Judul: Kajian perikanan trawl demersal: evaluasi tiga jenis Bycatch Reduction Device (BRD)
Abstrak: In recent years, global concern over the impacts of fishing activity on non-target species termed as “by-catch” has been increasing. Most of conventional shrimp trawls are poorly selective so they retain large quantities of bycatch (Saila 1983). The main objective of this research is to determine the type of bycatch reduction device which is appropriate for demersal trawl in Indonesia. This was achieved by three following objectives : 1) to compare the effectiveness three BRDs in reducing the bycatch from the industrial trawl fisheries, 2) to observe the process escapement of fish from three types of bycatch reduction device, and 3) to analyze characteristic of the bycatch from small scale demersal trawl fisheries. There were three types of BRDs tested for this study, i.e. the TED super shooter BRD, the square mesh window BRD, and the fish eye BRD. The TED super shooter BRD reduced reduced the compressed fish down to 4,98% and the anguilliform fish down to 0,47%, the square mesh window reduced the compressed fish down to 6,23% and the fish eye reduced the compressed fish down to 10,23% and the anguilliform fish down to 4,62%. Observation in the flume tank revealed that the BRD super shooter reduce compressed fish up to 30% and depressed fish 30%. The square mesh window reduced the compressed fish up to 50% and depressed fish 50%. While the fish eye BRD reduce compressed fish 30% and depressed fish 50%. The bycatch and target catch from 30 fishing trip in Blanakan in July 2007 were 52,92 kg and 354,88 kg (ratio of 1:6) and in December 2007 were 192 kg and 788 kg (ratio of 1:4). The bycatch and target catch from 30 fishing trip in Eretan Kulon in July 2007 were 101,38 kg and 273,43 kg (ratio of 1:3) and in December were 194,2 kg and 692 kg (ratio of 1:4). The bycath from Blanakan was dominated by compressed fish such as Leiognathidae, Sciaenidae, Nemipteridae and Mullidae, depressed fish from Platychepalidae. The composition of the bycatch from Eretan Kulon were dominated by compressed fish such as Sciaenidae, Leiognathidae, Nemipteridae and Mullidae, fusiform fish from Synodontidae. Since the bycatch was dominated by compressed fish, then bycatch reduction device fish eye and square mesh window are recommended to be used in Indonesian trawl fisheries.
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Judul: Pemasangan By-catch Reduction Device pada Jaring Arad (Mini Trawl
Abstrak: Alat tangkap efektif yang saat ini digunakan oleh nelayan tradisional untuk kegiatan operasi penangkapan udang adalah jaring arad (mini trawl). Kemudahan pengoperasian dan keragaan teknis jaring arad yang baik menjadikan alat ini sangat efektif dan produktif dalam penangkapan udang di perairan pantai. Permasalahan utama pada perikanan jaring arad adalah ketidakselektifan alat tangkap ini terhadap hasil tangkap sampingan (HTS). By-catch Reduction Device (BRD) merupakan salah satu alat yang didesain untuk: mengurangi HTS. Konstruksi perangkat seleksi ini adalah kerangka dan kisikisi yang dibuat dari bahan besi berongga dan pipa PVC. Penelitian dengan metode uji coba penangkapan ikan (experimental fishing) telah dilaksanankan di perairan Muarareja, Kota Tegal, yaitu untuk mengetahui pengaruh pemasangan BRD terhadap basil tangkapan dan selektivitas kisi BRD terhadap HTS dominan. Pengaruh pemasangan BRD terhadap basil tangkapan dianalisis secara statistika dan selektivitas kisi menggunakan model kurva logistik. Pemasangan BRD pada jaring arad berpengaruh nyata terhadap hasil tangkapan udang yaitu pada jarak kisi 2 dan 3 cm, sedangkan untuk HTS semua ukuran jarak kisi berpengaruh nyata bila dibandingkan dengan jaring arad standard (kontrol). Tingkat selek:tivitas kisi BRD terhadap HTS dominan yang meliputi gulamah, beloso, dan lidah yaitu semakin lebar jarak kisi menyebabkan ukuran ikan yang tertangkap pada kantong jaring arad maupun lolos ke cover net akan semakin besar.
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Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology