Judul: Mapping of Water Quality and Phytoplankton Distribution at Bomo and PT. Surya Windu Kartika Farms, Banyuwangi Jawa Timur Using Geographical Information System (GIS) to Support an Appropriate Management Model
Abstrak: Kualitas air dan fitoplankton merupakan parameter biologi yang dapat berpengaruh terhadap keseimbangan perairan, terutama pada aktivitas agromaritim di sekitarnya, salah satunya aktivitas tambak budidaya. Pemantauan keseimbangan perairan terkait distribusi plankton di perairan sangat diperlukan untuk membantu model teknologi yang tepat untuk pengelolaan dan keberlanjutan kegiatan tambak budidaya. Penelitian ini bertujuan untuk menganalisis kualitas perairan dan melakukan pemetaan kesuburan fitoplankton di perairan Bomo dan di tambak budidaya udang PT. Surya Windu Kartika. Data dikumpulkan melalui foto udara menggunakan drone dan pengambilan sampel in-situ. Sampel diambil dari sepanjang perairan pantai Bomo di sekitar PT. Surya Windu Kartika dengan tiga stasiun lokasi pengambilan sampel (di Perairan pantai Bomo, di tandon budidaya, dan tambak media budidaya). Masing-masing stasiun dilakukan pengulangan di 3 substasiun berjarak 500 m setiap stasiunnya secara horizontal. Metode yang digunakan adalah metode survei dan dianalisis deskriptif maupun kuantitatif berdasarkan variabel-variabel penelitian. Data sebaran fitoplankton juga didukung dengan interpolasi keadaan klorofil a di perairan dengan menggunakan GIS (Geographical Information System). Hasil penelitian menunjukkan total nitrogen tertinggi yang tercatat berkisar antara 30,82 – 32,28 mg.L-1. Fosfat tertinggi berkisar antara 0,55 – 1,61 mg.L-1, yang melebihi baku mutu air laut untuk biota laut menurut Keputusan Menteri Lingkungan Hidup (Kepmen LH). Selain itu ditemukan adanya sebaran distribusi plankton yang cukup signifikan, di mana dominansi fitoplankton di kolam lebih tinggi dibandingkan di air laut dan tandon. Hal ini juga didukung dengan adanya data klorofil a, di mana klorofil a di kolam (A, B, dan C) lebih tinggi dibandingkan di air laut dan tandon., Water quality and phytoplankton are biological parameters that can affect the balance of waters along the Bomo shore and all agri-maritime activities around it, with aquaculture farming ponds as an example. Monitoring water balance related to plankton distribution in the waters is needed to help on sustaining aquaculture activities. The study was conducted along the shore and PT Surya Windu Kartika farms. The method that was used was a survey and quantitative and descriptive analysis based on research variables. Data was collected through aerial photography using drones and in-situ sampling. Samples were obtained from the shore with three sampling stations (at the Bomo shore, farming reservoirs, and the farming ponds). Repetitions were done at three substations horizontally. Phytoplankton distribution data was also supported with interpolation of chlorophyll-a state using GIS (Geographical Information System). It was found that the highest recorded total nitrogen value is around 30,82 – 32,28 mg.L-1. The highest phosphate value recorded was at an interval of 0,55 – 1,61 mg.L-1, which is above the standard of seawater for oceanic biota according to the Decree of the Minister of Environment (Kepmen LH). The research has also shown that there is a fairly significant distribution of phytoplankton, its dominance was higher in the farming ponds compared to the open sea and reservoirs. This was also supported by the chlorophyll data, where its value in the ponds (A, B, and C) is higher than the sea and reservoir values.
Keyword: Bomo, fitoplankton, klorofil a, perikanan, SIG

Judul: Plankton Community Structure in Intensive Pond
Abstrak: Tambak merupakan suatu ekosistem perairan tertutup yang memiliki kondisi lingkungan berubah-ubah. Manajemen kualitas air menjadi hal yang penting untuk dilakukan karena berdampak pada komunitas plankton. Penelitian ini bertujuan untuk menganalisis kondisi struktur komunitas plankton di tambak udang yang dikelola secara intensif. Penelitian dilakukan di Tambak Sarjo, Sulawesi Barat dan di Laboratorium Biologi Mikro 1, Institut Pertanian Bogor. Data yang digunakan yaitu data primer (sampel plankton) dan sekunder (data kualitas air). Pengambilan sampel plankton dilakukan pada dua petak tambak berdasarkan kesamaan umur awal tebar dari benih udang selama tiga bulan. Data kualitas air diperoleh dari laboran tambak Sarjo. Analisis data yang digunakan adalah indeks diversitas meliputi indeks keanekaragaman, keseragaman, dan dominansi serta analisis komponen utama dan regresi linier berganda. Komunitas plankton yang ditemukan terdiri dari lima jenis fitoplankton dan empat jenis zooplankton dengan total 14 genus fitoplankton dan 9 genus zooplankton. Kelimpahan plankton yang ditemukan berfluktuasi. Kelas Dinophyceae dan Protozoa hampir ditemukan pada setiap kelompok waktu pengamatan. Struktur komunitas plankton selama pengamatan memiliki keanekaragaman rendah, keseragaman rendah hingga sedang, dan dominansi yang cenderung rendah hingga sedang untuk fitoplankton dan rendah dengan kecenderungan tinggi untuk zooplankton. Perubahan kelimpahan plankton berkorelasi kuat dengan parameter kualitas air yang ada., Ponds are closed aquatic ecosystems that have changing environmental conditions. Water quality management is an important thing to do because it impacts the plankton community. This research aims to analyze the condition of plankton community structure in intensively managed shrimp ponds. The research was conducted in Tambak Sarjo, West Sulawesi, and at Micro Biology Laboratory 1, Bogor Agricultural Institute. The data used are primary (plankton samples) and secondary (water quality data). Plankton sampling was carried out in two pond plots based on the similarity in the initial stocking age of the shrimp seeds for three months. Water quality data was obtained from the Sarjo Pond laboratory. The data analysis used is a diversity index including indices of diversity, evennes, and dominance, principal component analysis, and multiple linear regression. The plankton community consisted of five types of phytoplankton and four types of zooplankton with 14 phytoplankton genera and 9 zooplankton genera. The abundance of plankton found fluctuates. The Dinophyceae and Protozoa classes were almost found in every observation time group. The plankton community structure during observations had low diversity, low to moderate uniformity, and dominance that tended to be low to moderate for phytoplankton and low with a tendency to be high for zooplankton. Changes in plankton abundance are strongly correlated with existing water quality parameters.
Keyword: phytoplankton, ponds, water quality, zooplankton

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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