Current Ecological Status of Remote Coral Reefs of Clipperton Island, Tropical Eastern Pacific

Clipperton, an uninhabited and remote coral atoll from the Eastern Pacific, is an important steppingstone area that harbors a high marine biodiversity. Despite its biogeographic importance, little information on the ecological status of its coral reefs is available from the last decade. Herein, we characterized the benthic coral community and health status among four different shallow reef-zones (North to South) of Clipperton during the Tara Pacific expedition in 2018. The benthic composition and coverage percentage, as well as occurrence of a pink-spotted coral phenotype (trematodiasis infection) was assessed. Total live coral cover on Clipperton reefs was 66% (55-85%), differing between sites, with massive Porites and branching Pocillopora corals dominating the benthic community with an average 48% (32-66%), and 15% (3-21%), respectively. While Clipperton reefs exhibited significant live coral cover overall, the trematode infection was commonly observed, with a higher occurrence in massive corals (Porites 27%, and Pavona 31%). This observation is possibly related to the combined effects of previously heatwaves, and local inputs of guano-derived nutrients discharged during storms and hurricanes. These results demonstrates that even highly remote reefs supporting high coral cover can be subjected to local and global threats, including but not limited to parasite prevalence, likely in relation to natural disturbances such as thermal stress and tropical cyclones.

Characterizing the spatial distribution of coral reefs in the South-Central Coast region of Viet Nam using Planetscope imagery

This study aims to understand the spatial distribution of coral reefs in the central region of Viet Nam. We classified live coral cover in Son Tra Peninsula (ST) and Cu Lao Cham Island (CLC) in the South-Central Coast Region of Viet Nam using the Maximum Likelihood Classifier on 3 m Planetscope imagery. Confusion matrices and the accuracy of the classifier were assessed using field data (1,543 and 1,560 photographs in ST and CLC, respectively). The results showed that the reef’s width ranged from 30 to 300 m across the study site, and we were able to detect live coral cover across a depth gradient of 2 to 6 m below the sea surface. The overall accuracies of the classifier (the Kappa coefficient) were 76.78% (0.76) and 78.08% (0.78) for ST and CLC, respectively. We found that 60.25% of coral reefs in ST were unhealthy and the live coral cover was less than 50%, while 25.75% and 11.46% of those in CLC were in good and excellent conditions, respectively. This study demonstrates the feasibility of utilizing Planetscope imagery to monitor shallow coral reefs of small islands at a high spatial resolution of 3 m. The results of this study provide valuable information for coral reef protection and conservation.

Through the Boundaries: Environmental Factors Affecting Reef Benthic Cover in Marine Protected Areas in the Philippines

Philippine coral reefs have been on the decline since the 1970s, and this degradation has posed a risk to biodiversity, food security, and livelihood in the country. In an effort to arrest this degradation, marine protected areas (MPAs) were established across the country. MPAs are known to improve fish biomass, but their effect on live coral cover and other benthos is not yet well documented and understood. In this study, 28 MPAs across the Philippines were surveyed comparing benthic cover and indices between protected reefs and adjacent unprotected reefs. No consistent differences were found between reefs inside and outside MPAs through all the benthic categories and reef health indices considered that are indicative of protection effects or recovery within MPAs. However, there were notable site-specific differences in benthic cover across the study MPAs-suggesting that factors other than protection play important roles in influencing benthic cover inside and outside of MPAs. Storm frequency and proximity to rivers, as a proxy for siltation, were the strongest negative correlates to live coral cover. Also, high coastal population, a proxy for pollution, and occurrence of blast and poison fishing positively correlated with high dead coral cover. The lack of significant difference in benthic cover between reefs inside and outside MPAs suggests that protection does not necessarily guarantee immediate improvement in benthic condition. Correlations between benthic condition and storm frequency, siltation, and pollution suggest that it is necessary to augment MPAs with other management strategies that will address the multiple stressors that are usually indiscriminate of MPA boundaries. Supplementing long-term and systematic monitoring of benthic cover and biodiversity inside and outside of MPAs with data on other important environmental and human impact variables will help improve understanding of benthic cover and biodiversity dynamics inside and outside of MPA boundaries.

Site Selection for Coral Reef Restoration Using Airborne Imaging Spectroscopy

Over the past decade, coral restoration efforts have increased as reefs continue to decline at unprecedented rates. Identifying suitable coral outplanting locations to maximize coral survival continues to be one of the biggest challenges for restoration practitioners. Here, we demonstrate methods of using derivatives from imaging spectroscopy from the Global Airborne Observatory (GAO) to identify suitable coral outplant sites and report on the survival rates of restored coral at those sites. Outplant sites for a community-based, citizen science outplant event in Bávaro, Dominican Republic, were identified using expert-defined criteria applied to a suitability model from data layers derived from airborne imagery. Photo quadrat analysis of the benthic community confirmed the accuracy of airborne remote sensing maps with live coral cover averaging 3.5–4% and mean algal cover (macro algae and turf) ranging from 28 to 32%. Coral outplant sites were selected at 3–7 m depth with maximized levels of habitat complexity (i.e., rugosity) and live coral cover and minimized levels of macroalgal cover, as predicted by the imaging spectrometer data. In November 2019, 1,722 Acropora cervicornis fragments (80–180 mm in length) were outplanted to these sites. Surveys conducted in January 2020 in four of these sites confirmed that 92% of outplants survived after 3 months. By October 2020 (11 months after outplanting), survivorship remained above 76%. These results demonstrate higher than average success rates for coral outplant survival for this species. An online tool was developed to enable replication and facilitate future selection of coral restoration sites. Our objective is to present a case study that uses GAO-derived map products within a suitability model framework to provide a quantitative and replicable method for selecting coral restoration sites with the goal of increasing outplant survival over time.

Condition of coral reef in Batee Island waters, Peukan Bada Sub-District, Aceh Besar

Batee Island is one of the small islands in the Aceh Besar region and is uninhabited and directly faces the Indian Ocean. Batee Island's waters have the potential for marine biota, especially coral reef ecosystems, and other associated biotas. This study aims to determine the percentage and comparison of live coral cover in Batee Island waters and determine the genus' composition in Batee Island waters. This research was conducted in October-November 2016. Collecting coral reef data using the LIT (Line Intercept Transect) method. The results showed that the live coral cover in Batee Island's waters differed between the East and West Batee Islands. The coral reefs' average condition in Batee Island waters at shallow depths (0-5m) is 41.41%, and deep (6-10m) is 36.52%. Overall, the conditions and live coral cover in the waters of Batee Island are classified as moderate. In the waters of Batee Island, there are 31 coral genera. The highest percentage of corals was the genus Acropora (50.02%).Keywords:Batee IslandConditionCoral reefCoral cover

Coral Cover and Diversity Life form in Different Geomorpholgy Zone at Kampung Baru Waters, Bintan Island

The purpose of this study was to compare the percentage of cover conditions, diversity index, uniformited index and dominance index of life form coralin the zones reef flate and reef slope in Kampung Baru Lagoi, Bintan Regency. This research was conducted using the method Line Intersept Transect (LIT) with the line transect length used was 30 meters, three replications with a gap of 5 meters. The results showed, at point station 1 in the zone flate Reef the percentage of live coral cover was 36,92% are categorized as moderate. Forms the coral growth Life form were found as many 9 types of Life form hard corals namely ACB, ACT, ACE, ACS, ACD, CB, CM, CE, CS with a diversity index of 2,53 are categorized as moderate, a uniformited index of 0,80 are categorized as high, and a dominance index of 0,22 are categorized as low. At the point station 2 in the zone slope Reef the percentage of live coral cover was 50,44% are categorized as good. Forms of coral growth (Life form) were found as many as 8 types of Life form hard corals namely ACT, ACE, CB, CM, CE, CS, CF and CMR, with a diversity index of 2,13 are categorized as moderate, a uniformited index of 0,71 are categorized as high, and a dominance index of 0,30 are categorized as low.

Status of Coral Reefs in the Water of Spermonde, Makassar, South Sulawesi

Observations of the condition of coral reefs have been carried out in Spermonde waters from 2015 to 2018. The method used in this observation uses Underwater Photo Transect (UPT), and the data obtained is analyzed using CPCe (Coral Point Count with Excel Extensions) software. The results show that the percentage of coral cover has increased from year to year. The percentage of live coral cover in 2015 was 19.64%, 23.60 in 2016, 23.72% in 2017, and 27.83% in 2018. The increase in live coral cover from year to year is thought to occur due to the availability of nutrients. or increasing public awareness, considering this location is one of the most famous tourist attractions in Makassar. Coral reef health index values can be used to classify coral reef health. Through the analysis of the coral reef health index, an index value of 4 was obtained, which means that the condition of the coral reefs is in the “moderate” category.

Large-scale mapping of live corals to guide reef conservation

Coral is the life-form that underpins the habitat of most tropical reef ecosystems, thereby supporting biological diversity throughout the marine realm. Coral reefs are undergoing rapid change from ocean warming and nearshore human activities, compromising a myriad of services provided to societies including coastal protection, fishing, and cultural practices. In the face of these challenges, large-scale operational mapping of live coral cover within and across reef ecosystems could provide more opportunities to address reef protection, resilience, and restoration at broad management- and policy-relevant scales. We developed an airborne mapping approach combining laser-guided imaging spectroscopy and deep learning models to quantify, at a large archipelago scale, the geographic distribution of live corals to 16-m water depth throughout the main Hawaiian islands. Airborne estimates of live coral cover were highly correlated with field-based estimates of live coral cover (R2 = 0.94). Our maps were used to assess the relative condition of reefs based on live coral, and to identify potential coral refugia in the face of human-driven stressors, including marine heat waves. Geospatial modeling revealed that water depth, wave power, and nearshore development accounted for the majority (>60%) of live coral cover variation, but other human-driven factors were also important. Mapped interisland and intraisland variation in live coral location improves our understanding of reef geography and its human impacts, thereby guiding environmental management for reef resiliency.

Penilaian Indeks Kesehatan Terumbu Karang di TWP Selat Bunga Laut, Kabupaten Kepulauan Mentawai

Coral reefs condition in the protected marine area at Selat Bunga has decreased every year. The health of coral reefs is represented by coral index health. The purpose of this study was to analyze the coral reefs health index based on the condition of live coral cover, resilience level and condition of coral fish. Retrieval of coral reefs data using the Under Photo Transect Method and coral fish data collection using the Under Water Visual Census. The results of research at 9 research stations found that the average cover of live coral ranged from 1.40 - 44.68%, fleshy seaweed ranged from 0.13% - 12.87%, rubble ranged from 1.73 - 39.40%, and average total reef fish biomass ranged from 8.93 - 253.23 kg/ha. Coral reef health index values range between 3-6. Coral reefs health index of 67% of research stations is 3. The coral health index value 3 is indicated by a low percent live coral cover, a high resilience rate, and a low reef fish biomass.Kondisi terumbu karang di Kawasan Konservasi Taman Wisata Perairan (TWP) Selat Bunga Laut telah mengalami penurunan setiap tahun. Indeks kesehatan karang adalah nilai yang mengambarkan kesehatan karang antar lokasi penelitian. Tujuan penelitian ini adalah menganalisis indeks kesehatan terumbu karang berdasarkan kondisi tutupan karang hidup, tingkat resiliensi dan kondisi ikan karang. Pengambilan data terumbu karang dengan metode Under Photo Transect dan pengambilan data ikan karang mengunakan Under Water Visual Census. Hasil penelitian di 9 stasiun penelitian didapatkan persen rata-rata tutupan karang hidup berkisar 1.40- 44.68 %, fleshy seaweed berkisar 0.13% - 12.87%, pecahan karang berkisar 1.73 –39.40 %, dan rata-rata total biomassa ikan karang berkisar 8.93 – 253.23 kg/ha. Nilai indeks kesehatan terumbu karang berkisar antara 3-6. Sebanyak 67% stasiun penelitian mempunyai indeks kesehatan terumbu karang dengan skala 3. Indeks kesehatan karang skala 3 ditunjukkan oleh persen tutupan karang hidup yang rendah, tingkat resiliensi yang tinggi dan biomassa ikan yang rendah.

Kualitas Habitat Rekruitmen Juvenil Karang Di Perairan Pulau Kemujan, Karimunjawa

Pulau Kemujan merupakan salah satu pulau terbesar di Kepulauan Karimunjawa yang memiliki kerapatan terumbu karang yang beragam. Ekosistem terumbu karang memiliki peranan penting namun juga merupakan ekosistem yang rentan akan terjadinya kerusakan. Akibat penurunan kondisi kualitas lingkungan dapat memungkinkan untuk memberikan pengaruh terhadap habitat rekruitmen juvenil. Tujuan penelitian ini adalah untuk mengetahui kelimpahan juvenil karang berdasarkan perbedaan kedalaman, kesesuaian faktor fisika, kimia dan biologi yang mempengaruhi proses penempelan juvenil karang, kondisi terumbu karang berdasarkan perbedaan kedalaman serta hubungan antara kelimpahan juvenil karang dengan tutupan karang dan bahan organik di perairan Pulau Kemujan. Metode yang digunakan pada penelitian ini yaitu metode analisis deskriptif, sedangkan metode yang digunakan untuk pengumpulan data yaitu Line Intercept Transect (LIT) sepanjang 50 meter. Hasil yang diperoleh dari penelitian ini yaitu kelimpahan juvenil karang tertinggi berada di daerah reef flat sisi barat perairan Pulau Kemujan sebanyak 47 koloni, sedangkan kelimpahan terendah berada di daerah reef slope sisi timur sebanyak 7 koloni. Parameter perairan fisika, kimia dan biologi pada penelitian masih berada pada batas kisaran nilai optimum. Kondisi tutupan karang hidup pada sisi barat perairan Pulau Kemujan berkisar dari 46,60% hingga 53,62% sedangkan pada sisi timur yaitu berkisar dari 44,10% hingga 71,38%. Kelimpahan juvenil karang dengan tutupan karang hidup, pecahan karang serta bahan organik menunjukkan pola hubungan yang berbanding terbalik sedangkan dengan tutupan karang mati berbanding lurus. Berdasarkan peneltian ini dapat diketahui bahwa juvenil karang memiliki kecenderungan ditemukan lebih banyak pada tutupan karang mati dalam kondisi lingkungan yang optimum. Kemujan Island is one of the largest islands in the Karimunjawa which has a varying density of coral reefs. The coral reef ecosystem has an important role however it is vulnerable to damage. The purpose of this study is to determine the decline of coral juvenile based on the depth difference, the compatibility of chemical, physical and biological factors that enhance the resilience of coral juvenile, and the correlation of coral juvenile with the coral covers and the organic material in the waters of Kemujan Island. The method used in this research is a descriptive analysis method. The method used in data collection is Line Intercept Transect (LIT) 50 meter . The results from this study obtained that the highest abundance of juvenile corals was in the reef flat area of the west side from the waters of the Kemujan Island as many as 47 colonies while the lowest abundance was in the reef slope area of the eastern side as many as 7 colonies. The physical, chemical, and biological water parameters in the study were still in the optimum range. The condition of live coral cover on the west side of Kemujan Island waters ranged from 46.60% to 53.62% while on the east side it ranged from 44.10% to 71.38%. The abundance of juveniles coral with live coral cover, coral fragments, and organic matter showed inversed pattern relationship whereas with dead coral cover was directly proportional. Based on this study it can be known that corals juvenile have a tendency to be found more at dead coral in optimum environmental conditions.