Judul: The Impact of Trap and Fishing Lines on Fish  Resources in the Waters of Harapan Island, Kepulauan Seribu, Jakarta
Abstrak: Penggunaan bubu dan pancing di Perairan Pulau Harapan Kepulauan Seribu mengakibatkan ikan juvenile banyak tertangkap. Hal ini karena bubu tidak memiliki celah pelolosan ikan dan pada pancing ukuran mata pancing terlalu kecil. Intensitas penangkapan ikan yang semakin tinggi dapat berdampak negatif bagi kelestarian stok ikan dan keseimbangan rantai makanan. Penelitian ini bertujuan untuk mendeskripsikan konstruksi alat tangkap bubu dan kelompok pancing (pancing ulur, pancing kotrek, dan pancing rawai) yang berbasis di Pulau Harapan, Kepulauan Seribu; mendeskripsikan karakteristik hasil tangkapan bubu dan kelompok pancing (spesies, ukuran layak tangkap, jumlah individu, dan komposisi) di Perairan Kepulauan Seribu, khususnya yang didaratkan di Pulau Harapan; dan mengestimasi dampak perikanan bubu dan kelompok pancing terhadap ikan target dan keseimbangan rantai makanan. Hasil penelitian menunjukkan bubu kawat memiliki panjang 137 cm, lebar 97 cm, dan bukaan mulut 35 cm. Kail pancing yang digunakan adalah kail pancing nomor 7. Kapal yang digunakan pada kedua alat tangkap ini yaitu kapal fiber. Nilai indeks keragaman Shannon-Wiener tangkapan alat tangkap bubu sebesar 2,56 dan pada pancing sebesar 0,77. Ikan yang memiliki nilai panjang pertama kali matang gonad (Lm) sama dengan metadata fishbase yaitu ikan pisang-pisang (Lutjanus vitta) dengan porsi ukuran layak tangkap sebesar 70%. Ikan kerapu lumpur (Epinephelus coioides), Ikan tenggiri (Scomberomorus commerson), dan ikan baronang garis (Siganus javus) memiliki nilai Lm penelitian lebih kecil dibanding metadata fishbase. Tangkapan ikan didominasi tingkat trofik TL3 dan TL2. Secara teori, jika hal ini terus berlanjut akan mengancam keberlanjutan sumberdaya ikan pada semua tingkat trofik (rantai makanan)., The use of traps and fishing lines in the waters of Harapan Island, Kepulauan Seribu resulted in many juvenile fish being caught. This is because the trap does not have a gap for the fish to escape and the hook size is too small on the fishing line. Higher fishing intensity have a negative impact on the sustainability of fish stocks and the balance of the food chain. This study aims to describe the construction of trap fishing gear and fishing lines (handline, hook and line, and longline) based on Harapan Island, Kepulauan Seribu; to describe the characteristics of traps and fishing lines catches (species, allowable catch size, number of individuals, and composition) in the Kepulauan Seribu waters, especially those landed on Harapan Island; and estimating the impact of trap fisheries and fishing lines group on target fish and the balance of the food chain. The results showed that the wire traps had a length of 137 cm, a width of 97 cm and a mouth opening of 35 cm. The fishers used a fishing hook with number of 7. The ship used for these two fishing gears was a fiber boat. The Shannon-Wiener diversity index value for trap catches was 2.56 and for fishing lines was 0.77. The fish with the length at first maturity (Lm) was similar with Fishbase metadata, i.e. Brownstripe red snapper (Lutjanus vitta) with an allowable catch size portion of 70%. Orange-spotted grouper (Epinephelus coioides), Narrow-barred Spanish mackerel (Scomberomorus commerson), and Streaked spinefoot (Siganus javus) were a smaller Lm values than Fishbase metadata. The fish catches were dominated by the catches of TL3
Keyword: Wire traps, Fishing lines, Fishing impact, Allowable catch size, Trophic  level

Judul: Dampak Perikanan Bubu yang Berbasis di Pulau Lancang terhadap Ekosistem Perairan di Sekitarnya
Abstrak: Terdapat dugaan degradasi sumberdaya ikan yang terjadi di perairan Pulau Lancang dan sekitarnya karena intensitas kegiatan perikanan tangkap, khususnya pengoperasian alat tangkap bubu. Pemerintah daerah Kepulauan Seribu (terkhusus Pulau Lancang) memerlukan data dan informasi terkait dampak perikanan tersebut untuk merumuskan upaya pengelolan yang tepat. Sementara itu, informasi yang tersedia saat ini masih terbatas di Perairan sekitar Pulau Lancang. Penelitian ini bertujuan untuk: (1) mendeskripsikan karakteristik perikanan bubu yang berbasis di Pulau Lancang, Kepulauan Seribu; dan (2) mengevaluasi dampak perikanan bubu terhadap ekosistem. Metode pengumpulan data yang digunakan yaitu metode survei. Hasil penelitian menunjukkan bahwa jenis bubu yang digunakan di perairan tersebut saat ini adalah bubu tali dan bubu lipat dengan masing-masing berjumlah 7 unit dan 50 unit. Ikan hasil tangkapan utama dan ikan hasil tangkapan sampingan didominasi ukuran yang belum layak tangkap. Nilai indeks keragaman Shannon-Wiener alat tangkap bubu tali sebesar 3,32 dan bubu lipat sebesar 0,34. Bubu tali dan bubu lipat secara dominan menangkap spesies pada tingkat trofik 3 dan TL2., It has been considered that the degradation of fish resources has occurred in the waters of Lancang Island and its surroundings due to the intensity of capture fisheries activities, especially the operation of trap fishing gear. The local government (especially Lancang Island) need data and information regarding this matter formulate management measures to overcome them. Meanwhile, this information is still limited to the waters around Lancang Island. This study aims: (1) to describe the characteristics of the trap fishery based on Lancang Island, Seribu Islands; and (2) to evaluate the impact of the trap fishery on the ecosystem. A survey in the field study was used for data collection. The results showed that the traps currently used in these waters were rope and folding traps with seven and 50 units, respectively. Main-catch and by-catch fish were dominated by sizes lower than value. The Shannon-Wiener diversity index of the trap was 3.32 for the rope trap, and for the folding trap was 0.34. Rope and folding traps predominantly catch species at trophic levels (TL) 3 and TL2.
Keyword: catchable size, collapsible traps, impact of traps fishery, rope traps,  trophic level (TL)

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
Keyword: