Judul: Kelangsungan Hidup Ikan Betutu, Oxyeleotris marmorata (Blkr.), yang Dipelihara di Kabupaten Serang dan Bogor.
Abstrak: Upaya pembudidayaan ikan betutu telah dilakukan, baik di masyarakat maupun dalam berbagai uji coba pemeliharaan (pembesaran). Di masyarakat, kegiatan pembesaran sudah dilakukan yakni dengan mengumpulkan ikan yang belum mencapai ukuran pasar dari hasil tangkapan di alam. Pada usaha tersebut terjadi kematian ikan betutu yang tinggi, sehingga menjadi faktor penghambat bagi berkembangnya budidaya ikan ini. Informasi kuantitatif mengenai kelangsungan hidup dan faktor-faktor penentunya masih sangat sedikit. Padahal informasi tersebut dapat dijadikan landasan perbaikan dalam meningkatkan kelangsungan hidup pada usaha budidaya sehingga dapat meningkatkan produksi. Penelitian ini bertujuan untuk mengetahui tingkat kelangsungan hidup ikan betutu yang dipelihara dalam kolam dan bak di Kabupaten Serang dan Bogor. Selain itu faktor-faktor yang mempengaruhi kelangsungan hidup ikan ini juga dikaji.
Keyword: 

Judul: Pertumbuhan dan tingkat kelangsungan hidup larva ikan betutu, Oxyeleotris marmorata (Blkr.), yang diberi pakan alami infusoria
Abstrak: Penelitian ini bertujuan untuk mengetahui pertumbuhan tingkat kelangsungan hidup larva ikan betutu, dan Oxyeleotris marmorata (Blkr.), yang diberi pakan alami infusoria, dan dilaksanakan pada tanggal 19 Februari sampai 3 Maret 1991 di Kolam Babakan Darmaga, Bogor. Infusoria diberikan ke larva ikan betutu dengan kepadatan 100, 500 dan 900 individu/ml, masing-masing dengan tiga kali ulangan. Larva ikan dipelihara dalam akuarium dengan volume air sebanyak 40 liter dan kepadatan larva 40 ekor/liter. Penggantian air dilakukan setiap hari sebanyak 20% dari volume air sebelum pemberian pakan (pagi hari). Pengambilan contoh ikan sebanyak 10 ekor dilakukan 3 hari sekali. Dalam perut larva tidak ditemukan adanya infusoria sehingga diduga infusoria tidak dimakan oleh larva. Infusoria yang tumbuh dalam media kultur adalah dari jenis Euglena sp., Chilodonella sp. dan Vorticella sp.. Bobot larva ikan betutu menurun selama pemeliharaan. Laju pertumbuhan dan kelangsungan hidupnya meningkat masing-masing dari 7,55 hingga 3,11% per hari dan dari 1,94 hingga 3,40% dengan meningkatnya pemberian infusoria dari 100 hingga 900 individu/ml.
Keyword: 

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
Keyword: