No abstract

Dinamika kawasan pesisir mencakup proses erosi dan sedimentasi merupakan hal penting untuk mengetahui kondisi pantai. Pesisir Kecamatan Brebes merupakan salah satu kawasan di Pantai Utara Pulau Jawa yang memiliki dinimika perubahan pesisir sangat kuat. Studi sebaran jenis sedimen yang dilakukan secara terpadu di perairan Kecamatan Brebes ditunjukkan untuk memberikan gambaran proses transportasi dan pengendapan sedimen berdasarkan distribusi ukuran butir sedimen. Penelitian dilakukan dengan pengambilan sampel sedimen dasar perairan secara acak dan tersebar di sepanjang pesisir dengan metode grab sampler, kemudian dilakukan analisis lebih lanjut dengan metode granulometri. Hasil penelitian menunjukkan bahwa secara umum, pola sebaran sedimen permukaan dasar laut Kec.Brebes didominasi oleh sedimen berukuran lempung-pasir. Jenis sedimen berdasarkan ukuran butirnya yaitu pasir, pasir lanauan, lanau pasiran dan lanau. Kondisi hidro-oseanografi yang fluktuatif memberikan nilai sortasi buruk hingga sedang, dominasi ukuran halus tersebar pada bagian Timur, sedangkan fraksi kasar tersebar dibagian Barat dekat dengan laut lepas.  Kondisi tersebut menjadikan salah satu faktor tererosinya bagian pesisir Kecamatan Brebes dengan dinamika hidro-oseanografi yang berubah-ubah.

Morphological changes. i.e. shoreline change and bathymetry change of Serang District were significantly influence by natural factors as well as human activities of sand mining (seabed sand exploitation). Bathymetric data were obtained through direct bathymetry measurements using Single-Beam Echosounder (Echotrac CVM Teledyne Odom Hydrographic) and GPS- Real Time Kinematic (RTK) as well as through secondary data from digitization data of DISHIDROS and LPI BIG. The data obtained is then processed to obtain the volume of moved bed sediment using 2 different topography overlays, from the bathymetry analysis result, we obtained the volume of natural sediment transported is 95,800 m3 with the value of average thickness is 0.036 m. therefore, the volume which is caused by human factors (sand mining activities during 2003-2013) is 5,578,470 m3 with the sand mining area extents of 261.9 Ha. Resulting the small basin with 2.13 m depth.  Keywords: bathymetry, lontar village, morphology, sand mining,                            coastal zone

Perairan Keneukai merupakan salah satu penghasil sumber daya perikanan di Pulau Weh, Nanggroe Aceh Darussalam. Jumlah spesies ikan di perairan tersebut mengalami penurunan dari tahun 2008 hingga 2010. Penelitian yang dilakukan oleh Loka Riset Sumber Daya dan Kerentanan Pesisir (LRSDKP) pada tahun 2017 mempunyai salah satu tujuan untuk menentukan lokasi yang tepat untuk usaha budidaya perairan Keramba Jaring Apung (KJA) lepas pantai di Perairan Keneukai. Analisis yang dilakukan dalam penelitian ini adalah analisis arus, pasang surut, batimetri, serta kualitas perairan. Kecepatan arus di permukaan berkisar antara 0-0,9 m/s. Sementara itu, kecepatan arus dekat dasar berkisar antara 0-0,74 m/s. Profil vertikal arus menunjukkan mekanisme Spiral Ekman yang berpengaruh terhadap distribusi material-mateial organik secara vertikal dan didominasi oleh arus pasang surut. Topografi Perairan Keneukai termasuk landai dengan kedalaman berkisar 0-72 meter dan terdapat perubahan kedalaman yang signifikan di sejumlah area. Hasil analisis perairan untuk parameter Dissolved Oxygent (DO), salinitas, suhu, pH, kecerahan, nitrit, Biological Oxygent Demand (BOD dan amonia menunjukkan bahwa lokasi penelitian layak dan sesuai untuk dijadikan sebagai tempat budidaya KJA. Akan tetapi, hal tersebut tidak berlaku untuk parameter nitrat. Berdasarkan hasil analisis dan verifikasi lapangan dengan pertimbangan aspek fisik dan keterjangkauan lokasi, maka Perairan Keneukai dapat direkomendasikan untuk pengembangan budidaya keramba jaring apung.

Ambon Bay is divided by two thresholds, namely Teluk Ambon Dalam and Teluk Ambon Luar. Ambon bay is rich in marine potential both the unique of fisheries and coral reefs as well as the

The dynamics of erosion and accretion in the coastal area of Brebes Subdistrict have many impacts on mangrove destruction and coastal region. The erosion and accretion are influenced by oceanography parameters that can affect the distribution of coastal sediments. The aims of this research were to determine the characteristics of the phenomenon of erosion and accretion in coastal Brebes Subdistrict and shape appropriate mitigation to reduce the erosion. This research is done with the bed sediment sampling using grab sampler for 26 sampling point. Current and tide measurement are conducted wih ADCP deployment for 15 days' measurement. Sediment characteristic analysis done with granulometri and statistic analysis. The average of sediment sorting is 1.21, skewness is 0.088 and the kurtosis is 3.76. Generally, bed surface sediment distribution pattern is dominated by clay to sand, the grand size distribution of sediments are sand, silt, sandy silt and silty sand. Longshore current speed ranged between 0-0.12 m.s -1 at the spring tide condition and ranged between 0-0.08 m.s -1 at the neap tide condition, the domination of current direction towards to the East and Northeast. The mitigation is very needed to rearrange the mangrove areas, build the coastal protection and recover the main river line which is the sourceof the sediment materials, so that can be provide the supply of sediment deposition in the coastal area. ABSTRAK Dinamika kawasan pesisir Kecamatan Brebes berupa bencana abrasi dan akresi yang terjadi memiliki dampak besar terhadap kerusakan kawasan mangrove dan pesisir. Fenomena erosi dan akresi yang terjadi dipengaruhi oleh parameter oseanografi yang dapat mempengaruhi sebaran sedimen di pesisir. Penelitian ini bertujuan untuk mengetahui karakteristik distribusi sedimen dasar perairan sebagai upaya identifikasi bencana erosi yang terjadi di pesisir Kecamatan Brebes.Penelitian dilakukan dengan pengambilan sampel sedimen dasar perairan menggunakan metode grab sampler terhadap 26 titik pengambilan. Pengukuran kecepetan arus di lokasi penelitian dilakukan dengan pemasangan ADCP selama 15 hari. Analisis karakteristik sedimen dilakukan dengan metode analisis granulometri dan statistic sedimen. Nilai rata-rata sortasi 1.21, skewness 0.088 dan kurtosis 3.76. Secara umum, pola sebaran sedimen permukaan dasar laut Kec.Brebes didominasi oleh sedimen berukuran lempung-pasir. Jenis sedimen berdasarkan ukuran butirnya yaitu pasir, pasir lanauan, lanau pasiran dan lanau. Kecepatan arus sepanjang pantai hasil model pada kondisi purnama berkisar 0-0,12 m.s -1 dan pada saat perbani berkisar antara 0-0,08 m.s -1 , dengan dominasi arah arus menuju ke Timur dan Timur laut. Perlu dilakukan penataan ulang terhadap kawasan mangrove dan bangunan pelindung pantai serta melakukan pencodetan terhadap sungaisungai utama yang merupakan sumber pembawa material sedimen sehingga dapat memberikan suplay endapan sedimen di bagian pesisir.

Sabang coastal bay becomes the area of significance where the development centered in the semi-enclosed area. Sabang Bay is well-known as the center of marine economy (Aquaculture, Harbor, and marine tourism). Recently, there is a planning initiated by Ministry of Marine Affairs and Fisheries (MMAF) to install the floating fish cage aquaculture (KJA) in the offshore area of Sabang Bay which the planning becomes a controversy between local people, local government, and researchers as well. This study aims to evaluate and discuss the impacts that will be happened if KJA is applied. Field surveys on hydro-oceanography aspects were done measuring currents, tides, waves, winds, bathymetry, water quality, as well as tourism condition. Based on those hydro-oceanography conditions, Sabang Bay categorized into calm water area where the sea current is weak (ranging from 0-0.12 m/s), whilst the high values of pH, salinity, and temperature are identified within the bay during low tidal condition. If KJA is installed within the bay, automatically it will pollute the water due to the accumulation of remaining fish feeder wastes. Moreover, within the bay, there are several attractive marine tourisms such as diving sites, the conservation area of Sophie Rickmers shipwreck site, and hot bubble (fumaroles hydrothermal vent). The presence of KJA will possibly disrupt marine tourism activities so that the implementation of KJA needs to be considered the impacts before installation.

The waters of Weh Island, Aceh Province has potency become the area for offshore aquaculture. Offshore Floating Net Cages can be an appropriate technology in increasing the biomass cultivation in Weh Island waters. However, no feasibility study has been done.  Therefore, this study aims to examine the suitability of offshore aquaculture locations in the East and South regions of Weh Island Based on Hydro-oceanography parameters. The parameters examined were water quality parameters such as temperature, brightness, pH, salinity and dissolved oxygen. In addition, we also examined the aspects of physical oceanography such as tides, currents and bathymetry. The results show that the water depth ranged from 0-57 m. The tidal type in the Weh Island waters is mixed tide prevailing semidiurnal with the tidal range of 1.9 m. The average of current speed ranged from 19.03-37.67 cm/s with the directions predominantly toward northwest and southeast.  It is concluded that the water quality data show that the eastern and southern parts of Weh Island are categorized as the feasible locations for offshore aquaculture.  Keywords: Sabang, Hydro-oceanography, Fisheries, Offshoreaquaculture, Floating net cages