This study investigates the status and anthropogenic pressures on seagrass ecosystem. Urbanization and tourism in the coastal areas of Bintan, Indonesia were increasing in the recent years. They have become new pressures to intertidal ecosystem and habitats, particularly seagrass ecosystem. Seagrass meadows are the important ecosystem and habitats in Bintan region. They provide a wide range of ecosystem services, including for small-scale fisheries and have being Dugongs (Dugong dugon) habitats for food. Currently, the sea grass status is less healthy or damaged with 11 species. The anthropogenic disturbance processes have affected the spatial distribution, percent coverage, biodiversity, and community structure of sea grass. Moreover, several species are hard to find. Directly, sea grass meadows are impacted by introduced coastal development (i.e. settlement area, tourism accommodation, port, etc.), land-based pollution, reclamation, boating traffic, dredging activities and tourism activities. Sea grass conservation area and marine spatial planning based on the land- and seascape connectivity is important for conservation efforts and sustainable management of sea grass.

Seagrass transplantation in the large-scale requires a large number of seagrass individu from donor ecosystem. This may give negative impact as damage and reducing the number of seagrass in donor ecosystem. One of methods to overcome this case is by developing transplants using seagrass nut as source for seed. Substrate is one of factors that influence the growth of seagrass. The aim of this study was to compare the effect of differences in substrate composition on morphologi and growth of Enhalus acoroides seeds. Observations were carried out by treatment using mud, sand and mixed substrates sand with mud. The survival rate of Enhalus acoroides seeds was quite high of 100% but it had a lower value of 93.30% on sand substrate. The longest leaf is on the mud substrate with a length of 5.9 cm, the leaf width has the same size in each substrate with a value of 0.4 cm, the highest number of leaves were found in the sand and mixture substrate with 5 strands, the longest root size was in the mixed substrate with a length of 5 cm. The growth of Enhalus acoroides seagrass seeds did not show any significant difference. The highest growth was found in the mud substrate with a value of 0.10 cm/day. Keywords: Enhalus acoroides, seagrass,seed, substrate, transplantation

Macroalgae is one of the marine resources that have the ability as an antioxidant. Its ability is obtained from bioactive compounds produced through secondary metabolism. One type of macroalgae that has the potential as an antioxidant is Padina sp. This study aims to analyze the content of bioactive compounds in Padina sp and determine their antioxidant activity using DPPH as free radicals. Padina sp. was taken from the Bintan waters and shade-dried for three days. Bioactive compounds were analyzed through phytochemical screening to determine the content of flavonoid compounds, steroids, triterpenoids, saponins, and tannins. Determination of antioxidant activity begins with measuring the maximum wavelength of DPPH at 400-800 nm and determining the incubation time of the sample and DPPH. Antioxidant activity was determined based on the value of Inhibition concentration (IC50) at a wavelength of 515.5 nm; total phenolic content was determined using gallic acid standard (725 nm); total flavonoid content was determined using quercetin standard (415 nm), chlorophyll a and carotenoids were selected to determine pigment content on the sample. The results showed that Padina sp. contains flavonoid compounds, steroids, and tannins. Extract of Padina sp. has a total phenolic content of 46.02 mg/GAE g; total flavonoid content of 35.36 mg/QE g; chlorophyll content of 9.18 mg/g; and carotenoid content of 26.46 µmol/g. Methanol extract of Padina sp. has an IC50 value of 92.17 ppm and is classified as a strong antioxidant.

Uji gastropoda famili Neritidae terhadap habitatnya di ekosistem mangrove dilakukan di dua stasiun pengamatan di Pulau Tunda Serang Banten pada Januari 2014. Penelitian ini bertujuan untuk mengkaji dan menganalisis gastropoda famili Neritidae terhadap kesehatan hutan mangrove Pulau Tunda Serang Banten. . Pengumpulan data kondisi gastropoda famili Neritidae dilakukan dengan menggunakan plot berukuran 1 x 1 m dan dipasang pada plot transek vegetasi mangrove berukuran 10 x 10 m, dimana transek garis dan plot vegetasi mangrove ditarik dari titik acuan (tegakan mangrove bagian luar) dan tegak lurus terhadap garis pantai ke daratan.Kemudian keanekaragaman, dominansi, dan keseragaman gastropoda famili Neritidae dan hutan bakau Pulau Tunda Serang Banten dianalisis menggunakan indeks keanekaragaman Shannon-Weaver. Indeks dominasi Simpson dan indeks keseragaman Shannon-Weaver. Sedangkan hubungan kerapatan gastropoda famili Neritidae dan kerapatan hutan bakau Pulau Tunda Serang Banten dilakukan dengan menggunakan regresi linier sederhana. Hasil penelitian menunjukkan bahwa kerapatan gastropoda famili Neritidae lebih tinggi dan lebih banyak ditemukan di mangrove kerapatan tinggi. Kemudian keanekaragaman dan dominasi gastropoda famili Neritidae rendah, sedangkan keseragamannya dalam keadaan seimbang.Selain itu, penelitian ini juga mengungkapkan bahwa semakin tinggi kerapatan hutan mangrove maka kerapatan gastropoda famili Neritidae juga semakin tinggi, sehingga gastropoda famili Neritidae dapat digunakan sebagai bioindikator dalam menentukan kesehatan hutan mangrove.Sedangkan hubungan kerapatan gastropoda famili Neritidae dan kerapatan hutan mangrove Pulau Tunda Serang Banten dilakukan dengan menggunakan regresi linier sederhana. Hasil penelitian menunjukkan bahwa kerapatan gastropoda famili Neritidae lebih tinggi dan lebih banyak spesies ditemukan pada mangrove kerapatan tinggi. Kemudian keanekaragaman dan dominasi gastropoda famili Neritidae rendah, sedangkan keseragamannya dalam keadaan seimbang. Selain itu, penelitian ini juga mengungkapkan bahwa semakin tinggi kerapatan hutan mangrove maka kerapatan gastropoda famili Neritidae juga semakin tinggi, sehingga gastropoda famili Neritidae dapat digunakan sebagai bioindikator dalam menentukan kesehatan hutan mangrove. Sedangkan hubungan kerapatan gastropoda famili Neritidae dan kerapatan hutan mangrove Pulau Tunda Serang Banten dilakukan dengan menggunakan regresi linier sederhana. Hasil penelitian menunjukkan bahwa kerapatan gastropoda famili Neritidae lebih tinggi dan lebih banyak spesies ditemukan pada mangrove kerapatan tinggi. Kemudian keanekaragaman dan dominasi gastropoda famili Neritidae rendah, sedangkan keseragamannya dalam keadaan seimbang. Selain itu, penelitian ini juga mengungkapkan bahwa semakin tinggi kerapatan hutan mangrove maka kerapatan gastropoda famili Neritidae juga semakin tinggi, sehingga gastropoda famili Neritidae dapat digunakan sebagai bioindikator dalam menentukan kesehatan hutan mangrove. Kemudian keanekaragaman dan dominasi gastropoda famili Neritidae rendah, sedangkan keseragamannya dalam keadaan seimbang. Selain itu, penelitian ini juga mengungkapkan bahwa semakin tinggi kerapatan hutan mangrove maka kerapatan gastropoda famili Neritidae juga semakin tinggi, sehingga gastropoda famili Neritidae dapat digunakan sebagai bioindikator dalam menentukan kesehatan hutan mangrove. Kemudian keanekaragaman dan dominasi gastropoda famili Neritidae rendah, sedangkan keseragamannya dalam keadaan seimbang. Selain itu, penelitian ini juga mengungkapkan bahwa semakin tinggi kerapatan hutan mangrove maka kerapatan gastropoda famili Neritidae juga semakin tinggi, sehingga gastropoda famili Neritidae dapat digunakan sebagai bioindikator dalam menentukan kesehatan hutan mangrove.

Salah satu ekosistem pesisir yang dapat ditemukan di pesisir Pulau Bintan yaitu  ekosistem lamun. Ikan baronang merupakan ikan ekonomis penting yang berasosiasi dengan padang lamun. Kondisi struktur ekosistem lamun yang berbeda di perairan pulau Bintan diduga dapat berpengaruh terhadap persebaran ikan baronang pada ekosistem lamun. Penelitian ini bertujuan untuk mendeskripsikan kondisi tutupan lamun pada beberapa lokasi dan mendeskripsikan struktur populasi ikan baronang (Siganus sp) pada ekosistem lamun dengan tutupan berbeda di  perairan pulau Bintan. Metode sampling tutupan lamun menggunakan transek kuadrat berukuran 50 x 50 cm dan sampling ikan baronang menggunakan jaring insang dasaran (bottom gill net). Diperoleh 8 jenis lamun yang tersebar di 4 stasiun penelitian. Tutupan lamun tertinggi terdapat di stasiun Pengudang dengan nilai 65,20% dengan kondisi kaya/padat.  Terdapat 5 jenis ikan baronang. Jenis ikan baronang yang memiliki kelimpahan tertinggi yaitu Siganus canaliculatus. Tidak terjadi perbedaan yang signifikan untuk persebaran jenis ikan baronang pada lokasi penelitian  One of the ecosystems that can be found on the coast of Bintan Island is the seagrass ecosystem. SIganus sp are economical fish associated with seagrass beds. The structure of the seagrass ecosystem is thought to have an effect on the distribution of Siganus sp in the seagrass ecosystem. This study aims to describe the condition of seagrass cover at several locations in the waters of Bintan Island and to describe the population structure of Siganus sp in seagrass ecosystems with different cover in the waters of Bintan Island. The seagrass cover sampling method used a quadratic transect measuring 50 x 50 cm and the Siganus sp fish sampling used a bottom gill net. Obtained 8 types of seagrass spread over 4 research stations. The highest seagrass cover was found at Pengudang station with a value of 65.20% with rich/dense conditions. There are 5 types of baronang fish. The type of baronang fish that has the highest abundance is Siganus canaliculatus. There is no significant difference for the distribution of baronang fish species at the study site.

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Seahorses are marine biota that have distinctive body characteristics that can be distinguished from other fish. Male seahorses have brood pouches. Estimation of the presence of seahorses is still very limited, an effective approach is needed to detect the presence of seahorses. The approach is carried out with an underwater acoustic approach to predict the presence of seahorses by looking at observations, namely the strength of the target. This study aims to analyze the value of Target Strength (TS) of seahorses based on size. The method used is the method of collecting experimental data. The seahorse used collected ten samples. The object placement method uses the ikat method. The TS response value was recorded using a Simrad EK-15 instrument with a frequency of 200kHz and morphometric measurements were performed. Morphometric measurements in the form of standard length measurements, seahorse head length to record acoustic signals in 3 conditions, namely females, non-pregnant males and pregnant males. Analysis of the relationship between the value of the target strength with seahorse morphometrics using statistical analysis, namely linear regression, ANOVA analysis and Tukey's follow-up test. The resulting seahorse is a species of Hippocampus. The distribution range of the resulting TS response values ranges from -58.38 dB to -67.75 dB. The result of this study is the influence of the measuring variable on the TS value formed  Kuda laut merupakan biota laut yang memiliki karakteristik tubuh unik  yang dapat di bedakan dari ikan lainnya. Pendugaan keberadaan kuda laut di alam masih sangat terbatas, saat ini masih menggunakan teknik visual statistik yang bersifat sampling point. Pendekatan underwater acoustic diperlukan untuk menduga keberadaan dari kuda laut di perairan, dibutukan informasi  nilai pantulan akustik yang dikenal dengan target strength. Penelitian ini bertujuan untuk menganalisis nilai Target strength (TS) dari kuda laut berdasarkan ukuran. Metode yang perekaman sinyal akustik pada lingkungan alami dari habitat kuda laut. Kuda laut yang digunakan berjumlah sepuluh sampel denan metode pemeruman menggunakan thetred method. Perekaman nilai respon TS menggunakan alat scientific echosounder Simrad EK-15 frekuensi 200kHz. Pengukuran morfometrik berupa pengukuran panjang standar, panjang kepala. Data akustik dianalisis dengan perangkat lunak Sonar-5 Pro, selanjutnya analisis statistik regresi linear. Hasil penelitian menujukan hubungan nilai target strength rata-rata berkisar antara -58,38 (SD±2,93) sampai dengan -67,75 dB (SD±1,26). Hubungan TS terhadap panjang standar (PS) menunjukan hubungan positif, semakin besar ukuran kuda laut maka semakin besar pula nilai TS. Dengan formulasi TS = 20,62 log10 (PS) – 84,32 [dB], dengan koefisien determinasi  sebesar 14,1 %. Sementara itu hubungan TS terhadap Panjang Kepala (PK) diformulasikan menjadi TS = 11,43 log10 (PK) – 67,72 [dB] dengan koefisien determinasi 4,1 % lebih rendah dibandingkan dengan variabel panjang standar. Hasil ini telah mempertegas bahwa ukuran kuda laut dapat mempengaruhi nilai TS.

Several species of marine gastropod mollusk used by the community as economical food commodities, including the Strombus canarium was found in the Tanjung Sebauk, Bintan Island. The S. canarium diet as a deposit feeder significantly affects the consumption of the biota food varieties. Until now, there was limited information related to the classification of food consumed by S. canarium. Environmental factors affect S. canarium habitat substantially by providing a food source that is absorbed and influences the growth of S. canarium. Resettlement and restaurant activities in coastal areas affect changes in environmental conditions and modify the habitat and food variations of the organism. The Swept Area Sampling (SAS) method was applied to sweep and collecting S. canarium at a bed-ground area of 1500 m2 in Tanjung Sebauk. The shell splitting and surgery completion of S. canarium were handled in the laboratory. S. canarium samples were immersed with 10% formalin to serve and protect the gastric sample and prevent it from rupturing, including providing the possibility to observe the various food components from S. canarium. Each species of organism found in an S. canarium stomach sample was photographed and counted and measured three times. Photographs of the gastric sample obtained from observations in a microscope were analyzed and identified comprehensively to find the composition of food varieties from the S. canarium. The varieties of food composition obtained were distinguished by class and group of biota and analyzed using the Preponderance Index. The varieties of food composition in gastric samples from S. Canarium shown eight species with the majority composition from plankton groups (phytoplankton and zooplankton), and one species was the copepod class. The following species of biota found in the stomach S. canarium based on the Preponderance Index consisted of Thalassionema sp. (42.59%) as primary food, followed by Nocticula sp. and Coscinodiscus sp. as additional food with a percentage of 37.45% and 12.35%, respectively. In comparison, the variety of complementary food from S. canarium consisted of Entomoneis sp. (2.47%), Cymbella sp. (1.23%), Cochlodinium sp. (1.23%), Calanus sp. (1.85%), and Boreadinium sp. (0.82%).