Judul: Evaluasi Pendederan Ikan Lele (Clarias gariepinus) Ukuran 10 cm dalam Sistem RAS yang Menggunakan Trickling Filter
Abstrak: Penggunaan sistem resirkulasi yang diterapkan pada pendederan tahap lanjutan ikan lele merupakan upaya untuk mengoptimalkan penggunaan lahan dan air. Penelitian ini bertujuan mengevaluasi kinerja produksi pendederan ikan lele pada budidaya sistem resirkulasi menggunakan trickling filter dengan padat penebaran yang berbeda mencakup aspek bioteknik dan analisis usaha. Penelitian menggunakan Rancangan Acak Kelompok dengan 4 perlakuan dan 3 ulangan sistem, yaitu padat tebar 0,5; 1; 1,5; 2 ekor L-1. Ikan yang digunakan berukuran 5,87±0,43 cm dan 0,43±0,27 g. Wadah yang digunakan berupa akuarium yang dilengkapi dengan instalasi resirkulasi trickling filter. Ikan diberi pakan berkadar protein 39 – 41% secara ad satiation, Hasil penelitian menunjukkan bahwa padat penebaran berpengaruh terhadap kinerja produksi. Laju pertumbuhan spesifik, laju pertumbuhan harian, dan pertumbuhan panjang mutlak terbaik pada perlakuan padat tebar 0,5 ekor L-1. dengan nilai masing-masing, 10,99±0,14% hari-1; 0,37±0,02 g hari-1; 5,67±0,29 cm. Parameter laju pertumbuhan biomassa terbaik pada perlakuan padat tebar 2 ekor L-1 dengan nilai 30,90±3,00 g hari-1. Hasil analisis usaha didapatkan bahwa nilai tertinggi terdapat pada perlakuan padat tebar 2 ekor L-1 dengan nilai keuntungan sebesar Rp 4.877.425, rasio perimbangan penerimaan sebesar 1,12, titik impas penerimaan sebesar Rp 37.843.500, titik impas unit sebesar 56.483 ekor, jangka waktu pengembalian sebesar 2,87 tahun, serta harga pokok produksi sebesar Rp 598. Berdasarkan hasil produksi dan biomassa, hasil terbaik terdapat pada perlakuan padat tebar 2 ekor L-1.
Keyword: benih, lele, padat tebar, resirkulasi

Judul: Evaluasi Kinerja Pendederan Ikan Lele Clarias sp. Ukuran 5 cm di dalam Sistem Resirkulasi pada Padat Penebaran dan Sumber Benih yang Berbeda
Abstrak: Penelitian ini bertujuan untuk mendapatkan produktivitas yang optimal pada produksi pendederan lele ukuran 5 cm. Perlakuan penelitian ini adalah sumber benih yang berbeda yaitu benih produksi sendiri dan benih dari luar dengan padat penebaran 2000, 2500, dan 3000 ekor/m3 dengan sistem resirkulasi. Penelitian ini meliputi persiapan sistem resirkulasi, penebaran ikan, pemberian pakan, dan pencegahan penyakit. Ikan yang digunakan adalah benih lele dengan panjang ratarata 5,32±0,17 cm dan bobot rata-rata 1,41±0,10 gram. Pengamatan dilakukan selama 21 hari dengan mengukur bobot dan panjang ikan setiap minggu. Jika terdapat ikan yang mati akan diangkat dan dihitung jumlahnya untuk mengetahui pertumbuhan dan tingkat kelangsungan hidup. Hasil penelitian menunjukkan padat penebaran 3000 ekor/m3 dengan benih hasil produksi sendiri merupakan padat penebaran yang optimal yang menghasilkan produktivitas tertinggi dengan derajat kelangsungan hidup (KH) sebesar 77,63%; laju pertumbuhan harian (LPH) sebesar 11.09 %, dan efisiensi pakan sebesar 119.37 %.
Keyword: 

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite