Judul: Biological and Economic Evaluation of The Impact of Predators on Oyster Mortality (A Case study in Quiberon Bay, France).
Abstrak: Pacific oysters have been cultured in several country as a result, Crassostrea gigas has become the leading species in world culture, with an estimated production of 4.6 million tons in 2006. France producing around 130 000 tons of the cupped oyster C. gigas annually and a remaining 1 500 tons of the flat oyster Ostrea edulis. Quiberon Bay has a large production of oyster, approximately 15 000 tons annually which contributes to oyster production in France. These small scale industry activities contributes to largely to France economy. Since the year of 2000 and especially 2006, the oyster mortality rates have reached quite unusual, estimated at 60% mortality in a breeding cycle ending in late 2006, according to the response of 51 companies interviewed by the CRC. This mortality brought a great impact on the France's economy. So, in this study, we observed the effects of oyster mortality in terms of biology and economics. The objectives of this study are to analyse RISCO data on oyster mortality, to determine effect of predators on oyster culture, mapping the distribution of different types of predators and to calculate the economic analysis of oyster mortality. RISCO project is conducted by Ifremer with their partners. As present in the study area, this project is held in Quiberon Bay, France and the 15 station’s of oyster culture. The observations of this research have been conducted monthly (8 surveys) in May until December 2010. Each month, there are several analyses of RISCO project which have been done, one of them is analysis oyster growth and mortality (Spat and Adult). In each station, we counted the number of predators (starfishes and gastropods) on the cage and in each bag we calculated the numbers of dead oysters then we took sampling of 30 living oysters for growth and pathology analysis. In each dead oyster, we also observed the boring oyster by oyster drill and parasitism by Polydora. The result of this research showed that there were a potential role of two species of starfishes, Asterias rubens and Marthasterias glacialis and two species of gastropods, Ocenebra erinacea and Ocenebrillus inornatus. Marthasterias glacialis indicated a great impact on mortality of adult oysters. The relation between oyster's mortality and the presence of gastropods depended on time and according to reproductive cycle. Several months show clearly a predation of oysters and others show a concentration of gastropods for spawning. Predators on oyster culture also indicated a great impact in economic value. The economic value on oyster culture model applied in RISCO project shows that BSP was higher than BAP. Based on economic value analysis on RISCO project shows that BSP was higher than BAP. Economic loss in BAP greatly happen in station 2 and 5, approximately €81.28 - €81.83. On the contrary, station 15 indicate has the higher loss in BSP approximately €54.92 or 363 oysters and for the rest, the economic value was varies between €29.67 - €40.30.
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Judul: Business Analysis of Catching and Sustainable  Lobster Utilization in Pangandaran Regency, West Java
Abstrak: Lobster atau udang karang merupakan salah satu komoditas perikanan unggulan pada pasar domestik maupun ekspor. Stok komoditas lobster saat ini masih bergantung pada alam. Sebagian besar di wilayah pengelolaan perairan Indonesia telah mencapai batas maksimum jumlah tangkapan yang diperbolehkan. Usaha penangkapan lobster sebagai salah satu satu pengelolaan wilayah perairan Pangandaran perlu dikaji untuk mengetahui bagaimana sumberdaya lobster dapat dimanfaatkan secara optimal dan berkelanjutan. Tujuan penelitian ini adalah: (1) mengidentifikasi kondisi biologi lobster di Perairan Kabupaten Pangandaran Jawa Barat; (2) menganalisis kondisi pemanfaatan optimal lobster di Perairan Kabupaten Pangandaran Jawa Barat; (3) menganalisis kelayakan usaha finansial penangkapan lobster di Perairan Kabupaten Pangandaran Jawa Barat; dan (4) menganalisis strategi kebijakan pengelolaan lobster secara berkelanjutan di Kabupaten Pangandaran Jawa Barat. Metode yang digunakan pada penelitian ini yaitu: (1) analisis kondisi biologi lobster; (2) analisis bioekonomi spasial; (3) cost benefit analysis; dan (4) analisis deskriptif kualitatif. Penelitian ini menunjukkan rata-rata lobster yang tertangkap di Kabupaten tidak sesuai dengan ukuran layak tangkap. Tingkat CPUE lobster memiliki nilai yang berfluktuatif, namun terjadi penurunan secara signifikan pada tahun 2021, sehingga alokasi penangkapan optimal yang direkomendasikan yaitu 396 trip/bulan. Berdasarkan hasil analisis, usaha penangkapan lobster layak untuk dijalankan. Adapun strategi kebijakan pengelolaan lobster yang dapat dilakukan agar tetap lestari yaitu dimulai dari pelarangan penangkapan benih bening lobster kemudian diikuti dengan kebijakan lainnya. Perlu dilakukan penelitian lebih lanjut mengenai laju pertumbuhan dan perkembangan biomassa lobster dan pengembangan budidaya lobster di Perairan Kabupaten Pangandaran, Jawa Barat., Lobster or crayfish is one of the leading fishery commodities in the domestic and export markets. Lobster commodity stocks are currently still dependent on nature. Most of the Indonesian water management areas have reached the maximum allowable catch. Lobster fishing as one of the management of the Pangandaran waters area needs to be studied to find out how lobster resources can be used optimally and sustainably. The aims of this study were: (1) to identify the biological conditions of lobsters in the waters of Pangandaran Regency, West Java; (2) analyzing the condition of optimal utilization of lobsters in the waters of Pangandaran Regency, West Java; (3) analyzing the financial feasibility of catching lobsters in the waters of Pangandaran Regency, West Java; and (4) analyze the policy strategy for sustainable lobster management in Pangandaran Regency, West Java. The methods used in this study were: (1) analysis of the biological conditions of the lobsters; (2) spatial bioeconomic analysis; (3) costbenefit analysis; and (4) qualitative descriptive analysis. This research shows that the average size of lobsters caught in the district is not suitable for catching size. The lobster CPUE level has a fluctuating value, but there will be a significant decrease in 2021, so the recommended optimal catch allocation is 396 trip/month the harvest season. Based on the results of the analysis, the lobster-catching business is feasible to run. The lobster management policy strategy that can be implemented to remain sustainable is to start with a ban on catching clear lobster seeds, followed by other policies. It is necessary to carry out further research regarding the growth rate and development of lobster biomass and the development of lobster cultivation
Keyword: bioeconomy, optimal fishing, sea lobster, sustainable fisheries

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular