Judul: Trade and Harvest Characteristics of Asian Bockadam (Cerberus schneiderii) from West Java
Abstrak: Salah satu ular dari famili homalopsidae yaitu ular asin (Cerberus schneiderii) banyak diperdagangkan dari Indonesia. Namun, ular tersebut hanya sedikit diteliti di seluruh wilayah sebarannya yang luas. Data perdagangan dan biologis dari ular asin di Indonesia tidak terdokumentasi dengan baik. Berdasarkan data perdagangan dan pembedahan 3.382 ular yang dibawa ke fasilitas pemrosesan di Cirebon, Jawa Barat, kami mendokumentasikan volume dan karakteristik perdagangan, juga aspek biologi dari ular air yang memiliki habitat di daerah pesisir ini. Panen komersial dilakukan pada individu dewasa jantan dan betina. 43 Negara diketahui mengimpor ular asin dalam berbagai bentuk (kulit dan turunannya, daging, hewan hidup, dan spesimen) dari 1984-2020. Singapura menjadi negara terbesar yang mengimpor jenis ini dari Indonesia (>60%) setara dengan 2.176.477 individu. Ular asin didapatkan dari alam (W>60%) di sebagian pesisir utara Jawa Barat, dan Jawa Tengah. Ular asin diperoleh dari individu, dan kelompok pemburu ular. Ular asin dihargai 6000-12000 rupiah per kilogram. Ular asin yang diekspor sebagian besar berupa kulit dan daging. Berdasarkan data perdagangan ular asin tersebut, pejantan menunjukkan pembesaran testis di akhir tahun (Agustus-November), akan tetapi betina yang produktif dan tidak produktif dijumpai di sepanjang tahun. Betina dapat memiliki 3-45 anakan dalam satu waktu, lebih banyak pada betina dengan ukuran lebih besar. Jenis ini diketahui memiliki kemampuan pematangan awal dalam fase reproduksinya, serta beranak (ovovivipar) sepanjang tahun. Tekanan terhadap populasi ular asin akibat adanya panenan komersial dapat ditahan dengan membatasi panen di beberapa lokasi dan/atau beberapa waktu dalam setahun, sehingga dapat mengalihkan dampak panen dari kelompok kritis seperti betina dewasa., One of homalopsid snake, Asian bockadams (Cerberus schneiderii) is heavily traded from Indonesia. However, the snake has attracted relatively little study across their wide geographic range. Trade and biological data from Asian Bockadams in Indonesia are not well documented. Based on trade data and dissection of 3,382 snakes brought to a processing facility in Cirebon, West Java, we document the volume and characteristics of the trade, as well as the biology of the water snakes that have a habitat in the coastal area. 43 Countries are known to import asian bockadam in various forms (skins and derivatives, meat, live animals, and specimens) from 1984-2020. Singapore is the largest country that imports this species from Indonesia (> 60%), equivalent to 2,176,477 individuals. Asian bockadam are obtained mostly from nature (W> 60%), in parts of the north coast of West Java and Central Java. Asian bockadam are obtained from individuals and groups of snake hunters. Asian bockadam are valued at 6000-12000 rupiah per kilogram. Skin and meat are the most traded forms for asian bockadam. Among all of the snake that harvested from West Java, males showed testicular enlargement late in the year (August-November), but both reproductive and non-reproductive females were found year-round. Litters were large (3 to 45 offspring), especially in larger females. The commercial harvest falls mainly on adult snakes of both sexes. Life-history traits such as early maturation and frequent production of large litters render this species resilient to commercial harvesting. The data obtained can be used as a scientific basis in Asian Bockadams conservation management.
Keyword: Berkelanjutan, Homalopsidae, Konservasi, Perdagangan

Judul: Tata Niaga, Kelimpahan Dan Karakteristik Habitat Ular Jali Ptyas Mucosus (Linnaeus 1758) Di Jawa Tengah
Abstrak: The research of oriental rat-snake’s (Ptyas mucosus Linn 1758) abundance and its habitat is still rare. Oriental rat-snake is classified as a commerce species and is listed on Appendix II of CITES. This study was aimed at measuring the abundance and morphometric characteristic of oriental rat-snake in Central Java. In the present study, harvesting abundance was obtained from 7 major collectors, 3 medium collectors, 4 small collectors and 4 hunters/professional catcher. Information was also obtained by interviewing the managers of both of BKSDA and LIPI. The morphometric data collected from 159 living and 131 dead specimens from major collectors. Harvesting abundance derived from the average of rat-snakes that was received by major collectors. Descriptive analysis was used to process data morphometric. The multiple linier regressions were performed to determine the relationship between body mass and body size variables. In the trading system, there were traders, trade’s chain and price factors that influance its. The harvesting abundance of oriental rat-snake in Central Java were estimated annually a 132 000. Its abundance was mainly influenced by natural factor, especially paddy's crops cycles. Based on the descriptive analysis of morphometric data obtained, males had longer SVL and greater body masses than females of the same body length. Average of male’s snout-vent length was 142,67 (SD=14,09) and body mass is 0,95 kg, while for female’s SVL was 140,45(SD=12,99) and body mass is 0,93 kg. The analysis showed insignificant differences in body size between the sexes and in each collector’s level. At present, abundance of oriental rat-snake can support commercial harvesting. Habitat characteristic of oriental rat-snake’s nest were consisted of nine variables, i.e. hole and soil moisture, hole and soil temperature, soil pH, location altitude, distance from water and settlement, and slope. However, further studies are needed to assess sustainable levels of harvesting.
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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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