Judul: Perbandingan Hasil Tangkapan Bubu pada Terumbu Buatan Bambu dan Ban di Sekitar Pulau Pramuka Kepulauan Seribu
Abstrak: The objectives of the research were to compare fish composition and abundance between tire and bamboo reefs and to compare yields traps. The study was conducted in 4 steps i.e ; survey location, make the design tire and bamboo artificial reefs, construction and maintenance of artificial reefs, determination of physics parameters, collection of perifiton sample, observation fish abundance among artificial reefs, operation by fish traps, fish identification, determination of fishing catch and analyze data using t-test. The result showed that no difference fish composition collected in around artificial reefs. The fish collected consists of 15 family, 19 genus and 27 species with 789 and 402 fishes in tire and bamboo artificial reefs respectively. Dominant species were collected in artificial reefs are Caesio cuning, Scolopsis sp, Siganus sutor and Sargocentron cornutum. Catch of traps between tire and bamboo artificial reefs is significant (thit 3,6 dan ttab 1,7, α 0,05) which artificial reef made of tire more bigger than bamboo.
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Judul: Produktivitas Hasil Tangkapan Bubu pada Terumbu Karang di Pulau Pramuka Kepulauan Seribu DKI Jakarta
Abstrak: Artificial reef made of coconut shell is an artificial habitat which is created to resemble the characteristics of natural reefs and become the alternative to improve the natural coral reefs that have been damaged. The opportunity of artificial reef utilization was researched by using experimental fishing and laboratory observe methods. The use of experimental fishing is to do the catching proses around the artificial reefs. The research was done in August 2013. Laboratory observe was done in September 2013 by observe the sample of fish intestines to get the data of abundance plankton from the inside of fish stomach. The results showed that 64 fishes was catches by bubu consist of 12 species. Red Breast Wrasse (Cheilinus fasciatus) from family Labridae is the dominant species. The plankton composition from the laboratory observe showed that Rhizosolenia and Leptocylindricus are the dominant plankton which indicate that the water is on good condition. Artificial diversity index ranged between 0,52-0,66; the uniformity index ranged between 0,17-0,21 and dominance index-0,45.
Keyword: plankton, artificial reef, coral reef, trap

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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