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: Biodiversity of Protected Freshwater Stingray in Musi River, South Sumatera
Abstrak: Sungai Musi memiliki keanekaragaman hayati yang tinggi. Sungai Musi merupakan salah satu habitat ikan pari air tawar yang keberadaannya sangat langka dan hingga saat ini informasinya masih terbatas. Penelitian ini bertujuan untuk mendeskripsikan dan menganalisis keanekaragaman spesies ikan pari air tawar di Sungai Musi bagian tengah Provinsi Sumatera Selatan. Metode yang digunakan untuk mendeskripsikan ikan pari air tawar menggunakan pendekatan morfologis. Adapun keanekaragaman ikan pari air tawar dianalisis menggunakan pendekatan indeks keanekaragaman, indeks kemerataan, dan indeks dominansi. Ikan pari air tawar yang didapatkan sebanyak 42 ekor, yang terdiri dari enam spesies (Fluvitrygon signifer, Fluvitrygon oxyrhynchus, Fluvitrygon cf. oxyrhynchus, Fluvitrygon kittipongi, Pastinachus stellurostris, dan Urogymnus polylepis). Ikan pari air tawar di Sungai Musi memiliki kesamaan karakteristik, yaitu warna cakram dorsal kecoklatan hingga kehitaman, ekor sangat panjang seperti cambuk, terdapat 2 duri sengat, dan memiliki mata yang kecil. Hasil analisis menunjukkan bahwa keanekaragaman spesies ikan pari air tawar di Sungai Musi memiliki nilai H’= 1,38 dengan persebaran yang merata dan tak ada spesies yang mendominasi., The Musi River has a high biodiversity. The Musi River is one of the habitats of freshwater stingrays whose existence is very rare and until now the information is still limited. This study aims to describe and analyze the diversity of freshwater stingray species in the middle part of Musi River, South Sumatra Province. The method used to describe freshwater stingrays uses a morphological approach. The diversity of freshwater stingrays was analyzed using the diversity index, evenness index, and dominance index approaches. There were 42 freshwater stingrays that obtained during research, consisted of six species (Fluvitrygon signifer, Fluvitrygon oxyrhynchus, Fluvitrygon cf. oxyrhynchus, Fluvitrygon kittipongi, Pastinachus stellurostris, and Urogymnus polylepis). Freshwater stingrays in the Musi River have similar characteristics, namely brownish to blackish color of the dorsal disc, very long whip-like tail, 2 stinging spines, and small eyes. The analysis showed that the species diversity of freshwater rays in the Musi River has a value of H'= 1.38 with an even distribution and no dominant species.
Keyword: diversity, freshwater stingray, Musi River, protected

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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