Judul: Some Changes in Specification of Fishing Units and Fishing Areas of Shark Fishers From Tanjung Luar, East Lombok
Abstrak: Nelayan Tanjung Luar menggunakan rawai hanyut dan rawai dasar untuk menangkap hiu. Hiu lanjaman (C. falciformis), salah satu jenis yang tercantum pada Appendiks II CITES, adalah jenis ikan yang dominan tertangkap. Pemerintah Indonesia memerlukan sejumlah informasi dalam pengelolaan perikanan ini dengan melakukan pemantauan. Informasi yang diperlukan seperti, komposisi hiu yang tertangkap, perkembangan unit penangkapan, daerah penangkapan serta persepsi nelayan. Informasi tersebut berguna untuk menyusun strategi pengelolaan perikanan hiu. Penelitian bertujuan mengidentifikasi perubahan spesifikasi unit penangkapan, daerah penangkapan, komposisi hasil tangkapan selama 2014-2020, persepsi serta optimisme nelayan hiu. Pengumpulan data melalui pengamatan lapang dan mewawancarai 30 nelayan serta analisis statistik perikanan Dinas Kelautan dan Perikanan NTB yang bersumber dari hasil pemantauan Wildlife Conservation Society. Analisis deskriptif dan buffer analysis dilakukan terhadap data yang diperoleh. Hasil penelitian menunjukkan jumlah kapal penangkap hiu berkurang karena rusak, jumlah maksimum pancing yang dibawa berkurang sesuai dengan kebijakan lokal. Daerah operasi penangkapan hiu cenderung mengarah ke timur, fokus pada perairan sebelah barat Pulau Sumba. Ukuran hiu lanjaman yang tertangkap semakin besar, petunjuk bahwa stok hiu lanjaman dalam status terjaga, porsi hiu lanjaman yang tertangkap rawai hanyut semakin banyak sedangkan yang tertangkap rawai dasar semakin sedikit. Nelayan masih optimis dengan penangkapan hiu sebagai mata pencaharian utama mereka., Fishers from Tanjung Luar operate drift longlines and bottom longlines to catch sharks. Silky sharks (C. falciformis), a species under CITES Appendix II, is a dominant species of their catch. Government of Indonesia needs some information for managing the fisheries by conducting monitoring program. The information needed includes, among others, the species composition of captured sharks, changes in fishing units and fishing ground, and the fishermen's perception. This information can be used for determining fisheries management strategies. This study aims to identify some changes in the specifications of fishing units, fishing grounds, catch composition, perceptions and optimism of the fishers during 2014-2020. Data collection was conducted through field observations, interviews with 30 fishers and some analysis on fisheries statistics from the Agency of Marine Affairs and Fisheries of NTB generated from monitoring program conducted by the Wildlife Conservation Society. Descriptive and buffer analysis were performed to provide the needed information. The results showed a reduction in the number of shark fishing vessels due to physical damage and reduction in the number of fishing hooks per fishing vessel due to local fisheries regulation. Fising operation for shark has been shifting eastward with a focus of around the western waters of Sumba Island. The capture size of the silky shark is getting larger, an indication of a stable status of the fish stock, the portion of the silky shark in the catch from the drift longlines has been increasing while that from the bottom longines is getting fewer. Fishers are still optimistic about their fisheries as their livelihood.
Keyword: capture fisheries, CITES, shark conservation, shark fishing

Judul: Sharks and Rays Bycatch in Small Fisheries in Kebumen  Waters, Central Java
Abstrak: Minimnya pendataan hiu dan pari telah menjadi isu penting mengingat jumlah penangkapannya yang terus meningkat saat populasinya terus berkurang. Hal tersebut juga terjadi di PPI Karangduwur dan PPI Argopeni. Penelitian ini bertujuan untuk mendeskripsikan unit penangkapan dan hasil tangkapan gillnet, mengidentifikasi jenis hiu dan pari serta mengklasifikasikan status konservasinya, dan mengevaluasi parameter biologinya (panjang dan berat). Analisis yang digunakan adalah analisis deskriptif dan deskriptif komparatif. Hasil penelitian menunjukkan bahwa unit penangkapan ikan yang ada di perairan Kebumen mayoritas menggunakan alat tangkap gillnet dengan kapal 1-2GT. Selain itu, terdapat 4 jenis hiu dan 6 jenis pari yang didaratkan. Hiu dan pari yang ditemukan berada pada status critically endangered (CR), endangered (EN), vulnerable (VU), dan near threatened (NT) yang terdiri dari Chiloscyllium indicum 72 ekor, Sphyrna lewini 8 ekor, Carcharhinus limbatus sebanyak 68 ekor, dan Atelomycterus marmoratus 30 ekor. Sedangkan pari terdiri dari Hemitrygon akajei 809 ekor, Gymnura marmorata 359 ekor, Manta birostis 8 ekor, Rhinobatus typus 71 ekor, Aetobatus ocellatus 69 ekor, dan Rhinoptera bonasus 78 ekor. Mayoritas hiu dan pari yang tertangkap masih dalam kategori tidak layak tangkap., The minimum data on sharks and rays has become an important issue, considering the catches are increasing while their populations decrease. This also happened at PPI Karangduwur and PPI Argopeni. This research aims to describe fishing units and gillnet catches, identify and classify the conservation status of sharks and rays, and evaluate their biological parameters (length and weight). The analysis used is descriptive analysis and comparative descriptive. The research results showed that most fishing units in Kebumen waters use gillnet with 1-2GT fishing boats. There were 4 types of sharks and 6 types of rays. The sharks and rays found are in status critically endangered (CR), endangered (IN), vulnerable (VU), then near threatened (NT), which consists of 72 Chiloscyllium indicus, 8 Sphyrna lewini, Carcharhinus limbatus as many as 68 tails, and Atelomycterus marmoratus 30. While stingrays consist of Hemitrygon akajei, Gymnura marmorata, Manta birostis, Rhinobatus typus, Aetobatus ocellatus, and Rhinoptera bonasus as many as 809, 358, 8, 71, 69 and 78 respectively. The majority of sharks and rays caught are still in the below Length of Maturity.
Keyword: hasil tangkapan sampingan, hiu, jaring insang, pari, PPI Kebumen, bycatch, gillnet, sharks, rays

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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