Judul: Molecular Identification of the Freshwater Stingrays Based on COI Gene Markers in Musi River, Palembang, South Sumatera
Abstrak: Ikan pari dari famili Dasyatidae memiliki karakteristik yang hampir mirip, sehingga diperlukan metode yang akurat dalam validasi spesiesnya. Selain itu, ketersediaan informasi dan data ilmiah mengenai genetik ikan pari air tawar masih minim di Indonesia. Oleh karena itu, penelitian ini bertujuan untuk mengidentifikasi spesies, kekerabatan genetik, dan keragaman genetik ikan pari air tawar berdasarkan variasi basa nukleotida Gen COI di Sungai Musi, Sumatera Selatan. Pengambilan sampel dilakukan pada bulan Februari hingga Mei 2023 di Sungai Musi. Analisis laboratorium dilakukan pada bulan Juni hingga September 2023. Ekstraksi DNA sampel menghasilkan 12 DNA total. Hasil penelitian menunjukkan dua spesies ikan pari air tawar berhasil divalidasi, yaitu Fluvitrygon signifer dan Pastinachus stellurostris dengan kemiripan 99,30% hingga 100%. Sementara itu, pari tutul (kode B) dan pari sungai tepi putih moncong panjang (kode C) belum tervalidasi secara genetik, dengan tingkat kemiripan 89,24% hingga 89,70%.Keragaman genetik ikan pari air tawar di Sungai Musi tergolong rendah, dengan rentang nilai haplotype Hd 0-0,667. Hasil konstruksi pohon filogeni menunjukkan Fluvitrygon signifer dan Pastinachus stellurostris memiliki kekerabatan jauh dengan pari tutul dan pari tepi putih moncong panjang., Stingrays from the family Dasyatidae have almost similar characteristics, so accurate methods are needed to validate the species. Apart from that, the availability of scientific information and data about the genetics of freshwater stingrays is still minimal in Indonesia. Therefore, this study aims to identify species, genetic relationships and genetic diversity of freshwater stingrays based on nucleotide base variations of the COI gene in the Musi River, South Sumatra. Sampling was carried out from June to September 2023. DNA extraction of the samples produced 12 DNAs in total. The research results showed species freshwater stingrays were successfully validated, namely Fluvitrygon signifer and Pastinachus stellurostris with 99,30% to 100% similarity. The spotted ray (code B) and the long-snouted white edge ray (code C) have not been genetically validated yet, with a similarity level of 89,24% to 89,70%. The genetic diversity of freshwater stingrays in the Musi River is relatively low, with a range of haplotype Hd values of 0-0,667. The results of the phylogenetic tree construction show Fluvitrygon signifer and Pastinachus stellurostris distantly related to marbled whipray and long-snouted white edge ray.
Keyword: COI, identifikasi morfologi, pari air tawar, sungai musi

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: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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