Judul: Composition of Catch and Pattern of Fishing Season for  Mini Purse Seine at The Tasikagung Fishing Port Rembang
Abstrak: Penangkapan ikan menggunakan alat tangkap mini purse seine banyak dilakukan oleh nelayan di Kabupaten Rembang. Nelayan melakukan aktivitas penangkapan di setiap bulan, hal ini dapat dilihat dari total hasil tangkapan perbulannya, pada bulan-bulan tersebut terdapat musim puncak, musim sedang, dan musim paceklik penangkapan. Musim penangkapan tersebut dapat memengaruhi tinggi rendahnya hasil tangkapan nelayan. Hal ini perlu dilakukan penelitian lebih lanjut untuk mengetahui bagaimana musim penangkapan ikan khususnya musim penangkapan ikan hasil tangkapan utama. Tujuan penelitian adalah mengidentifikasi komposisi hasil tangkapan mini purse seine dan pola musim hasil tangkapan mini purse seine. Metode penelitian yang digunakan adalah observasi dan mengambil sampel nelayan yang diwawancarai menggunakan teknik accidental sampling. Analisis data yang digunakan yaitu komposisi hasil tangkapan dalam bentuk grafik dan analisis data pola musim penangkapan menggunakan analisis deret waktu dengan metode rata-rata bergerak. Hasil penelitian menunjukkan bahwa hasil tangkapan utama memiliki persentase 87,7%, hasil tangkapan sampingan memiliki persentase 12,3%. Hasil tangkapan utama meliputi ikan layang (Decapterus macrosoma) dengan musim puncak penangkapan pada bulan Agustus, ikan tembang (Sardinella fimbriata) pada bulan Oktober, ikan tongkol (Auxis thazard) pada bulan November, ikan selar (Selaroides leptolepis) pada bulan Mei, ikan kembung (Restrelliger brachysoma) pada bulan Juli, dan ikan bentong (Selar crumenopphthalmus) pada bulan Juni., Fishers mainly do fishing using mini purse seine fishing gear in Rembang Regency. Fishers do fishing activities every month, as seen in the monthly catch. In these months are peak seasons, mild seasons, and fishing famine seasons. The fishing season can affect the high and low catches of fishers. It is necessary to do further research to find out how the fishing season, especially the fishing season for the main catch. The study aimed to identify the composition of the mini purse seine catch and the seasonal pattern of the mini purse seine catch. The research method uses observation by taking samples using accidental sampling techniques and fishers as respondents. Data Analysis used composition of catches in the form of graphs and fishing season patterns using time series analysis with the moving average method. The results showed that the main catch had a percentage of 87.7%, and the by-catch had a 12.3%. The principal catches include scad fish (Decapterus macrosoma) with peak fishing season in August, sardine fish (Sardinella fimbriata) in October, tuna fish (Auxis thazard) in November, mackerel fish (Selaroides leptolepis) in May, long-jawed mackerel (Restrelliger brachysoma) in July, and bigeye scad fish (Selar crumenopphthalmus) in June.
Keyword: catch, composition, mini purse seine, seasonal index, Tasikagung coastal fishing port

Judul: Seasonal Patterns and Feasibility of Handline Fishing Activities at Pondokdadap Coastal Fisheries Port in Malang Regency
Abstrak: Perubahan pola musim penangkapan ikan hasil tangkapan utama dan peningkatan armada dapat mengakibatkan kerugian bagi nelayan pancing ulur, sehingga diperlukan analisis pola musim dan kelayakan usaha penangkapan pancing ulur. Sampel data primer berupa nilai investasi, biaya operasional dan nilai pendapatan diambil dari kapal berukuran 10 – 19 GT dan 20 – 29 GT untuk mewakili ukuran kapal yang mendominasi, sedangkan data sekunder berupa data logbook kapal pancing ulur diambil dengan melakukan studi literatur. Hasil menunjukkan bahwa terdapat 6 jenis ikan hasil tangkapan utama yang didominasi dari spesies TCT yaitu ikan tuna dengan musim puncak pada bulan Mei - Agustus, cakalang pada bulan Juni dan tongkol pada bulan Oktober. Armada pancing ulur 10 – 19 GT dan 20 – 29 GT berturut-turut memiliki nilai keuntungan bersih Rp132.849.798,00 dan Rp211.122.924,00; nilai R/C ratio 1,77 dan 1,83; nilai PP 2,35 dan 2,85; nilai BEP penjualan Rp72.868.128,00 dan Rp98.133.162,00; BEP unit 3234 kg dan 5205 kg; serta nilai ROI 43% dan 35%., Changes in the fishing season patterns, main catch, and increase in the fleet can result in losses for handline fishermen. Therefore, an analysis of seasonal patterns and the feasibility of handline fishing operations is needed. Primary data samples, including investment values, operational costs, and income values, were collected from vessels ranging from 10 to 19 GT and 20 to 29 GT to represent the dominant vessel sizes. Meanwhile, secondary data, such as handline fishing vessel logbook data, were obtained through literature studies. The results indicate that there are six main catch species dominated by tuna species, with the peak season in May - August for tuna, June for skipjack tuna, and October for mackerel tuna. The handline fishing fleets with the size of 10 - 19 GT and 20 - 29 GT respectively yielded a net profit of Rp132,849,798.00 and Rp211,122,924.00, an R/C ratio of 1.77 and 1.83, a PP value of 2.35 and 2.85, a sales break-even point (BEP) of Rp72,868,128.00 and Rp98,133,162.00, a unit BEP of 3,234 kg and 5,205 kg, and an ROI of 43% and 35%.
Keyword: business feasibility, handline fishing, PPP Pondokdadap, primary catch, seasonal fishing patterns

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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