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: Catching productivity and biotechnical economic analysis of Danish Seine Net Fishing Units at Palabuhanratu Fishing Port
Abstrak: Volume produksi ikan tongkol di PPN Palabuhanratu tahun 2017 sampai 2021 menunjukkan trend menurun. Salah satu alat tangkap yang menangkap tongkol adalah payang. Penelitian ini bertujuan menganalisis produktivitas penangkapan dan bioteknik ekonomi unit penangkapan payang di PPN Palabuhanratu. Analisis yang dilakukan yaitu CPUE, komposisi hasil tangkapan, korelasi Pearson, dan analisis ekonomi. Penelitian dilakukan di PPN Palabuhanratu, pada bulan April sampai Mei 2022, menggunakan metode observasi dan wawancara. Produktivitas unit penangkapan payang mengalami fluktuasi dan pada tahun 2021 terjadi penurunan sebesar 50% tetapi trend yang dihasilkan masih stabil. komposisi hasil tangkapan payang di antaranya cakalang, eteman, peperek, tongkol lisong, tongkol banjar, dan tongkol abu-abu. Terdapat beberapa jenis ikan dengan volume produksi yang rendah tetapi bernilai ekonomis di antaranya ikan selar bentong, kuwe, dan gulamah. Faktor teknis yang mempengaruhi produksi kegiatan penangkapan adalah lama setting dan hauling, jumlah ABK mempengaruhi waktu yang dibutuhkan untuk melakukan setting dan hauling. Analisis ekonomi dari kelayakan usaha diperoleh keuntungan sebesar Rp79.928.095,00, PP selama tiga tahun delapan bulan, dan ROI sebesar 20,88%, kelayakan investasi menunjukkan nilai NPV sebesar Rp230.766.053,00, nilai IRR sebesar 24,1%, dan nilai Net B/C 1,786 sehingga usaha menguntungkan dan investasi layak dilakukan., The volume of mackerel tuna production at Palabuhanratu Fishing Port in 2017 to 2021 shows declining trend. One fishing gear that catches mackerel tuna is danish seine net. This study aims to analyze catching productivity and biotechnical economic of danish seine net fishing unit at Palabuhanratu. Analysis carried out is CPUE, catch composition, Pearson correlation, and economic analysis. The research was conducted at Palabuhanratu Fishing Port, in April to May 2022, using observation and interview methods. The productivity of danish seine net fluctuates, in 2021 there will be a 50% decrease in productivity, but resulting trend is still stable. The composition of danish seine net catch included skipjack tuna, moonfish, ponyfish, bullet tuna, black skipjack, and longtail tuna. Fish with low production but high economic value include bigeye scad, giant trevally, and leaftail croaker. Technical factors that affect the production of fishing activities are the length of setting and hauling, number of crews affects time needed to setting and hauling. Economic analysis of business feasibility obtained profit Rp79.928.095.00, PP for three years and eight months, and ROI 20,88%, investment feasibility shows NPV value Rp230.766053.00, IRR value 24,1%, and Net B/C value is 1,786, so that business is profitable and investment is feasible.
Keyword: biotechnical economic analysis, catching productivity, danish seine net, mackerel tuna

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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