Coral Cover Research Articles

Abundance Megabentos in Coral Reef Ecosystems in the Waters of Gelasa Island, Central Bangka Regency.

Megabenthos is a group of fauna that inhabits the benthic zone, which is the bottom or substrate of aquatic environments (both infauna and epifauna), with a body size exceeding 10 mm (1 cm). This study aims to analyze the abundance of megabenthos in the coral reef ecosystem, examine the relationship between megabenthos abundance and the physical and chemical parameters of the aquatic environment in the coral reef ecosystem, and analyze the relationship between megabenthos abundance and coral life forms in the waters of Gelasa Island. This research was conducted in September 2022 in the waters of Gelasa Island. Megabenthos data were collected using the Bentos Belt Transect (BBT) method, while coral data were collected using the Underwater Photo Transect (UPT) method. The study identified 10 species of megabenthos in the coral reef ecosystem of Gelasa Island. The species found at the research site include Diadema setosum, Diadema antillarium, Echinothrix calamaris, Drupella cornus, Drupella rugosa, Trochus conus, Tectus pyramis, Tridacna squamosa, Tridacna crocea, and Acanthaster planci. The percentage of live coral cover at the research site ranged from 26.60% to 71.00%. Megabenthos abundance was analyzed using Principal Component Analysis (PCA) to examine the relationship between megabenthos and the physical and chemical parameters of the aquatic environment and the relationship between megabenthos and coral life forms.

Thermal bleaching in the northern South China Sea: impact of abnormal environment and climate on high-latitude coral reefs.

Extensive coral bleaching events can result in catastrophic degradation of coral reefs and reorganization of coral communities. In the present study, we analyzed the spatial differences in coral bleaching and possible reasons of large-scale coral bleaching, based on the results of a survey carried out in the northern South China Sea in 2020. In addition, we have continuously monitored the sea surface temperature (SST) of the northernmost Weizhou Island for more than six years. The living coral cover at Weizhou Island (W), Xuwen Nature Reserve (X), and Haihua Island (H) was relatively high at 24.6% ± 4.8%, 12.1% ± 3.8%, and 8.1% ± 2.6%, respectively, whereas their bleaching rates were 9.7% ± 2.6%, 9.7% ± 3.3%, and 6.9% ± 2.1%, respectively. Among them, the living coral cover of W was significantly different from those of X and H, whereas the bleaching rate was not significantly different among the three areas. In all three areas, the massive and encrusting corals predominate and exhibit relatively high bleaching rates, with Porites lutea and Bernardpora stutchburyi being the dominant species. In addition, the temperature monitoring results of Weizhou Island for six consecutive years showed that the critical SST of coral bleaching was 31.5 ℃. The monitoring results also showed that the average SST of Weizhou Island was 32.1 ℃, exceeding 32 ℃ in July 2020 for up to 533h. The longest continuous time when the SST exceeded 32 ℃ was 97h. These findings indicated that the coral bleaching event that occurred in the Beibu Gulf during 2020 was a large-scale and high-temperature transient event that presented a relatively homogeneous threat to the coral communities. We inferred that this sudden heat stress event was caused by the enclosed tidal current in the Beibu Gulf, which prevented the southern upwelling from reaching the north, as well as by the inability of the SST to decrease without rainfall caused by typhoon cyclones. Our findings suggested that abnormal heat waves can result in coral bleaching at high latitudes and even coral reef degradation. Furthermore, our study provides a new perspective for investigating the self-recovery and reorganization of coral communities following accumulated coral bleaching.

Assessment of Community Structure of Macroinvertebrates, Coral Cover and Water Quality in Sempu Strait, Malang Regency, East Java

Assessment of Community Structure of Macroinvertebrates, Coral Cover and Water Quality in Sempu Strait, Malang Regency, East Java

The biological and ecological impact of the ship grounding and ore nickel spill of the barge ship in Morowali Waters, Central Sulawesi, Indonesia

This study’s purpose is to know the condition of corals in locations that are under pressure due to high sedimentation and coral damage due to ship aground. The research was carried out in August 2021 by collecting data related to the coral reef’s condition. The method used the Underwater Photo Transect (UPT) at 2 location points as controls which were assumed not to be affected by the ship aground and 2 location points where the ship ran aground. The study was successful to obtain data on the affected corals on the BG Financia 22 ship at 13.13%, while at the control location, live coral cover was obtained by 17.16%, grouped in very damaged condition. Observations on the BG Intan Kelana 3 ship from a total observation area of 127,600 cm2, obtained a live coral cover of 24.70%, this condition is grouped in very damaged coral conditions. Types of coral were found in 17 genera from 247 colonies observed during the study. Coverage at affected locations is 4.20%. Observations in this study can be concluded at the location where the condition of the coral is very damaged plus the pressure due to the ship aground, thus worsening conditions in the area.

Assessment of the utility of underwater hyperspectral imaging for surveying and monitoring coral reef ecosystems

Technological innovations that improve the speed, scale, reproducibility, and accuracy of monitoring surveys will allow for a better understanding of the global decline in tropical reef health. The DiveRay, a diver-operated hyperspectral imager, and a complementary machine learning pipeline to automate the analysis of hyperspectral imagery were developed for this purpose. To evaluate the use of a hyperspectral imager underwater, the automated classification of benthic taxa in reef communities was tested. Eight reefs in Guam were surveyed and two approaches for benthic classification were employed: high taxonomic resolution categories and broad benthic categories. The results from the DiveRay surveys were validated against data from concurrently conducted photoquadrat surveys to determine their accuracy and utility as a proxy for reef surveys. The high taxonomic resolution classifications did not reliably predict benthic communities when compared to those obtained by standard photoquadrat analysis. At the level of broad benthic categories, however, the hyperspectral results were comparable to those of the photoquadrat analysis. This was particularly true when estimating scleractinian coral cover, which was accurately predicted for six out of the eight sites. The annotation libraries generated for this study were insufficient to train the model to fully account for the high biodiversity on Guam’s reefs. As such, prediction accuracy is expected to improve with additional surveying and image annotation. This study is the first to directly compare the results from underwater hyperspectral scanning with those from traditional photoquadrat survey techniques across multiple sites with two levels of identification resolution and different degrees of certainty. Our findings show that dependent on a well-annotated library, underwater hyperspectral imaging can be used to quickly, repeatedly, and accurately monitor and map dynamic benthic communities on tropical reefs using broad benthic categories.

Structural Complexity of Coral Reefs in Guam, Mariana Islands

The complexity of tropical reef habitats affects the occurrence and diversity of the organisms residing in these ecosystems. Quantifying this complexity is important to better understand and monitor reef community assemblages and their roles in providing ecological services. This study employed structure-from-motion photogrammetry to produce accurate 3D reconstructions of eight reefs in Guam and quantified the structural complexity of these sites using seven terrain metrics: rugosity, slope, vector ruggedness measure (VRM), multiscale roughness (magnitude and scale), plan curvature, and profile curvature. The relationships between terrain complexity, benthic community diversity, and coral cover were investigated with generalized linear models. While the average structural complexity metrics did not differ between most sites, there was significant variation within sites. All surveyed transects exhibited high structural complexity, with an average rugosity of 2.28 and an average slope of 43 degrees. Benthic diversity was significantly correlated with the roughness magnitude. Coral cover was significantly correlated with slope, roughness magnitude, and VRM. This study is among the first to employ this methodology in Guam and provides additional insight into the structural complexity of Guam’s reefs, which can become an important component of holistic reef assessments in the future.

Conditions Of Scleractinian Coral Cover Percentage On The North Coast Of Ambon Island, Maluku Province

Coral reefs are one of the most ecologically productive and diverse ecosystems. This study aims to determine the condition of scleractinian coral cover in the northern coastal waters of Ambon Island. Data collection in the field is carried out using the systematic sampling method. A quadrant measuring 1x1 m2 becomes the sampling area. Quadrants are placed on transects 20 m long with quadrant intervals on transect lines of 5 m (0, 5, 10, 15, and 20 m). The transects are placed parallel to the shoreline at depths of 3 m and 10 m, with four transects at each depth, and the distance between transects is 1 m. The data obtained were then analyzed to see the percentage of coral cover in each category and component. The results showed that the percentage of the benthic substrate of coral reefs on the North Coast of Ambon Island to a depth of 3 meters was dominated by rubble with a percentage of 26.33% - 54.83%, and for a depth of 10 meters the percentage value of ruble was 11.33% - 48.83% and sand (4% - 54.50%). The category of Acropora corals both at a depth of 3 meters and 10 meters dominated by Acropora branching (ACB), while the non-acropora category is dominated by Coral Branching (CB), Coral Encrusting (CE), and Coral Massive (CM). Overall, the condition of live coral cover on the North Coast of Ambon Island is categorized as in poor condition.

Comparison of feeding preferences of herbivorous fishes and the sea urchin Diadema antillarum in Little Cayman.

On Caribbean coral reefs, losses of two key groups of grazers, herbivorous fishes and Diadema antillarum, coincided with dramatic increases in macroalgae, which have contributed to decreases in the resilience of these coral reefs and continued low coral cover. In some locations, herbivorous reef fishes and D. antillarum populations have begun to recover, and reductions in macroalgal cover and abundance have followed. Harder to determine, and perhaps more important, are the combined grazing effects of herbivorous fishes and D. antillarum on the structure of macroalgal communities. Surprisingly few studies have examined the feeding preferences of D. antillarum for different macroalgal species, and there have been even fewer comparative studies between these different herbivore types. Accordingly, a series of in-situ and ex-situ feeding assays involving herbivorous fishes and D. antillarum were used to examine feeding preferences. Ten macrophytes representing palatable and chemically and/or structurally defended species were used in these assays, including nine macroalgae, and one seagrass. All species were eaten by at least one of the herbivores tested, although consumption varied greatly. All herbivores consumed significant portions of two red algae species while avoiding Halimeda tuna, which has both chemical and structural defenses. Herbivorous fishes mostly avoided chemically defended species while D. antillarum consumed less of the structurally defended algae. These results suggest complementarity and redundancy in feeding by these different types of herbivores indicating the most effective macroalgal control and subsequent restoration of degraded coral reefs may depend on the recovery of both herbivorous fishes and D. antillarum.

Impact of Climate Change on Coral Reefs Degradation at West Lombok, Indonesia

Coral reefs are one of the ecosystems that provide economic and environmental benefits to coastal communities in Indonesia. However, coral reef ecosystems are also one of the ecosystems threatened by climate change at the local scale. The waters of North Sekotong, West Lombok, Indonesia, are a tropical coastal system with beautiful coral reefs and marine ecosystems. Coral reef damage has been widespread in this area due to increased water temperatures. Increased water temperature results in coral reef degradation. Field surveys were conducted on May 23-28, 2016, in collaboration with the Marine and Coastal Resources Research and Development Center, Ministry of Marine Affairs and Fisheries, and coral reef mapping using Landsat 7 and Landsat 8 during 2002 - 2016 as well as processing monthly sea surface temperature (SST) data from the AquaModis and Oi SST V2 satellites and daily SST data from the NOAA Coral Reef Watch satellite. Changes in coral cover area were compared with temperature changes due to climate change. The increase in temperature creates a hotspot phenomenon in the coral reef ecosystem, resulting in coral reef degradation. The results showed that coral reefs in this area have degraded by 17.55% or 78.21 Ha from 455.68 Ha (2002) to 367.46 Ha (2016), with a degradation rate of 2.8 Ha/year in 2002 - 2014; 8.1 Ha/year (2014 - 2014) and 36 Ha/year (2015 - 2016) caused by an increase in SST which caused a hotspot phenomenon with a high enough intensity that there was an increase in temperature in 2016 which reached 9.77oC.

Recent and rapid reef recovery around Koh Phangan Island, Gulf of Thailand, driven by plate-like hard corals.

Mass bleaching events and local anthropogenic influences have changed the benthic communities of many coral reefs with pronounced spatial differences that are linked to resilience patterns. The Gulf of Thailand is an under-investigated region with only few existing datasets containing long-term developments of coral reef communities using the same method at fixed sites. We thus analyzed benthic community data from seven reefs surrounding the island of Koh Phangan collected between 2014 and 2022. Findings revealed that the average live hard coral cover around Koh Phangan increased from 37% to 55% over the observation period, while turf algae cover decreased from 52% to 29%, indicating some recovery of local reefs. This corresponds to a mean increased rate of coral cover by 2.2% per year. The increase in live hard coral cover was mainly driven by plate-like corals, which quadrupled in proportion over the last decade from 7% to 28% while branching corals decreased in proportion from 9% to 2%. Furthermore, the hard coral genus richness increased, indicating an increased hard coral diversity. While in other reefs, increasing live hard coral cover is often attributed to fast-growing, branching coral species, considered more susceptible to bleaching and other disturbances, the reefs around Koh Phangan recovered mainly via growth of plate-like corals, particularly of the genus Montipora. Although plate-like morphologies are not necessarily more bleaching tolerant, they are important for supporting reef fish abundance and structural complexity on reefs, aiding reef recovery and sturdiness. Hence, our findings indicate that the intensity of local stressors around Kho Phangan allows reef recovery driven by some hard coral species.

Complex drivers of invasive macroalgae boom and bust in Kāne'ohe Bay, Hawai'i

Invasive macroalgae Eucheuma sp. and Kappaphycus spp. (E/K) became a dominant benthic feature in Kāne'ohe Bay throughout the past four decades - occurring on up to 74 ha of reef area and growing up to three meters thick, which prompted intensive management action. In 2013, E/K cover began decreasing at managed and unmanaged sites. This study examined the extent and timing of the E/K decline and evaluated environmental and ecological drivers beyond management contributing to the decline. E/K continued to recede into 2017 and remains sparse in Kāne'ohe Bay today. Increasing over the sampling period, herbivore biomass was negatively correlated with E/K cover, and other significant, non-linear relationships emerged between E/K cover and coral cover, sea surface temperature, wind, and rainfall. This study uncovers several possible mechanisms explaining a boom and bust in E/K abundance, emphasizes the importance of herbivory, and highlights the resilience of coral reefs in Kāne'ohe Bay.

An integrative analysis of proteomics and metabolomics reveals the effects of active restoration on Acropora hyacinthus

This study aimed to investigate the impact of active restoration on the physiology and metabolism of Acropora hyacinthus by comparing physiological, proteomic, and metabolomic differences between transplanted and natural corals. The results revealed that transplanted A. hyacinthus exhibited significantly higher quantum yield (Fv/Fm) and zooxanthellae density than natural corals. The proteome of the two groups was analyzed qualitatively and quantitatively, and 202 up-regulated and 284 down-regulated differential proteins were found. In addition, the differential metabolites between the two groups were screened and classified, ultimately identifying 314 up-regulated differential metabolites and 29 down-regulated differential metabolites. A comprehensive analysis of the enrichment pathways reveals that three pathways, namely arachidonic acid metabolism, glycerophospholipid metabolism, and cysteine and methionine metabolism, were found to be implicated in both the differential proteins and differential metabolites. Transplanted A. hyacinthus had low levels of (12S)-HETE, which may affect subsequent growth and development of the coral. This study demonstrates that aggressive restoration has contributed to an increase in coral cover, but the health of transplanted corals cannot be overlooked. Proteomics and metabolomics studies can offer essential insights for addressing potential coral health issues.

Live slow, die old: larval propagation of slow-growing, stress-tolerant corals for reef restoration

Efforts to restore coral reefs usually involve transplanting asexually propagated fast-growing corals. However, this approach can lead to outplanted populations with low genotypic diversity, composed of taxa susceptible to stressors such as marine heatwaves. Sexual coral propagation leads to greater genotypic diversity, and using slow-growing, stress-tolerant taxa may provide a longer-term return on restoration efforts due to higher outplant survival. However, there have been no reports to date detailing the full cycle of rearing stress-tolerant, slow-growing corals from eggs until sexual maturity. Here, we sexually propagated and transplanted two massive slow-growing coral species to examine long-term success as part of reef restoration efforts. Coral spat were settled on artificial substrates and reared in nurseries for approximately two years, before being outplanted and monitored for survivorship and growth for a further four years. More than half of initially settled substrates supported a living coral following nursery rearing, and survivorship was also high following outplantation with yields declining by just 10 to 14% over four years. At 6-years post-fertilisation over 90% of outplanted corals were reproductively mature, demonstrating the feasibility of restoring populations of sexually mature massive corals in under a decade. Although use of slower growing, stress tolerant corals for reef restoration may provide a longer-term return on investment due to high post-transplantation survival rates, considerable time is required to achieve even modest gains in coral cover due to their relatively slow rates of growth. This highlights the need to use a mix of species with a range of life-history traits in reef restoration and to improve survivorship of susceptible fast-growing taxa that can generate rapid increases in coral cover.

Condition of Coral Diversity in Kuta Mandalika Coastal, Central Lombok Regency

Development and operational activities in KEK Mandalika can increase sedimentation of waters caused by erosion of construction material activities, this have an impact on coral reef ecosystems. Coral reef ecosystems have several important roles in support life of various aquatic organisms, Damage to the coral reef ecosystem directly and indirectly, sooner or later will threaten the sustainability of the use of these resources (social economy) and the safety of the community. Observations were conducted in KEK Mandalika coastal at 6 observation points less than 10 m. The results showed that the highest percentage of live coral cover was found in Kuta Mandalika coastal at PIT 4 area (30%, damaged category, moderate status). While the lowest percentage of coverage was at PIT 5, which was 2% (damaged category, bad status). Overall the percentage of coral cover in the Kuta Mandalika area is included in the damaged category. One of the reasons is because at the lowest tide on the beach, the volume of water is very small so that many hard corals are exposed to solar radiation. This limits the types of hard corals that can grow in the intertidal zone of Mandalika coastal. Genus diversity at this location is low, ranging from 0.0782 to 0.1288. Several genera of the Nephtheidae family dominate the observation sites and form colonies of the same genus with a fairly large distribution. The average value of environmental parameter measurements in the Mandalika coastal is included in the good category for soft coral habitat and growth.

Temporal study of coral reef health in Kepulauan Seribu Marine National Park

Coral reefs are one of ecosystems that have high biodiversity and productivity. The condition of coral reefs in Seribu Islands is currently being threatened by various marine industry development activities. This study aims to determine coral reef health in Seribu Islands, DKI Jakarta. The study was conducted at eight observation stations in Kepulauan Seribu Marine National Park area on 7-10 March 2022 (First Monitoring) and 31 May until 3 June 2022 (Second Monitoring). Coral reef data collecting were using Underwater Photo Transect (UPT) method. Reef fish data collecting were using Underwater Visual Census (UVC) method. While for macrobenthos data collecting were using the Belt Transect method. The coral reef health index was determined based on two main components, there are benthic component and reef fish component. Overall, coral reef health from eight observation stations during two monitoring sessions had high recovery potential, although some stations had low coral cover and low target fish biomass. In addition, several species of macrobenthos are bioindicators that can contribute to purifying waters.

Irrelationship between live coral cover and reef fish: an interim study of marine habitat dynamic on Mandangin Islands

Most coral reef ecosystems with high coverage of living coral would escalate the reef fish abundance and species richness as one of the correlatable communities to the coral reef. However, reef fish could only utilize one of the coral reef ecosystems to provide to the reef fish community that still withstand and adapt to those conditions. This study aims to assess the coral reef ecosystem quality on Mandangin Islands and the correlation between the benthic substrate to the reef fish structure. Coral reef ecosystem was assessed using Line Intercept Transect and Underwater Visual Census. A linear model or regression analysis was built to identify the key predictors driving factor in the ecosystem. Rock, Sand, and Rubble are the highest benthic substrate around Mandangin Islands. Reef fish have a high abundance along the observation site with exhaustive trophic level, high major functional group, broad bodied size with high abundance small to moderate bodied-size. Rock has a positive correlation to reef fish abundance; Sand has possibilities to escalate species richness, whereas live coral negatively correlates to reef fish. Historically Mandangin Islands contained a healthy coral reef ecosystem that degraded after years, yet reef fish withstand and adapt to the Mandangin Islands’ degraded coral reef ecosystems. Rock is coral that loses several of its function, especially as direct nourishment. This study showed that reef fish should be considered as one of the primary data to strengthen the decision-making of Integrated Coastal Management and Oil Spill Contingency Plans by the Oil and Gas Company.

Turbid reefs experience lower coral bleaching effects in NE Borneo (Sabah, Malaysia)

The impacts of climate change are becoming more evident in recent years. Future projections suggest that heat stress events will likely be more frequent and severe over the next century, threatening the high diversity of the Coral Triangle. Shallow turbid reefs may help dampen some of these effects as several studies have shown their inherent resilience to heat stress events. Therefore, our main goal was to test this hypothesis by assessing the response of corals to the heat stress event of 2020. We conducted bleaching surveys in two contrasting habitats in Darvel Bay, Sabah: the turbid reef of Sakar, and the clear-water reef of Blue Lagoon. Relatively high coral cover (40–43%) was observed on both reefs in 2019. Underwater data loggers were used to monitor temperature and light. Coral colonies were scored from video transects of 100 m at 5 m and 10 m depth in both localities, with an additional transect at 15 m depth in Blue Lagoon. A total of 1326 coral colonies were evaluated for bleaching presence and bleaching severity based on the six-point scoring method. Bleaching severity varied significantly between both reefs. Low bleaching impacts were observed in the high turbid reef, with an average of 9.6% of colonies having bleached. Meanwhile, the clear-water reef of Blue Lagoon had an average of 37.1% of coral colonies affected by bleaching. Bleaching severity also varied significantly among depth, where corals in deeper depths bleached less in Blue Lagoon. Foliose coral forms were most affected in Blue Lagoon, while massive coral forms suffered the most in Sakar reef. Bleaching responses were also significantly different among coral genera. While Ctenactis and Herpolitha were consistently resistant in both reefs, Leptoseris, Fungia and Goniopora were most affected in the 5 m of Blue Lagoon. Meanwhile, Pachyseris was notably more affected in Sakar reef at 10 m than in Blue Lagoon. Overall, bleaching indices within these two reefs are lower than most that were assessed around the globe during heat stress events in 2020. These outcomes support the hypothesis of turbid reefs hosting resilient coral communities in the face of climate change.

Effects of territorial damselfish on corallivorous fish assemblage composition and coral predation in the Mauritian lagoon

Predation is a significant stressor for many coral species. Understanding how predation interacts with factors such as climate change is key to coral conservation. Territorial damselfish of the genus Stegastes form territories on branching corals (genus Acropora) on which they cultivate algae, and while defending these territories, provide corals with indirect protection from predation. However, it is not known how the protection afforded by Stegastes spp. varies with corallivorous fish assemblage composition, nor whether corallivore assemblages themselves may be affected by the presence of Stegastes spp. and their associated Acropora spp. habitats. This study examined relationships among predation protection by Stegastes spp., branching Acropora coral cover, and the number and species richness of corallivorous fish present within a given area, namely the Mauritian lagoon in the western Indian Ocean. Predation on bleaching-resilient massive Porites lutea corals within and outside Stegastes territories was surveyed at sites around Mauritius island. Corallivorous fish assemblages, branching coral cover, and Stegastes spp. density were also surveyed at each site visit. Results show that high predation was correlated with the presence of high numbers of corallivores, but predation was lower within Stegastes spp. territories irrespective of all observed corallivore densities. Greater numbers of Stegastes spp. were correlated with increasing density of obligate corallivores. Non-Acroporid coral cover was positively correlated with species richness of obligate corallivores, while branching Acropora coral cover was negatively correlated with overall corallivore density. This study shows for the first time that predation on bleaching-resilient massive corals is lower within Stegastes spp. territories regardless of the number of corallivores present, adding to the growing body of knowledge on the complex relationships between Stegastes spp. and their environment. The findings also indicate possible effects of the presence of Stegastes spp. and their branching Acropora habitats on corallivorous fish density in areas with low coral diversity, which may warrant further study.

Evidence of Sexual Reproduction in Out-Planted Coral Colonies

Intervention techniques to restore coral communities have become an important management tool to help recover and rehabilitate damaged reefs. The direct transplantation of healthy coral fragments is the most common method; however, there is controversy in the long-term success, as using coral clones may diminish the genetic diversity of the coral population. Genetic recombination can be achieved when the coral colony produces gametes and eventually reproduces; therefore, it is important to provide evidence that restored colonies produce gametes as their naturally recruited counterparts with similar colony size (age). Natural and restored Pocillopora coral colonies of the same size range (between 40 and 50 cm in diameter) were tagged and sampled during the rainy season to determine gamete maturation. Our results show no differences in the reproductive activity among colonies: natural and restored coral colonies matured gametes from June to October, with a peak in sexually active coral colonies in July. Also, gamete malformation was not observed. During the gamete production period, the area’s temperature ranged from 27.9 to 30.02 °C. The results’ evidence that coral colonies formed through active restoration contribute not only to the increase in live coral cover as seen in previous studies but potentially contribute in the medium term (>5 years after out-planting) to the production of larvae and local and subsidiary recruitment, since they exhibit the same reproductive patterns as their naturally formed counterparts and no differences in the reproductive activity among coral colonies. Therefore, long-term coral restoration projects contribute to maintaining the live coral cover and the genetic diversity in the region, eventually rehabilitating the coral community.

Coral reefs in the northeastern Saudi Arabian Red Sea are resilient to mass coral mortality events

We conducted an integrated survey combining visual census and baited remote underwater video survey on the coral reefs in the northeastern Red Sea and examined their health by comparing the baseline information from two decades ago. The mean coverage of the corals of all stations was 36 %, including 32 % stony corals and 4.0 % soft corals, significantly higher and lower to previous baseline. Observed high proportion of dead corals indicated the occurrence of the events of mass mortality, and the heating events were the most likely cause. Similar levels of coral coverage compared to two decades ago indicated their resilience to past events with mass coral mortality. Small proportions of macroalgae and sea urchins indicated that they might be controlled by their predators frequently observed in both visual census and underwater video survey. Regular monitoring and careful development plans are needed to safeguard these invaluable reefs.