Judul: Teknologi Penangkapan Pilihan untuk Perikanan Rajungan di Perairan Gebang Mekar Kabupaten Cirebon
Abstrak: The commence of swimming crab on market export tend to increase the price, that cause becomes one of the motivator of Gebang Mekar fishermen participating on swimming crab fishery. Since 2001 swimming crab fishing technology become changed from set bottom gillnet to trap at Gebang Mekar waters. The objectives of this research are: to determine swimming crab fishing technology alternative which more effective, efficient and suistainable and then to determine development strategy of swimming crab fishery. Some analysis used in this research were (1) Scoring method, to determine the best of swimming crab fishing technology pursuant to biological, technical, social and economic aspects; (2) Feasibility analysis, to determine the suitable swimming crab fishing technology; (3) SWOT analysis, to determine development strategy of swimming crab fishery. The result of this research is the swimming crab trap fishing technology which effective, efficient and suistainable. The development strategy of swimming crab fishing with trap at Gebang Mekar waters are: (1)Optimizing swimming crab fishery with trap; (2)Development swimming crab fishery in line 2; (3)Increase the effort management of fisherman; (4)Developing of fishing vessel; (5)Repairing infrastructure facilities fisheries.
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Judul: Dampak Penangkapan Rajungan (Portunus pelagicus) terhadap Target dan Non Target Spesies di Perairan Cirebon dan Sekitarnya
Abstrak: Kondisi tangkap lebih mengancam keberlanjutan stok rajungan di perairan. Rendahnya selektivitas alat tangkap mengakibatkan tertangkapnya hasil tangkapan sampingan (bycatch) dalam jumlah cukup besar. Penelitian ini bertujuan: (1) mendeskripsikan unit penangkapan rajungan yang berbasis di Desa Gebang Mekar Kabupaten Cirebon; (2) mengevaluasi status stok rajungan; dan (3) mengevaluasi dampak penangkapan rajungan, khususnya terhadap sumber daya ikan non target tangkapan. Data dianalisis dengan beberapa metode yakni analisis mortalitas dan laju eksploitasi, ukuran layak tangkap, serta jenis dan proporsi hasil tangkapan. Hasil penelitian menunjukkan unit penangkapan rajungan di lokasi studi yaitu jaring kejer sebanyak 102 unit, bubu lipat 25 unit, jaring arad 100 unit, dan garuk 100 unit. Laju eksploitasi (E) rajungan jantan 0,66 dan betina 0,60 per tahun. Rajungan ukuran boleh ditangkap (legal size) oleh jaring kejer berjumlah 97%, bubu lipat 97%, jaring arad 83%, dan garuk 19%. Bycatch jaring kejer, bubu lipat, jaring arad, dan garuk sebagian besar belum memenuhi ukuran layak tangkap. Proporsi hasil tangkapan sampingan jaring kejer 51%, bubu lipat 55%, jaring arad 95%, dan garuk 59%. Indeks keragaman Shannon – wiener (H’) hasil tangkapan jaring arad sebesar 3,52, jaring kejer 3,37, bubu lipat 1,82, dan garuk 1,52. Pemerintah perlu meningkatkan penyadaran nelayan agar tidak menggunakan alat tangkap jaring arad dan garuk karena melanggar hukum dan berdampak negatif terhadap sumber daya ikan., Over fishing threatens the sustainability of crab stocks in the waters. The low selectivity fishing gears resulted in a relatively large number of caught bycatch species. This study aims to describe the blue swimming crab fishing unit based in Gebang Mekar Village, Cirebon District; to evaluate the status of the crab stock, and to evaluate the impact of crab fishing, especially on non-target species. The analyses of mortality and exploitation rate, allowable (legal) catch size, and catch composition were conducted. The results showed that the fishing units of blue swimming crab at the study site were 102 units of kejer nets, 25 units of collapsible traps, 100 units of arad nets, and 100 units of dredged nets. The exploitation rate (E) of male crabs was 0.66 and for females was 0.59 per year. For the kejer nets 97% of the crabs caught were in the legal size, 97% for collapsible traps, 83% for arad nets, and 19% for dredged nets. Most of the bycatch of kejer nets, collapsible traps, arad nets, and dredged nets did not meet the allowable catch size. The proportion of the bycatch for kejer nets was 51%, collapsible traps was 55%, arad nets was 95%, and dredged nets were 59%. Shannon – wiener diversity index (H’) of arad nets catches were 3.52, kejer nets (3.37), collapsible traps (1.82), and dredged nets (1.52). Government should disseminate to fishers not to used arad, and dredged nets for crabs fishery due to illegal fishing gears and negative impact on the fish resources.
Keyword: blue swimming crab, bycatch, Cirebon waters, Gebang Mekar, fishing impact, dampak penangkapan, rajungan, perairan Cirebon

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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