Judul: Utilization Status and Sustainability of Wedgefish Fishery Based on Tegalsari Coastal Fishing Port, Central Java
Abstrak: Wedgefish has been included in the CITES Appendix II list since 2019. The conservation status of wedgefish based on IUCN as "Critically Endangered" due to population decline by fishing activities. The over-exploitation is due to the high price of wedgefish fins. Indonesia is one of the biggest countries that caught wedgefish globally, with one of the landing sites at Tegalsari Coastal Fishing Port. However, in Indonesia, the study on wedgefish fisheries is still limited. The scientific information is important to achieve sustainable management. The aims of this study were (1) to describe the conditions of the wedgefish fishery based on the Tegalsari Coastal Fishing Port; (2) to assess the utilization status of wedgefish fishery based on Tegalsari Coastal Fishing Port; (3) to prove whether wedgefish are the main catch target by cantrang based on Tegalsari Coastal Fishing Port; and (4) to provide scientific recommendations for the sustainable management of the wedgefish fishery. The field study was conducted from January to February 2020 at the Tegalsari Coastal Fishing Port, Central Java. Types of data collected were boat size, fishing method, number of vessels, number of fishermen, fishing area location, trade chain, economic value, species type, total length (cmTL), Frequency (No. Inds.), and wedgefish sex. In addition, data from monitoring the catch of wedgefish from April to December 2019 sourced from the Wildlife Conservation Society (WCS) and the Rekam Nusantara Foundation were used in this study. The results showed that wedgefish landed based on Tegalsari Coastal Fishing Port get caught by cantrang as fishing gear. There were three (3) species of the wedgefish, namely: Rhynchobatus springeri, R. laevis, and R. australiae. All part of the wedgefish bodies (fins, meat, skin, and bones) have a market value. The fin has the highest price of Rp3.000.000,00/kg in the local market. The fishing grounds of the wedgefish were in the Java Sea, Bangka Belitung Waters, and Karimata Strait. The utilization status of wedgefish species based on the exploitation rate parameter (E) were: R. springeri with E = 0,80 (overfishing), R. laevis at E= 0,82 (overfishing), and R. australiae at E= 0,81 (overfishing). Wedgefish was not the main target of cantrang, but squid as the primary target. Wedgefish was a bycatch that has high economic value. The recommendations for wedgefish management based on this study are: establishing a marine protected area (MPA), particularly in the spawning and nursery areas, implementing a regulation of allowable catch quota, collaboration among stakeholders for wedgefish management, implementing the allowable catch of wedgefish: (R. springeri males >120 cmTL and females >158 cmTL, R. laevis males >131 cmTL and females >174 cmTL, and R. australiae males >129 cmTL and females >171 cmTL), limiting fishing activities, close during the mating season (indicate in the August to November), reducing wedgefish as bycatch of the seine net (cantrang), and increasing capacity of the fishers on bycatch handling.
Keyword: seine net, cantrang‟, sustainable management, PPP Tegalsari, wedgefish

Judul: Oceanography Condition and Fishing Ground of Wedgefish in the Java Sea
Abstrak: Pari kekeh memiliki nilai ekonomis karena nilai jual siripnya yang tinggi. Permintaan sirip pari yang semakin meningkat telah mempengaruhi jumlah populasi ikan pari kekeh di alam. Pengelolaan pari kekeh terkendala dengan sedikitnya informasi mengenai kondisi oseanografi di habitat pari kekeh. Penelitian bertujuan mengidentifikasi unit penangkapan dan hasil tangkapan ikan, memetakan daerah penangkapan, memetakan kondisi oseanografi habitat pari kekeh meliputi suhu, klorofil-a, arus dan substrat dasar di Perairan Utara Jawa, memetakan dan menganalisis kondisi oseanografi pari kekeh di daerah penangkapan pari kekeh. Metode yang digunakan adalah metode deskriptif dan spasial dengan menganalisis data hasil pendaratan ikan dari PPP Tegalsari Tegal, PPP Bajomulyo Pati dan PPP Tasik Agung Rembang dan data citra satelit suhu, klorofil-a, arus dan substrat dasar selama periode Maret 2020 dan Agustus 2020. Hasil penelitian menunjukkan bahwa tercatat empat jenis pari kekeh, yaitu Rhina ancylostoma, Rhynchobatus australiae, Rhynchobatus springeri, dan Rhynchobatus laevis dengan menggunakan armada cantrang dan rawai dasar berukuran 17 – 180 GT. Ikan pari kekeh ditemukan di perairan dengan substrat berlumpur, suhu (27,4 °C – 29,76 °C), klorofil-a (0,16 – 3,13 mg/m3), dan arus (0 m/s – 0,24 m/s). Rekomendasi pengelolaan terkait penangkapan pari kekeh, yaitu menetapkan ukuran minimum ikan pari kekeh yang layak tangkap.
Keyword: CITES, daerah penangkapan ikan, habitat, IUCN, pari kekeh

Judul: Grup Abelian Berhingga dari Barisan Genomik DNA  (Deoxyribonucleic Acid)
Abstrak: Informasi genetik yang memprogram semua aktivitas sel terdapat dalam bentuk kode di dalam molekul DNA. Grup kodon dari basa nukleotida DNA {A, C, G, U} tidak dapat merepresentasikan daerah non kode dalam genom yang disebabkan oleh mutasi penghapusan serta penyisipan pada barisan genomik DNA. Dalam karya ilmiah ini grup kodon diperluas dengan menambahkan huruf O untuk menandakan mutasi penghapusan atau penyisipan pada kodon untuk semua triplet diperluas 1 2 3 X X X dengan i X Î{O, A, C, G, U} dari barisan genomik DNA. Grup kodon yang diperluas isomorfik dengan grup bilangan bulat modulo 125. Grup abelian berhingga dari barisan genomik DNA yang dibentuk dari himpunan seluruh pasangan terurut triplet ekson dan intron pada untai DNA isomorfik dengan grup jumlah langsung bilangan bulat modulo 64 dan 125. Kemudian grup abelian berhingga tersebut direpresentasikan sebagai grup jumlah langsung 2-grup dan 5-grup homosiklik. Bagian barisan genomik DNA tanpa penyisipan membangun blok gen yang direpresentasikan oleh 2-grup homosiklik, sedangkan bagian barisan genomik DNA yang dipengaruhi oleh penyisipan direpresentasikan oleh 5-grup homosiklik.
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