Spermonde Archipelago Research Articles

Sex ratio, maturity stage and fist maturity of yellowfin parrotfish Scares flavipectoralis Schultz, 1958 in Wallace line at Spermonde Archipelago, South Sulawesi

Yellowfin parrotfish Scarus flavipectoralis has a wide distribution in Indo-Pacific waters which has an important ecological role in maintaining the balance of coral reef ecosystems, as well as having important economic values that need to be managed sustainably. This study aims to analyze the sex ratio, gonad maturity stage, and the size at first maturity. This study was conducted on a population of yellowfin parrotfish in the Wallace line at Spermonde Archipelago, South Sulawesi. Fish samples were obtained from catches of fishermen who were landed at the Rajawali Fish Landing Area of Makassar City. The results of this study indicate that the sex ratio of yellowfin parrotfish not balanced between male and female, there was more female than male; the development of gonad maturity stage is synchronous between male and female; and the size at the first maturity sexual of yellowfin parrotfish female was 18 cm and the male was 21.7 cm.

Sex ratio and first maturity of blackeye thicklip wrasse Hemigymnus melapterus Bloch, 1791 in Spermonde Archipelago

Blackeye thicklip wrasse Hemigymnus melapterus is a Labridae that was widespread throughout the tropical and subtropical waters of Indo-Pacific. In eastern Indonesia, blackeye thicklip wrasse found from the Strait of Bali, Mentawai Islands, Raja Ampat Islands, Manado and surrounding areas, and Banggai; while in central Indonesia, blackeye thicklip wrasse found in the waters of the Spermonde Archipelago. This research aims to analyze the sex ratio, gonad maturity stage, and the size at first maturity of blackeye thicklip wrasse in the Spermonde Archipelago. This research was done on the population of blackeye thicklip wrasse in the Spermonde Archipelago, South Sulawesi, Indonesia. Samples were collected from fishermen caught landed in the Rajawali Makassar Fisheries Port at Makassar City. Blackeye thicklip wrasse sex ratio was not balanced. This imbalance was thought to have something to do with the “r” reproductive strategy where blackeye thicklip wrasse tries to produce as many eggs as possible to maintain its population. The success of this strategy probably supported by protogyny reproduction patterns where young fish can produce eggs as fast and as much as possible before being devoured by predators. Based on its gonad structure, blackeye thicklip wrasse could be classified as fish with a total spawning pattern that take place long spawning period or individual different spawning period throughout the year. The size at the first maturity of blackeye thicklip wrasse female was 21.4 cm; it was much smaller than half the size that has ever been caught.

Sex ratio and maturity of orange-dotted tuskfish Choerodon anchorago Bloch, 1791 in Wallace Line at Spermonde Archipelago

Orange-dotted tuskfish Choerodon anchorago was a Labridae family that could be found in coral reef and seagrass ecosystems. Orange-dotted tuskfish has a wide distribution in Indo-Pacific waters which has an important economic value that needs to be managed sustainably. This study aims to analyze the sex-ratio and maturity of orange-dotted tuskfish. The samples were collected from fishermen catches that were landed at the Rajawali Makassar Fishing Port at Makassar city. The orange-dotted tuskfish sex ratio was not balanced between males and female. Macroscopically, it was seen that orange-dotted tuskfish was a hermaphrodite. The synchronicity of maturity stages between male and female, both based on the sampling period, and the length class indicated that the process of reproduction, especially fertilization, was relatively safe. Female orange-dotted tuskfish that reach the first maturity earlier than male; suggest that orange-dotted tuskfish was most likely a protogyny.

Reef fishes abundance and assemblages in six islands (Kapoposang, Lanyukang, Lumu-Lumu, Badi, Ballang Lompo and Karanrang island) of spermonde archipelago during El Nino 2016, South Sulawesi, Indonesia

Overfishing in the Spermonde Archipelago has resulted in long-term changes in fishery composition and structure, as well as in resource utilization patterns. Later on, the patterns of resource use are highly variable, with new activities and new target species, e.g., ornamental corals and intensive coral reef fishery being a relatively recent phenomenon in the area. This research aims at measuring the coral fishes abundance and assemblages in six islands (Kapoposang, Lanyukang, Lumu-Lumu, Badi, Ballang Lompo, and Karanrang), representing off-shore and in-shore of Spermonde Archipelago waters during the occurrence of the 2016 El Nino. Underwater Visual Census (UVC) method was done to measure coral fish abundance, once every seasonal interval, totaling four times for every island, on 70 meter transects covering an area of 350 m2 (2.5 m to the right and left and 5 m above). Fish species found were identified by following several coral fish identification books Data was analyzed for their total species abundance based on the family. Results showed that coral fish abundance by the family was found to be lowest (less than 10.000 individuals/hectare) all through the year in Karanrang Island. The most abundance was found in Lanyukang Island (84.600 individu/hectare) during the month of September, followed by Badi Island (59.971 individu/hectare). In February, fish abundance of 35. 743 and 46.886 individu/hectare were only found in Kapoposang and Badi islands. All in all, on average, Badi island showed for having relatively equal coral fish abundance in all four seasons. One hundred species were found in Lanyukang, while 78 species were found in Lumu-Lumu, totaling 136 species of coral fishes of 28 families. Coral fishes species always found in all trips were 20 species in Lanyukang and 11 species in Lumu-Lumu. Four species always found in both islands were Thalassoma hardwicke, Neoglyphidodon nigroris, Labroides dimidiatus, Cirrhilabrus ryukyuensis. Fishes found most abundance were from Labridae and Pomacentridae families, each of 31 and 30 species. The temporary conclusion was that Lanyukang has more species than Lumu-Lumu.

Decline in seagrass carbon uptake on Bonebatang Island, Spermonde Archipelago, Indonesia during the period of 2001-2017

The activities of coastal and small islands communities can have an impact on the condition of the adjacent aquatic ecosystems. The magnitude of the impact depends on the type and intensity of the activities carried out. One ecosystem that is prone to be affected is the seagrass ecosystem due to its presence in shallow waters and proximity to the coast. The study was conducted to examine changes in seagrass carbon uptake on Bonebatang Island over a period of 16 years from 2001 to 2017. Estimation of carbon uptake of seven species of seagrasses, i.e., Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, Halodule uninervis. Halophila ovalis, Halophila minor, and Syringodium isoetifolium were carried out using the oxygen change method that utilized clear bottles. The percentage of seagrass coverage was calculated using a 50cm x 50cm plot. The average composition of seagrass species from all plots and the capability of each seagrass species to uptake carbon was used as a basis to estimate the capability of seagrass to uptake the carbon per unit area. Changes in carbon uptake were determined using an approach that estimates changes in the seagrass bed areas. Landsat image analysis was used to estimate the area of seagrass in 2001, 2009, and 2017. The results showed that the area of seagrass beds in the period of 2001-2017 decreased by 8.62 ha, from 37.08 ha in 2001 to 28.46 ha in 2017 or decreased by approximately 1.54% per year. As a result of this diminishing in the area, carbon uptake by seagrasses was estimated to decrease by 19.67 MgCO2 per year from 79.62 MgCO2 per year in 2001 to 59.95 MgCO2 per year in 2017. The average decrease in a year reached 1.23 MgCO2.

Mangrove and sand cay dynamics on Australian and Indonesian low wooded islands: A 45 year comparison of changes from remote sensing

Changes to coral reef landscapes are driven by regional processes that are unique to particular localities, yet much of our global knowledge about how landscape changes manifest in coral reef environments is generalised from work undertaken on the Great Barrier Reef. We compare observations of 45 years of change on sand cays and mangroves associated with low wooded islands in Australia and Indonesia. We draw on field observations from ground referencing campaigns, alongside remote sensing technology, including satellite images and unmanned aerial vehicle campaigns. Four low wooded island sites are compared: two in the Great Barrier Reef (GBR), Australia (Nymph Island and Two Isles) and two in the Spermonde Archipelago, Indonesia (Sabangko and Tanakeke Island). The Spermonde and GBR sites can be distinguished in relation to the process regimes that entrain, distribute and deposit sediments on the reef surface thereby providing a substrate for further mangrove colonisation, particularly the presence or absence of cyclones as a key determinant of sediment transport. The influence of human populations inhabiting these sites is also an important control on their geomorphology. In the Spermonde Archipelago, local communities have altered sand cays through the development of infrastructure and converted mangroves to shrimp farms, while sand cays and mangroves have remained largely unaltered by humans on the GBR. This comparative evaluation of changes to sand cays and mangrove forest across low wooded islands emphasises the importance of considering changes within the context of their local geographic setting, inclusive of natural environmental and anthropogenic drivers of change.

Late Holocene (0–6 ka) sea-level changes in the Makassar Strait, Indonesia

Abstract. The Spermonde Archipelago, off the coast of southwest Sulawesi, consists of more than 100 small islands and hundreds of shallow-water reef areas. Most of the islands are bordered by coral reefs that grew in the past in response to paleo relative sea-level changes. Remnants of these reefs are preserved today in the form of fossil microatolls. In this study, we report the elevation, age, and paleo relative sea-level estimates derived from fossil microatolls surveyed in five islands of the Spermonde Archipelago. We describe 24 new sea-level index points, and we compare our dataset with both previously published proxies and with relative sea-level predictions from a set of 54 glacial isostatic adjustment (GIA) models, using different assumptions on both ice melting histories and mantle structure and viscosity. We use our new data and models to discuss Late Holocene (0–6 ka) relative sea-level changes in our study area and their implications in terms of modern relative sea-level estimates in the broader South and Southeast Asia region.

Assessment of coral reef ecosystem status in the Pangkajene and Kepulauan Regency, Spermonde Archipelago, Indonesia, using the rapid appraisal for fisheries and the analytic hierarchy process

Coral reefs in the world’s tropical and subtropical oceans have long been under considerable threat. The aims of this study were to identify the types of threat affecting coral reefs, to conduct a sensitivity analysis to assess the sustainability of coral reef ecosystems, and to suggest alternative strategies that should be deployed to improve the status of coral reef ecosystems in the Pangkajene and Kepulauan (PANGKEP) Regency, Spermonde Archipelago, Indonesia. The data obtained were analyzed using the rapid appraisal technique for fisheries (RAPFISH) and the analytic hierarchy process (AHP). The RAPFISH analysis identified 41 types of threat to the status of coral reef ecosystems, based on five indices: economic (51.92), social (47.33), technological (47.26), legal and institutional (45.60), and ecological (37.65). The averaged cumulative index of coral reef ecosystem sustainability was 45.95, within a threshold denoting a “less sustainable” status. The AHP analysis suggested that several alternative strategies are needed to improve the status of coral reef ecosystems, with greater prioritization of socialization, campaigns, and education, followed by law enforcement, selectivity in the use of fishing gear, rehabilitation of coral reef ecosystems, and restocking of fish in coral reefs. The findings of this study can be used as points of reference when local policymakers begin to formulate appropriate strategies for the sustainable use of coral reef ecosystems.

The relationship between blue swimming crab (Portunus pelagicus) abundance and environmental parameters in Spermonde Archipelago

Management and conservation of the blue swimming crabs by the marine protected area method require the abundance and environmental parameter information of the blue swimming crab. The aim of this study is to analyze the changes in the relative abundance of the blue swimming crab and its environmental parameters. The study was conducted from March to July 2015, in the waters of Salemo Island, Spermonde Archipelago. The specimens were collected at the three fishing locations around the mangrove, seagrass, and coral reef ecosystems. The variable of relative abundance of the blue swimming crab is determined catch per effort. Samples of environmental parameters such as temperature and current speed are measured in situ. However, for the salinity, dissolved oxygen, ammonia, nitrate, plankton, and chlorophyll-a were analyzed in the laboratory. A comparison of the blue swimming crab abundance in each ecosystem was conducted by One Way ANOVA. Moreover, the relationship between blue swimming crab abundance with environmental parameters was analyzed by multiple regression. The results show that the blue swimming crab is abundant in the seagrass and coral reefs. The environmental parameter that significantly influences the abundance of the blue swimming crab is salinity. The suitable area for blue swimming carb protection based on abundances are seagrass and coral reef ecosystems.

Genetic patterns of the corals Euphyllia glabrescens and Lobophyllia corymbosa across the Indonesian Archipelago

Abstract. Jompa J, Umar W, Yusuf S, Tassakka ACM, Limmon GV, Rahmi, Putri AP, Halwi, Tamti H, Moore AM. 2020. Genetic patterns of the corals Euphyllia glabrescens and Lobophyllia corymbosa across the Indonesian Archipelago. Biodiversitas 21: xxxx. Scleractinian corals can reproduce in several ways, with two main sexual reproduction modes known as brooding and broadcast spawning. In this study, we described patterns of genetic variation within and connectivity between coral populations in western Indonesia (Seribu Archipelago), central Indonesia (Spermonde Archipelago), and eastern Indonesia (Ambon). We sampled two readily identifiable corals popular in the marine aquarium trade, one species widely reported as a brooder (Euphyllia glabrescens), the other as a broadcast spawner (Lobophyllia corymbosa). The mitochondrial COI genome was amplified for 117 samples. Within-population genetic variation was high, especially at the eastern Indonesia (Ambon) site. The genetic connectivity patterns were similar for the two corals, with high connectivity between the Seribu and Spermonde Archipelagos (despite a geographical separation of more than 1,000 km) and a lack of connectivity between these two sites and Ambon. These results indicate a potential barrier to gene flow between coral populations in western/central Indonesia and those to the east of Sulawesi Island.

Evaluation of the Quality of Coastal Ecosystems in the Spermonde Archipelago Using Macroalgae as Indicators

The quality of water in Spermonde Archipelago, South Sulawesi has decreased as a result of high human activities and land use, this can have an impact on the life of marine biota. Macroalgae is suitable for bioindicators because they live in a sessile manner, can accumulate metals and distributed widely. This research aimed to determine coastal ecosystem quality by using macroalgae as indicators on five islands that had different anthropogenic stresses. The research was carried out in April 2019 on Barrang Caddi, Bonebatang, Barrang Lompo, Kodingareng Keke, and Badi Islands. Community structures observed included taxa richness, diversity, evenness, dominance of macroalgae and physicochemical parameters (temperature, turbidity, pH, salinity, DO, BOD, H 2 S, oil, grease, total Phosphate, and nitrate) as well as the measurement of the ecological condition using Quality of Rocky Bottoms (CFR) index. The results showed that physicochemical parameters (temperature, turbidity, pH, salinity, DO, H 2 S, oil, grease, total Phosphate) of the water still met the quality standards of sea water based on Decree of the State Minister for Environment No. 51/2004 for marine biota and other standards for macroalgae growth. BOD and nitrate have exceeded sea water quality standards for marine biota (20 mg/L for BOD and 0.008 mg/L for nitrates). A total of nine species of macroalgae were found in Barrang Caddi and Badi Island, three species in Bonebatang, and five species in Kodingareng Keke and Barrang Lompo Island. The result of Principal Component Analysis (PCA) and Biplot showed that physicochemical water quality has an influence on the macroalgae community structure. While the CFR index shows Barrang Caddi and Badi Island have poor ecological conditions and Bonebatang, Barrang Lompo, and Kodingareng Keke have bad ecological condition.

Hunting in the seas: population status and community perspectives on giant clams (Tridacnidae) and Napoleon wrasse (Cheilinus undulatus), endangered marine taxa of the Wallacea Region, Indonesia

Giant clams (Tridacnidae) and the Napoleon wrasse (Cheilinus undulatus) are valued fisheries commodities for local consumption and trade. Heavy exploitation has greatly reduced their abundance in the Wallacea Region. This study on giant calm and Napoleon wrasse around Sulawesi is based on data from biophysical (SCUBA diving) and socioeconomic surveys from 2004 to 2016 in the Spermonde Archipelago and around Selayar Island, South Sulawesi; and in Central Sulawesi (primarily in the Togean Islands) between 2001 and 2015. Giant clam population abundance declined, with some larger species (Tridacna gigas, T. derasa, T. squamosa, Hippopus porcellanus) no longer found at many sites. Despite increasing awareness regarding the protected status of giant clams, exploitation has continued, including mass collection for traditional festivals in the South Sulawesi islands. Specifically intended for export, fishing uses destructive methods, Napoleon wrasse abundance also declined. Habitat (coral reef) degradation likely also had a negative impact. Low densities could threaten reproductive success. Effective protection measures are needed to rebuild depleted giant calm and Napoleon wrasse populations. This is done to promote the natural process of reproduction and recruitment, and degraded habitat should be rehabilitated through passive or active coral reef restoration. Ex-situ (hatchery) breeding and restocking could speed the recovery of depleted giant clam populations.

Heavy metals Cd and Cr found in sponges (porifera) at spermonde archipelago Zone II

Samalona and Barrang Lompo Islands are located in zone II of Spermonde Archipelago with the nearest distance is about 5 km from Makassar city beach. The close distance causes heavy metals as pollutants produced from activities in Makassar city and it surroundings to be carried out to zone II of Spermonde Archipelago waters. Marine biotas used as a bioindicator of heavy metals (Cd and Cr) pollution were sponges (Porifera). Analysis results by ICP-OES indicated that the largest quantities of the heavy metals (Cd and Cr) were found in sponge Xestospongia, i.e 1.250 mg/kg and 5.400 mg/kg dry weight, respectively.

Water Quality Evaluation of Some Beach With Variations of Human Activities and Land Use in Spermonde Archipelago of Makassar South Sulawesi

Spermonde Archipelago, Makassar South Sulawesi consists of hundreds of small islands with varied land uses and human activities. This will have an impact on decreasing the quality of coastal waters. The purpose of this study was to analyze the relationship between land use and human activities with water quality on the coast around the island. The study was carried out on five islands in the Makassar Spermonde Archipelago of South Sulawesi (Barrangcaddi, Badi, Baranglompo, Bonebatang and Kodingarengkeke Island). Water quality was measured included pH, DO, salinity, turbidity, BOD, nitrate, TP, H2S, oil and grease, and Pb. The coastal water quality observation of each island was carried out in 1-3 stations depending on the size of the island. Repetition of water quality measurements for each station 3 times. Observation of land use and human activities in the study area using the environmental services indices (Hemeroby and Naturalness). The results showed pH (7.99-8.39), turbidity (0.6-1.3 NTU), total phosphate (<0.010 mg/L), H2S (<0.01 mg/L), oil and fat (<0.1 mg/L), and Pb (<0.005 mg/L) still met quality standards of sea water based on Decree of the State Minister for Environment No. 51/2004 for marine biota. DO Levels of Baranglompo and Badi islands (6.1-7.7 mg / L) have met seawater quality standards for marine biota which require DO levels to be more than 5 mg/L. DO levels of water on the other coast of the island 4.6-4.9 mg / L. Water salinity in all water have range 29-30%o. BOD levels (25.4-29.8 mg / L) and nitrate (0.03-0.17 mg / L) have exceeded sea water quality standards for marine biota (20 mg / L for BOD and 0.008 mg / L for nitrates). Baranglompo Island with the highest land use and human activities (Hemeroby 5 and Naturalness 3) has had an impact on water quality degradation reflected in the high turbidity and BOD levels. Bonebatang and Badi islands which have the lowest human activity and land use (Index of Hemeroby 3 and Naturalness 5) have better water quality with low to moderate BOD and turbidity. In order to improve water quality on the coast, human activities on five islands need to be controlled.

Recent Analysis of Carbon, Nitrogen, and Lignin Phenol Compositions in the Suspended Particulate Matters at Spermonde Archipelago, South Sulawesi, Indonesia

This study analyzed the composition of monomer lignin phenols and its derivatives at the Spermonde Archipelago, South Sulawesi-Indonesia. Water samples were collected in the dry season (June 2017) and the rainy season (January 2018) from the river estuaries of Tallo-Makassar, and Pangkep. Analysis of carbon and nitrogen contents was conducted by EA-IRMS (elemental analyzer-isotope ratio mass spectrometry), while lignin phenol was analyzed by Chromatography Gas-Mass Spectroscopy (GC-MS). Spatially, the six lignin phenols () content in the Tallo river estuary into several outermost islands is higher than of the Pangkep river mouth.  values in the rainy season were higher (0.92-2.30) than in the dry season (0.62-2.07). In the dry season, the range of values for ratios of syringyl/vanillyl and cinnamyl/vanillyl was 0.35 to 1.12 and 0.39 to 0.57 indicating a low contribution of angiosperm plant tissue. In the rainy season, the values of ratios for syringyl/vanillyl and cinnamyl/vanillyl ranged from 0.37 to 1.18 and 0.32 to 0.62. The syringyl/vanillyl ratio indicates the contribution of plant tissue to angiosperms. The cinnamyl/vanillyl value is greater than 0.1, indicating a significant contribution of non-woody plant tissue. Spatially, the range of syringyl/vanillyl and cinnamyl/vanillyl ratios at the estuary of the Tallo river (0.37 to 1.12 and 0.32 to 0.57) were higher than at the Pangkep river estuary (0.35 to 1.18 and 0.39 to 0.62).

Preliminary study: human trampling effects on seagrass density

This preliminary study performed a small-scale experimental evaluation of the effects of trampling on tropical seagrass meadows. The study site was Barrang Lompo Island, in the Spermonde Archipelago, South Sulawesi, Indonesia. The experimental design comprised two trampling treatments (trampling by an adult and by children) and a control plot (no trampling). The trampling was carried out daily over a three week period. After trampling (adult or children), the detached seagrass leaf biomass was higher than uprooted seagrass biomass. Trampling by an adult had a greater effect on seagrass density than trampling by children. Three weeks after trampling ceased, both treatment plots exhibited substantial recovery, with final density closer to control density in the plot trampled by children.

Studies on microplastic contamination in seagrass beds at Spermonde Archipelago of Makassar Strait, Indonesia

There is growing awareness and concern on microplastics pollution in marine environments. Seagrasses are among the most productive shallow water ecosystems, serving a diverse assemblage of fish and invertebrates. Sediment and benthic animal samples collected from small islands at Spermonde archipelago confirmed the presence of microplastics with different levels of contamination. The occurrence of microplastics for up to 28.29% and 25% of contamination level in sediments and benthic animals, respectively, clearly indicated an alarming state of the microplastics pollution in rich and productive shallow water seagrass ecosystem of tropical seas. Moreover, all positively contaminated microplastics of benthic animals are for human consumption and therefore pose threats for microplastics transfers which may facilitate pathways for a wide spectrum of organic pollutants entering the food web and affecting human health.

Holocene sea levels in Southeast Asia, Maldives, India and Sri Lanka: The SEAMIS database

We assembled a database of Holocene relative sea-level index points (n = 213) and marine (n = 211) and terrestrial (n = 122) limiting points for the broader South and Southeast Asian region including the Maldives, India and Sri Lanka. The standardized review of published age-elevation information from corals, deltaic, estuarine and mangrove deposits, beachrocks and tidal notches, yielded a new suite of relative sea-level index and limiting points produced according to a standardized protocol. Expected spatial variability in Holocene relative sea-level change due to glacial isostatic adjustment was accounted for, by first subdividing the study area into ten geographic sub-regions from the Central Indian Ocean to the Western Tropical Pacific, and second by comparing sub-regional relative sea-level data to model predictions of glacial isostatic adjustment. Results show that some of the regionally constrained relative sea-level data are characterized by significant inconsistencies that cannot be explained by glacial isostatic adjustment. Such inconsistencies of standardized relative sea-level data become particularly obvious in areas around the Red River Delta in Vietnam, the Gulf of Thailand, the northwest coast of Malaysia and the Spermonde Archipelago in Indonesia. Based on a critical evaluation of the reviewed relative sea-level indicators, we discuss possible sources of local divergence and identify regions where data are currently insufficient to constrain glacial isostatic adjustment predictions. The remaining quality-controlled and consistent relative sea-level data show that glacial isostatic adjustment and syn-/post-formational influences such as tectonic uplift, subsidence and compaction were the dominant local drivers of Holocene relative sea-level change. Collectively, the results of this review suggest that Holocene sea levels in South and Southeast Asia and surrounding regions have been controlled by a variety of global and local drivers and imply that additional index points from the Java Sea in Indonesia would be valuable to better assess the spatial variability, and to calibrate geophysical models of glacial isostatic adjustment.

Remote Sensing Analysis of Seagrass Beds in Bontosua Island, Spermonde Archipelago

Research on mapping and monitoring of seagrass ecosystems using satellite imagery data is still lacking. The availability of spatial information on benthic habitat is becoming very important with the increasing awareness of environmentally based management. Various methods of analysing remote sensing information on benthic habitat have been developed and utilized, such as the application of the Lyzenga algorithm. This algorithm requires data on the variation of water depth in the coastal areas to be mapped. The purpose of this research was to study the effect of using Lyzenga algorithm on the mapping of coral reef / seagrass ecosystem by comparing the results of seabed classification from Sentinel-2a imagery processed and without using the Lyzenga algorithm. Image classification with Lyzenga algorithm is easily recognizable with the Lyzenga index value format that has been freed from the effect of water depth. In this study, benthic cover in the shallow waters around Bontosua Island, Spermonde Archipelago-Indonesia, was classified using six habitat types: aquatic, land, sand, rubble, coral and seagrass. Seagrass habitat was further classified based on percentage cover as class 4 (76-100%), class 3 (51-75%), class 2 (26-50%) and class 1 (0-25%). Based on the analysis of Sentinel-2a data, the area with seagrass cover was estimated at 31.27 Ha. Seagrass mapping using medium-resolution satellite imagery can be helpful in providing data over a more extensive area than is likely to be possible using direct observation in the field alone.

Social Networks and the Live Reef Food Fish Trade: Examining Sustainability

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