Reef Cover Research Articles

Sabellaria wilsoni Lana and Gruet, 1989 on the Brazilian Amazon coast: Fast growth with high mortality, production, and turnover rate

Given the enormous ecological importance of sabellariid (Annelida: Sabellariidae) reefs for marine environments, data on the life history traits of these reef builders are essential for understanding ecosystem function. We assessed the functional parameters of a population of Sabellaria wilsoni (Annelida: Sabellariidae) on the Brazilian Amazon coast, where this polychaete builds extensive reef systems. The species had fast growth, a relatively short life span (1.30 years), and a high mortality rate (3.87 year−1). The mean annual biomass (58 g AFDM m−2) and production (233 g AFDM m−2 year−1) were very high and resulted in a high production-to-biomass ratio (P/B ratio: 4.02 year−1). The months with the highest productivity were those with the greatest reef coverage and density of worms, which coincided with the periods of reef growth. The high P/B ratio indicates the rapid replacement of biomass in this tropical population. These data support the hypothesis that S. wilsoni is an r-strategist, which is favored by the elevated temperatures and abundance of feeding resources and grains (for tube building) found on the Amazon coast. The present study is the first to produce systematic data on the population dynamics and production of a sabellariid species in the Western Atlantic Ocean. These data provide a baseline for understanding how shallow-water trophic webs function, as well as for monitoring these coastal habitats in the tropics.

A generalized machine learning model for long-term coral reef monitoring in the Red Sea

Coral reefs, despite covering less than 0.2 % of the ocean floor, harbor approximately 35 % of all known marine species, making their conservation critical. However, coral bleaching, exacerbated by climate change and phenomena such as El Niño, poses a significant threat to these ecosystems. This study focuses on the Red Sea, proposing a generalized machine learning approach to detect and monitor changes in coral reef cover over an 18-year period (2000–2018). Using Landsat 7 and 8 data, a Support Vector Machine (SVM) classifier was trained on depth-invariant indices (DII) derived from the Gulf of Aqaba and validated against ground truth data from Umluj. The classifier was then applied to Al Wajh, demonstrating its robustness across different sites and times. Results indicated a significant decline in coral cover: 11.4 % in the Gulf of Aqaba, 3.4 % in Umluj, and 13.6 % in Al Wajh. This study highlights the importance of continuous monitoring using generalized classifiers to mitigate the impacts of environmental changes on coral reefs.

Loss of coral thermotolerance following year-long in situ nursery propagation with a consecutively high summer heat-load

Exposure to more frequent ocean warming events is driving the loss of coral reef cover as the window of recovery between episodes of bleaching reduces. Coral propagation via in situ nurseries and subsequent outplanting have increased worldwide to support replenishing coral cover on degraded reefs. However, challenges in identifying fast-growing and bleaching-resistant target corals have limited how informative we can be regarding the resilience of outplanted corals. Here, we employed short-term thermal stress assays using the Coral Bleaching Automated Stress System (CBASS) to assess the thermal threshold of a fast-growing coral pre- and post-propagation on in situ nursery frames. We show that year-long nursery-propagated corals exhibit a statistically significant reduction in thermal thresholds (i.e., ED50s) compared to their corresponding reef-based donor colonies based on dose–response modelling of dark acclimated photosynthetic efficiency. RNA-Seq was then used to assess the underlying drivers of this thermotolerance reduction, identifying that processes involved in metabolic and oxidative stress management were disrupted in nursery versus donor heat-treated corals. Whether trade-offs during potential growth-focused phases (post-fragmentation), nursery conditions, and/or a consecutively high summer heat-load drove the lower thermal capacity remains to be determined. However, nursery corals expressed genes associated with telomere maintenance, which are typically expressed in stress-sensitive fast-growing corals under seasonal environmental stress, suggesting consecutively high summer heat-loading contributed to the observed patterns. Our results highlight that thermal tolerance is (i) variable and (ii) subject to acclimation to varying degrees across colonies. Thus, a path forward for reef practitioners to improve propagation efforts may entail the initial screening of a larger reef population from which thermally superior colonies can be selected for propagation.

Designation of a maritime conservation area in the waters of Haruku-Sameth, Central Maluku Regency

Two traditional villages in the Central Maluku Regency are called Haruku-Samet. They have unique historical and ecological potential, as well as being locations for traditional ceremonies and historical maritime landmarks. The potential exists for development as a marine conservation area. The study’s objectives are to evaluate and identify the type of designated maritime conservation area. The study was carried out from April through October 2020. Data on the species and density of seagrass and mangroves, as well as the percentage of coral reef cover, were gathered by surveys and observations. Community organizations and fishermen participated in participatory mapping, interviews, and discussions to gather data on the potential and uses of coastal and marine resources. Mangrove, seagrass, and coral reef habitat distribution was determined by field surveys, with supported by an examination of Landsat 8 imagery. In compliance with the E-KKP3K Supplement Guidelines (Supplement 1), 20 assessment indicators are analyzed for the identification, inventory, and reserve of Maritime Conservation Areas. According to the results, the candidate for the traditional marine conservation area of the Haruku-Sameth villages was deemed highly suitable for development as a conservation area under the category of Maritime Conservation Area, specifically classified as a Maritime Indigenous Protection Area.

THREE-DECADE changes of reef cover in Pulau Layang-Layang, Malaysia using multitemporal Landsat images

Over the years, coral reefs in the South China Sea have degraded and faced severe threats from rapid development, coral bleaching, and Crown-of-Thorns Starfish (COTS) outbreak. There is limited knowledge relating to the effects of anthropogenic disturbances and natural events on the coral reefs of Pulau Layang-Layang. This study aims to assess reef cover changes by utilizing Landsat satellite images spanning from 1989 to 2022. Using the object-based image analysis method, this study classified the reef cover into three categories: coral, rock and rubble, and sand. The supervised classification had an overall accuracy of 86.41–87.38 % and Tau's coefficients of 0.80–0.81. The results showed island development and construction of artificial bird sanctuary have led to an increase in coral cover. Furthermore, it was illustrated that the impact of COTS outbreaks in 2010 and 2020 differed significantly, with the latter showing no signs of recovery. Our study underscores the importance of timely intervention to mitigate the spread of COTS. This study provides insights into the resilience and vulnerability of these ecosystems in the face of various stressors.

Reef fish community structure in the waters of small islands Central Bangka Regency

This study aimed to analyze the community structure of reef fish in the small island waters of Central Bangka. The research was conducted in March 2022 in the waters of Bebuar Island, Ketugar Island, Ketawai Island, and Gusung Asam Central Bangka Regency, Bangka Belitung Islands Province. The coral reef survey method uses purposive sampling and the coral reef fish visual census with data analysis of abundance, diversity index, uniformity, and dominance. In-site water quality measurements included six parameters: temperature, salinity, current, brightness, depth, and pH. The results showed that coral reef cover from 44.60 - 87.00% with the medium to very good category. The abundance of reef fish from 1 to 3 individuals/m2 was dominated by 18 species of the Pomacentridae family. The reef fish diversity index ranged from 2.47 to 2.90, including the medium category. The uniformity index value ranged from 0.79 - 0.94, including the high category, indicating that the species found were evenly distributed across all stations. The dominance index value ranges from 0.07 to 0.15, including low, where no species dominates significantly and the fish are evenly distributed. Temperature, brightness, pH, and salinity are factors that support the growth of coral and reef fish. A water current speed of 0.05 – 0.20 m/s is quite helpful in cleaning coral reefs from mud and can supply oxygen. Water conditions were categorized as good and fulfilled the seawater quality standards.

Building your own mountain: the effects, limits, and drawbacks of cold-water coral ecosystem engineering

Abstract. Framework-forming cold-water corals (CWCs) are ecosystem engineers that build mounds in the deep sea that can be up to several hundred metres high. The effect of the presence of cold-water coral mounds on their surroundings is typically difficult to separate from environmental factors that are not affected by the mounds. We investigated the environmental control on and the importance of ecosystem engineering for cold-water coral reefs using annotated video transect data, spatial variables (MEMs), and hydrodynamic model outputs in a redundancy analysis and with variance partitioning. Using available hydrodynamic simulations with cold-water coral mounds and simulations where the mounds were artificially removed, we investigated the effect of coral mound ecosystem engineering on the spatial configuration of reef habitat and discriminated which environmental factors are and which are not affected by the mounds. We find that downward velocities in winter, related to non-engineered environmental factors, e.g. deep winter mixing and dense-water cascading, cause substantial differences in reef cover at the broadest spatial scale (20–30 km). Such hydrodynamic processes that stimulate the food supply towards the corals in winter seem more important for the reefs than cold-water coral mound engineering or similar hydrodynamic processes in summer. While the ecosystem-engineering effect of cold-water corals is frequently discussed, our results also highlight the importance of non-engineered environmental processes. We further find that, due to the interaction between the coral mound and the water flow, different hydrodynamic zones are found on coral mounds that likely determine the typical benthic zonations of coral rubble at the mound foot, the dead coral framework on the mound flanks, and the living corals near the summit. Moreover, we suggest that a so-called Massenerhebung effect (well known for terrestrial mountains) exists, meaning that benthic zonation depends on the location of the mound rather than on the height above the seafloor or water depth. Our finding that ecosystem engineering determines the configuration of benthic habitats on cold-water coral mounds implies that cold-water corals cannot grow at deeper depths on the mounds to avoid the adverse effects of climate change.

Population biology of the reef crab Eriphia gonagra (Fabricius, 1781): Spatial variations and anthropogenic impacts in the Western Tropical Atlantic

The red-finger rubble crab, Eriphia gonagra, plays a fundamental ecological role in maintaining reef cover and is an important component of the reef food web. This study aimed to compare population aspects of E. gonagra in four reef areas in Northeastern Brazil and investigated the effects of anthropogenic impacts upon the community, including trampling, sewage discharge, and one of the largest oil spills in Brazilian history, which occurred in August 2019. Over the course of a year, 222 individuals of E. gonagra were examined. The oil spill impact did not affect the studied aspects of the population, but results pointed out that tourism caused a decrease in the average carapace size and maturation in Ponta Verde and Carneiros compared to less frequented areas. While the current study found no apparent impact of the oil spill on the studied aspects of the population, it underscores the ongoing need for research into the sub-lethal effects of oil spills. Continued investigation is crucial for a comprehensive understanding of potential long-term impacts and to refine our knowledge in this area. This study highlights the importance of research into the effects of human activities on benthic crustacean species in reef environments to better understand their overall health.

Condition of Coral Reefs and Abundance of Coral Fishes of the Chaetodontidae Family in the Waters of Sironjong Gadang Island, Pesisir Selatan District, West Sumatra Province

Sironjong Gadang Island is one of the islands in the Mandeh Tourism area in Pesisir Selatan Regency, West Sumatra, Indonesia. One of the ecosystems affected by tourism activities is coral reefs. Monitoring the coral reefs' condition and the abundance of coral fish in the Chaetdontidae family is carried out to find out this. This research uses survey research methods. The temperature measurement results obtained an average of 30.2oC, current speed measurements received an average of 0.12 m/s, salinity measurements obtained an average of 30 ppt, and brightness measurements show that the brightness of these waters is 9 m. Tide measurements in the waters of Sironjong Gadang Island, carried out on March 7–8, 2023, are double daily tides (semi diurnal tide). Then, the results from the coral reef cover of Sironjong Gadang Island waters obtained a percentage ranging from 2.34 - 12.83%, with an average rate of live coral reef cover of 5.96%, which is included in the poor category. Furthermore, the results at each research station in the waters of Sironjong Gadang Island showed that 54 coralfish individuals were found, with the number of coralfish at each depth ranging from 4 - 10 individuals. The most common types of coral fish are species. Acuminate had 18 individuals; the fewest types of coral fish found were Chaetodon trifasciatus and C. tristichous, each numbering two individuals. There is a solid relationship between live coral reef cover and the abundance of coral fish in the Chaetodontidae family, where live coral reef cover influences the plenty of coral fish by 61.11%, which means that the higher the percentage of live coral cover, the higher the value of coral fish abundance.

Correlation between Coral Reef Cover Condition and the Abundance of Megabenthos on Setan Island, West Sumatra

In the coral reef ecosystem, there is a food source for small fish, which are prey for various kinds of associated biota; one of the biota that lives in the coral reef ecosystem is megabenthos. Megabenthos is influenced by the quality of the coral reef ecosystem, where if conditions are good, the coral will have a greater chance of high megabenthos diversity. This research was carried out in March 2023 in Setan Island, West Sumatra. This research analyzes the relationship between coral reef conditions and megabenthos abundance. The method used in this research is a survey method. Observations of coral reef cover were carried out using the Underwater Photo Transect (UPT) method, and megabenthos abundance was measured using the Bhentos Belt Transect (BBT) method. Observations were carried out at four stations (3 and 6 m deep) with a transect length of 50 m. Based on the average value of the percentage of coral reef cover, it is still categorized as being in poor condition, namely 18.87%. There is a relationship between the percentage of live coral reef cover and the abundance of megabenthos with a percentage of 55.27%, with the types of megabenthos clams (Tridacna sp), sea cucumbers (Holothuria sp), snails (Trochus sp), lobsters (Panulirus sp), fur pigs (Diadema sp), snails (Drupella sp), and starfish (Acanthasper sp).

Condition of Coral Reefs in the Ciletuh Geopark Area, SukabumiIndonesia

Ciletuh Geopark has unique natural resources, namely the natural beauty of the sea. Coral reefs are one of the most productive marine ecosystems with diverse biodiversity. Data and information regarding coral reefs in the south of Java Island, especially in the Ciletuh Geopark area, Sukabumi is still minimal, and their existence is rarely exposed. Therefore, we carry out research activities related to the condition of coral reefs using the underwater photo transect method. Data were taken at a depth of 6 meters with a transect length of 50 m and analyzed using CPCe 4.1 and Microsoft Excel 2010 software. Observations of the condition of coral reefs at Pasir Putih Beach in the Ciletuh Sukabumi Geopark area show that the percentage of cover is in the criteria of quite good (25-49.9%) and poor (0-24.9%). The observation results show that the percentage of coral reef cover at station I (28.88%) is quite good, station II (35.75%) is quite good, and station III (22.48%) is in the poor category. The highest diversity index (1.68) and Variety Index (0.25) was found at station II and the lowest was at station I with a diversity value of 1.07 and a diversity value of 0.16.

Precision and accuracy of common coral reef sampling protocols revisited with photogrammetry

The rapid decline of coral reefs calls for cost-effective benthic cover data to improve reef health forecasts, policy building, management responses and evaluation. Reef monitoring has been largely based on divers’ observations along transects, and secondarily on quadrat-based protocols, video and photographic records. However, the accuracy and precision of the most common sampling approaches are not yet fully understood. Here, we compared benthic cover estimates from three common sampling protocols: Reef Check (RC), Atlantic and Gulf Rapid Reef Assessment (AGRRA) and photoquadrats (PQ). The reef cover of two contrasting sites was reconstructed with ∼450 m2 orthomosaics built with high resolution Structure-from-Motion (SfM) photogrammetry, which were used as references for comparisons among protocols. In addition, we explored sample size requirements for each protocol and provided cost-effectiveness comparisons. Our results evidenced between-reef differences in the accuracy and precision of estimates with the different protocols. The three protocols performed similarly in the reef with low macroalgal cover (<0.5%), but PQ were more accurate and precise in the reef with relatively high (∼20%) macroalgal cover. The sample size for estimating coral cover with a 20% error margin and a 0.05 significance level was lower for PQ, followed by AGRRA and RC. Considering performance, cost surrogates and equipment needs, cost-effectiveness was higher for PQ. We also discuss costs, limitations and advantages/disadvantages of SfM photogrammetry as a sampling approach for coral reef monitoring.

Location assessment for coral reef transplantation program in Karawang Waters, Indonesia

Environmental degradation caused by anthropogenic activities and climate change has an impact on the habitat of organisms and biodiversity. Coral reefs are one of the sensitive ecosystems that are strongly influenced by environmental changes. Poor environmental conditions in the Java Sea and global warming are the main factors that affect the sustainability of coral reef ecosystems in Karawang waters. Coral reef transplantation is a method that has long been used to revitalize coral reef ecosystems. This study aims to assess the ideal location used for coral reef transplantation program in Karawang Waters. Through a field survey, the percentage of coral reef cover, dead coral, hard coral, algae, and biotic and abiotic components at several sampling points in 2019 to 2022 was obtained. The sampling location with the poor conditions are considered to be used as transplant locations. Based on analysis result, only 1 out of 3 locations that are suitable to be used as locations for coral reef transplantation programs.

Coral reef rehabilitation sites selection based on seasonal waves and environmental quality as ecological supporting system on Mandangin Island

The natural rehabilitation process in the coral reef ecosystem requires a genuinely suitable environment minimum disturbance marine threats. Baby coral is a fragile organism used to increase the quantity of coral reef cover during rehabilitating coral reef ecosystems— determination for coral rehabilitation sites with minimum marine threats for increasing success. The destructive fishing around Mandangin Island induces a declination of live coral coverage. On average, live coral cover around Mandangin Islands is under 10 percent. However, there is high coverage of dead coral that is still functional as a shelter for reef fish in the southeast Mandangin Islands. The dead reef structure can still prevent the coastal area from high seasonal waves hitting the southeast coast from July to September. A large-scale reef structure makes it difficult for small-scale fishers to disturb the rehabilitation area. Water quality indicated that east-to-south coastal areas are considered coral rehabilitation sites. Unique water quality affects the coral adaptation on Mandangin Island. East to Southeast coastal areas are considered coral reef rehabilitation locations based on coral reef cover, water quality, and seasonal waves. The limitation of the coral fragment from Mandangin Islands became the most concerned variable for rehabilitation and reef-structure design to anticipate the seasonal waves.

Coral Detection, Ranging, and Assessment (CDRA) algorithm-based automatic estimation of coral reef coverage

Climate change poses significant threats to the health of coral reefs. The detection of coral coverage is a quantitative method for assessing the health of coral reefs. Valuable insights into the effects of climate change on coral reef ecosystems and the trends in coral reef development can be gained through the monitoring of coral coverage. However, traditional manual methods for estimating coral coverage are time-consuming and labor-intensive, limiting the scalability and efficiency of coral surveys. The field of automated processing for coral video imagery is currently limited, impeding the development of effective techniques for comprehensive coral monitoring and further hindering progress in coral ecosystem monitoring. To cope with these challenges, there is a crucial need for automated systems to efficiently handle large volumes of video data, thereby transforming imaging devices, such as underwater robots, into autonomous sensors capable of conducting reliable and comprehensive surveys. In response to this pressing issue, this study presents a novel video analysis approach, termed the Coral Detection, Ranging, and Assessment (CDRA) algorithm, which combines cutting-edge computer vision techniques including You Only Look Once version 5 (YOLOv5) object detection, binocular stereo vision, and tracking algorithms. The CDRA algorithm aims to analyze continuous video segments of coral reefs, enabling the identification, counting, and estimation of size and location of individual coral colonies. Experimental evaluations conducted in controlled pool environments demonstrated the high accuracy of the proposed method, with an average accuracy of 90.7% in estimating coral coverage at different locations. Moreover, field trials conducted in Xidao Island of China verified the effectiveness and robustness of the CDRA algorithm under varying water quality and lighting conditions. The findings of this study represent a significant step towards the development of reliable and automated techniques for coral reef detection, contributing to the advancement of coral reef conservation efforts.

STUDY OF GIANT CLAMS RESOURCES AND CORAL REEF ECOSYTEM FOR MARINE ECOTURISM MANAGEMENT

ABSTRACTGiant clams that protected by CITES Appendix II is important marine organism as a stock in and also has potential as a marine tourism. This study aims to analyze the potential of clams which are part of the coral reef ecosystem as an alternative ecotourism management of diving and snorkeling in Morella and analyzing appropriate management strategies for the development of tourism areas in Morella. The method used for the analysis of clams is 1) the density of clams Di = ni / A; 2) diversity index H '= - (∑ni (ln (ni / N)); 3) dominance index D = ∑ [Ni / N] 2, and Analysis Hierarchy Process (AHP) method. There are five types of clams such as Tridacna maxima, T. squamosa, T. gigas, T. crocea and Hippopus hippopus. The widest distribuiton was T. maxima, which was found at each research areas and the lowest was H. Hippopus. The population of clams was found at Lettang Beach with the most species being T. squamosa. The highest percentage of coral reef cover was found at Lubang Buaya Beach at 81.10% and the lowest at station I at 55.53%. The highest number of species of reef fish is found at Lettang Beach, which is 197 types. The management strategy that needs to be prioritized is integrated management, which takes into account all aspects of ecological, economic, social and institutional aspects.

Documenting Loss and Fragmentation of Intertidal Oyster (Crassostrea virginica) Reefs in a Subtropical Estuary

Intertidal reefs of Crassostrea virginica (eastern oyster) provide ecologically valuable habitat in estuaries along the Atlantic coast of North America. In Mosquito Lagoon, a shallow-water estuary on the east coast of central Florida, USA, historical aerial imagery was used to document a 24% decline in the live C. virginica reef area between 1943 and 2009. Using 2021 imagery, every living and dead reef in the same region was manually digitized to identify changes during the intervening 12 years. Positive impacts of C. virginica reef restoration that took place between 2007 and 2021 were also digitized to quantify long-term restoration impact. Natural, live C. virginica reef coverage throughout the system was found to have decreased by 50.6% between 2009 and 2021 and, thus, 62.6% between 1943 and 2021. This was attributed to reef fragmentation, reef footprint loss, boating activity, and mangrove expansion. Of the 2542 live reefs identified using 2009 imagery, 219 reefs fragmented, 988 reefs no longer had an identifiable footprint, and 598 reefs contained visible mangroves with non-continuous canopies. Conservatively, 63.6% of directly restored reef area was classified as living reef in 2021, and 74.5% of restoration projects were more than 50% live reef. Dead reef area decreased by 57.9% throughout the system. Understanding changes in C. virginica reef acreage, reef numbers, and mangrove expansion is essential for resource management, restoration practices, and tracking climate change impacts on publicly protected estuaries.

Zonation of The Waters of Spermonde Archipelago Base on Nutrient Concentration and Its Impact to Coral Reef Ecosystem

The Spermonde Archipelago is divided into four zones, the division of zones is based on the distribution of coral reefs, distance from the mainland, and water depth, but this condition tends to change as a result of high anthropogenic activity in the Spermonde Islands. Based on this, it is very necessary to re-zoning the Spermonde Archipelago Waters based on the condition of nutrient distribution. The research method uses the integration of remote sensing data analysis, field surveys, and secondary data which are then analyzed using the Boleean method for re-zoning. The results showed that the nutrient, in this case, chlorophyll-a, was concentrated in the deep zone (near the mainland) and the concentration was higher during the rainy season, this condition affected the coral reef cover in the Spermonde Islands. Based on these conditions, the Spermonde Islands waters are divided into three zones, namely the inner zone with high nutrient conditions with a benthic cover dominated by fleshy macroalgae, the middle zone with low nutrient conditions with crustose coralline dominance, and the outer zone with low nutrient conditions with algal turf dominance turf alga/corals.

Analysis of Coral Reef Coverage Condition in The Waters of Central Bangka Regency

This research aims to discover the percentage of coral reef coverage and the condition of the coral reef ecosystem in small islands in Central Bangka regency waters. The research was conducted on May 2022 on six small islands: Panjang Island, Semujur Island, Ketawai Island, Ketugas Island, Gusung Asam Island, and Bebuar Island. The method used was underwater photo transect (UPT) and then analyzed using Coral Point Count with Excel extension software (CPCe). The result shows that of 6 small islands, only Semujur Island is populated. Coral reefs in small islands in Central Bangka regency were a type of fringing reef dan patch reefs with 3,0 - 8,8 meter depth. Standard damage criteria show that the damage was Moderate (44,60%) to Excellent (87,00%). The details were Moderate category on Ketugar Island, Good category was in Panjang Island, Gusung Asam Island, and Bebuar Island, while the coral reefs in Excellent category were in Semujur Island and Ketawai Island. 24 lifeform types were found with a dominant percentage value of approximately 18,47 - 46,87%. Lifeform was dominated by Coral Foliose (CF), Acropora Tabulate (ACT), dan Dead Coral with algae (DCA). Live coral reefs closer were dominated by healthy lifeforms, with most of the close being Dead Coral with algae. It showed that coral reefs might get disturbed by algae occurrence and triggers massive algae expansion. Fish in Coral reefs primarily targeted fish. It prefers the lifeform type to dead coral with algae lifeform.

Persentase Tutupan Karang Di Perairan Teluk Akle Kecamatan Semau Selatan Kabupaten Kupang Nusa Tenggara Timur

Akle Bay is one of marine aquaculture area in Semau island and it has coral reef potention. The coverage percentage of coral reef in the ocean might be decline by human activities and also by nature itself. The aimed of this research was analyzed to know the percentage of coral reef coverage in Akle Bay, South Semau District. This study conducted in Akle Bay, South Semau District on May 18, 2023st . Underwater Photo Transect (UPT) was used to take a sample in five meter depth at two different sites in Akle Bay waters. Data was analyzed by software CPCe 4.1. Result showed the highest benthic coverage percentage is soft coral. There were eleven genus of hard coral was found and its dominated by Porites genera. The percentage of hard coral coverage in S1 was 9.14%, while in S2 was 6.11% and was categorized in worst condition. The decline of coral reef coverage percentage in this area was expeted due to of human activities such as coral removal, the usage of anchor and the destructive fishing gear like a bomb, and also a sedimentation. According to the lifeform, covarage percentage of hard coral was dominated by coral branching. The average of current velocity in Akle Bay was 0,417 m/s with the range of waves was 0.1 to 0.5 meters. Conclusion of this research is the percentage of coral coverage in Akle Bay is worst. It was becacuse of human activities and sedimentation.