The floating breakwater is a protective structure that can absorb waves and can be used effectively in coastal areas with moderate wave environmental conditions. The stability of the floating breakwater is affected by the tension of the mooring line and the weight of the anchor. This research was conducted experimentally with a model scale of 1:10 on a floating breakwater with mooring systems and concrete anchor blocks with three types of configurations. The experiment was carried out on irregular waves with the following variations: wave height and period, mooring angle, structure width, and anchor weight. The results of this study indicate that at a wave steepness of 0.02–0.025 floating breakwater, which is installed with a mooring angle of 45 deg, configuration 3 has the largest stability parameter among other configurations. However, if the structure is installed at a mooring angle of 90 deg and cross, configurations 2 and 3 have almost the same stability. The test results also show that the relative width will affect the stability parameters. Configuration 3 (B = 30 cm) has the largest stability-parameter value among other configurations (B = 10 cm and 20 cm).

This study evaluates the health and condition of coral reefs in the Mapur Island - Bintan Conservation Area, located in the Riau Islands Province, Indonesia. The research was conducted at 5 site locations using the Underwater Photo Transect (UPT) method, with a focus on hard coral cover and the Coral Health Index (CHI). Coral lifeform data were analyzed using Coral Point Count with Excel extensions (CPCe) software. The results revealed significant variability in coral cover, ranging from 14.47% to 59.27%, with an average of 39.36%, placing the coral reefs in the “Moderate” category. However, despite high hard coral cover at some sites, coral health varied, with certain locations exhibiting significant disease prevalence. Among the 5 sites surveyed for CHI, four were classified as “healthy,” while one were categorized “diseased.” Statistical analyses, including Welch’s t-test and Bayesian inference, indicated no significant difference between the CHI and hard coral cover, suggesting that high coral cover does not necessarily imply a healthier reef. Diseases such as Pink- Blotch Syndrome, Black Band Disease, and White Syndrome were prevalent across several sites, highlighting the influence of environmental stressors on coral health. The study underscores the importance of regular coral health monitoring and the need for conservation efforts to mitigate the impact of coral diseases and climate change. These findings provide crucial insights into the status of coral reefs in the Mapur Island - Bintan Conservation Area and contribute to broader efforts to preserve marine biodiversity.

In river mouths and coastal areas, sediment carried by water flows often clogs the estuaries and causes silting lagoons, impacting the prevalence of coral disease. Ten sediment traps were installed in the river 25 cm from the bottom to record the data for 21 days in Kawal River. Oceanographic and current flow data were collected using CTD and a Current meter using the Eulerian method with a depth interval installation of 0.25 to 0.75 from the river surface. The Underwater Photo Transect (UPT) is a method to analyze the condition of coral reefs and coral disease. CTD the temperature data ranged from 30.471 ± 0.001 °C to 31,609. ±0.001°C, salinity value ranges from 29.643 ± 0.001 PSU to 32.336 ± 0.001 PSU and current flow ranged from 0.063 ± 0.010 m/s to 0.281 ± 0.012 m/s. The results of the sediment trap, the dry weight value of sediment deposited in the sediment traps ranges from 0.89 grams, and for the largest of 48.45 grams, the turbidity ranged from 0.77 NTU to 4.22 NTU. The prevalence of coral disease was 56.40%. The conclusion indicates that excessive sedimentation rates at river mouths can result in a high incidence of coral disease.

The Coral Reef Ecosystems of Batanta and Salawati Islands, Raja Ampat is a critical habitat for grouper species (Family Serranidae), which play essential roles in coral reef ecosystems. This study assessed the species composition, abundance, and biomass of groupers across 12 sampling sites in the region. Using the Underwater Visual Census (UVC) method, we identified 14 grouper species, with Plectropomus areolatus classified as vulnerable by the IUCN. Our results revealed an average grouper abundance 17.33 ind/350m² for Batanta and 18.33 ind/350m² for Salawati. An average biomass the mean biomass 4288.16 gr/350m² for Batanta and 1881.10 gr/350m² for Salawati, indicating substantial biomass within the area. Statistical analyses, including the Kruskal-Wallis test and t- tests reveal no significant difference in abundance between the two locations, as indicated by the non-significant p-value (p = 0.87). Correlation analysis demonstrated a very strong positive relationship between grouper abundance and biomass, suggesting that the Anthropogenic activities have not yet significantly impacted the grouper populations in Salawati and Batanta. The study emphasizes the importance of habitat protection and sustainable fisheries management to support grouper populations. Additionally, ongoing monitoring and adaptive management strategies are necessary to ensure the long-term health of grouper populations and the coral reef ecosystems they inhabit.

Human activities in coastal areas have the potential to cause heavy metal pollution. The impact of heavy metal pollution causes the accumulation of heavy metals in the body of marine biota, including the Gonggong Snail (S. Canarium). This study aims to analyze the concentration of heavy metals Pb in Gonggong snails in two different characteristics of aquatic ecosystems. Purposive sampling used as a sampling method of Gonggong Snail. The Analysis of heavy metal concentrations from Pb using the ICP (Inductively coupled plasma). The results showed the heavy metal concentration of Pb was 0.427 mg/kg for Malang Rapat Village and 0.71 mg/kg for Tanjung Siambang village. The difference between the two locations possibly due to differences in the aquatic characteristics at the study site. Aktivitas manusia di kawasan pesisir berpotensi menyebabkan terjadinya pencemaran logam berat. Dampak dari pencemaran logam berat dapat menyebabkan terakumulasinya logam berat pada tubuh biota laut, salah satunya yaitu Siput Gonggong (S.Canarium). Penelitian ini bertujuan untuk menganalisis konsentrasi logam berat Pb pada Siput Gonggong yang terdapat pada dua ekosistem perairan yang memiliki karakteristik perairan berbeda. Pengambilan sampel siput gonggong dilakukan dengan cara purposive sampling. Analisis konsentrasi logam berat menggunakan bantuan alat ICP (Inductively coupled plasma). Hasil penelitian menunjukkan bahwa konsentrasi logam berat Pb sebesar 0,427 mg/kg untuk Desa Malang Rapat dan 0,71 mg/kg untuk desa Tanjung Siambang. Terjadi perbedaan antara kedua lokasi kemungkinan dikarnakan adanya perbedaan karakteristik perairan pada lokasi penelitian.

The objective of this research was to collect the comprehensive information about the characteristics of sea waves in the northern and eastern of Bintan Island Sea based on differentiation in oceanographic conditions between the north and east coast of Bintan Island. The north coast of Bintan Island faces the open seas directly with a potential high wave and cause several characters of coastal damage, including coastal abrasion. The characteristics of sea waves are obtained by forecasting, namely converting wind speed values using the SPM (Shore Protection Manual) method. The results of this study collected comprehensive information of sea waves on the north coast during the 2015-2019 period showed a dominant pattern with the direction of sea wave propagation from north and south, while for the eastern region the wave propagation trends prevailing from north and southeast. The maximum sea wave height in the northern of Bintan Island Sea reaches 3.32 m with a period of 8.70 s while in the eastern of Bintan Island Sea the maximum of wave height condition reaches 2.90 m with a period of 8.32 s. The maximum sea wave conditions on the north and east coasts of Bintan Island occur during the north wind season (December-February) and is directly proportional to the requirements of higher wind speeds. The minimum sea wave conditions occur during the east monsoon (March-May) where during that period the wind speeds that blow are very low condition. The results of this study indicate that wind speeds in northern Bintan Island are related to wave conditions. Our research proves that higher wind speeds form higher wave conditions.