Judul: Supply Chain and Sustainable Management Strategy for Protected Freshwater Stringrays on Musi River, South Sumatera
Abstrak: Pemerintah Indonesia telah menerbitkan aturan perlindungan penuh terhadap tiga spesies pari air tawar di Sungai Musi yaitu pari tutul (Fluvitrygon oxyrhynchus), pari pinggir putih (Fluvitrygon signifier), dan pari raksasa (Urogymnus polylepis) melalui Keputusan Menteri Kelautan dan Perikanan (Kepmen-KP) Nomor 1 Tahun 2021 tentang Jenis Ikan yang Dilindungi. Namun, peraturan tersebut terbukti belum efektif dan masih terjadi penangkapan bahkan perdagangan pari air tawar di pasar lokal secara bebas. Penelitian ini bertujuan mengungkap kondisi ekonomi yang melatarbelakangi penangkapan ilegal pari air tawar dan dan menyusun strategi untuk mendukung konservasi pari air tawar di Sungai Musi, Sumatera Selatan. Penelitian ini menggunakan metode analisis deskriptif, margin pemasaran, matrix of alliance, conflicts, tactical objectives, and recommendations (MACTOR), dan analytical hierarchy process (AHP). Hasil analisis menunjukkan bahwa rantai pasok pari air tawar singkat dan melibatkan aktor pemasaran yang terbatas. Perdagangan pari air tawar ilegal menghasilkan margin pemasaran yang tinggi sehingga mendorong terjadinya perdagangan ilegal. Program konservasi yang menjadi prioritas diantaranya sosialisasi kepada masyarakat, penelitian terkait pari air tawar, serta peningkatan pengawasan melalui penambahan jumlah pengawas perikanan ataupun peningkatan peran Pokmaswas. Peran dari relay actors penting untuk mendukung keberhasilan program konservasi., The Indonesian government has issued full protection rules for three species of freshwater stingrays in the Musi River, namely spotted stingrays (Fluvitrygon oxyrhynchus), white edge stingrays (Fluvitrygon signifier), and giant stingrays (Urogymnus polylepis) through a Decree of the Minister of Maritime Affairs and Fisheries (Kepmen-KP) Number 1 of 2021 concerning Protected Fish Species. However, these regulations have proven to be ineffective and there are still free fishing and even trading of freshwater stingrays in the local market. This study aims to reveal the economic conditions behind the illegal fishing of freshwater stingrays and develop a strategy to support the conservation of freshwater stingrays in the Musi River, South Sumatra. This study uses descriptive analysis methods, marketing margins, matrix of alliances, conflicts, tactical objectives, and recommendations (MACTOR), and analytical hierarchy process (AHP). The results of the analysis show that the supply chain of freshwater stingrays is short and involves limited marketing actors. The illegal freshwater stingrays trade generates high marketing margins which encourages illegal trade. Priority conservation programs include socialization to the community, research related to freshwater stingrays, and increased supervision through increasing the number of fishery supervisors or increasing the role of Pokmaswas. The role of relay actors is important to support the success of conservation programs.
Keyword: AHP, konservasi, MACTOR, margin pemasaran, spesies dilindungi

Judul: Analisis Pendapatan dan Livelihood Assets Nelayan Pari Air Tawar di Sungai Musi, Kota Palembang, Sumatera Selatan
Abstrak: Pari air tawar berperan terhadap fungsi ekologis maupun ekonomi di Sungai Musi, namun keberadaan pari air tawar di Sungai Musi terancam akibat faktor alam dan manusia. Pari air tawar telah masuk dalam daftar spesies terancam punah yang dikeluarkan oleh IUCN dan peraturan perundang-undangan di Indonesia. Pari air tawar menjadi salah satu livelihood masyarakat di Sungai Musi. Penelitian ini bertujuan untuk mendeskripsikan tingkat trofik pari air tawar, karakteristik, pendapatan, dan livelihood assets nelayan pari air tawar. Analisis dilakukan dengan metode systematic literature review, statistik deskriptif, analisis pendapatan, dan analisis livelihood assets. Hasil penelitian menunjukkan bahwa pari air tawar merupakan predator menengah. Nelayan pari air tawar memiliki karakteristik armada berukuran 1,2 – 3 GT dan menggunakan berbagai jenis alat tangkap. Nelayan memiliki karakteristik sosial ekonomi berupa nelayan skala kecil dan sebagian besar pengeluaran untuk konsumsi dan modal melaut. Rata-rata pendapatan responden nelayan sekitar Rp419.648,56 – Rp671.375,00 per trip per hari dengan R/C ratio > 1. Share penerimaan per trip per hari dari hasil tangkapan pari air tawar pada keempat kecamatan bernilai rendah hingga sangat rendah yaitu sekitar 0,09 – 25,72 pada musim paceklik dan 0,09 – 39,73 pada musim normal. Livelihood assets nelayan di Kota Palembang memiliki nilai indeks keberlanjutan sedang yaitu bernilai 0,48 – 0,50., Freshwater stingrays play a crucial role in the Musi River's ecological and economic functions. However, their existence in this river is currently threatened by a combination of natural and human factors. Recognizing their vulnerable status, freshwater stingrays have been listed as endangered species by the IUCN and are subject to regulations in Indonesia. The livelihoods of many individuals along the Musi River depend on freshwater stingrays. This study aims to provide a comprehensive description of the trophic level of freshwater stingrays, as well as the characteristics, income, and livelihood assets of fishermen engaged in catching them. The research methodology employed a systematic literature review, descriptive statistics, income analysis, and livelihood assets analysis. The findings indicate that freshwater stingrays occupy an intermediate position within the predator hierarchy. The fishing boats used by freshwater stingray fishermen typically range from 1,2 to 3 GT, and they employ various types of fishing gear. Socioeconomic characteristics of the fishermen reveal predominantly small-scale fisheries, with a major portion of their expenses allocated towards consumption and fishing capital. The average daily income of the surveyed fishermen ranges from IDR 419.648,56 to IDR 671.375,00, with an R/C ratio > 1. The share of daily revenue derived from the catch of freshwater stingrays in the four sub-districts is relatively low, ranging from 0,09 to 25,72 during the lean season and 0,09 to 39,73 during the normal season. Assessing the sustainability of fishermen's livelihood assets in Palembang City, it is found that the value exhibits a moderate sustainability index, ranging from 0,48 to 0,50.
Keyword: characteristics of fishermen, elasmobranch, livelihood assets, systematic literature review

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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