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: Zooplankton Community Structure in Banten Bay to Describe the Health of the Aquatic Environment
Abstrak: Perairan Teluk Banten merupakan wilayah perairan yang dipengaruhi oleh berbagai aktivitas seperti kegiatan industri maupun berbagai aktivitas manusia sehingga dapat dikhawatirkan dapat menyebabkan penurunan kondisi perairan serta perubahan komposisi dan kelimpahan zooplankton. Penelitian ini bertujuan untuk menganalisis kondisi perairan Teluk Banten berdasarkan struktur komunitas zooplankton untuk menggambarkan kesehatan lingkungan perairan. Pengambilan contoh dilaksanakan pada bulan Oktober hingga Desember 2021, meliputi19 stasiun di muara Sungai Berung, muara Sungai Cibanten, muara Sungai Pamong, serta 16 stasiun di perairan laut. Parameter kualitas air yang diukur meliputi suhu, salinitas, kecerahan, dan klorofil-a. Analisis data meliputi kelimpahan zooplankton, indeks keanekaragaman, keseragaman, dan dominansi. Sebaran kelimpahan zooplankton dianalisis menggunakan Surfer 16 (Golden Software). Hubungan klorofil-a dan zooplankton dianalisis menggunakan regresi linear. Zooplankton yang ditemukan selama penelitian terdiri dari 29 genera dan 1 stadia. Zooplankton didominasi oleh Copepoda dan organisme yang mendominasi secara keseluruhan adalah krustasea Nauplius stadia. Kelimpahan zooplankton di perairan Teluk Banten berkisar 13,47–305,09 ind/L. Persebaran zooplankton lebih tinggi di area dekat pantai dan semakin rendah ke arah sisi luar teluk. Struktur komunitas zooplankton memiliki keanekaragaman rendah, keseragaman besar, dan dominansi rendah-sedang. Kelimpahan zooplankton berkorelasi signifikan dengan klorofil-a., Banten Bay is estuary that are affected by various human activities such as industrial and non-industrial activities, which can cause concerns about the decline in water quality conditions and changes in the composition and abundance of zooplankton. This research aims to analyze estuary conditions based on the structure of the zooplankton community to describe the health of the aquatic environment. Sampling and measurements were carried out from October to December 2021 at 19 stations, including the river mouth of Berung River, Cibanten River, Pamong River, and 16 other sea sites stations. Water quality parameters measured include temperature, salinity, water clarity, and chlorophyll-a. Data analysis includes zooplankton species abundance, diversity index, uniformity and dominance. The distribution of zooplankton abundance was analyzed using Surfer 16 (Golden Software). The relationship between chlorophyll-a and zooplankton was analyzed using linear regression. The zooplankton found during the research consisted of 29 genera and 1 stage. Zooplankton community was dominated by Copepods and the Nauplius of Crustacea dominates overall community. The abundance of zooplankton in the Banten Bay ranges from 13.47–305.09 ind/L. The distribution of zooplankton near the coast tends to be higher and lower towards outer side of the bay. The zooplankton community structure has low diversity, great uniformity, and low - medium dominance. The relationship between chlorophyll-a and zooplankton shows that zooplankton abundance can be influenced by chlorophyll-a.
Keyword: zooplankton, abundance, structure community, Banten Bay

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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