Judul: Determination of Upwelling Locations As An Indicator of Potential Fishing Ground Area in The Southern Waters of Yogyakarta
Abstrak: Informasi tentang daerah penangkapan ikan bagi nelayan di Perairan Selatan Yogyakarta masih terbatas sehingga operasi penangkapan ikan menjadi tidak efisien. Hal ini dapat diatasi dengan menentukan keberadaan lokasi upwelling sebagai indikator DPI potensial. Metode untuk mengidentifikasi lokasi upwelling dilakukan dengan menganalisis dan menginterpretasi data spasiotemporal data suhu permukaan laut, klorofil-a, dan anomali tinggi muka laut yang diunduh dari Marine Copernicus yang dapat dijadikan sebagai acuan untuk mengeksplor karakteristik dan potensi DPI. Lokasi upwelling perlu verifikasi dan validasi menggunakan data spot penangkapan dan hasil tangkapan untuk membuktikan bahwa lokasi upwelling dapat dijadikan sebagai indikator DPI potensial. Nilai SPL, klorofil-a, dan TML pada musim timur mendukung adanya lokasi upwelling di Perairan Selatan Yogyakarta.Puncak upwelling terjadi di bulan Agustus yang ditandai dengan nilai SPL terendah, klorofil-a tertinggi, dan TML terendah. Puncak musim penangkapan ditandai dengan jumlah hasil tangkapan dan nilai CPUE (Catch per Unit Effort) tertinggi terjadi di bulan Agustus. Hasil validasi dan verifikasi lokasi upwelling teridentifikasi pada spot 1, 2, dan 3 pada bulan Agustus dan September., Information about fishing ground areas for fishermen in the Southern Waters of Yogyakarta is still limited so that fishing operations become inefficient. This can be overcome by determining the presence of upwelling locations as an indicator of potential FGA. The method for identifying upwelling locations is carried out by analyzing and interpreting the spatiotemporal data of sea surface temperature, chlorophyll-a, and sea surface height data downloaded from Marine Copernicus which can be used as a reference for exploring the characteristics and potential of FGA. Upwelling locations need to be verified and validated using data on fishing spots and catches to prove that upwelling locations can be used as indicators of potential FGA. The values of SST, chlorophyll-a, and SSH in the east monsoon support upwelling location in the Southern Waters of Yogyakarta. The peak of upwelling occurred in August which was marked by the lowest SST value, the highest chlorophyll-a, and the lowest SSH. The peak of fishing season is marked by the number of catches and CPUE (Catch per Unit Effort) reached the highest value in August. The results of the validation and verification of upwelling locations were identified at spots 1, 2, and 3 in August and September.
Keyword: Chlorophyll-a, FGA, Southern Waters of Yogyakarta, SST, Upwelling

Judul: The Potential Fishing Area in the Sunda Strait Based on the Intensity of Fishing
Abstrak: Perairan Selat Sunda memiliki potensi sumberdaya perikanan yang tinggi dan menjadi salah satu lokasi kegiatan perikanan tangkap baik ikan pelagis maupun demersal. Tujuan dari penelitian ini adalah menganalisis daerah potensial penangkapan ikan pada perairan Selat Sunda dengan melakukan pemetaan daerah penangkapan eksisting di Selat Sunda, pendataan hasil tangkapan sebagai profil biologi perikanan, identifikasi musim penangkapan dan sebaran oseanografi. Analisis data terdiri atas pemetaan jalur penangkapan ikan nelayan, jenis dan ukuran ikan tangkapan, ukuran pertama kali matang gonad, pola musim penangkapan, suhu permukaan laut dan klorofil-a. Penelitian dilakukan pada bulan September sampai Desember 2019 dengan lokasi pengambilan data di wilayah penangkapan ikan Selat Sunda serta PPP Labuan dan PPP Lempasing. Umumnya ikan-ikan yang ditangkap oleh para nelayan di Selat Sunda cenderung berasal dari daerah disekitar pesisir, pulau-pulau kecil serta teluk. Hasil dari penelitian menunjukkan bahwa terdapat wilayah-wilayah potensial lainnya berdasarkan rentang nilai rata-rata suhu permukaan laut dan klorofil-a pada jalur penangkapan yang dilalui karena memiliki hubungan dengan hasil tangkapan ikan., Sunda Strait has high potential fishery resources and locations for fishing activities for both pelagic and demersal fish. This research aims to spatial analyse the waters of the Sunda Strait by collecting data on fish capture, identifying the changes of capture fish pattern area, and mapping the potential fishing areas. The data analysis consists of the type and size of the captured fish, first size mature gonad and capture, fishing season patterns and the sea surface temperature. This research was conducted from September to December 2019 with data collection in PPP Labuan and PPP Lempasing. Usually, fishermen’s the capture fish by fisherman in the Sunda Strait is from several fishing areas, including Lada Bay, Panaitan Island, Krakatau Island, Sebesi Island, Sebuku Island, and Legundi Island. The result shows that high fishing efforts occurred in areas close to the coast, small islands, and bays in the Sunda Strait. Fishery Management efforts must be created by considering sustainability for the long term.
Keyword: Cartography, Chlorophyll-a, Potential fishing area, Sunda Strait, Sea surface temperature

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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