<2 cm) had the highest survival and growth rates. However, the nursery‐reared fragments acquired greater structural complexity (arborescent morphology), and they were all alive 156 days after transplantation and presented a maximum linear growth rate of over 2 cm, which was higher than that of the directly transplanted fragments. Apparently, the arborescent morphology acquired during the nursery period provides advantages to the colonies that favor greater success when transplanted. Therefore, nursery‐reared fragments of P. damicornis between 2 and 4 cm are the most appropriate for use in restoration projects.     

Spatial patterns of self‐recruitment of a coral reef fish in relation to island‐scale retention mechanisms

Oceanographic features influence the transport and delivery of marine larvae, and physical retention mechanisms, such as eddies, can enhance self‐recruitment (i.e. the return of larvae to their natal population). Knowledge of exact locations of hatching (origin) and settlement (arrival) of larvae of reef animals provides a means to compare observed patterns of self‐recruitment ‘connectivity’ with those expected from water circulation patterns. Using parentage inference based on multiple sampling years in Moorea, French Polynesia, we describe spatial and temporal variation in self‐recruitment of the anemonefish Amphiprion chrysopterus, evaluate the consistency of net dispersal distances of self‐recruits against the null expectation of passive particle dispersal and test the hypothesis that larvae originating in certain reef habitats (lagoons and passes) would be retained and thus more likely to self‐recruit than those originating on the outer (fore) reef. Estimates of known self‐recruitment were consistent across the sampling years (~25–27% of sampled recruits). For most (88%) of these self‐recruits, the net distance between hatching and settlement locations was within the maximum dispersal distance expected for a neutrally buoyant passive particle based on the longest duration of the larval dispersive phase and the average direction and speed of current flow around Moorea. Furthermore, a parent of a given body size on the outer (fore) reef of Moorea was less likely to produce self‐recruits than those in passes. Our findings show that even a simple dispersal model based on net average flow and direction of alongshore currents can provide insight into landscape‐scale retention patterns of reef fishes.     

Bommies away! Logistics and early effects of repositioning 400 tonnes of displaced coral colonies following cyclone impacts on the Great Barrier Reef

For over 40 years, management of the Great Barrier Reef Marine Park (GBRMP) in Australia has focused on limiting human‐use impacts to facilitate natural resilience and recovery. Compounding acute disturbances and chronic stressors have resulted in degradation of coral reef habitats in many areas of the Marine Park. Given current trends and predictions of escalating climate‐driven disturbances, it is increasingly evident that effective management of the GBRMP requires adaptive and novel approaches to protect and restore coral reef health. Here, we provide an overview of the logistical requirements and early‐stage ecological benefits of repositioning 400 tonnes of moderately sized (1–3 m diameter) Porites spp. coral colonies (bommies) that were displaced by cyclone‐generated swells that impacted reefs in the Whitsunday Islands during March 2017. An ecological survey conducted 16 months after the bommie repositioning revealed that several genera of hard coral had settled onto the bommies and that a range of reef fish species were associating with the restored habitat. Early findings suggest that the repositioning of the displaced bommies has assisted in restoring reef habitat structure and settlement habitat for juvenile corals, while improving natural aesthetics, vessel access and tourist experiences at Manta Ray Bay.     

Coralclip®: a low‐cost solution for rapid and targeted out‐planting of coral at scale

Re‐attaching or out‐planting coral as fragments, colonies, and on larval settlement devices to substrates is a major bottleneck limiting scalabilty and viability of reef restoration practices. Many attachment approaches are in use, but none that are low‐cost, opportunistic, rapid but effective, for integration into existing tour operations on the Great Barrier Reef (GBR) where staff and boat time is a major cost and chemical fixatives cannot be easily used. We describe a novel attachment device—Coralclip®—developed to meet this need and so aid maintenance and restoration of GBR tourism sites. Coralclip® is a stainless steel springclip attached by a nail integrated through the spring coil, and can be deployed with a coral fragment in as fast as 15 seconds. Initial laboratory tests demonstrated that Coralclip® secured coral fragments or larval settlement tiles under dynamic flow regimes characteristic of exposed reefs. Coral out‐planting from fragments of opportunity and from nurseries (n = 4,580; 0.3–1.9 coral/minute; US$0.6–3.0/coral deployed) or larval settlement tiles (n = 400; 2.5 tiles/minute; US$0.5 tile deployed^?1) when deployed by divers from routine boat operations at Opal Reef confirmed highly effective attachment, with ≤15% failure of clips found after 3–7 months. We discuss how Coralclip® is a cost‐effective means to support reef maintenance and restoration practices.     

Survival and settlement success of coral planulae: independent and synergistic effects of macroalgae and microbes

Restoration of degraded coral reef communities is dependent on successful recruitment and survival of new coral planulae. Degraded reefs are often characterized by high cover of fleshy algae and high microbial densities, complemented by low abundance of coral and coral recruits. Here, we investigated how the presence and abundance of macroalgae and microbes affected recruitment success of a common Hawaiian coral. We found that the presence of algae reduced survivorship and settlement success of planulae. With the addition of the broad-spectrum antibiotic, ampicillin, these negative effects were reversed, suggesting that algae indirectly cause planular mortality by enhancing microbial concentrations or by weakening the coral’s resistance to microbial infections. Algae further reduced recruitment success of corals as planulae preferentially settled on algal surfaces, but later suffered 100% mortality. In contrast to survival, settlement was unsuccessful in treatments containing antibiotics, suggesting that benthic microbes may be necessary to induce settlement. These experiments highlight potential complex interactions that govern the relationships between microbes, algae and corals and emphasize the importance of microbial dynamics in coral reef ecology and restoration. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Patterns of recruitment of coral reef fishes in a monsoonal environment

The abundance of newly settled recruits of coral reef fishes was monitored at a total of 11 sites at two islands and two coastal locations in the central Philippines for a 20-month period (February 2008 to September 2009) that included two monsoon cycles. Recruitment occurred throughout the year. Most of the abundant species exhibited protracted recruitment seasons. This confirms the expectation of extended breeding of reef fishes at lower latitudes. The annual pattern of recruitment of reef fishes as a group was predictable. Annual fluctuations of sea surface temperature and wind strength largely explained the pattern. Rainfall, however, did not significantly influence the pattern of recruitment. Peaks in density and species richness of recruits occurred during the southwest monsoon and the second inter-monsoonal period of the year (July to October) when temperatures were highest and when most of the sites were sheltered from winds or when winds were weak. Conversely, lowest density and species richness were observed during the northeast monsoon (November to March) when temperatures were lowest and most sites were exposed to winds. The same pattern could also be seen in the recruitment of both damselfishes (Pomacentridae) and wrasses (Labridae), notwithstanding a tenfold difference in abundance of recruits between the two families. The pattern was fairly consistent across most sites, among most of the species that were examined, and between the 2 years that were sampled. This study is one of the few to provide insights into the influence of environmental factors on the recruitment patterns of fishes on Indo-Pacific coral reefs situated at lower latitudes.     

Evidence of stable genetic structure across a remote island archipelago through self‐recruitment in a widely dispersed coral reef fish

We used microsatellite markers to assess the population genetic structure of the scribbled rabbitfish Siganus spinus in the western Pacific. This species is a culturally important food fish in the Mariana Archipelago and subject to high fishing pressure. Our primary hypothesis was to test whether the individuals resident in the southern Mariana Island chain were genetically distinct and hence should be managed as discrete stocks. In addition to spatial sampling of adults, newly‐settled individuals were sampled on Guam over four recruitment events to assess the temporal stability of the observed spatial patterns, and evidence of self‐recruitment. We found significant genetic structure in S. spinus across the western Pacific, with Bayesian analyses revealing three genetically distinct clusters: the southern Mariana Islands, east Micronesia, and the west Pacific; with the southern Mariana Islands being more strongly differentiated from the rest of the region. Analyses of temporal samples from Guam indicated the southern Mariana cluster was stable over time, with no genetic differentiation between adults versus recruits, or between samples collected across four separate recruitment events spanning 11 months. Subsequent assignment tests indicated seven recruits had self‐recruited from within the Southern Mariana Islands population. Our results confirm the relative isolation of the southern Mariana Islands population and highlight how local processes can act to isolate populations that, by virtue of their broad‐scale distribution, have been subject to traditionally high gene flows. Our results add to a growing consensus that self‐recruitment is a highly significant influence on the population dynamics of tropical reef fish.     

The effect of microhabitat patch size on settlement differs among co-occurring coral reef fishes

Over small spatial scales, coral reefs represent a mosaic of suitable settlement microhabitat patches of varying size for late-stage larval reef fishes. Few studies have specifically examined how variation in patch size influences density of recently settled coral reef fishes (recruits). Using standardized units of coral rubble settlement substrate deployed on sandy bottom, we monitored the concurrent settlement of three reef fish taxa onto differently sized patches (0.28–1.68 m²) at 5-d intervals during a lunar settlement peak. We found marked differences among taxa in how recruit density scaled with patch size. Recruit density of a damselfish and a parrotfish decreased and increased, respectively, with the increase in patch size, while that of a wrasse was similar among patch sizes. Our results highlight the importance of the interaction between taxon-specific settlement behaviour and patch size in establishing initial spatial differences in density within and among coral reef fish taxa in a heterogeneous landscape.

     

Motivations,success, and cost of coral reef restoration

Coral reef restoration is an increasingly important part of tropical marine conservation. Information about what motivates coral reef restoration as well as its success and cost is not well understood but is needed to inform restoration decisions. We systematically review and synthesize data from mostly scientific studies published in peer‐reviewed and gray literature on the motivations for coral reef restoration, the variables measured, outcomes reported, the cost per hectare of the restoration project, the survival of restored corals, the duration of the project, and its overall spatial extent depending on the restoration technique employed. The main motivation to restore coral reefs for the projects assessed was to further our ecological knowledge and improve restoration techniques, with coral growth, productivity, and survival being the main variables measured. The median project cost was 400,000 US$/ha (2010 US$), ranging from 6,000 US$/ha for the nursery phase of coral gardening to 4,000,000 US$/ha for substrate addition to build an artificial reef. Restoration projects were mostly of short duration (1–2 years) and over small spatial extents (0.01 ha or 108 m²). Median reported survival of restored corals was 60.9%. Future research to survey practitioners who do not publish their discoveries would complement this work. Our findings and database provide critical data to inform future research in coral reef restoration.     

Highlighting ontogenetic shifts in habitat use by nocturnal coral reef fish

The lagoon of Moorea Island was characterised by 12 distinct reef zones. Visual censuses allowed us to document the spatial distributions of recently settled juveniles vs adults of 17 nocturnal fish species among the 12 reef zones. Five distinct patterns in habitat use were found: an increase in the number of reef zones used during the adult stage (four species); a decrease in the number of reef zones adults used compared to recently settled juveniles (two species); the use of different reef zones (one species); the use of same reef zones but with relative densities different (one species); and no change in habitat use (nine species). Overall, this study is the first to explore the use of space by a broad range of nocturnal fish taxa to document the patterns and determinism of habitat shifts between juvenile and adult life stages.     

Strategies for Gardening Denuded Coral Reef Areas: The Applicability of Using Different Types of Coral Material for Reef Restoration

Recreational and other human activities degrade coral reefs worldwide to a point where efficient restoration techniques are needed. Here we tested several strategies for gardening denuded reefs. The gardening concept consists of in situ or ex situ mariculture of coral recruits, followed by their transplantation into degraded reef sites. In situ nurseries were established in Eilat's (Northern Red Sea) shallow waters, sheltering three types of coral materials taken from the branching species Stylophora pistillata (small colonies, branch fragments, and spat) that were monitored for up to two years. Pruning more than 10% of donor colonies' branches increased mortality, and surviving colonies displayed reduced reproductive activity. Maricultured isolated branches, however, exceeded donor colony life span and reproductive activity and added 0.5–45% skeletal mass per year. Forty‐four percent of the small colonies survived after 1.5‐year mariculture, revealing average yearly growth of 75 ± 32%. Three months ex situ maintenance of coral spat (sexual recruits) prior to the in situ nursery phase increased survivorship. Within the next 1.5 years, they developed into colonies of 3–4 cm diameter. Nursery periods of 2 years, 4–5 years, and more than> 5 years have been estimated for small colonies, spat, and isolated branches, respectively. These and other results, including the possible use of nubbins (minute fragments the size of a single or few polyps), are discussed, revealing benefits and drawbacks for each material. In situ coral mariculture is an improved practice to the common but potentially harmful protocol of direct coral transplantation. It is suggested that reef gardening may be used as a key management tool in conservation and restoration of denuded reef areas. The gardening concept may be applicable for coral reefs worldwide through site‐specific considerations and the use of different local coral species.     

Restoration Strategies for Coral Reefs Damaged by Recreational Activities: The Use of Sexual and Asexual Recruits

The unique marine ecosystems of coral reefs express varying levels of degradation as a result of increasing anthropogenic pressures. This is the main reason why more than 200 coral reef localities were proclaimed as natural reserves or marine parks under varying legislation, rules, and monitoring and management programs. Ironically, the conventional management plans increased accessibility to many reef localities and enhanced dramatically the impact of tourism on reef habitats. Recreational activities including SCUBA and skin diving, fishing, human trampling, sediment re-suspension, and other damage caused by “innocent” visitors are causing a rapid deterioration of many reefs. Their destruction requires years and decades for full recovery. I propose to rehabilitate such damaged habitats by the alternate strategy of “gardening coral reefs” with asexual and sexual recruits. Coral branches, colony fragments, and whole small colonies (asexual recruits) and laboratory or in situ settled planula-larvae (sexual recruits) are designed to be transplanted into denuded reefs for restoration. This approach is further improved when the sexual and asexual recruits are maricultured in situ within special protected areas, before being transplanted. The use of sexual recruits ensures an increase in genetic diversity. I discuss several methodologies and results already accumulated showing the applicability of this gardening strategy for rehabilitation of denuded coral reefs. This restoration strategy should be integrated with proper management similar to that of already established reforestation in terrestrial habitats. The best candidates for employing this strategy are the fast-growing coral species, usually branching forms and species that brood their planulae larvae.     

Optimizing industrial‐scale coral reef restoration: comparing harvesting wild coral spawn slicks and transplanting gravid adult colonies

Accelerating coral reef restoration is a global challenge that has been attempted around the world. Previous attempts show varying levels of success at localized scales, but comparisons of cost and benefits to evaluate large‐scale reef restoration approaches are lacking. Here, we compare two large‐scale restoration approaches: the harvesting, development, and release of wild coral spawn slicks onto a target reef, with the transplantation of gravid coral colonies to provide a seed population and local source of larvae. Comparisons incorporate the best available information on demographic rates to estimate population growth, beginning at embryo production to colony maturity 4 years following deployment. Cost‐effectiveness is considered in a coarse manner. The harvesting, development, and controlled release of coral spawn slicks is anticipated to achieve large‐scale restoration of coral communities with low‐impact technology at low cost per colony. Harvesting wild spawn slicks has the potential to (1) transport billions of larvae up to thousands of kilometers that (2) are relevant to coral restoration efforts at vast geographical scales while (3) benefitting from the use of technology with extremely low impact on wild populations and (4) retaining natural genetic and species diversity needed to enhance the resilience of restored communities. Transplanting colonies is most useful from reefs designated to be impacted by infrastructural development by providing an opportunity for transfer to high value zones, from dedicated nurseries, and for brooding species. Our contribution provides insights into critical elements of both concepts, and we highlight information gaps in parameter uncertainties.     

Parentage analyses identify local dispersal events and sibling aggregations in a natural population of Millepora hydrocorals,a free‐spawning marine invertebrate

Dispersal is a critical process for the persistence and productivity of marine populations. For many reef species, there is increasing evidence that local demography and self‐recruitment have major consequences on their genetic diversity and adaptation to environmental change. Yet empirical data of dispersal patterns in reef‐building species remain scarce. Here, we document the first genetic estimates of self‐recruitment and dispersal distances in a free‐spawning marine invertebrate, the hydrocoral Millepora cf. platyphylla. Using twelve microsatellite markers, we gathered genotypic information from 3,160 georeferenced colonies collected over 27,000 m² of a single reef in three adjacent habitats in Moorea, French Polynesia; the mid slope, upper slope, and back reef. Although the adult population was predominantly clonal (85% were clones), our parentage analysis revealed a moderate self‐recruitment rate with a minimum of 8% of sexual propagules produced locally. Assigned offspring often settled at <10 m from their parents and dispersal events decrease with increasing geographic distance. There were no discrepancies between the dispersal distances of offspring assigned to parents belonging to clonal versus nonclonal genotypes. Interhabitat dispersal events via cross‐reef transport were also detected for sexual and asexual propagules. Sibship analysis showed that full siblings recruit nearby on the reef (more than 40% settled at <30 m), resulting in sibling aggregations. Our findings highlight the importance of self‐recruitment together with clonality in stabilizing population dynamics, which may ultimately enhance local sustainability and resilience to disturbance.     

Large‐scale,multidirectional larval connectivity among coral reef fish populations in the Great Barrier Reef Marine Park

Larval dispersal is the key process by which populations of most marine fishes and invertebrates are connected and replenished. Advances in larval tagging and genetics have enhanced our capacity to track larval dispersal, assess scales of population connectivity, and quantify larval exchange among no‐take marine reserves and fished areas. Recent studies have found that reserves can be a significant source of recruits for populations up to 40 km away, but the scale and direction of larval connectivity across larger seascapes remain unknown. Here, we apply genetic parentage analysis to investigate larval dispersal patterns for two exploited coral reef groupers (Plectropomus maculatus and Plectropomus leopardus) within and among three clusters of reefs separated by 60–220 km within the Great Barrier Reef Marine Park, Australia. A total of 69 juvenile P. maculatus and 17 juvenile P. leopardus (representing 6% and 9% of the total juveniles sampled, respectively) were genetically assigned to parent individuals on reefs within the study area. We identified both short‐distance larval dispersal within regions (200 m to 50 km) and long‐distance, multidirectional dispersal of up to ~250 km among regions. Dispersal strength declined significantly with distance, with best‐fit dispersal kernels estimating median dispersal distances of ~110 km for P. maculatus and ~190 km for P. leopardus. Larval exchange among reefs demonstrates that established reserves form a highly connected network and contribute larvae for the replenishment of fished reefs at multiple spatial scales. Our findings highlight the potential for long‐distance dispersal in an important group of reef fishes, and provide further evidence that effectively protected reserves can yield recruitment and sustainability benefits for exploited fish populations.