Coral Growth Research Articles

Exploring the potential of native sea urchins as ex situ coral propagation allies

Caribbean coral reefs face unprecedented decline due to anthropogenic and environmental stressors, necessitating active restoration efforts. Among the strategies to conserve and restore reef ecosystems, land‐based sexual propagation of corals is crucial for preserving genetic diversity and population resilience. This study explores the efficacy of utilizing native sea urchin herbivory to control benthic macroalgal proliferation and enhance coral growth in land‐based propagation systems. Three captive‐reared urchin species—Lytechinus variegatus, Tripneustes ventricosus, and Diadema antillarum—were evaluated for their influence on algal cover and growth of sexually propagated brain coral Pseudodiploria strigosa. Juveniles of each urchin species were co‐cultured with 6‐month‐old coral colonies over a 105‐day experiment. Results indicated that all urchin treatments effectively reduced algal cover compared to controls; however, only T. ventricosus significantly increased coral growth rate, while the other urchin species did not have a notable effect. Despite differences in growth, coral survival was consistently high across all treatments. Benthic community analysis revealed shifts in algal composition, with D. antillarum grazing associated with increased crustose coralline algae. However, overgrazing by D. antillarum may have resulted in mild peripheral tissue damage to some corals. Urchin survival remained high, suggesting potential for downstream utilization in restoration (e.g. urchin population enhancement). This study highlights the potential of native urchins as biocontrol agents in coral propagation, emphasizing the importance of species‐specific interactions in shaping benthic communities and promoting coral resilience.

Flow rates alter the outcome of coral bleaching and growth experiments

It is important to consider flow rate explicitly in coral growth and bleaching studies across multiple species with differing life histories to guide coral conservation, management and captive culture. We quantified growth rates and coral bleaching responses to thermal stress (approx. 18 DHW) in flow-through aquaria with various current velocities to test whether flow conditions alter experimental outcomes. Across natural flow rates (< 1 to over 50 cm/sec), Montipora capitata, Pocillopora acuta, and Pocillopora meandrina showed increased growth and bleaching recovery at intermediate flow rates. Growth rates for all species increased from no flow to intermediate (50–100 turnovers-per-hour, ~ 10–30 cm/s), but then decreased at highest flow (> 190 tph, > 50 cm/s) although this trend was not significant for P. meandrina. The flow treatment with highest recovery from temperature stress differed across species, ranging from 4 tph in the flow-loving P. meandrina to 210 tph in the lagoonal M. capitata, indicating that natural flow regime alone is not predictive. Fragments from the same individual (e.g., P. acuta colony 8) held under identical thermal conditions continue bleaching and die under one flow regime (4 tph), whereas they recover from bleaching (30 tph) or grow fastest (105 tph) under different flow treatments. Flow is rarely reported in the literature, but uncontrolled flow effects may help to explain some of the variation in coral bleaching results reported across the literature. Significant differences among individual colonies, and colony-by-flow interactions, preclude generalizations beyond that flow rates can alter the outcome of both coral growth and bleaching experiments.

Acclimation and size influence predation, growth, and survival of sexually produced Diploria labyrinthiformis used in restoration

Stony coral tissue loss disease (SCTLD) has swept through Florida reefs and caused mass mortality of numerous coral species. In the wake of these losses, efforts are underway to propagate coral species impacted by SCTLD and promote population recovery. However, numerous knowledge gaps must be addressed to effectively grow, outplant, and restore populations of the slower growing, massive species that were lost. Here, we used sexual recruits of Diploria labyrinthiformis spawned in captivity to understand how conditioning, coral size, and nutritional status at outplanting affect coral survivorship, growth, and susceptibility to predation. We found that ex situ conditioning with supplemental feeding increased coral growth rates, resulting in larger sized corals at the time of outplanting. In turn, these corals had higher growth rates in the field and a lower probability of being removed by predators than outplants that were conditioned in in situ nurseries. Additionally, we found that coral size was an important predictor of survivorship, suggesting that hastening the speed at which young corals grow and outplanting larger juveniles can improve restoration outcomes. Taken together, our results suggest that providing supplemental food to corals at ex situ facilities confers benefits that could help restore populations of massive coral species impacted by SCTLD.

Differential responses in recovery, growth and survival between intertidal and subtidal corals after acute thermal stress

Sea temperature increases may compromise ecological restoration as a tool for recovering degraded coral reefs. A potential solution may lay within using corals with naturally higher thermal resilience, such as intertidal corals. This study aimed at comparing thermal resilience, growth and survival between intertidal and subtidal corals in a reciprocal transplant experiment. Sixty coral nurseries were installed in a shallow coral reef area in Kenya: half were placed in the intertidal zone and half in the subtidal zone. At both zones, intertidal and subtidal Pocillopora cf. damicornis coral fragments were cultured in equal proportions, resulting in 15 replicate nurseries for four treatments. After an initial culture phase of 1 month in situ, six nurseries per treatment were thermally stressed ex situ by exposing corals for 5 days to a temperature of 32 °C (3 °C above summer maximum), after which they were returned in situ to recover. Fragment brightness was measured as the response variable to thermal stress. Intertidal and subtidal corals increased brightness (i.e., bleached) at a similar rate, but during recovery intertidal corals returned quicker to their original brightness in both culture environments. Coral growth was highest for intertidal corals in the intertidal zone during cooler months and was highest for subtidal corals in the subtidal zone during peak temperatures. Intertidal corals transplanted to the subtidal zone registered the lowest survival. Thus, intertidal corals display higher thermal resilience through quicker recovery, but potential trade-offs require further investigation before these corals can be used as a climate-proof broodstock for reef restoration.

Coral growth along a natural gradient of seawater temperature, pH, and oxygen in a nearshore seagrass bed on Dongsha Atoll, Taiwan.

Coral reefs are facing threats from a variety of global change stressors, including ocean warming, acidification, and deoxygenation. It has been hypothesized that growing corals near primary producers such as macroalgae or seagrass may help to ameliorate acidification and deoxygenation stress, however few studies have explored this effect in situ. Here, we investigated differences in coral growth rates across a natural gradient in seawater temperature, pH, and dissolved oxygen (DO) variability in a nearshore seagrass bed on Dongsha Atoll, Taiwan, South China Sea. We observed strong spatial gradients in temperature (5°C), pH (0.29 pH units), and DO (129 μmol O2 kg-1) across the 1-kilometer wide seagrass bed. Similarly, diel variability recorded by an autonomous sensor in the shallow seagrass measured diel ranges in temperature, pH, and DO of up to 2.6°C, 0.55, and 204 μmol O2 kg-1, respectively. Skeletal cores collected from 15 massive Porites corals growing in the seagrass bed at 4 sites revealed no significant differences in coral calcification rates between sites along the gradients. However, significant differences in skeletal extension rate and density suggest that the dynamic temperature, pH, and/or DO variability may have influenced these properties. The lack of differences in coral growth between sites may be because favorable calcification conditions during the day (high temperature, pH, and DO) were proportionally balanced by unfavorable conditions during the night (low temperature, pH, and DO). Alternatively, other factors were simply more important in controlling coral calcification and/or corals were acclimated to the prevailing conditions at each site.

Seabird nutrients increase coral calcification rates and boost reef carbonate production

While excessive anthropogenic nutrient loads are harmful to coral reefs, natural nutrient flows can boost coral growth and reef functions. Here we investigate if seabird-derived nutrient subsidies benefit the growth of two dominant corals on lagoonal reefs, submassive Isopora palifera and corymbose Acropora vermiculata, and if enhanced colony-level calcification rates can increase reef-scale carbonate production. I. palifera and A. vermiculata colonies close to an island with high seabird densities displayed 1.4 and 3.2-times higher linear extension rates, 1.8 and 3.9-times faster planar area increase, and 1.6 and 2.7-times higher calcification rates compared to colonies close to a nearby island with low seabird densities, respectively. While benthic ReefBudget surveys in combination with average coral growth rates did not indicate differences in reef-scale carbonate production across sites, coral carbonate production was 2.2-times higher at the seabird-rich island when using site-specific linear growth rates and skeletal densities. This study shows that seabird-derived nutrients benefit fast-growing branching as well as previously unstudied submassive coral taxa. It also demonstrates that nutrient subsidies benefit colony-scale and reef-scale calcification rates, which underpin important geo-ecological reef functions. Restoring natural nutrient pathways should thus be a priority for island and reef management.

Microbial Communities and their Functional Role Associated with the Localised Outbreak of Coral Growth Anomalies in Eastern Arabian Sea

Microbial Communities and their Functional Role Associated with the Localised Outbreak of Coral Growth Anomalies in Eastern Arabian Sea

Validating effectiveness of crown-of-thorns starfish control thresholds to limit coral loss throughout the Great Barrier Reef

AbstractPopulation irruptions of the Pacific crown-of-thorns starfish (CoTS, Acanthaster cf. solaris) are a key source of coral loss on Australia’s Great Barrier Reef (GBR). CoTS management currently involves their manual control (culling) to threshold densities below which net coral decline theoretically ceases based on analysis of a validated population dynamics model. Spatial variability in coral growth and community composition, and their predicted changes under continuing global warming, necessitate further consideration of current coral representation in CoTS models. Here, we consider the sensitivity of equilibrium coral-CoTS thresholds to coral growth rates and consider how the demographic composition of CoTS at a site may relate to culling thresholds. We found thresholds should be location-specific if the objective of CoTS control is coral recovery, but location-specific thresholds may not be needed if the objective is to limit coral cover loss based on coral growth and CoTS demography. The consequence of using a higher CPUE threshold than the analytical equilibrium coral-CoTS thresholds in terms of coral cover loss is suggested to be limited at coral cover &lt; 40%, and varying control thresholds thereof may make little difference. Introducing a 0.06 CoTS.min−1 threshold for 40–60% coral cover may reduce coral loss at ~ 40% where it is likely greatest. With regional GBR coral cover averaging &lt; 40%, this study validates the 0.04–0.08 CoTS.min−1 tiered threshold system for CoTS control and suggests methods developed from localised studies can be more broadly applicable and well-defined objectives (e.g. avoiding coral cover decline at a site) can help guide what thresholds are used and the sensitivity around these.

Calcification and growth of the reef coral Porites panamensis in a shallow hydrothermal field in the Gulf of California, Mexico

Calcification and growth of the reef coral Porites panamensis in a shallow hydrothermal field in the Gulf of California, Mexico

Long-term variability of the Kuroshio since 1788 based on coral records

The Kuroshio transports warm water poleward from low- to mid-high latitude regions and strongly affects ocean-atmosphere-land interactions. Previous studies have shown that the Kuroshio has strengthened at its origin during recent decades. However, changes in the Kuroshio on a centennial timescale are unclear due to the lack of observations before the Industrial Revolution. In this study, a precisely dated and monthly resolved Porites coral Sr/Ca record from south of Taiwan island, where coral growth is influenced by the Kuroshio, was used to generate a continuous reconstruction of Kuroshio transport (KT) during the period from 1788 to 2013. The data show a consistent decline in KT since 1788, with the rate of decline increasing since the 1950s, probably due to rapid oceanic warming. The southward shift of the bifurcation latitude of the North Equatorial Current, which is related to accelerated global oceanic warming, might have led to the decrease in KT. Natural variability in the phase transition of the Pacific Decadal Oscillation and El Niño-Southern Oscillation might also influence the long-term changes in KT, particularly before the 1950s.

Unraveling the physiological responses of morphologically distinct corals to low oxygen

Background Low oxygen in marine environments, intensified by climate change and local pollution, poses a substantial threat to global marine ecosystems, especially impacting vulnerable coral reefs and causing metabolic crises and bleaching-induced mortality. Yet, our understanding of the potential impacts in tropical regions is incomplete. Furthermore, uncertainty surrounds the physiological responses of corals to hypoxia and anoxia conditions. Methods We initially monitored in situ dissolved oxygen (DO) levels at Kham Island in the lower Gulf of Thailand. Subsequently, we conducted a 72-hour experimental exposure of corals with different morphologies—Pocillopora acuta, Porites lutea, and Turbinaria mesenterina—to low oxygen conditions, while following a 12/12-hour dark/light cycle. Three distinct DO conditions were employed: ambient (DO 6.0 ± 0.5 mg L−1), hypoxia (DO 2.0 ± 0.5 mg L−1), and anoxia (DO &lt; 0.5 mg L−1). We measured and compared photosynthetic efficiency, Symbiodiniaceae density, chlorophyll concentration, respiratory rates, primary production, and calcification across the various treatments. Results Persistent hypoxia was observed at the study site. Subsequent experiments revealed that low oxygen levels led to a notable decrease in the maximum quantum yield over time in all the species tested, accompanied by declining rates of respiration and calcification. Our findings reveal the sensitivity of corals to both hypoxia and anoxia, particularly affecting processes crucial to energy balance and structural integrity. Notably, P. lutea and T. mesenterina exhibited no mortality over the 72-hour period under hypoxia and anoxia conditions, while P. acuta, exposed to anoxia, experienced mortality with tissue loss within 24 hours. This study underscores species-specific variations in susceptibility associated with different morphologies under low oxygen conditions. The results demonstrate the substantial impact of deoxygenation on coral growth and health, with the compounded challenges of climate change and coastal pollution exacerbating oxygen availability, leading to increasingly significant implications for coral ecosystems.

The impact of macroalgae on reef-building corals depends on their species, density, and contact status

Coral reefs are severely threatened by global and local disturbances that can shift reefs from coral to algal dominance. Coral-macroalgae competition is expected to exacerbate coral decline as the interactions increase in frequency. Whereas numerous studies over the last decade have aimed to characterize the interactions and impacts on coral growth and physiology, the underlying mechanisms remain controversial. This study tested the impact of different macroalgal species, densities, and contact status with corals on the physiological response of corals in Sanya Reefs. The results revealed that direct contact with increasing densities of fleshy macroalgae had a negative impact on the photosynthesis, growth rate, and tissue biomass of the two common corals. However, calcified macroalgae did not significantly affect the corals, regardless of whether there was direct contact or not. Under the same conditions, Acropora intermedia appeared to be more susceptible to fleshy macroalgae compared to Porites lutea. This suggested that different corals varied in their susceptibility to various macroalgae. Additionally, the results of the generalized linear mixed model revealed that macroalgal species and contact status with corals were the most important predictors of the impacts of macroalgae on corals, and macroalgal density was another nonnegligible parameter. Overall, macroalgae may have caused a potential functional shift in the composition of coral assemblages on the Sanya reefs by further reducing the already depauperate reef-building coral populations. The negative impacts of macroalgae in Sanya Reefs may serve as an early warning that the persistence of the invaluable ecological functions provided by coral reefs will be increasingly threatened throughout the South China Sea. Our findings could contribute to improving the scientific and effective management practices, fostering sustainable coral reef development in China and beyond.

Age and growth of a habitat-forming deep-sea coral Solenosmilia variabilis in the New Zealand region: implications for fisheries management

ABSTRACT One of the most widespread and abundant habitat forming deep-sea corals in the South Pacific region is Solenosmilia variabilis. The age of this species was assessed using radiocarbon content (14C) on long dead, recently dead, and live branch sections of coral reef matrix sampled from the New Zealand region. Conventional 14C colony ages (yrs BP), for the living, recently dead, and long dead samples, ranged from 803 to 1186 years (Graveyard Knolls, Chatham Rise), and 907 to 11, 694 years (Louisville Seamount Chain east of New Zealand). Overall calendar ages, ranged from 84 to 292 years, and similar linear and step-wise growth rate data were obtained. Linear growth ranged from 0.2 to 1.3 mm/yr. From a conservative estimate of matrix height of ∼20 cm, it could take hundreds of years (∼150–660) of growth for a colony of S. variabilis to attain this height, and around ∼2000 years to build a colony diameter of 1 metre. Defining the age, growth and recovery timeframes of deep-sea coral can inform risk assessments of the level of susceptibility to trawling activity and their potential to recover, as well as provide options for the considered management of deep-sea habitats.

Testing the feasibility of coral nurseries in an upwelling area in the North Pacific of Costa Rica

The decline of coral reefs has increased interest in ecological restoration. Due to the scarcity of coral gardening projects in the Eastern Tropical Pacific, improving our understanding of such techniques is key. We report the results of coral gardening using the branching Pocillopora spp. and massive coral species (Pavona gigantea, Pavona clavus and Porites lobata) in an upwelling area in Costa Rica. We examined whether nursery type influenced Pocillopora spp. survival and growth, and how environmental conditions shaped restoration. We monitored the survival and growth of Pocillopora spp. fragments (n = 334) and microfragments of massive species (P. gigantea [n = 148], P. clavus [n = 37], P. lobata [n = 66]) over 11 months. Survival at the end of the gardening period was 51% for Pocillopora spp., 59% for P. clavus, 55% for P. gigantea, and 17% for P. lobata, with a decline after a cease in maintenance caused by the COVID-19 lockdown. Pocillopora spp. fragments in the floating nurseries exhibited higher growth (7.52 ± 1.98 and 6.64 ± 2.91 cm yr-1) than in the A-frame (4.16 ± 2.35 cm yr-1), which suggests the benefits of suspending fragments. For massive microfragments coral growth was 1.92-4.66 cm2 yr-1 and were affected by pigmentation loss, causing partial tissue loss and mortality. Our results point towards acclimation to local conditions, and show the need to develop site-specific cost-efficient gardening techniques for massive species, allowing for a multi-species approach to ensure long-term ecosystem recovery.

Phenomenological investigation of organic modified cements as biocompatible substrates interfacing model marine organisms.

Organic modification can generally endow inorganic materials with novel and promotional characteristics to fit into new functionalities. In this paper, new cement-based composite materials, with Portland cement as the substrate and polyacrylamide (PAM, alone) and PAM/chitosan as the functional components mixed with cement (bulk modified) or served as the surface coating (surface modified), were prepared and engineered as sampling substrates for biofilm and coral co-culture. In comparison to the bulk modified substrate and pure cement material, the surface modified substrate showed a balanced mechanical property, considering both bending and compressive strengths and distinctive surface features toward facilitating biofilm and coral growth, as characterized by spectroscopic, morphological, mechanical, and biofilm and coral co-culture experiments. We, thus, believe that the as-prepared surface modified substrate has the very potential to be applied as a substitute/alternative for the conventional cement material in the construction and engineering of artificial facilities with ecological protection functions.

Changing disturbance regimes, material legacies, and stabilizing feedbacks: Dead coral skeletons impair key recovery processes following coral bleaching.

Ecosystem responses to disturbance depend on the nature of the perturbation and the ecological legacies left behind, making it critical to understand how climate-driven changes in disturbance regimes modify resilience properties of ecosystems. For coral reefs, recent increases in severe marine heat waves now co-occur with powerful storms, the historic agent of disturbance. While storms kill coral and remove their skeletons, heat waves bleach and kill corals but leave their skeletons intact. Here, we explored how the material legacy of dead coral skeletons modifies two key ecological processes that underpin coral reef resilience: the ability of herbivores to control macroalgae (spatial competitors of corals), and the replenishment of new coral colonies. Our findings, grounded by a major bleaching event at our long-term study locale, revealed that the presence of structurally complex dead skeletons reduced grazing on turf algae by ~80%. For macroalgae, browsing was reduced by >40% on less preferred (unpalatable) taxa, but only by ~10% on more preferred taxa. This enabled unpalatable macroalgae to reach ~45% cover in 2 years. By contrast, herbivores prevented macroalgae from becoming established on adjacent reefs that lacked skeletons. Manipulation of unpalatable macroalgae revealed that the cover reached after 1 year (~20%) reduced recruitment of corals by 50%. The effect of skeletons on juvenile coral growth was contingent on the timing of settlement relative to the disturbance. If corals settled directly after bleaching (before macroalgae colonized), dead skeletons enhanced colony growth by 34%, but this benefit was lost if corals colonized dead skeletons a year after the disturbance once macroalgae had proliferated. These findings underscore how a material legacy from a changing disturbance regime can alter ecosystem resilience properties by disrupting key trophic and competitive interactions that shape post-disturbance community dynamics.

Growth rates of five coral species across a strong environmental gradient in the Colombian Caribbean

Coral calcification is critical for reef growth and highly dependent on environmental conditions. Yet, little is known about how corals calcify under sub-optimal conditions (e.g., turbid waters, high nutrients, sedimentation) or coral growth in understudied regions such as the Colombian Caribbean. We therefore assessed the calcification and linear extension rates of five coral species across an inshore-to-offshore gradient in the Colombian Caribbean. A suite of environmental variables (temperature, light intensity, visibility, pH, nutrients) measured during the rainy season (May – November 2022) demonstrated more sub-optimal conditions inshore compared to offshore. Across all species, calcification rates were 59% and 37% lower inshore compared to the offshore and midshore sites, respectively. Across all sites, massive corals calcified up to 92% more than branching species but were more susceptible to heat stress and sub-optimal inshore conditions. However, branching species had reduced survival due to extreme climatic events (i.e., bleaching, hurricanes). A comparison with published rates for the wider Caribbean revealed that massive species in the Colombian Caribbean grow up to 11 times more than those in the wider Caribbean while branching species generally have similar growth rates, but this finding may have been influenced by fragment size and/or heat stress. Our findings indicate that present-day environmental conditions, coupled with more frequent extreme climatic events, will favor massive over branching species in midshore areas of the Colombian Caribbean. This suggests a possible shift towards faster calcifying massive species in future coral communities, possibly exacerbating the ongoing regional decline in branching species over the last decades.

Different bacterial communities of the coral area and its surrounding sediments in Daya Bay, South China Sea

Sediment in coral reef habitats has a tight interaction with coral reefs. Bacterial communities are a critical part of sediments and play a vital role in marine ecosystems, as well as coral reef habitats. To determine whether the bacterial structure of sediments differs between the inside and surrounding coral area, we compared the bacterial community on the surface of the dead coral skeleton (CS) and three soft sediment sites (SS, SS10, SS50) in and around the coral reef distribution of Dalajia Island in Daya Bay. Our results showed that bacterial diversity and composition of the coral skeleton had a significant difference with that of surrounding soft sediments. Proteobacteria and Actinobacteria were dominant in CS, and Proteobacteria and Bacteroidetes were dominant in SS, SS10, and SS50. Substrate type and environmental parameters are the main factors in the separation between coral skeletons and sediment. Salinity and pH were largely negatively correlated with CS, indicating they are primary factors that potentially impact coral mortality and revival. Heavy metals were positively related to sediments and they are potential threats to coral growth. Our work provides updated data on bacterial structure in the coastal coral area, contributing to policy-making and management of coastal activities to minimize the degradation of coral reefs.

Hurricane Irma Linked to Coral Skeletal Density Shifts on the Florida Keys Reef Tract.

Coral reefs are at risk due to various global and local anthropogenic stressors that impact the health of reef ecosystems worldwide. The most recent climate models predict that climate change will increase the frequency and intensity of tropical storms. This increased storm occurrence and strength will likely compromise coral reef structures and habitats for reef-dwelling organisms, including across the Florida Keys Reef Tract (FKRT), the most extensive tropical reef system along the US coast. While several recent studies reveal the chronic impacts of tropical storms on corals, relatively little is known about the effects of major storm events on coral growth and how these effects vary over spatiotemporal scales. Here, I characterize the skeletal growth of two common Caribbean reef-building coral species, Siderastrea siderea and Pseudodiploria strigosa, before and after Hurricane Irma to investigate the storm's impact on coral skeletal growth on inner and outer reefs of the FKRT. Coral cores were extracted from both species at four inner and four outer reef sites in May 2015, before Hurricane Irma struck the Florida Keys in September 2017. Subsequently, 33 micro-cores were collected in May 2019, two years after the storm traversed our previously cored coral colonies. A three-way ANOVA model with storm, species, and reef location as the three factors was used to assess the impact of the storm on each of three growth parameters: skeletal density, linear extension, and calcification rates. Results reveal no difference in the coral annual skeletal growth parameters pre- and post-Hurricane Irma, although previously quantified differences in these growth parameters across species and location were observed. However, analysis of the "yearly" change in annual skeletal growth parameters showed significant differences in skeletal density across groups before and after Hurricane Irma, but not for linear extension and calcification rates. Our findings improve an understanding of the impacts of tropical storms on coral skeletal growth and offer new insights into how we can employ corals' innate growth capacities to help conserve coral reefs under climate change.

Corals that survive repeated thermal stress show signs of selection and acclimatization.

Climate change is transforming coral reefs by increasing the frequency and intensity of marine heatwaves, often leading to coral bleaching and mortality. Coral communities have demonstrated modest increases in thermal tolerance following repeated exposure to moderate heat stress, but it is unclear whether these shifts represent acclimatization of individual colonies or mortality of thermally susceptible individuals. For corals that survive repeated bleaching events, it is important to understand how past bleaching responses impact future growth potential. Here, we track the bleaching responses of 1,832 corals in leeward Maui through multiple marine heatwaves and document patterns of coral growth and survivorship over a seven-year period. While we find limited evidence of acclimatization at population scales, we document reduced bleaching over time in specific individuals that is indicative of acclimatization, primarily in the stress-tolerant taxa Porites lobata. For corals that survived both bleaching events, we find no relationship between bleaching response and coral growth in three of four taxa studied. This decoupling suggests that coral survivorship is a better indicator of future growth than is a coral's bleaching history. Based on these results, we recommend restoration practitioners in Hawai'i focus on colonies of Porites and Montipora with a proven track-record of growth and survivorship, rather than devote resources toward identifying and cultivating bleaching-resistant phenotypes in the lab. Survivorship followed a latitudinal thermal stress gradient, but because this gradient was small, it is likely that local environmental factors also drove differences in coral performance between sites. Efforts to reduce human impacts at low performing sites would likely improve coral survivorship in the future.