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Monitoring coral cover can describe the ecology of reef degradation, but rarely can it reveal the proximal mechanisms of change, or achieve its full potential in informing conservation actions. Describing temporal variation in Symbiodiniaceae within corals can help address these limitations, but this is rarely a research priority. Here, we augmented an ecological time series of the coral reefs of St. John, US Virgin Islands, by describing the genetic complement of symbiotic algae in common corals. Seventy-five corals from nine species were marked and sampled in 2017. Of these colonies, 41% were sampled in 2018, and 72% in 2019; 28% could not be found and were assumed to have died. Symbiodiniaceae ITS2 sequencing identified 525 distinct sequences (comprising 42 ITS2 type profiles), and symbiont diversity differed among host species and individuals, but was in most cases preserved within hosts over 3 yrs that were marked by physical disturbances from major hurricanes (2017) and the regional onset of stony coral tissue loss disease (2019). While changes in symbiont communities were slight and stochastic over time within colonies, variation in the dominant symbionts among colonies was observed for all host species. Together, these results indicate that declining host abundances could lead to the loss of rare algal lineages that are found in a low proportion of few coral colonies left on many reefs, especially if coral declines are symbiont-specific. These findings highlight the importance of identifying Symbiodiniaceae as part of a time series of coral communities to support holistic conservation planning. Repeated sampling of tagged corals is unlikely to be viable for this purpose, because many Caribbean corals are dying before they can be sampled multiple times. Instead, random sampling of large numbers of corals may be more effective in capturing the diversity and temporal dynamics of Symbiodiniaceae metacommunities in reef corals. [ABSTRACT FROM AUTHOR]

As the major form of coral reef regime shift, stony coral to macroalgal transitions have received considerable attention. In the Caribbean, however, regime shifts in which scleractinian corals are replaced by octocoral assemblages hold potential for maintaining reef associated communities. Accordingly, forecasting the resilience of octocoral assemblages to future disturbance regimes is necessary to understand these assemblages' capacity to maintain reef biodiversity. We parameterised integral projection models quantifying the survival, growth, and recruitment of the octocorals, Antillogorgia americana, Gorgonia ventalina, and Eunicea flexuosa, in St John, US Virgin Islands, before, during, and after severe hurricane disturbance. Using these models, we forecast the density of populations of each species under varying future hurricane regimes. We demonstrate that although hurricanes reduce population growth, A. americana, G. ventalina, and E. flexuosa each display a capacity for quick recovery following storm disturbance. Despite this recovery potential, we illustrate how the population dynamics of each species correspond with a longer-term decline in their population densities. Despite their resilience to periodic physical disturbance events, ongoing global change jeopardises the future viability of octocoral assemblages. [ABSTRACT FROM AUTHOR]

In 1983 to 1984, a mass mortality event caused a Caribbean-wide, >95% population reduction of the echinoid grazer, Diadema antillarum. This led to blooms of algae contributing to the devastation of scleractinian coral populations. Since then, D. antillarum exhibited only limited and patchy population recovery in shallow water, and in 2022 was struck by a second mass mortality reported over many reef localities in the Caribbean. Half-a-century time-series analyses of populations of this sea urchin from St. John, US Virgin Islands, reveal that the 2022 event has reduced population densities by 98.00% compared to 2021, and by 99.96% compared to 1983. In 2021, coral cover throughout the Caribbean was approaching the lowest values recorded in modern times. However, prior to 2022, locations with small aggregations of D. antillarum produced grazing halos in which weedy corals were able to successfully recruit and become the dominant coral taxa. The 2022 mortality has eliminated these algal-free halos on St. John and perhaps many other regions, thereby increasing the risk that these reefs will further transition into coral-free communities. [ABSTRACT FROM AUTHOR]

Sessile organisms exploit a life-history strategy in which adults are immobile and their growth position is determined at settlement. The morphological strategy exploited by these organisms has strong selective value, because it can allow beneficial matching of morphology to environmental and biological conditions. In benthic marine environments, a 'sheet-tree' morphology is a classic mechanism exploited by select sessile organisms, and milleporine hydrocorals provide one of the best examples of this strategy. Using 30-year analysis of Millepora sp. on the reefs of St. John, US Virgin Islands, I tested for the benefits of a sheet-tree morphology in mediating the ecological success of an important functional group of benthic space holders. The abundance of Millepora sp. chaotically changed from 1992 to 2021 in concert with hurricanes, bleaching and macroalgal crowding. Millepora sp. responded to these disturbances by exploiting their morphological strategy to increase the use of trees when their sheets were compromised by bleaching and spatial competition with macroalgae, and the use of sheets when their trees were broken by storms. Together, these results reveal the selective value of a plastic sheet-tree morphology, which can be exploited by sessile organisms to respond to decadal-scale variation in environmental conditions. [ABSTRACT FROM AUTHOR]

Most tropical coral reefs are experiencing declining coral cover, yet interpretation of this generality is tempered by spatial variation in coral cover among reefs separated over 20–200 km. This study addresses such landscape scale variation in coral reefs at 12 sites (7–10 m depth) around St. John (18° 18´ 37.04 N, 63° 43´ 23.17 W) and St. Thomas (18° 20´ 43.57 N, 65° 55´ 13.88 W), US Virgin Islands. Surveys completed from 2011 to 2021 were used to test for spatial variation in community dynamics among islands, shores, and sites. Community synchrony (φ) was used to evaluate portfolio effects in mediating changes in coral communities. From 2011 to 2021, changes in benthic communities differed among sites and times (i.e., there were site × year interactions), and, while coral cover declined at 11 sites, the decline was 2.6-fold faster around St. Thomas than St. John. The loss of coral cover was driven by multiple taxa that differed among sites, thus revealing asynchronous responses to prevailing conditions. Asynchrony suggests that coral communities at some of the sites have the capacity to exploit portfolio effects to modulate stability, yet these effects did not prevent declines in coral cover that reflect island-scale phenomena. In the US Virgin Islands, coral death is overwhelming the capacity for resilience of coral communities that historically may have benefitted from portfolio effects. Until coral assemblages are depleted through taxonomic extirpation, maintenance of the assemblage composition retains the possibility that increased resilience might emerge if environmental challenges can be alleviated. [ABSTRACT FROM AUTHOR]

The biological world is rapidly changing following decades of anthropogenic disturbances. Under these conditions, species with stable or increasing abundances have been described as winners with the potential for future success, but this assertion is unreliable without knowledge of the selective basis of winning. The incentive to find winners is acute for reef corals, for which large declines in abundance have motivated restoration efforts targeting winning corals. On Caribbean reefs, Porites astreoides has emerged as a potential winner, but the demographic basis of this categorization is poorly known. Here we test for demographic benchmarks of winning in this species by quantifying abundances and sizes of colonies over 28 yr on the south coast of St. John, US Virgin Islands. From 1992 to 2001, the density of colonies of P. astreoides showed little variation while colonies increased in size by 58%, but from 2002 to 2019, population density increased 2.7‐fold, and colony size declined by 41%; accompanying these trends, the mean absolute cover of Porites spp. declined by 46% from 2010 to 2019. Low recruitment and rising abundances of colonies ≤4 cm diameter suggest that partial mortality and fission depressed colony sizes. The reversal over three decades of a positive demographic trend for a ubiquitous coral underscores the challenges of identifying winners from short‐term population performance. Without a mechanistic understanding of fitness, the search for winners based on demographic trends may be futile. [ABSTRACT FROM AUTHOR]

The supply of propagules mediates recruitment and population dynamics, thereby driving community resilience following disturbances. These relationships are of interest on tropical reefs, where coral populations have drastically declined in abundance and sexual recruitment is the only means by which they will recover. To better understand the causes and implications of variation in this vital rate (i.e., recruitment), coral recruitment was measured in Mo'orea, French Polynesia, and St. John, U.S. Virgin Islands, using settlement tiles deployed from 2005 to 2019. The results were used to test two hypotheses: (1) annual variation in recruitment is a weak predictor of long‐term variation in recruitment, but (2) it is associated with seawater temperature. Coral recruitment varied over space and time, so that differences in recruitment between consecutive years were uninformative of long‐term trends. Recruitment varied among years in an apparently chaotic manner, but the variation reflected linear and quadratic associations with mean annual temperature and the daily variation in temperature. These associations are consistent with theory addressing the mechanisms by which temperature affects coral larvae and recruitment. Comprehension of these mechanisms is required to accurately interpret evidence of coral recruitment collapse, and to elucidate the conditions favoring recovery of coral communities through recruitment. [ABSTRACT FROM AUTHOR]

Within the past decade, a functional group of encrusting red macroalgae defined as peyssonnelid algal crusts (PAC) has been rapidly spreading on shallow Caribbean reefs, frequently encrusting corals and sponges. This study focused on PAC growing on the reefs of St. John, US Virgin Islands, to (1) expand the monitoring of PAC abundance in this location, and (2) test two mechanisms, rapid linear growth and competitive dominance, by which PAC is hypothesized to enhance its capacity to spread. In August 2019, we found that the percentage coverage of PAC reached 46.6% at Tektite (3 m depth), and 63.8% at Cabritte Horn (3 m depth). Overall, the cover of PAC at these sites in 2019 was identical to, or up to 2.4-fold higher than in August 2017, and 2.1–3.7-fold higher than in November 2017, just after two category 5 storms impacted St. John. PAC was 1.8–29.1-fold more abundant at 3 m versus 9 m depth, and 1.4–22.0-fold more abundant at sites close to the tips of headlands than sites sheltered within bays. From August 2019 to January 2020, the rate of linear extension of PAC at each site and depth ranged from 26 to 43 µm d − 1, and of 80 PAC-coral interactions that were tagged in August 2019, none involved corals that had become completely overgrown by PAC by January 2020. The slow linear growth and absence of cases in which PAC completely overgrew coral colonies in 6 months are inconsistent with the high rate at which PAC has occupied space on Caribbean reefs over the past decade. One means to reconcile these observations is the possibility that recruitment of peyssonnelid spores to benthic surfaces facilitates the rapid spread of PAC. [ABSTRACT FROM AUTHOR]

With coral cover declining on most tropical reefs, efforts are intensifying to understand the mechanisms by which environmental stressors are driving populations into demographic deficit. Here, the population dynamics of sexual cohorts of small corals (≤ 4 cm diameter) in St. John, US Virgin Islands were used to test the hypothesis that the association of vital rates with environmental conditions has changed over 22 yr. The annual fate of 3999 corals at six sites and 7--9 m depth were used to populate Leslie Matrices and calculate assemblage growth rates (λ, without recruitment), mortality of the smallest corals, and graduation from the largest size class. Vital rates were tested for associations with temperature, the number of days with seawater warmer than 29.4°C (i.e., hot days), and rainfall. Transition probabilities varied among years, and usually more corals remained in their original size class than moved among size classes. Corals in the smallest size class had the highest mortality rate (42% yr-1), λ had a grand mean of 0.688, and there were trends for λ to vary with the number of hot days and rainfall through quadratic relationships. The linear dependence of λ on rainfall over consecutive 3-yr periods declined over two decades, suggesting that this colony size-defined coral assemblage has undergone phenotypic change in their responsiveness to varying environmental conditions. [ABSTRACT FROM AUTHOR]

In recent decades, many Caribbean reefs have experienced large declines in abundance of scleractinian corals, and blooms of fleshy macroalgae have often accompanied these trends. In 2010 a new macroalgal threat emerged in Lac Bay, Bonaire, where peyssonnelid algal crusts (PAC) rapidly spread in shallow water and overgrew corals and sponges. Similar growths have been reported in Puerto Rico and the Virgin Islands, and here, we describe the spread of PAC on the shallow reefs of St. John, US Virgin Islands, ~ 760 km northeast of Bonaire. In 2015, PAC covered 0.2–20.6% of hard benthic surfaces at ≤ 7 m depth. By August 2017, at the same sites, PAC had increased to 3.2–61.0% cover, at 5 m depth at 10 other sites along 5 km of shore, it covered 1.4–61.6% of reef surfaces, and at 9 m depth at five sites, it covered 0.8–41.0% of reef surfaces. At 5 m depth in August 2017, scleractinians and octocorals were frequently contacting PAC (42–47% of colonies), and more scleractinians (74%) than octocorals (39%) were overgrown by PAC. Following surveys in August 2017, St. John was hit by two Category 5 hurricanes, yet the shore-wide mean cover of PAC at 5 m depth was only reduced from 26 to 23%. Our results suggest PAC is poised to cause significant ecological change on the reefs of St. John and potentially will promote a community shift favoring octocorals over scleractinians. PAC constitutes an emerging regional threat on shallow Caribbean reefs to which researchers and resource managers will need to quickly respond. [ABSTRACT FROM AUTHOR]

Since about 2000, octocorals on the shallow reefs of St. John, US Virgin Islands, have increased in abundance to form dense stands analogous to terrestrial forests. In this study, the ecology of octocoral forests was explored by testing for an effect of their canopies on the light regime and benthic invertebrate community in the understory habitat. Octocoral forests at five sites (7–13 m depth) were quantified on a spatial scale of meters by the height and density of octocoral colonies. Their effects on the understory habitat were evaluated through measurements of downwelling light, benthic invertebrate community structure, and the photophysiology (i.e., induction time) of the common coral, Porites astreoides (Lamarck, 1816). Octocoral forests composed of dense (> 5 octocorals m−2) and tall (mean height of 42 cm) octocoral colonies created an understory habitat characterized by flashes of bright light (i.e., sunflecking). Within the understory habitat at two of three study sites, the community structure of benthic invertebrates was modified by the octocoral canopy, but it remained unaffected at a third site. A test for the effects of sunflecking on the induction time of P. astreoides found no difference between colonies in the understory versus the open reef habitat. These results do not support the notion that the physiological phenotype of autotrophs in the understory habitat is modified to exploit sunflecking. The analysis of the benthic invertebrates in the understory habitat suggests that octocoral forests can change the community structure of this group of organisms, relative to the open reef. The causes of this change are unclear, but its absence at the most sheltered study site suggests that water motion may be a contributing factor. The strong likelihood that octocoral forests mediate ecologically significant changes in the community structure of invertebrates within their understory habitat warrants further investigation. • Octocoral forests support unique invertebrate communities. • Spectral analysis shows increased high frequency sunflecking within understories. • Octocorals function as ecosystem engineers by modifying light variability. • Photosynthetic induction by hard corals was unaffected by octocoral canopies. • Octocoral density and resilience will likely define future benthic communities. [ABSTRACT FROM AUTHOR]

Tropical coral reefs exemplify ecosystems imperiled by environmental change. Anticipating the future of reef ecosystems requires understanding how scleractinian corals respond to the multiple environmental disturbances that threaten their survival. We analyzed the stability of coral reefs at three habitats at different depths along the south shore of St. John, U.S. Virgin Islands, using multivariate autoregression (MAR) models and two decades of monitoring data. We quantified several measures of ecosystem stability, including the magnitude of typical stochastic fluctuations, the rate of recovery following disturbance, and the sensitivity of coral cover to hurricanes and elevated sea temperature. Our results show that, even within a ~4 km shore, coral communities in different habitats display different stability properties, and that the stability of each habitat corresponds with the habitat's known synecology. Two Orbicella-dominated habitats are less prone to annual stochastic fluctuations than coral communities in shallower water, but they recover slowly from disturbance, and one habitat has suffered recent losses in scleractinian cover that will not be quickly reversed. In contrast, a shallower, low-coral-cover habitat is subject to greater stochastic fluctuations, but rebounds more quickly from disturbance and is more robust to hurricanes and seawater warming. In some sense, the shallower community is more stable, although the stability arguably arises from having little coral cover left. Our results sharpen understanding of recent changes in coral communities at these habitats, provide a more detailed understanding of how these habitats may change in future environments, and illustrate how MAR models can be used to assess stability of communities founded upon long-lived species. [ABSTRACT FROM AUTHOR]

Using the coral reefs of St. John, US Virgin Islands, as an experimental system, we tested the hypothesis that the distribution of hermit crabs (Calcinus tibicen Herbst, 1791 and Pagurus brevidactylus Stimpson, 1859) is associated positively with the distribution of the cerithid gastropods shells they favor as homes. Cerithium spp. were surveyed on shallow (<6 m) reefs along 10 km of the south shore of St. John, in 2011 (6 sites) and 2012 (7 sites); they were categorized as live shells (LS), empty shells (ES), or occupied shells (OS, containing hermit crabs). In both years, densities of LS and ES differed significantly among sites and were higher in the east compared to the west; densities of OS did not vary among sites in 2011, but in 2012 were marginally more abundant to the west. Densities of OS were not correlated with the density of LS in either year. The distribution of cerithids is consistent with the hypothesized origin in a patch-depletion model for larval supply, in which recruitment declines along the shore as larvae are transported farther from their eastern sources. In contrast, the distribution of hermit crabs was more uniform along the shore, suggesting dispersal in the pelagic realm or on the benthos was more active than for cerithids. Hermit crabs did not occur simply where live cerithids were found, but instead favored locations where suitable shells (i.e., OS + ES of sufficient size) were common, and potentially dispersed to these locations. [ABSTRACT FROM AUTHOR]

The article presents a study on long-term changes in the concentration of zooplankton and particulate material over a fringing reef in Saint John, U.S. Virgin Islands. Seawater quality was evaluated from concentrations of particulate matter (PM), particulate organic matter (POM) and zooplankton. The hypothesis that seawater quality over Caribbean reefs has changed over forty years is said to be consistent with the results of the study.

In this study, long-term (1987-1998) dynamics are described on a local scale (<20 km) for coral reefs in St. John, US Virgin Islands, which are located in a marine protected area (MPA). The study consists of two sites (Yawzi and Tektite) which were selected in 1987 based on relatively high coral cover (=32%), and six sites that were randomly selected in 1992. Over 12 years, mean coral cover at Yawzi (9 m depth) changed significantly, declining from 45 to 20% cover between 1987 and 1998 (a 56% reduction). Less than 1 km away at Tektite (14 m depth), coral cover also changed significantly, but here it increased 34% (from 32 to 43% cover). Over the same period, macroalgal cover showed a significant upward trend at both sites, increasing from 2 to 26% at Yawzi, and from 6 to 13% at Tektite. The random sites (7-9 m depth) differed from the initial sites in both community structure and dynamics. Mean coral cover at the random sites (~8%) was less than one third of that at Yawzi and Tektite, and varied significantly among sites and years in an idiosyncratic pattern. The percentage cover of macroalgae and the pooled coverage of crustose coralline algae, algal turf, and bare space showed a strong site 2 time interaction, illustrating that the sites differed in dynamics, but that the differences varied among times. Thus, as has been reported elsewhere in the Caribbean, serious reef degradation has occurred on at least one reef in St. John, but the patterns of change vary markedly on a kilometer-wide scale. In comparison with other long-term studies of Caribbean coral reefs, the degradation of a coral reef in an MPA around St. John is noteworthy since there are few local anthropogenic disturbances that can be held responsible for the decline. The strong possibility that large-scale events such as hurricanes and global warming have played a pivotal role in the decline of at least one reef in St. John emphasizes the need to embrace landscape- and regional-scale phenomena... [ABSTRACT FROM AUTHOR]

Peyssonnelid algal crusts (PAC) have rapidly spread on coral reefs throughout the Caribbean since 2010 and have become dominant space holders in multiple locations. In 2019, PAC covered 31–86% of the shallow reefs (< 6-m depth) at two sites in St. John, US Virgin Islands, but within halos around aggregates of the echinoid, Diadema antillarum , PAC was absent and small corals were common. To test the hypothesis that the density of small corals is greater in Diadema halos versus on adjacent substrata, and that this effect is accentuated by high coverage of PAC, the shallow reefs of St. John were surveyed in July/August 2019 and January 2020. Densities of small corals (pooled among taxa) in Diadema halos were equal to, or greater than, densities on adjacent substrata, and were highest in Diadema halos adjacent to areas with high coverage of PAC. Where the cover of PAC was ≥ ~ 10%, the mean (± SE) density of small corals was 23.3 ± 2.1 colonies m−2 in Diadema halos, but was 67% lower at 7.5 ± 1.2 colonies m−2 on adjacent substrata; where the cover of PAC was < ~10%, densities of small corals were nearly identical in Diadema halos (9.1 ± 0.9 colonies m−2) and on adjacent substrata (9.0 ± 1.1 colonies m−2). Similar results were obtained when the analyses were repeated for the common corals, Porites spp., Siderastrea radians , and S. siderea. As Diadema halos remained in the same location for at least 6 months, they may function as refuges for coral recruitment in locations where PAC is becoming spatially dominant. • Peyssonnelid algal crusts (PAC) are rapidly occupying Caribbean reefs. • PAC overgrows corals and other organisms and deters coral settlement. • Grazing halos around sea urchins provide coral recruits with refuges from PAC. [ABSTRACT FROM AUTHOR]

This study tested the hypothesis that sponge assemblages on the reefs of St. John, US Virgin Islands (18.315°N, 64.716°W), changed from 1992 to 2017. Sponges were identified to species or genus in photoquadrats and were quantified at 2–3 y intervals by density, with linear dimensions used to estimate volume as a proxy for biomass. From 1992 to July 2017, overall sponge density (pooled among taxa) increased, although trends varied among the most common species for which density increased (four species), decreased (one species), or showed no linear relationship with time (2 species). Hurricanes Irma and Maria caused a 51% decline in overall sponge density from July to November 2017, with density in November 2017 being 31% lower than in 1992. For the common sponges, densities of 6 declined by 82–100% between July and November 2017, but densities in November 2017 were 13–736% higher than in 1992 for four species, and 47–100% lower than in 1992 for 3 species. Sponge volume did not change linearly between 1992 and November 2017, but it was reduced by 54% following the hurricanes. Multivariate variation over time in benthic community structure was not strongly associated with sponge density alone, although a significant association with rainfall highlighted the potential roles of this environmental factor in directly, or indirectly, mediating changes in community structure. Overall, the mean density of sponges, as well as most of the common sponge species, trended upwards prior to the hurricanes, but these trends reversed following the storms. [ABSTRACT FROM AUTHOR]

On most tropical coral reefs, decades of disturbances have ratcheted down coral cover to create low abundance communities. In such a state, the reefs of St. John, US Virgin Islands, were hit by two Category 5 hurricanes in September 2017, yet the effects on two sites dominated by Orbicella annularis were minor in terms of coral cover. To explore the implications of this outcome, the fates of O. annularis colonies were determined from photoquadrats and used to prepare size‐based matrix models for the year preceding the storms and the four months bracketing the storms. The populations displayed contrasting dynamics from 1988 to July 2017, with coral cover declining from 43% to 5% at Yawzi Point but remaining at ~30% at Tektite. Over this period, colony sizes declined, with ≥82% having planar areas ≤50 cm2 (i.e., the smallest size class) by July 2017, and while densities declined from 47 to 8 colonies/m2 at Yawzi Point, they increased from 36 to 51 colonies/m2 at Tektite. Hurricanes Irma and Maria depressed coral cover by 1–4%, transitioned colonies into the smallest size class (>87% by November), killed 27% and 5% of the colonies in the smallest size class at Yawzi Point and Tektite, respectively, and depressed the 5‐yr intrinsic rate of population growth (λ) to 0.53–0.87. Twenty‐year projections suggested these demographic effects will not have ecologically meaningful impacts on population size, at least compared to projections initiated assuming Hurricanes Irma and Maria had not occurred. With low cover of O. annularis distributed among many small colonies, future disturbances may play more important roles in winnowing the few remaining host genotypes rather than further depressing coral cover. [ABSTRACT FROM AUTHOR]

The article discusses a study on the growth of large numbers of Acropora palmata in shallow water in Saint John, U.S. Virgin Islands. The study conducted snorkel surveys to estimate the population density of the coral. The surveys revealed the abundance of the coral in the marine area between Cabritte Horn and White Point.

To evaluate the possibility that density-associated effects modulate octocoral abundance on a Caribbean coral reef, we tested the hypothesis that the density of octocoral recruits (colonies ≤ 4 cm tall) and adult colonies are positively associated on shallow reefs (≤ 14 m depth) in St. John, US Virgin Islands. Both life stages were censused for density at 8–10 sites along 7 km of shore in 2013 and 2014, and a correlative approach was used to evaluate the extent to which the densities were associated using sites as replicates. For 8 sites censused in both years, mean densities of adults (pooled among taxa) varied from 2.95 ± 1.16 colonies m − 2 to 20.60 ± 2.62 colonies m − 2 in 2013, and from 3.20 ± 0.75 colonies m − 2 to 13.00 ± 1.04 colonies m − 2 in 2014; for recruits, mean densities varied from 1.05 ± 0.34 colonies m − 2 to 4.25 ± 0.81 colonies m − 2 in 2013, and from 0.60 ± 0.31 colonies m − 2 to 1.44 ± 0.40 colonies m − 2 in 2014 (all ± SE). The most common taxa in both years among all sites were Antillogorgia spp., Gorgonia spp., and plexaurids. Density of recruits was significantly and positively correlated with population density of adult octocorals (pooled among taxa) and plexaurids in both years, and for Gorgonia spp. in 2013 (with a similar trend in 2014). Densities of recruits and adults of Antillogorgia spp. were not associated in either year. Together, these data suggest that densities of adult octocorals positively influence the density of co-occurring octocoral recruits, thereby potentially promoting population growth. [ABSTRACT FROM AUTHOR]