Judul: Production Performance of Nursery Eel Anguilla bicolor bicolor Grading Results in Recirculation System
Abstrak: Laju pertumbuhan bervariasi tinggi pada pendederan ikan sidat. Variasi ukuran menimbulkan kompetisi dalam memperoleh pakan, hal ini menyebabkan pembantutan pada ikan yang berukuran lebih kecil. Keadaan tersebut berujung pada besarnya biaya produksi akibat efisiensi pemanfaatan pakan yang buruk. Grading perlu dilakukan secara periodik untuk memperbaiki kinerja produksi pendederan. Kualitas air terkendali oleh sistem resirkulasi yang dapat mendukung kinerja produksi melalui pendegradasian senyawa toksik. Penelitian ini bertujuan untuk menganalisis kinerja produksi dan kinerja usaha pendederan ikan sidat (Anguilla bicolor bicolor) hasil grading pada batch yang sama dalam sistem resirkulasi. Rancangan acak lengkap (RAL) yang terdiri dari tiga perlakuan dengan empat ulangan digunakan pada penelitian ini. Perlakuan meliputi pendederan ikan sidat hasil grading selama 60 hari pada tiga kelompok ukuran bobot awal yaitu 0,35±0,00 g (A); 0,50±0,00 g (B); dan 1,04±0,00 g (C). Ikan sidat pada setiap ulangan berjumlah 344 ekor (A), 239 ekor (B), dan 116 ekor (C). Kinerja produksi pendederan terbaik diperoleh pada perlakuan 1,04±0,00 g, serta kinerja usaha pendederan terbaik diperoleh pada perlakuan 0,50±0,00 g.
Keyword: Anguilla bicolor bicolor, grading, production performance, recirculation system

Judul: Kinerja Produksi Pendederan Elver Ikan Sidat Anguilla bicolor bicolor pada Sistem Resirkulasi dengan Periode Pergantian Air Berbeda
Abstrak: Ikan sidat Anguilla bicolor bicolor merupakan komoditas akuakultur yang bernilai ekonomis tinggi. Budidaya ikan sidat pada sistem resirkulasi dapat menyebabkan penurunan kualitas air seperti peningkatan amonia akibat buangan metabolik. Hal tersebut harus diikuti dengan pergantian air. Penelitian ini bertujuan untuk menentukan periode pergantian air yang terbaik pada pendederan ikan sidat Anguilla bicolor bicolor dalam sistem resirkulasi melalui kajian parameter produksi dan parameter kualitas air. Penelitian ini menggunakan rancangan acak lengkap dengan perlakuan pergantian air sebanyak 20% setiap 2, 4, dan 6 hari sekali yang masing-masing diulang tiga kali. Wadah yang digunakan adalah akuarium dengan top filter sebagai sistem resirkulasi. Komposisi top filter yang digunakan yaitu dakron sebagai filter fisik, karang aktif dan zeolit sebagai filter kimia. Ikan sidat yang digunakan berbobot rata-rata 10,00 ± 0,98 g yang dipelihara selama 60 hari. Kinerja produksi terbaik pada pemeliharaan elver ikan sidat Anguilla bicolor bicolor di akuarium dihasilkan oleh pergantian air 20% setiap dua hari sekali.
Keyword: ikan sidat, kinerja produksi, pergantian air, sistem resirkulasi

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