Judul: Production Performance and  Business Enlargement of Sand Lobster (Panulirus homarus) at Different Initial Sizes  in Bottom Net Cages
Abstrak: Budidaya lobster masih mengandalkan benih dari tangkapan alam dengan ukuran benih beragam sehingga perlu pengelompokkan benih untuk menghindari terjadinya kanibalisme. Penelitian ini bertujuan untuk menganalisis kinerja produksi dan kinerja usaha pembesaran lobster pasir di karamba jaring dasar dengan ukuran benih berbeda, yaitu lobster rentang ukuran 70–99 g untuk lobster kecil 82,52±1,57 g dan lobster rentang ukuran di atas 100 g untuk lobster besar 121,06±11,46 g. Penelitian ini adalah studi kasus menggunakan data 3 siklus produksi September 2022 hingga Juni 2023 di PT. Teras Samudra Sejahtera Bangsring, Banyuwangi. Hasil penelitian menunjukkan bahwa kinerja produksi pembesaran lobster pasir menghasilkan tingkat kelangsungan hidup lobster kecil 76,30±3,23%, lobster besar 73,40± 7,69%, laju pertumbuhan bobot mutlak lobster kecil 0,54±0,15 g/hari, lobster besar sebesar 0,27±0,09 g/hari, laju pertumbuhan bobot spesifik lobster kecil 0,46±0,11%/hari, lobster besar 0,20±0,06%/hari, dan ukuran panen lobster kecil 186,12± 17,87 g, lobster besar 200,37±28,30 g. Kinerja usaha pada lobster kecil dengan keuntungan yang diperolah sebesar Rp2.147.599 dan mencapai titik impas jika menjual sebanyak 114,06 kg ke restoran perusahaan dan 41,59 kg ekspor. Kinerja produksi dan usaha pembesaran lobster pasir ukuran lobster kecil didapatkan nilai terbaik dibandingkan dengan ukuran lobster besar., Lobster farming still relies on seeds from the natural catch with a variety of seed sizes so it is necessary to group the seeds to avoid cannibalism. This study aims to analyze the production performance and business performance of sand lobsters in bottom net cages with different seeds sizes, namely lobster size range 70–99 g for small lobsters 82.52±1.57 g and lobsters size range above 100 g for large lobsters 121.06±11.46 g. This study is a case study using data from 3 production cycles from September 2022 to June 2023 PT. Teras Samudra Sejahtera Bangsring, Banyuwangi. The results of the study show that the production performance of sand lobster cultivation produces survival rates of 76.30±3.23% for small lobsters, and 73.40±7.69% for large lobsters, absolute weight growth rates of 0.54±0.15 g/day for small lobsters, and 0.27±0.09 g/day for large lobsters, specific weight growth rates of 0.46±0.11%/day for small lobsters, and 0.20±0.06%/day for large lobsters, and harvest sizes of 186.12±17.87 g for small lobsters, and 200.37±28.30 g for large lobsters. Business performance for small lobsters with a profit of Rp 2,147,599 is obtained, reaching the breakeven point if selling 114.06 kg to company restaurants and 41.59 kg for export. The production and business performance of sand lobster cultivation with small lobster size obtained the best value compared to large lobster size.
Keyword: break even point, growth, milk disease, survival

Judul: Kinerja Produksi Pendederan II Lobster Pasir (Panulirus homarus) dalam Karamba Jaring Tenggelam dengan Kedalaman Berbeda
Abstrak: Kedalaman air laut berpengaruh terhadap faktor lingkungan seperti suhu, oksigen terlarut, kecepatan arus, gelombang, pH, salinitas, dan tekanan. Perubahan kondisi perairan laut dapat berdampak langsung terhadap kondisi fisiologi dan biokimia biota kultur, dan pada akhirnya akan berpengaruh kepada kinerja produksi. Tujuan penelitian ini adalah menentukan kedalaman yang memberikan kinerja produksi terbaik dan keuntungan yang maksimal pada pendederan II lobster pasir dalam karamba jaring tenggelam. Penelitian ini menggunakan rancangan acak lengkap dengan tiga perlakuan kedalaman dasar wadah 1, 3, dan 5 m dari permukaan air laut dengan tiga kali ulangan. Wadah yang digunakan berupa karamba jaring tenggelam (sub-mersible cage) berukuran 60 × 60 × 60 cm. Lobster pasir (Panulirus homarus) berbobot rata-rata 10,84±0,42 g dan panjang rata-rata 7,07±0,20 cm ditebar dengan padat tebar sebanyak 15 ekor/karamba dan dipelihara selama 40 hari. Lobster diberi ikan rucah segar sebanyak 10% dari biomassa per hari. Parameter uji pada penelitian ini meliputi kinerja produksi, kualitas air, dan analisis usaha. Data dianalisis menggunakan ANOVA dengan selang kepercayaan 95%. Hasil penelitian menunjukkan kedalaman 3 m memberikan kinerja produksi terbaik dan keuntungan yang maksimal pada pendederan II lobster pasir dalam karamba jaring tenggelam karena memiliki tingkat kelangsungan hidup, pertumbuhan, dan produktivitas yang tinggi, serta rasio konversi pakan yang rendah., The depth of sea water affects environmental factors such as temperature, dissolved oxygen, current speed, waves, pH, salinity, and pressure. Changes in marine water conditions can have a direct impact on the physiological and biochemical conditions of cultured biota, and will ultimately affect production performance. The purpose of this study was to determine the depth that gives the best production performance and maximum profit in nursery II spiny lobster in submersible cage. This study used a completely randomized design with three treatments for the bottom depth of the container 1, 3, and 5 m above sea level with three replications. The container used is a sub-mersible cage measuring 60 × 60 × 60 cm. Spiny lobster (Panulirus homarus) with an average weight of 10,84±0,42 g and an average length of 7.07±0.20 cm was stocked with a stocking density of 15 fish/karamba and reared for 40 days. Lobsters were given fresh trash fish as much as 10% of the total biomass per day. The test parameters in this study include production performance, water quality, and business analysis. Data were analyzedusing ANOVA with 95% confidence interval. The results showed a depth of 3 m gave the best production performance and maximum profit in nursery II spiny lobster in sinking net cages because it had a high survival rate, growth, and productivity, as well as a low feed conversion ratio.
Keyword: depth, production performance, spiny lobster

Judul: : Persamaan Tunggal sebagai Representasi Kurva Komposit
Abstrak: A mathematical method is introduced to represent a composite curve based on an extension of analytic geometry. The representation is given either with a single equation or with two equations, in the case of parametric representation. This method permits the representation of composite curves in similar manner to the conventional representation of non-composite curves. Some mathematical tools, including Heaviside unit step function and periodizer function, are used in the establishment of a single equation. In this paper, regular equations of regular and irregular polygon, as well as composite curves of two dimensions, are implemented using a computer algebraic system, Mathematica.
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