Judul: Technical Performance and Effectiveness of Using Bait on the Dragon Traps (Accordion-shaped Traps) in Bondet Waters Cirebon West Java
Abstrak: Hasil tangkapan yang diperoleh nelayan sedikit menyebabkan pendapatan nelayan tidak dapat menutupi kebutuhan sehari-hari, sehingga diperlukan cara untuk meningkatkan produktivitas bubu naga, salah satu caranya dengan penggunaan umpan. Penelitian ini bertujuan untuk mendeskripsikan unit penangkapan bubu naga, menghitung komposisi hasil tangkapan yang menggunakan umpan dan tidak menggunakan umpan pada bubu naga, dan menghitung pendapatan usaha perikanan bubu naga. Metode yang digunakan dalam penelitian adalah experimental fishing dengan menggunakan umpan ikan rucah sebanyak 20 kali ulangan (trip) di lapangan. Hasil penelitian menunjukkan bahwa dimensi bubu naga yang digunakan dalam penelitian (50 cm x 37 cm x 35 cm) dengan panjang bubu yaitu 10 m. Total hasil tangkapan bubu naga kontrol atau tanpa umpan yaitu 82,53 kg (672 ekor) dengan 11 jenis ikan dan total hasil tangkapan bubu naga perlakuan 131,721 kg (904 ekor) dengan 11 jenis ikan. Usaha perikanan bubu naga layak untuk dilanjutkan. Umpan ikan rucah dapat dijadikan sebagai implementasi teknologi tepat guna untuk alat tangkap bubu naga karena hasil tangkapan bubu naga yang menggunakan umpan lebih banyak jika dibandingkan dengan bubu naga yang tidak menggunakan umpan. Selain itu, Ikan rucah juga lebih mudah didapatkan dan harganya terjangkau., The catch obtained by fishers is few cause make fishers income not able to cover their daily needs, so way required to increase the productivity of dragon traps, the one way to use bait. This study aims to describe the dragon traps fishing unit, counting species caught in dragon traps using bait and without bait, and counting the revenue of the dragon traps fishing business. This research method was experimental fishing with 20 repetitions using trash fish bait operations in the field. The results show that the size of the dragon traps used in the research (50 cm x 37 cm x 35 cm) with a length trap of 10 m, control dragon traps or without bait 82.53 kg (672 individual of fish) with 11 species and the total catch of the treated dragon traps was 131.721 kg (904 individual fish) with 11 species. The dragon trap fishing business deserves to be continued. Because dragon traps with bait catch more fish than dragon traps without bait, trash fish can be used as a suitable technology applied for dragon traps. In addition, trash fish are readily available and affordable.
Keyword: bait, dragon traps, profit, total catch, trash fish

Judul: The Use of Trash Fish Diluted with Squid (Loligo spp.) Bait on Bottom Gillnet in Palabuhanratu Bay
Abstrak: Perikanan jaring rampus saat ini belum mengalami banyak kemajuan dan hasil tangkapannya yang tidak selalu meningkat. Penelitian ini bertujuan untuk membandingkan komposisi hasil tangkapan jaring rampus berumpan ikan rucah yang dilarutkan cumi dengan jaring rampus tanpa umpan, menentukan pengaruh penggunaan umpan, dan menentukan produktivitas jaring rampus perlakuan dan kontrol. Penelitian dilakukan di Teluk Palabuhanratu, Kabupaten Sukabumi, menggunakan metode eksperimental fishing dengan mengikuti operasi penangkapan selama 16 trip. Hasil tangkapan pada piece jaring rampus perlakuan sebesar 69,83 kg dan piece kontrol sebesar 42,93 kg dengan rata-rata jumlah jenis ikan pada piece perlakuan yaitu 8  0,47 sedangkan kontrol yaitu 7  0,45. Hasil tangkapan dominan pada penelitian ini adalah swanggi (Priacanthus tayenus), gulamah (Johnius trachycephalus), layang anggur (Decapterus kurroides), selar bentong (Selar crumenophthalmus), dan kakap (Lates calcarifer). Perlakuan menggunakan umpan ikan rucah yang dilarutkan cumi memberikan pengaruh nyata terhadap berat total dan jumlah ekor hasil tangkapan. Penggunaan umpan membantu kenaikan persentase produktivitas piece jaring rampus perlakuan sebesar 62,7% dengan produktivitas per-piece perlakuan lebih besar dibandingkan kontrol dengan masing-masing nilainya sebesar 1,09 kg/piece dan 0,67 kg/piece dan untuk nilai produktivitas satu piece perlakuan yaitu Rp19.181,00 sedangkan kontrol yaitu Rp6946,00 sehingga didapatkan persentase produktivitas hasil tangkapan piece perlakuan terhadap piece kontrol sebesar 176,1%., Currently, bottom gillnet fishing has not made much development, and its catches are not always increasing. This study aimed to compare the composition of the catch bottom gillnet with trash fish diluted squid bait and without bait, determine the effect of bait use, and determine the productivity of treatment and control bottom gillnet. The research was conducted in Palabuhanratu Bay, Sukabumi Regency, using experimental fishing methods by following fishing operations for 16 trips. The catch on the treated piece was 69,83 kg, and the control piece was 42,93 kg, with the average number of fish species in the treated piece was 8  0,47 while the control was 7  0,45. The dominant catches in this study were bigeye bullseye (Priacanthus tayenus), leaf tail croaker (Johnius trachycephalus), redtail scad (Decapterus kurroides), bigeye scad (Selar crumenophthalmus), and snapper (Lates calcarifer). Trash fish diluted squid bait significantly affected the total weight and number of fish caught. The use of bait helped to increase the percentage of productivity of treated net pieces by 62,7%, with productivity per treated piece more significant than the control with a value of 1,09 kg/piece and 0,67 kg/piece. The productivity value of one piece of treated was Rp19.181,00 while the control was Rp6946,00, so the percentage of productivity of the treated piece catch against the control piece was 176,1%.
Keyword: bait attractor, bottom gillnet, Palabuhanratu Bay, squid, trash fish

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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