Table of contents

Indonesia is a maritime country that has a very large marine area and has been assured of sustaining high biodiversity, is expected to achieve the 14^th Sustainable Development Goal (SDGs) goal (Life Below Waters). The SDGs aim to sustainably manage and protect marine and coastal ecosystems from pollution, as well as the address of the impacts of ocean acidification. Enhancing the conservation and the sustainable use of ocean-based resources through international law will also help mitigate some of the challenges facing our oceans.

All papers published in this volume of IOP Conference Series: Earth and Environmental Science have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

Morotai Island Regency is located in the adjacent of three National Fisheries Management Area of Indonesian Republic (WPPNRI 715, WPPNRI 716, WPPNRI 717). Geographically Morotai Island's waters lie in two Indonesian hydro-oceanography phenomenon, namely Throughflow and Eddy Halmahera which affect the abundance of marine resources. This study aims to determine the utilization status of Yellowfin Tuna (Thunnus albacares) in Morotai Island regency including: catch per unit effort (CPUE), maximum sustainable yield (MSY), total allowed catch (TAC) and Utilization rate. Within a period of ten years (2009-2018) Yellowfin productivity was fluctuating with a CPUE of 4.1 kg/trip. Fox surplus production model calculation showed that MSY of yellowfin resource was amounted of 8,657,679 kg/year with a maximum effort value of 42,429 trips/year. The number of TAC value was amounted of 6,926,143 with a utilization level of 12.23%. Yellowfin utilization level was amounted of less than 33.3% which is relatively low. This shows that Yellowfin Tuna stock in Morotai Island regency has not been optimally utilized.

Coastal upwelling event can be observed clearly from drastic changes of seawater temperature and chlorophyll-a before and during the event. From observation and model output, time-series data of these variables provide important datasets to be used for further analysis, such as developing gaussian empirical model of net marine primary productivity (NPP). Here, the objectives of this study are to analysis variation of temperature and chlorophyll-a (chl-a) from both observation and model output datasets, and to evaluate model temperature and chl-a for estimating the NPP prior to and during the upwelling event in Bali Strait. The archive CTD collected in April, June and August 2013 and model output datasets were used in this study. It is shown that during peak of upwelling event in August 2013, observed temperature is minimum and chl-a is maximum in the upper 50 m depth. It is found surfacing isotherm of 25-26°C from sub-surface to sea surface. Furthermore, model output of temperature was in good agreement with observed data, complementing the evolution of upwelling for entire year. Estimated NPP from empirical model suggested that a high NPP distribution occurred in the eastern part of Bali Strait during peak of upwelling event.

Eastern pathway of the Indonesia Throughflow (ITF) conveys a secondary ITF inflow that brings North/South Pacific water entering interior Indonesian Seas. The transformation occurred along the Pacific water mass journey towards the Indonesian sea. For the first time since 2016, CTD Argo float measurement is available following the ITF path – along Maluku-Seram- Banda Seas, providing prime datasets to be able seen change of ITF water. This paper aims to investigate transformation of ITF water masses and the percentage of water mass contribution (with Optimum MultiParameter method) along its eastern path of ITF between Maluku – Seram and Banda Seas. The result shows that along the path, North Pacific water origin is predominant in Southern Banda Sea, but lower thermocline water of South Pacific water origin in South Maluku and Seram Sea. Large transformation of ITF water is indicated with salty upper-thermocline water in Maluku-Seram Seas, but fresh thermocline water in Banda Sea. Spatial variation of mixing layer depth and thermocline depth is also found. The percentage of the water mass contribution of the North Pacific water NPSW and NPIW gets bigger along the journey to the Banda Sea, while the dominant of SPSLTW was found in Maluku Sea and Seram Sea.

This study aims to investigate a depth-latitude spatial and temporal variability of ITF front at 115°E, using 15-years (2004–2018) of monthly gridded CTD Argo float dataset in the Indo–Australia Basin. The Empirical Orthogonal Function method was performed to analysis these time-series data. It is shown that mean meridional extent of ITF front is established between 14°S and 10°S. The ITF front can be described by the first five modes of potential temperature and salinity EOF's, which accounted for 88.6% and 80.7% of the total variance, respectively. The first EOF mode (67.9%) of depth-latitude temperature reveals spatial pattern which is out-of-phase between near-surface layer (<100 m) and thermocline layer, for example, during the northwest monsoon period, warmer and saltier water in the upper-layer and colder and fresher thermocline water are frequently observed, which differ to those observed during the southeast monsoon period. EOF principal components of temperature and salinity exhibit strong annual variation, followed by intraseasonal and interannual scales. On inter-annual scales, fluctuation of temperature and salinity is well correlated with ENSO and IODM, as previously expected.

Tambelan Islands is one of the coral reef habitats in Indonesia. This area is the southern part of Natuna Sea and South China Sea Throughflow (SCSTF) exit area, which influenced the dynamics of the ocean and climate in Indonesia. Foraminifera is one of the potential bioindicator that can be used to determine the conditions of waters and the environmental health of coral reef. Twenty surface sediment samples were taken and quantitative analysis were made in order to obtain the condition of waters. This analysis including calculation of abundance, community structure, and analysis of biozonation (cluster and SHEBI). Meanwhile, to determine the condition of coral reef was using FORAM Index (FI). The results showed that there were 52 species of benthic foraminifera included in 41 genera. The most abundant genera were Amphistegina (average 28.08%) and Operculina (average 23.85%) which were a type of genera that associated with coral reefs. The FI values range from 3.57–9.12 indicating that environmental conditions are conducive to coral reefs. Biozonation from the cluster and SHEBI showed different results, indicating that the abundance of foraminifera in research area are influenced by complex factors such as substrate conditions and the activities on land.

The small island coast is an area that is vulnerable to environmental problems. Debris problems occur in some areas of Tunda Island with low human activity, due to current and wind factors that can distribute the debris. The speed and direction of wind and currents in Indonesia are influenced by the seasons, so the seasons have an influence on the accumulation of debris in a place. This study aims to determine the effect of the season on the distribution of debris and potential sources that influence the presence of debris on the coast of Tunda Island, Banten. This study uses MIKE 21 software to determine current and wind patterns and movement of macro debris particles. Based on season research, it influences the pattern of macro debris distribution in this area. In the east season, the increase in the litter is 9 kg from the weight of the debris in the west season. Also, there is an increase in debris in several categories including the most likely to find items, fishing gear, packaging material, small pieces trash, and base wood materials. The potential source that affects the presence of debris on the coast of Tunda Island, Banten is Muara Ciujung.

Bidadari Island is one of the tourism area, located in the southern part of Kepulauan Seribu. Tourism activities and its location that directly facing Jakarta Bay, obviously will affect the quality of the waters and ecosystems in Bidadari Island. A study of benthic foraminifera was carried out in 10 surface sediments and water quality samples, collected from the Bidadari Island, in order to determine the connection between abudance of foraminifera with the environmental conditions. Quantitative analysis, including calculation of abundance, community structure, and biplot analysis conducted to obtain this information. The results showed that there were 2473 individuals benthic foraminifera with a total of 33 species from 23 genera. The most abundant genera were Amphistegina, Calcarina, and Operculina. Based on the calculation of the community structure (diversity, evenness, and dominance index), benthic foraminifera on Bidadari island are in the low to moderate category, it indicating that the environmental condition in this area has begun to declined.

The Senindara River area, which is part of Bintuni Bay, was influenced by the dynamics of the seawater and widely used to support community and industries activities. Alluvium land conditions and partially cliff were potential to abrasion. The research location was Senindara River with focused in Maga River area. This study aims was to obtain potential abrasion hazard of the study area. Numerical modelling was used to analysed the data. Tidal observations were carried out for 15 days with peilschaal and processed using Admiralty method. Current measurements were conducted for 26 hours using the Eulerian method. Modeling using MIKE21 FM Model with momentum, temperature, and density equations. Spatial discretion of the equation was done using the cell-centered finite volume method. Model calibration was done by comparing the output of the model (current and water level) with the observation results. The study shows the value of the basic shear stress of the average model value was greater than the value of the basic shear stress critical model erosion 0.1 N/m2. This shows that at the observation location has a high risk abrasion, especially in the industrial supporting area. Therefore, prevention of abrasion hazards was indispensable.

Pathogenic bacteria, especially Mycobacterium, to be one of the causes of disease in society. Sponge bacterial symbionts are one of the potential sources for producing new antibacterial compounds. This study was carried out for investigating the antimycobacterial compounds derived from the Callyspongia aerizusa's bacterial symbiont. Antimycobacterial compound isolation was done by growing selected bacteria SP.PP.3 in marine broth then continued for active compound separation. The separation of an active compound was carried out using High Performance Liquid Chromatography (HPLC), whereas the antibacterial activity was tested using agar diffusion method against Mycobacterium smegmatis. The compounds were identified by spectroscopy method (LC-MS). An antimycobacterial compound was detected in the HPLC fraction with code FH8. LC-MS and ¹HNMR analysis predicted that there was a bromophycolide compound that contained active fractions. 16S rRNA molecular identification indicated that the strain SP.PP.3 was closely related to Erythrobacter sp. with 99% homology similarity.

At low tide condition, the Semak Daun Lagoon (SDL) barrier reef is drowned during high tide and appeared to the surface during low tide. How are hydrodynamics in low tide and tidal conditions? This study aims to examine the pattern and current velocity in the SDL under four tidal conditions. The two-dimension model is built based on two motion generations namely wind pressure and tides. The discretization of the equation uses the finite volume method. Domain discretization is divided into 14,575 triangular elements with a grid area of 1,000 m². The results of the model, verified with observational data in the field, show the similarity of tidal patterns and current velocity as indicated by the MAPE value of 7.9%, meaning that the model is well constructed. Current patterns generally move from southwest to northeast at high tide to low tide condition and vice versa at low tide to high tide condition. At low tide, there is a buildup of water mass in the lagoon because the only channel north is functioning as an outlet. This causes a slowing of current flow inside the lagoon and acceleration in the northern canal. Current velocity ranges from 0.02-0.51 m.s⁻¹. The pattern and speed of the current in the lagoon are dominantly influenced by tidal dynamics. Residual current velocity varies in the range of 0.01-0.04 m.s⁻¹.

To select a rehabilitation area of coral reefs in Pahat Island within Anambas Islands, this study was conducted to asses coral reefs condition using diver-towed or manta tow surveys and underwater photo transects (UPT). The results of the manta tow surveys showed coral cover dominated by hard corals percentage ranged between 11% and 50% (categories 2 and 3) in the western, northern and southern parts of Pahat Island. Distribution of hard coral percentage with more than 50% (Category 4: 51% - 75% and 5: 76% -100%) was observed in the eastern part of Pahat Island. While results from UPT showed the hard coral percentage of 62.5%, 33.67% and 17% in the eastern, western and northern of Pahat Island, respectively. There are similarities in the results of coral reef cover Obtained by the manta tow and UPT methods. Conclusions, this study recommends western Pahat Island as a good alternative for a rehabilitation site as the coral coverage was in poor condition.

In this study, we used Markov chain approach to analyze rainfall dataset from one buoy (4N90E) in the eastern Equatorial Indian Ocean. This study aims to determine the opportunity for transition (displacement) of daily rainfall intensity, where there are six states or conditions of rainfall intensity, i.e. no rain, very weak, weak rain, moderate rain, heavy rain, and very heavy rain. The Markov Chain method used is the Chapman-Kolmogorov equation and the steady state equation. The investigation of the 6-states in Markov chain model show that dynamic probability of transition state for rainfall data is reflexive properties majority. By using the model, it is concluded that the transition rate matrix of the largest transition probability in the area of 4N90E occurs at the transition from state-1 to state-1 as much is 0.72 and state-2 to state-2 is 0.60. The transition probability value becomes 0.5184 and 0.36 for the same state dominant of two periods P². The use of the 1st order Markov chain is better than 2nd order.

Ulee Lheue serve as ferry ports in Banda Aceh, covering an area of ±8 ha. The information on water flow entering the port channel is needed to determine the quantity of water and facilitating transportation at the port. This study includes the measurement of water depth, channel width, current velocity, water discharge, and tides which was conducted every 3 hours at three different water depth. On Jumada I (Jumadil awal) 1-29, 1435 Hijra, the highest and lowest water depth of 6.06 and 3.82 meters occurred in the 23rd and 10th day at 09:00 and 16:00 local time, respectively. The highest and lowest velocity of 0.357 and 0.01 m/s occurred in the 15th and 18th day at 09:00 and 12:00 local time, respectively. The strongest and weakest discharges of 177.93 m³/s and 9.47 m³/s occurred in the 12th and 28th day at 09:00 local time, respectively. The results found a strong correlation between water discharge and current velocity. Thus water discharge and currents play an important role in the channel stability and in controlling sea transportation in terms of scheduling the departures and arrival of ships.

The present status of marine radioecology condition at the coastal of Kalimantan was determined based on monitoring of the radionuclides concentration in marine compartment of West, South and East Kalimantan. The characteristicof Pacific Ocean contribute to the distribution of radionuclide in Kalimantan from the Indonesian Through Flow (ITF) that passes through the Makassar Strait. The aim of this research is to determine the concentration of radionuclides and regional oceanographic effects on the distribution of radionuclides in the coasts of Kalimantan. Gamma radionuclides activity concentration were measured using High Purity Spetrometer Gamma Detector (HPGe) that is integrated with Genie 2000 software analysis. Modelling processes and field observation from previous study become reflelction of Kalimantan regional sea characteristic. The result of this research shows that the baseline data that represented natural and antrophogenic radionuclides are comparable with other regions in Indonesia. The concentration of natural radionuclides in the sediments showed that there are no contamination of Naturally Occurring Radioactive Material (NORM) and ¹³⁷Cs.

The Banda Sea region is one of the locations in Indonesian waters that have high Coastal Upwelling intensity which related to the monsoon pattern. The calculation of Upwelling Index (UI) based on Wind data show that the peak coastal upwelling is from June to September. Analysis of SST trends was carried out in the July-September period based on NOAA OISST data from 1982-2017. The results show that there are differences in the value of SST trends that occur in the Coastal and Oceanic regions. In general, the SST trend in the Banda Sea waters has a positive value (warming) in both the coastal and ocean areas. While the UI trend in coastal and oceanic regions in the Banda Sea tends to decline from the 1982-2017 period. This condition shows that external factors quite influence oceanographic conditions in Banda Sea waters. It is also thought to have caused a decrease in the intensity of the upwelling trend found in the Banda Sea. The results show that the SST trend in the Banda Sea tends to increase during the peak upwelling season (June-September). Meanwhile, the Upwelling intensity trend shows a decreasing pattern which is also confirmed by decreasing trend in chlorophyll concentration.

During Marine Science Summer Course 2017, a continuous 24-h conductivity-temperature-depth (CTD) "yoyo" measurement has been carried out at the entrance of Padangbai Lombok Strait to investigate seawater properties variations on semidiurnal tidal-scale which is dominant in the strait. The SBE CTD 19 plus is equipped with optional sensors such as pH, turbidity and chlorophyll-a derived-fluoro. During 24-h field observation, 15 CTD casts from sea surface to about 60 m depth have been acquired. It is shown that observed seawater properties fluctuate strongly four times a day, following semidiurnal-tide period with two flood-tide and two ebb-tide conditions. During flood-tide, water mass is derived from open strait with colder, saltier, denser and low dissolved oxygen characteristics. In contrast, during ebb-tide, local water mass is recirculated back from the inner bay to the open strait. It is interesting to note that fluctuation of chlorophyll-a indicates a diurnal signal. In addition, fluctuation of pH, turbidity and dissolved oxygen showed a weak semidiurnal signal.

Indonesian shortfin eel, Anguilla bicolor (McClelland, 1844) is one of fish that have swim bladder to assist swim and doing migration. Every fish has different shape, gas volume, dimension, and length ratio of swim bladder, which can play role in the difference in backscattering of acoustic energy. This study aims to determine the shape, dimensions and ratio of Anguilla bicolor's swim bladder and their effect on target strength (TS) values. The research was conducted in two places, in the Acoustic lab, Department of Marine Science and Technology, Bogor University and Laboratory of Histology and Embryology, Faculty of Biology, Universitas Gadjah Mada. Retrieving data using the EK-15, Frequency 200 KHz tool and also the X-ray photo. The results show the shape of the swim bladder of Anguilla bicolor is elongated and consists of 1 room which is generally called a closed swim bladder. Acoustic detection results show that fish with large swim bladder volumes have large TS values and conversely fish with small swim bladder volumes have a small TS value.

Macroalgae is one of the marine biological resources that have the potential to be utilized further by humans. This research aims to study macroalgae diversity in Pari Island. The study was conducted at two stations using the line transect method at the reef flat area. The results of this study indicate that there are 3 class macroalgae found in Pari Island. 17 species of macroalgae found in the south of Pari Island and 10 species found at the North of Pari Island. Macroalgae species with high abundance are Padina minor and Halimeda opuntia. The highest macroalgae diversity was found at south Pari Island with a diversity value index 2.02.

The Sunda Shelf Throughflow (SSTF) is defined as a seasonal reversal shallow current system flowing from the South China Sea to the Indonesian Throughflow (ITF) region via the Natuna and Java Seas. This current system plays an important role on transferring heat and freshwater fluxes into the ITF system and vice versa. This paper aims to investigate seasonal changes of transport volume in three sections within the Sunda Shelf region (namely Natuna, Karimata and Java section). We used the validated daily ocean circulation model outputs from INDESO configuration between 2008 and 2014. It is shown that mean transport volume of the SSTF is relatively small on the order of -0.5Sv toward the ITF region (1Sv=10⁶m³/s) due to a strong seasonal reversal flow of the SSTF forced by the monsoonal winds. However, on seasonal scale this transport volume strengthens drastically to about 2-3Sv (1-2 Sv) during the northwest (southeast) monsoon period, which is in good agreement with previous studies. Transport estimate in Java section is reduced to about -0.1Sv may be due to a leakage of the flow via Sunda Strait and also a strong recirculation of Makassar ITF into Java Sea.

Sangiang Island had been established as a Nature Recreation Park (TWA) in Indonesia, that requires comprehensive data support for good management. The rise of marine tourism that increased in TWA Sangiang Island behoove to be a concern, especially in coral reef ecosystem. The study aimed to determined the condition of the coral cover and the biomass composition of coral reef fishes, then to identify parameters that affect coral health and the coral reefs health index in TWA Sangiang Island. The observation was carried out in area near to the estuary (Legon Waru), entry point for shipping (Tembuyung), and diving tourism (Legon Bajo). The highest of biomass of target fish was Legon Bajo (0.013 kg / ha) and the lowest was Tembuyung (0.002 kg / ha). Coral reefs health index values in each station varied from 1 (low) to 4 (high). Coral reefs health index in Legon Waru was strongly influenced by live coral cover, and also in Legon Bajo was influenced by live coral cover, rubble and biomass of target fishes, while in Tembuyung was much influenced by fleshy seaweed cover. The results indicated that the coral reef ecosystem on Sangiang Island wasn't in good condition as a whole.

Over the past several years, a number of algal bloom incidents has been increasingly observed in Jakarta Bay. The increasing frequency of algal bloom incidents, and subsequent environmental impacts are a rising threat to the coastal resources, economy and public health. Eutrophication, tidal and climatic are the three processes that suspected to have a potential role with algal bloom incidences in this bay. To understand the role of these three processes, a monitoring program had been conducted from 2008 until 2015. The study reveals that algal bloom occurrences have a strong relationship with major nutrients ratio. Besides that, the bloom incident occurred particularly after the rainy season to dry season. The tides have a potential role in the spread of bloom formation and stratification. During the study the concentration of phosphate in these waters ranging from 0.01-2.5 μg/L and nitrate 0.01-15.89 μg/L. The ratio of major nutrient (N/P ratio) in this waters ranging from 0.2 - 45.4. The N/P ratio tends to be higher in 2010, where the abundance of phytoplankton raising conspicuously. The N/P ratio may controlling the occurrences of algal bloom, while tidal responsible in bloom distribution, and climatic particularly precipitation, effecting nutrients availability.

Necessity electricity in the society especially in industrial activities every year there is an increase in demand. The technology that used in production electricity is one of the Steam Power Plant (PLTU), where Paiton Power Plant is one of the largest power plant in Indonesia and can distribute electricity to Java and Bali. The purpose of this research is to know the process of hot water waste distribution from PLTU Paiton either horizontally or vertically with observation method and numerical model. Tidal model validation with observation data has a high correlation value (r = +0,908). Validation model of hot water waste distribution on surface with observation result has RMSE value equal to (e = 0,96). The observation results show the temperature of the hot water waste in front of the outlet is recorded between 30 °C to 40 °C. Vertically, the distribution of hot water waste near the outlet reaches a depth of 5 m and horizontally the thickness becomes thinner at a distance of about 500 m from the outlet mouth. The model result shows that the distribution of hot water waste distribution occurs more broadly when the low tide.

Phosphate is one indicator of water fertility and is needed to support the life of organisms, especially phytoplankton. The main source of phosphate in the waters naturally originates from the processes of decomposition, weathering or decomposition of plants and comes from the remains of dead organisms. Besides this phosphates in coastal areas are sourced from rivers that carry waste from land, so phosphates in the river mouth are larger than the surrounding waters. The purpose of this study was to describe the pattern of phosphate distribution in the West and East seasons in the Tallo estuary, Makassar using hydrodynamic and distribution models of pollutants. The results of this study indicate the pattern of spreading phosphate in the study site is strongly influenced by oceanographic conditions of the waters.

The Balikpapan Bay waters is influenced by freshwater discharge from many rivers and its distribution is affected by tidal current. This study aims to estimate seawater intrusion during flood and ebb tides, using the box model and freshwater fraction methods. The data used in this study for calculating freshwater fraction and its transport volume were 45 conductivity- temperature-depth CTD casts and single moored ADCP current measurement, carried out between 17 and 25 May 2018. The budget of the box model system is calculated using evaporation and precipitation data. The results show that estimated freshwater fraction and transport volume during flood tide vary between 16.92 and 36.26%, and between 2.048 and 9.661x10⁹ m³day⁻¹, respectively. Near the entrance of the bay, seawater flux urges freshwater westward with surface salinity budget of -95.352x10⁶ psu.m³day⁻¹. Furthermore, during ebb tide, freshwater fraction and transport volume are estimated to be 19.33 – 34.5% and 2.048–9.661x10⁹ m³day⁻¹, respectively. Near the mouth of estuary, freshwater pushes seawater toward east side of the bay with salinity budget of -186.187x10⁶ psu.m³day⁻¹. During flood tide (ebb tide) estimated surface salinity budget in transect 5 that came out from the system is about -135.512x10⁶ psu.m³day⁻¹ (-143.794x10⁶ psu.m³day⁻¹) toward the southern bay.

Upwelling Index which is processed from satellite imagery of wind stress and Sea Surface Temperature (SST) were examined to describe upwelling and its dynamics along the southern coast of Java. Analysis in September as the peak of upwelling shows that the commonly use of Ekman Transport-based Upwelling Index mostly shows higher values on the western part of south coast of Java as the alongshore wind stress is stronger to the west. But on the contrary, the SST-based Upwelling Index shows a relatively intense and persistent upwelling on the eastern part of south coast of Java and strengthened in El Nino year of 2015. The intense upwelling is indicated by the lowest value of SST minimum and the maximum value of thermal gradient SST up to 75 km off shore. Thus, for upwelling areas that are not predominantly induced by offshore Ekman Transport, the dynamics of upwelling would be better seen through an SST-based upwelling index. The use of both upwelling indices, will complement each other so that upwelling and its dynamics can be precisely understood.

The Northern Lembata Waters (NLW) is located in the Flores Sea that its dynamics is strongly affected by Monsoon Current and the Indonesian Throughflow (ITF). This study aims to describe the physical characteristics of the waters and geostrophic current, using observation CTD data from OTEC Cruise 2017. The type of water mass is identified using T-S diagram, and geostrophic currents is determined using a reference level at 600 dbar. From its characteristics such as temperature, salinity, and density it can be deduced that the waters vertically stratified. It is revealed a strong geostrophic flow due to water density differences. In the upper layer (0–300 dbar) geostrophic velocity ranged from 12.59 to 343.93 cm s⁻¹ flowing eastward and in the deeper layer (300–600 dbar) geostrophic velocity (in section B) ranged from 7.66 to 49.19 cm s⁻¹ flowing westward. The eastward flow is considered to be part of the ITF, and the westward flow at deeper layer may be associated with density-driven flow between Banda and Flores Seas.

Coral reef has been facing rapid destruction nowadays. Raja Ampat Islands in Papua has one of the highest coral reef diversities and is located within the Coral Triangle area. The coral condition in Raja Ampat is still categorized as healthy. However, it started to show some of the habitat degrading signs. Coral disease is one of the main causes in coral reef ecosystem decline. This study aims to measure the level of coral disease based on coral disease category prevalence observation at Mansuar Island in Raja Ampat, Papua. The method used in data sampling is by using 5 x 50 m Belt Transect. The results show that as many as 28 coral genera were found from all of the observation sites with Fungia being the most abundant. There are 7 coral health categories, dominated by Tissue Discoloration Non-White. There are 5 coral diseases found namely Yellow Band Disease, White Syndrome, Brown Band Disease, Atramentous Necrosis, and Ulcerative White Spots.

Sufficient availability of good food quality is important for fish aquaculture in order to increase fish production. Microalga is one of alternative protein sources, and one among those is Chorella sp. Protein content of Chlorella sp. is very high, around 51- 58 % and consists of various kinds of essential fatty acids, which is important for fish nutrition. Recently, Algae also prospective source of ethanol biofuel. Ethanol extraction usually produce waste material, which still consist of high protein content, which valuable for fish feed sources. Therefore, the study aimed to examine the effects of fish food derived from algae biofuel-waste on growth and histological structure of wader pari (Rasbora lateristriata) intestine. Fish were divided into 5 groups of control negative (no additional protein), feed with waste algae, waste + Fresh algae, fresh algae and commercial fish food, respectively. The fish morphometry, weight, and intestine histological structure were examine. The results showed that fish feed treatment gave effect on fish growth and instestine histological structure. Algae waste feed showed similar performance to commercial fish feed on fish growth and showed no negatif effect on intestine villi length and goblet cells number, evidenced good prospect of algae waste as fish feed.

Mangrove area as nursery grounds for the fish larvae in Semarang and Demak. Fish larvae were collected during August - February representing dry and rainy seasons from three mangrove station swamps by a beach seine net. The net was dragged on the bottom for 100 m three times. A total of 291 fish larvae were collected, representing 5 families. The most abundant species formed about 76 % of all collected fishes. Two fish larvae family were collected for the first time from mangrove areas in the Timbulsloko. Most of the collected fishes are economically important fishes. Moreover five families were belonging to demersal fishes. The highest species richness value was recorded in Timbulsloko mangroves at night in the river. This Finding showed that mangroves could support the life history of many demersal and pelagic fish.

The seagrass ecosystem is rich in organic materials such as nitrates, carbon, and phosphates. Potential nutrient content available in water and sediments influences the presence of an associative bacterial community. This study aimed to explore associative bacteria in seagrass ecosystems which have potentially producing antibacterial activity and cellulase enzymes. Associative bacterial isolation was carried out on sediment samples and seagrass leaves Thalassia hemprichii which was found as the dominant ecosystem compiler. The antibacterial test was carried out using agar diffusion method against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, and Vibrio parahaemolyticus. Meanwhile, assay on cellulase activity of the actinomycetes bacteria was using agar diffusion method on CMC media. Isolation of endophytic bacteria of seagrass leaves produced 12 isolates with 2 isolates which could inhibit all targeting bacteria and 3 isolates which could inhibit several targeting bacteria. ANOVA test showed that the sampling location significantly affected the antibacterial activity. Meanwhile, 5 isolates of actinomycetes bacteria were found from the sediments, with 4 isolates having cellulase activity. ANOVA test showed that cellulase activity of the actinobacteria was associated with the density of Cymodocea rotundata and T. hemprichii seagrass species with moderate to high category.

Real marine seismic data are typically embedded with free-surface multiples energy, which are troublesome in imaging an accurate seismic cross-section. In addition, more challenging situation is to bring optimum result with a short-offset streamer due to the coherent nature of multiples. In this study, we present a comparison of three methods for attenuating free-surface multiples energy in short-offset 2D seismic data from Cendrawasih Bay. Multiple attenuation methods include F-K filter, Radon transform, and Surface Related Multiple Elimination (SRME) are processed until the final Pre-Stack Time Migration (PSTM) results. Predictive deconvolution is applied in order to suppress short period multiples prior to free-surface multiple attenuation method. Predictive deconvolution successfully identifies and removes the predictable wavelet of short period multiples. Radon transform shows poor result in short-offset seismic data even if it is combined with F-K filter method. Combination of both F-K filter and SRME are successfully attenuate free-surface multiples and should be considered as proper solution to increase signal to noise ratio.

The primary objective of seismic data processing is to generate seismic cross-section with an optimum signal to noise ratio to model geological structures imaging as accurately as possible with the actual condition. However, we may look onto complex geological structures with less than adequate number of fold coverage seismic data. In this study, Common Reflection Surface (CRS) method is applied to generate 2D marine seismic cross-sections with better reflector continuity of 3 (three) real data seismic lines. It is based on obtaining the suitable aperture value along the attributes namely RN, RNIP, and a. Its results are compared to conventional Common Mid-Point (CMP) ones. The final products are presented in multiple- attenuated and time-migrated cross-section with Surface Related Multiple Elimination (SRME) and Kirchhoff Migration techniques, respectively. Comparison of final time-migrated both CRS and CMP stacks show the CRS method is more effective and reliable to model accurate complex marine geological structures with high signal to noise ratio based on reflector continuity and noise reduction.

Seismic method is a good geophysical method in imaging the subsurface conditions using the principle of seismic wave propagation. This method is often used in hydrocarbon exploration. One important step in hydrocarbon exploration is seismic interpretation. In the stages of seismic interpretation, a good basic knowledge of geophysical and geological knowledge is needed regarding the existence and characterization of hydrocarbon reservoirs. One method used in interpreting seismic data is the acoustic impedance inversion method. In this study, 2D seismic inversion was carried out to determine the reservoir characteristics of the MCL-1 well in the Nias basin. This study uses model-based on inversion which aims to obtain the value of acoustic impedance which is useful for the identification of distribution, porosity values and reservoir conditions of the target zone. The results obtained are the target reservoir zone at a depth of 6649-7434 feet or 1705-1810ms for MCL-1 wells with a range of acoustic impedance values of 25556 ((ft/s) * (g/cc)) - 46885 ((ft/s) * (g/cc)) with the type of rock that fills the reservoir is the type of limestone rock. The correlation value for model-based inversion has a relatively small error. This can characterize the hydrocarbon reservoir well.

The method used to determine the condition of marine biological resources is still conventional, not systematic and not comprehensive. So far, the methods used include divers where the depth of observation is very limited. Another method using sonar for which the acquisition of data is still qualitative. For this reason, it is necessary to strive for new methods that can guarantee careful and accurate observation. This study proposes the detection, classification and quantification of underwater target algorithms using Intelligent Biomass Active Sonar Transducer (IBAST) using a microcontroller unit. IBAST uses acoustic pulses and features that are narrow spectral so as to provide the ability to detect underwater targets (underwater targets) accurately and be able to classify such targets as fish, zooplankton, marine mammals, coral reefs, and other targets. IBAST uses a tracking algorithm and output detector which reduces errors in target detection. The application of the algorithm will be carried out to test the classification method and quantification of underwater targets. This research is very useful in the aspects of quantification of marine life, protection of fishery resources and seabed habitat.

Suspended sediment concentration (SSC) is important to measure for knowing photosynthesis activity and as indicator of marine pollution. Now days, measurement method to study about SSC were used conventional and optical techniques. These methods had a limitation in providing temporal data of SSC. Acoustic Doppler Current Profilers (ADCP) originally designed for measuring ocean current and its velocity profiles. In fact, ADCP is not only limited to measure the ocean current velocity and direction, but include measuring acoustic backscattering intensity which is related to the concentration of suspended sediment. Based on sonar equations, we computed and analysed the relationship between the backscattering intensity and suspended sediment concentration. In study area of Jakarta Bay, the highest SSC was 70 mgL⁻¹ and the lowest SSC was 30 mgL⁻¹. Compared to the traditional method, ADCP method has many advantages in providing spatial and temporal data.

Procambarus clarkii is one of the freshwater lobsters which has its own characteristics. Those characteristics used to identify Procambarus clarkii in nature. One of those characteristics is the sound which can be determined using the bioacoustic method. This research uses the bioacoustics method to obtain the sound characteristics from Procambarus clarkii considering this species is invasive in Indonesia. Sound characteristic of this species are obtained by processing sound data into FFT value. The results of processing sound data from recording for three days show that Procambarus clarkii produces snap sound with an average frequency range from 0.3-0.4 kHz.

Information on fish resources and its distribution in the waters around Alor Island, East Nusa Tenggara is still relatively unknown. For that matter, the objective of this study is to determine the distribution of fish density horizontally (latitude or longitude) or vertically (depth) in the waters at the eastern region of Alor Island, using acoustic scientific echosounder SIMRAD EK500 instrument. This instrument is equipped with split beam echosounder transducer system with operating frequency of 38 kHz and 120 kHz. The acoustic survey was conducted in the waters off the north, east and south coast of eastern part of the Alor Island. The result of the survey showed that fish density detected in the surface water dominated by 0,1-100 individual/m³ fish density, in 60-80 meters depth was dominated by 0,1-10 individual/m³, and in 80-200 meters depth was dominated by 0,1-100 individual/m³ of fish density. In addition, the 38 kHz detect higher density of fish compare to 120 kHz.

Autonomous Underwater Vehicle (AUV) is a type of underwater robot that can move and perform pre-assigned the missions based on a program which is installed in the microprocessor in the body of the vehicle. AUV uses thrusters to maneuver underwater and may be supported by a compass, various sensors, and a camera that are attached to the vehicle. In this paper, we present the development of N3-AUV and a pool test of this performance. N3-AUV uses 8 thrusters, 2 webcam cameras, Raspberry Pi, a depth sensor, and a compass. The vehicle has a torpedo-like shape so that it is easier to move underwater relatively faster. With 2 webcam cameras, where the first one is placed under the frame to record images of the conditions beneath the vehicle and the second one is placed in front of the frame to record the conditions in front of the vehicle. A pool test was conducted by means of pre-assigning missions, such as navigating pass the goal post, and finding and knocking down an underwater object. N3-AUV can complete three mission of four. Missions that have been carried out successfully are navigation, acquisition, and localization. N3-AUV has a maximum speed of about 1 m/s.

Geostrophic current variability in the Indo-Australian Basin (IAB) of eastern Indian Ocean is analyzed by using monthly gridded salinity and temperature data sets (between 2004 and 2016), from CTD ARGO Float. Geostrophic current is derived from dynamic height calculation. We applied time-series EOF analysis by decomposing geostrophic zonal component into dominant variability in several major modes. The variability of geostrophic currents from CTD Argo data analysis had differences, both spatial and temporal variability. There were four major modes, accounting for of 50.47% of the sum explained variance. The anomaly that occurred near the southern coast of Java cannot be detected due to the limited spatial coverage of the ARGO Float distribution. The spatial pattern in the first mode was indicated by positive anomaly at 110°E-114°E and 7°S-13°S. Furthermore, negative anomaly showed in the southern part of the study area. Variability oscillated with annual, semi-annual and inter-annual periodicity. In the second mode, there was a negative anomaly at 10°S-16°S, the rest of area were shown as the positive anomaly. Variability oscillated with semi-annual, annual and interannual periodicity. In the third and fourth mode, they showed variability with the semiannual, annual and inter-annual periodicity.

Remote sensing technology can provide spatial information for mapping shallow water benthic habitat, a case study conducted on Sebaru Besar Island. The purpose of this study was to analyze mapping accuracy of shallow water benthic habitats usings WorldView 2 and SPOT 6 (201 imageries). The classification of multispectral images is carried out using the Depth Invariant Index (DII) transformation and by applying the Maximum Likelihood (MLH) algorithm to both satellite images. The number of benthic habitat classes produced are eight habitat classes from each image used. The results of the analysis show that the overall accuracy in Worldview 2 and SPOT 6 images is 61.29% and 51.61%. Results of Z-statistic comparison between Worldview-2 and SPOT-6 imagery was 1,04, means that the results did not differ significantly.

Spatio-temporal analysis of yellow fin tuna fishing activity could give us new perception and perspective on studying this fisheries resource exploration. This study was carried out in Eastern Indian Ocean off Sumatera. Fishing data were collected between 2014 until 2018 from the hand line fishermen's daily logbooks accessed from Bungus fishing port. Data were organized into a database and structured on a geographical reference to allow GIS-Based analysis. We performed raster calculator analysis and spatial statistical analysis to understand spatiotemporal distribution behaviour and fishing activity also employed the generalized additive model to understand the habitat preferences. The result of GIS-based analysis shows the dynamics of catch, effort and catch per unit effort distribution patterns, underlining the annual differences of geographical distribution and fishing pattern. The most concentrated fishing activity monitored in 2014 while the more dispersed fishing activity monitored in 2017. The geographic orientation of spatial distribution monitored at range between 72.90 degrees until 176.15 degrees. GIS provide an important and powerful tool to analyse fishing information to help decision makers in the EIO off Sumatera on Tuna management.

Waveform re-tracking analyses have been proven to increase the accuracy of sea surface height (SSH) estimation from satellite altimeters specifically in coastal areas. However, each re-tracking algorithm has its strengths and weaknesses so that no dominant algorithm can be applied to any water condition. The study purpose was to obtain the best SSH estimation from altimeter satellite data using waveform re-tracking analyses with fuzzy logic system. The fuzzy logic system was used to select the best SSH values from the results of waveform re-tracking analyses. The data used in this study were level-2 SGRD data from Jason-2 and Jason-3 in Natuna Waters in 2016-2018. Waveform re-tracking with fuzzy logic system can reduce standard deviation of SSH up to 23.3 cm from the on-board (oceanic) algorithm standard deviation. The highest Improvement Percentage (IMP) value from each observation track was constantly generated by re-tracking with fuzzy logic system up to 70.3%. The result of this study showed that this analysis can produce SSH values with the best accuracy in each track observation.

The Eastern Indian Ocean off Southern Java is one of the bigeye tuna fishing hotspots and has a fishing potential of 27%. Analyses of bigeye tuna fishing areas focus on the South Java-Bali waters at coordinates of 105°-120 ° E and 5 ° - 20 ° S. Oceanographic parameters affect the habitat of Bigeye tuna. Sub surface temperature is an important and major factor in fishing layers. Time series of sub surface temperature data from 2005-2017 was used as an input for the analysis of the fuzzy inference system method. This method has been widely used in fisheries areas but has not yet been applied to fishing ground predictions. The use of vertical temperature data variation such as 100 m, 150 m, 200 m, 250 m, and 300 m are expected to be able to map the most optimal fishing potential area for bigeye tuna fishing ground. The model output is verified using actual coordinate data to obtain a relationship between the model results and coordinate catch point. The result show that at 200 m is the best fishing layer of bigeye tuna.

Object-based image analysis (OBIA) method has been proven to improve the accuracy value on benthic habitat mapping. The purpose of this study was to assess the accuracy of several classification algorithms on benthic habitat mapping based on OBIA method with and without input feature of Hue Saturation Intensity (HSI) in the Pajenekang island waters, South Sulawesi, Indonesia. Sentinel-2A satellite imagery with 10 m² spatial resolution acquired on 3 September 2018 was used in this study. During OBIA analyses, we segmented the object into 5, 10, and 15 classes and treated each of them with input features of mean+ratio vs mean+ratio+hue saturation intensity (HSI). We later classified the benthic habitat by applying several classification algorithms such as the Bayes, K-Nearest Neighbour (KNN), Support Vector Machine (SVM), and Decision Tree (DT). The results showed that the Bayes algorithm produced highest accuracy of 78.35% within 10 segmentation classes and input features of mean+ratio+HSI followed by the KNN of 71.13% with 5 segmentation classes and input features of mean+ration+HSI. The addition of HSI input features into OBIA analyses increased the accuracy of benthic habitat classification mapping of 4.13% with the Bayes classification algorithm.

Swarm Intelligence (SI) is an artificial intelligence algorithm related with collective work of individuals intelligence. To date, SI has been developed and installed on autonomous surface vehicle (ASV). ASV use global positioning system (GPS) in determining position, relative orientation to other ASV, and ability to move to desire direction. Aim of this research is to designing ASV and then apply SI algorithm on three ASV to moving simultaneously with preprogrammed formation. These three ASV were divided into two parts, master ASV as a master (order giver) and slave ASV as ASV that follow master ASV. SI algorithm developed using python as its programming language. The formation developed in this research is line and triangle formations. The ASV has 68 x 35 x 20 cm dimension and 0.7 m/s maximum speed. Autonomous system test show that ASV can follow waypoint with 2.3 m and 2.4 m average error at X axis and Y axis and the three-ASV can communicate each other to make formation.

Reef fishes is an important part in maintaining the balance of various components in the coral reef ecosystem. The existence of reef fish on coral reef ecosystems is a marker of the ecosystem in good condition. Furthermore, it is important to observe the condition of reef fish in a coral reef ecosystem to determine the population and diversity of reef fish in the ecosystem. Observation of reef fish generally by performing a manual visual census by scuba diver. In entering the industrial revolution 4.0 era there is a need to develop technology that is used to monitor the condition of reef fish in a coral reef ecosystem. The development of technology will certainly help researchers, and later on ecosystem manager, in observing the condition of reef fish with automatic identification. The technological development that can be done to observe reef fish is by applying deep learning. In this research we used YOLO deep learning algorithm for automatic identification. YOLO has the advantage of faster object detection. Application of deep learning to identify fish automatically is illustrated using underwater video recording of reef fish.

Indonesian seas have not been used as a source of electricity yet. One of the potential and abundant sources of energy from the sea is ocean waves. This study describes the measurement of the wave characteristics and calculates its spatial and temporal energy in Pari Island which can be utilized as electrical energy using overtopping ocean wave power plants scheme. The energy that can be harvested from ocean waves is calculated by wave energy converter using the Wave Dragon WEC. This converter is the terminator type. Sea waves on the Pari Island are classified as the smooth sea with 0.16-0.51 meters significant wave height and 2–4 seconds period. The calculated WEC can produce energy up to 28 Mega Joules and power up to 6 Mega Watts. Based on this calculation, Wave Dragon which is an overtopping WEC is able to meet the electricity needs on Pari Island with two options, The first one is using 35 units of WD 1 on the Pari Island Coast with a 500 m distance from the settlement, or the second one is using 6 units of WD 2 which is located in the northeast region of Pari Island waters with 18 Km distance from the settlement of Pari Island.

Cyprinu scarpio, Oreochromis niloticus, Pangasius, Anguilla sp, Ospronemus goramy and Serrasalmus sp are the types of fresh fish consumed widely by Indonesian society. Each type of fish has different acoustic backscatter strength influenced by meat, swim bladder and fish behavior at the time of data collection. This acoustic backscatter value has a decibel unit (dB). The purpose of this research is to get the value of single fish acoustic backscatter from those species. Data was recorded using single beam equipment frequency 200 kHz (cruzpro and Simrad EK-15 echosounder equipment). The results show the TS value of the six fish varies between -53 dB to -41dB. The TS relationship with length has a correlation coefficient value (R) greater than 0.5, which means that fish length has contribution more than 50%. Data was observed in a July 2015 trial using the same equipment and software. It was found that fish with the same length, which is 19 cm of different species (C. carpio, Pangasius and O. niloticus) but had different weights, turned out to have the different TS values. It is assumed that the characteristics of each fish body are different.

Squid nets technology (Bouke Ami) are the most used fishing gear by fishermen in the Nusantara Fishing Port (PPN) Kejawanan. This research was conducted in April 2019. The purpose of this study was to analyse the level of friendliness of the bouke ami fishing gear based on the Responsible Fisheries Ethics Code (CCRF). The research method used survey and indepth interviews with related parties related to the results of research and the level of friendliness of environmental equipment. Data analysis was carried out in accordance with 9 criteria for environmentally friendly fishing gear from the Food and Agriculture Organization (FAO). The results of the study showed that 27 species of bouke ami were captured with a total catch of 1,939 tons. The composition of the main catch is greater, which is equal to 82.69% compared to 17.31% bycatch. The value in the bouke ami environment is 27. Based on this value, the bouke ami is classified as a fishing gear which is categorized as an environmentally friendly fishing gear.

In intensive shrimp cultivation system, residual waste that settled at the bottom of the pond is impacting water quality. Therefore, there is a need to regularly clean this residual to maintain the water quality in good condition. In this paper we describe the automatic instrument system to clean up the bottom of the pond. This waste cleaning instrument uses the principle of equilibrium between the main component in the form of a pyramid and supporting components, namely the water container. The pyramid has a dimension of 2x2x1.3m and 4 poles that serve as rails and support for pulleys that hang both components. The framework of the pyramid is made of pipes and then the frame is coated with HDPE sheets and solar flat. The pyramid will go up and down in accordance with the water container, if it is filled with water and empty automatically because it is installed two submersible pumps to drain and fill the water container. From the field test results it was found that this instrument works effectively, where in one cleaning, it can be done in less than 5 minutes compared to conventional cleaning which takes hours.

We analyzed the distribution of Purse seine fishing vessels using fishing lamps derived from the Day/Night Band Visible Infrared Imaging Radiometer Suite (DNB-VIIRS) sensor and Vessels Monitoring System (VMS) platform in the Java Sea. The data of fishing vessel distribution derived the DNB-VIIRS sensor and VMS platform was provided by NOAA Center for Environment Information and Global Fishing Watch respectively. The intensity of lights during the fishing operation was measured by a lux meter. The fishing vessel types that used light during fishing operations were small (< 15 units lamps) and large vessels (>15-unit lamps). The intensity of light in the big vessels (> 2,000 Lux) was higher than the small vessels (< 2,000 Lux). The average number of fishing vessels operating during the Southeast monsoon were more than those of the Northwest monsoon. The distribution of fishing vessels derived from the DNB-VIIRS sensor has a similar pattern with the VMS platform. Generally, the fishing vessels are concentrated along the southern coast of Borneo but in the Northwest monsoon shift towards the northwest of Java approaching the island of Sumatra.

Pandeglang District becomes a concern because one of the locations had an impact on the Tsunami on December 22, 2018. Its position in the western waters and directly facing the Anak Krakatau Volcano is very potentially vulnerable. The Tsunami triggered by the volcanic activity of Anak Krakatau Volcano, mountain avalanche material. Evaluation regarding coastal land affected is also needed to anticipate future disasters. The study of the coastal areas affected by extraordinary events, such as the Tsunami, was carried out by stakeholders in evaluating coastal land to be more responsive to disasters. Three sub-districts with different morphology selected as samples of the affected areas, Labuan, Sumur, and Panimbang. We used highresolution Sentinel 2.0 images and Elevation Model Data (SRTM DEM) with unsupervised classification method to perform analysis of the area affected by Tsunami condition on coastal features. The results showed that the area affected especially the low land, as open land area at Labuan Sub-district was 189,298 Ha, Sumur Sub-district, 144,837 Ha, and Panimbang Sub-district was 282.852 Ha. Varied inundation range 50 - 200 meters from the coastline. The elevation of the three sub-districts shows vulnerable areas with an elevation of <2.5 m to 0.5 m above sea level.

Coral reefs interference by multiple threats from local and global source. The aggregate effects of local stressors such as tourism activity, pollution, overfishing, and coral harvesting can decrease resilience of the reefs. Furthermore, increased ocean temperatures, changing ocean chemistry, and sea level rise are the greatest global threats to coral reef ecosystems. The objective of this work is to assess coral reefs ecosystem degradation at Nusa Penida (NP), Bali. In this works, monitoring of coral reef ecosystem was conduct by transect photographs on May and October 2018. We observed the evidence of coral reefs degradation in the site, particularly on the northern and southern reefs area. We also found that algal cover much higher than our previous monitoring activities, linked to higher coral mortality at these locations.

Batbitim marine conservation area (MCA) of Misool, Raja Ampat has been set as an area that is prohibited for fishing activities since 2005. The only activities allowed in that area are tourism and research activities. The difference in the management status between area inside the Batbitim MCA and outside the MCA might affect ecosystem components such as fish and coral reef in the respective area. The present study aims to investigate the ecological status of target fishes in the two areas. Data were collected by using an underwater visual census at 5 sites, in which at each site 3 transects were placed. Collected data are then used to assess ecological indices for the target fishes. It is found that there were 38 species of target fish belonging to 13 families. The diversity index of Shannon was found to be in the range between 0.99 (inside MCA) to 1.67 (outside MCA) and dominance index ranged between 0.26 (outside MCA) and 0.61(inside MCA). The abundance of individual target fish in each location varies between 960 ind ha⁻¹ (outside MCA) and 9413 ind.ha⁻¹ (inside MCA). Those results indicate that there is a discrepancy between the ecological status of the target fish at locations inside and outside the MCA.

Shrimp is one of the agricultural commodities which has high economic value with global and increasing market value abroad. Thus, Shrimp production continues to increase. Shrimp production in Indramayu Regency in 2017 was 191,919.41 tons. This makes Indramayu Regency the largest producer of shrimp in West Java (BPS, 2017). Meanwhile, Mangrove is an area that has a high contribution. Mangrove ecosystems have an association with pond productivity. This study aims to analyze the productivity value of shrimp in Indramayu Regency and its effect on the mangrove ecosystem in Indramayu Regency in that particular area. The method that is used to change identify mangrove forests is Landsat 8 image then continued with composite band 564 and NDVI (Normalized Difference Vegetationation Index) with a distance of 1 Km, 2 Km, and 3 Km from the mangroves. Furthermore, the result of the interviews is used to find out the value of shrimp productivity. Analysis of data is calculated through regression methods to see the–relation proximity between shrimp productivity and mangroves. The regression result between the distance of mangroves and productivity yields with the value of R Square equals 71.7%. This result indicates a positive link between shrimp productivity and mangrove ecosystem.

Investigation has been carried out using a sponge Niphates sp. as biodegradation agent of the aliphatic hydrocarbon component of crude oil sludge. The experiment was carried out by colonizing and making suspension of Bacillus pumilus strains GLB197 and Bacillus cohnii strains of DSM 6307, isolated from sponge Niphates sp. Both types of micro symbiont suspension were mixed with sludge waste for 30 days. There are five biodegradation parameters observed, carried out every five days of incubation. Parameters that observed during incubation were pH, gas bubbles and fermentation odor. Meanwhile, the optical density of the media was measured using spectrometer-D20+, Aliphatic components degradation was measured using GC-MS. Observation of biodegradation parameters showed there was a change in pH from 7 to 6, formed gas bubbles, resulting in fermentation odors and showed an increased optical density by an average of 35%. These four parameters occur during the interaction of 10-20 days of interaction in the media. There were 20 types of aliphatic components identified in the crude oil sludge waste. Analysis of four aliphatic components, namely Tridecane, Octadecane, Tricosane, and Nonacosane showed a decrease in the average concentration of 48.11 %.

Mangrove forests damage may decrease their function and ecological role in relation to litter production which support the sustenance of aquatic resources. This research aimed to determine and estimate productivity and decomposition rate of mangrove Rhizophora mucronata and Avicennia alba litter, and their effect on water nutrients. The research was conducted at three stations in Pantai Mekar Village, Muara Gembong District for 60 days observation during period of April–September 2018. Litter productivity was measured using litter traps and litter decomposition rate was estimated using litter bags. The concentration of water nutrient (nitrate, ammonium and phosphate) was obtained through a laboratory analysis. Litter productivity of R. mucronata and A. alba stands reached 4.68 and 7.11 g m⁻² day⁻¹ respectively with the biggest contributed from leaves litter. Observed different rates of mangrove decomposition was due to the lignin content. The decomposition rate of R. mucronata and A. alba were Y=12.841e^−0.382X (R²=0.97) and Y=11.958e^−0.478X (R²=0.91) respectively. The productivity and decomposition rate of A. alba litter was greater and faster than R. mucronata. Increased nitrates was indicated of nitrification process, while phosphate and ammonium showed decreased concentration during experiments. Aside from that, water nutrient concentration was affected by dissolved oxygen availability.

Study about water mass transport within Balikpapan Bay (BB) is crucial since many watersheds discharge from this bay which directly flows into Makassar Strait. To understand transport of water mass within BB, INDESO data was made monthly in 2015. The annual volume, heat, salt and freshwater transport are estimated to be 18.02 mSv, 2.14 PW, 0.64 x 109 kgs-1, and 1.05 mSv, respectively. Compared to the annual mean volume transport of Makassar Strait (6.4 Sv), the annual transport of water mass from BB is likely contribute less amount of volume and heat transport with the weighted-transport temperature at 30.37 °C. They are somewhat smaller than the difference between each season. This difference may be attributed by the external force, i.e. current circulation and tidal wave, as well as the precipitation along BB.

This study was conducted to observe the dynamic of shoreline changes in Sangsit Region, Bali Province using multi-temporal remote sensing datasets. The remote sensing data were acquired from several Landsat images in the period of 2000-2019 (20 years) with 30-meter spatial resolution. Digital Shoreline Analysis System (DSAS) method was used to analyse data images to determine the shoreline changes. Prior to the analysis, the images were corrected by ground check data. It revealed that the shoreline changes has occur in Sangsit Region for period of 20 years (2000-2019). The results obtained indicate that there is a change in shoreline with mild accretion to less extreme abrasion categories which occurred in the Sangsit Region in that period. From 2000-2005 it shows an accretion of 221.03 m which is categorized as mild accretion and from 2005-2019 the shoreline changes that occur is only an abrasion its categorized as mild to less extreme abrasion. The highest abrasion occurred in the period of 2010-2015 which the abrasion is around 49.65 m.

This study was conducted to analyze the changes in mangrove area and the density level of mangrove based on satellite imagery and field surveys in Untung Jawa Island. The image data used was Landsat image data acquired in 2000, 2005, 2010, 2015 and 2019. Apart from those, sentinel-2 data received in April 2019 were also retrieved to be compared with field data to see the density level and its accuracy. Image analysis to determine the area and density of mangroves was the Normalized Difference Vegetation Index (NDVI) model. Measurement of mangrove vegetation in the field was obtained by the line plot transect method. The results of temporal image data analysis showed the changes in mangrove area from 2000 (8.46 ha), 2005 (7.56 ha), 2010 (8.45 ha), 2015 (10.65 ha) and 2019 (6.89 ha). In 2019 the mangrove density was dense, while the result of the field survey was categorized as very dense. The level of accuracy for density using remote sensing data is 92.5%. Through the results of the field survey, the mangrove diversity was relatively low, mangrove species on the island was very uneven, and the dominant species was Rhizophora mucronata.

Nuclide ²¹⁰Po is the main contributor to internal doses due to ingestion of radionuclide in humans, and enters the human body through the consumption of food, including seafood. The research aim is to analyse the activity of the ²¹⁰Po, in several species of biota that commonly available in the Jakarta Bay. The sample consist of tuna, tenggiri (mackerel), kakap merah (red snapper), Shrimp and green mussel were collected in 2017. The activity of ²¹⁰Po in the edible part of that biota ranged from 9.05 ± 3.05 to 137.37±37 Bq/kg of fresh biota, and the highest activity in the green mussel and the lowest for tuna. This result were comparable to those presented by other study from several regions of the world and the UNSCEAR data. The daily intake of ²¹⁰Po from these biota varied between 0.24 and 14.27 Bq year–1. The estimated dose of ²¹⁰Po intake ranged from 0.03 – 3.6 μSv year–1 are lower than the average natural radiation received by humans globally. This study contributes to the Indonesia baseline data of ²¹⁰Po in marine biota.

River estuary in coastal areas, is highly affected by inland water conditions such as freshwater and sediment flows, ocean water such as tides, waves, and the substitution of saltwater to land. Large ecological and economic potential causes logical consequences for ecosystem changes, including the condition of fish resources that have habitat and life cycles directly related to conditions that occur upstream. The purpose of this study was to examine ecological stresses and fishing activity in Mahakam Estuary represented by mangrove crabs, cat fish and giant prawns. The main analysis in this study was the calculation of vulnerability values with concepts and approaches to vulnerability of catfish populations, giant prawns and mangrove crabs, based on two functions of vulnerability, namely exposure and sensitivity. The vulnerability analysis of three types of fisheries commodities refers to the method used by NOAA with some modifications to the assessment component. It is known that catfish are in a low level of vulnerability, giant prawns are at a high level of vulnerability, mangrove crabs are in a very high level of vulnerability or very vulnerable.

Absrtact. Indian Scad (Decapterus russelli, Rupell, 1928) is one of small pelagic fish that have important values in the south of China Sea. The objective of the study was to investigate some biology aspects of Indian scad caught by purse seine in the south of China Sea. The research was conducted from March to August 2014. This study used 395 fish samples with size between 14.1-21.9 cmFL (average 18.9 cmFL) and the sex ratio between female and male was 1:1.09. The growth patterns of Indian scad for male and female were positive allometric expressed by the following equation: W=0.0093L3.1309 (R2=0.8719) for male and W=0.0094L3.1359 (R2=0.8576) for female. The condition factors were about 0.25-6.22. Indian scads observed ranged between Maturity stage I and maturity stage V with GI for male and female were 0.056–6.36 % and 0.09 – 6.35 %, respectively. The Von Bertalanffy Growth Equation of Indian scad in the South of China Sea was Lt = 23.60 (1 - e 0.6(t+-0.2789)) with the length of infinity (L∞)=23.60 cmFL, coefficient of growth (K) = 0.6 year-1 and the theoretical age (t0) Indian scad that was equal to (t0) = - 0.2789.

Seaweed represents an important economical resource in Indonesia. They are potentially as good source of nutrient. Furthermore, they have the most nutritious and rich in mineral than any other feedstock. The levels of minerals are ten to twenty times from total mineral content of terrestrial plants. This experiment was carried out to evaluate the nutritional value and mineral content of several seaweeds namely Caulerpa, Palmaria and Ulva, in order to utilize as fish feed ingredient. Seaweeds were collected from Binuangeun Beach, Banten and south coast of Java Island. Carbohydrate by different (NFE) and ash contents were the most two abundant components. Seaweeds Caulerpa, Palmaria and Ulva contained 44.73%, 53.74%, 55.31% NFE; and 27.36%, 22.81%, 20.51% ash based on dry weight, respectively. These contained high amounts of Na, K, Ca, and Mg ranged 0.72-5.65 g 100g⁻¹, Fe, Mn, Cu, and Zn ranged 2.09x10⁻⁴-0.09 g 100g⁻¹. The quantity of the bio-essential elements (Fe, Zn, Cu) followed as Fe>Zn>Cu. The iron content was rich in the sequence of Caulerpa>Palmaria>Ulva and its range was found to be 0.01-0.09 g 100 g⁻¹ in dry weight. The result showed that Caulerpa, Palmaria and Ulva are valuable resource and potentially to be utilized as fish feed ingredient.

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In the section 2., the following text appears:

"2. Materials and metodhs"

This should read:

"2. Materials and methods"

In the 2.2. Research procedure section, the following text appears:

"This velocity measurement was held four times a day at the three depths, as presented in Figure 2."

This should read:

"This velocity measurement was held four times a day at the three depths, as presented in Figure 1."

Page 3:

In the 3.1. Water depth section, the following text appears:

"The data concerning water depth from the week I to IV are presented in Figure 3 to 6."

This should read:

"The data concerning water depth from the week I to IV are presented in Figure 2 to 5."

Page 5:

In the 3.2. The current velocity section, the following text appears:

"Figure 7 shows that is the current velocity of the 5th day at 03:00 pm was the highest in the first week, that was 0.26 m/s."

"Based on Figure 8, the current velocity on 12th Jumada I at 09:00 am was 0.35 m/s because the depth of the water also headed towards the tide, resulting in the large current into the port channel."

This should read:

"Figure 6 shows that is the current velocity of the 5th day at 03:00 pm was the highest in the first week, that was 0.26 m/s."

"Based on Figure 7, the current velocity on 12th Jumada I at 09:00 am was 0.35 m/s because the depth of the water also headed towards the tide, resulting in the large current into the port channel."