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 Shrimp Waste as Artificial Bait in Trap Fishing Operation
Abstrak: Nelayan bubu di Pulau Panggang masih menggunakan berbagai macam umpan (ikan rucah, bulu babi dan bintang laut) dengan sistem try and error untuk memikat ikan masuk ke dalam bubu, namun hasilnya belum memuaskan. Limbah udang menjadi alternatif umpan dalam pengoperasian bubu. Penelitian ini bertujuan mendeskripsikan komposisi hasil tangkapan bubu tambun dengan umpan limbah udang, menentukan pengaruh umpan buatan dari limbah udang terhadap jumlah tangkapan serta menghitung efektivitas penangkapan ikan target menggunakan umpan buatan limbah udang. Penelitian menggunakan metode experimental fishing menggunakan 6 unit bubu tambun dengan 3 perlakuan yaitu bubu dengan umpan limbah udang, ikan rucah, dan bubu tanpa umpan. Tiga unit bubu dengan umpan limbah udang, ikan rucah dan tanpa umpan dioperasikan sekaligus dalam suatu perairan serta 3 unit bubu lainnya dioperasikan pada perairan yang berbeda. Hasil penelitian menunjukkan bahwa bubu tambun menggunakan limbah udang paling efektif dibandingkan umpan dari ikan rucah dan tanpa umpan. Namun, penggunaan umpan ikan rucah lebih efektif dibandingkan dengan bubu tanpa umpan untuk menangkap ikan. Hasil tangkapan utama bubu di Pulau Panggang Kepulauan Seribu tercatat 526 ekor (68,58%) dan hasil tangkapan sampingan sebanyak 241ekor (31,42%). Selain itu, umpan buatan dari limbah udang berpengaruh signifikan terhadap jumlah hasil tangkapan bubu di perairan Pulau Panggang Kepulauan Seribu., Trap fishers in panggang Island have used various kinds of bait with a try and error system to catch fish, but the catch results were not satisfactory. Shrimp waste can be used as an alternative bait in trap fishing operations. The research aims to describe the composition of the trap catches with shrimp waste bait, determine the effect of shrimp waste bait on the number of trap catches, and calculate the effectiveness of fish targets using shrimp waste bait. The study used an experimental fishing method with six traps with three bait treatments: shrimp waste bait, trash fish bait, and no bait, as the control treatment. The three traps are operated simultaneously in a fishing ground, and the other three are operated in different fishing ground. The results showed that the shrimp waste baits trap was the most effective than trash fish baits and without baits. However, trash fish baits are more effective than no baits. The main catch of traps in Panggang Island’s water was recorded at 526 fish (68.58%) and by-catch at 241 fish (31.42%). In conclution, shrimp waste bait has a significant effect on the number of traps caught.
Keyword: traps, main catches, by catches, shrimp waste bait, artificial bait

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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