Peningkatan Efisiensi Akuabisnis Pendederan Ikan Kerapu (Epinephelus sp.) melalui Pengembangan RAS, Aplikasi Bioremediasi, dan Padat Tebar

Abstract

Pendederan ikan kerapu (Epinephelus sp.) umumnya dilakukan dengan penebaran benih berukuran kecil, padat tebar tinggi, serta pergantian air rutin setiap hari sehingga rentan terhadap fluktuasi kualitas air dan penurunan kinerja produksi. Pendederan ikan kerapu dengan sistem resirkulasi dan bioremediasi diharapkan dapat meningkatkan kinerja produksi melalui perbaikan kualitas air pada padat tebar lebih benih tinggi. Penelitian ini bertujuan untuk menganalisis efisiensi akuabisnis melalui pengembangan sistem dan intensifikasi budidaya pendederan ikan kerapu yang dilakukan melalui dua tahap percobaan. Percobaan pertama menganalisis efektivitas tiga sistem pendederan: 1) konvensional, 2) recirculating aquaculture system (RAS), dan 3) RAS dengan bioremediasi terhadap kinerja produksi pendederan kerapu. Percobaan kedua menganalisis efektivitas peningkatan padat tebar pada sistem terbaik terhadap efisiensi akuabisnis. Percobaan dilakukan dua tahap dengan waktu masing-masing 40 hari menggunakan rancangan acak lengkap dengan tiga perlakuan dan empat kali ulangan. Pada percobaan pertama dengan padat tebar masing-masing 500 ekor/m3 dikaji sistem konvensional tanpa resirkulasi dan tanpa bioremediasi (SK), sistem resirkulasi tanpa bioremediasi (RAS), serta sistem resirkulasi dan bioremediasi (RB). Hasil sistem pendederan terbaik dari percobaan pertama dipakai sebagai dasar percobaan kedua dengan perlakuan padat tebar berbeda, yaitu 500, 750, dan 1.000 ekor/m3. Bak beton berukuran 1 m × 2 m × 0,8 m diisi air laut sebanyak 1 m3 digunakan pada masing-masing tahap percobaan. Filter pada sistem resirkulasi terdiri dari busa sintetis (dakron), pasir, zeolit, arang aktif, dan bioball. Air dipompa dari wadah pemeliharaan ke dalam filter dengan debit 1.600 L/jam. Bioremediasi air dilakukan dengan penambahan Lactobacillus casei dan Saccharomyces cerevisiae. Uji pendahuluan dilakukan sebelum penelitian untuk menentukan dosis bioremediator terbaik dalam air pemeliharaan. Perlakuan dilakukan dengan penambahan dosis bioremediator berbeda, yaitu 3, 6, 9 dan 12 mL/m3 dan setiap dosis diulang 2 kali. Ikan kerapu cantik ukuran 3,2±0,3 cm dipelihara dengan padat tebar 500 ekor/m3 dan dipelihara selama 7 hari, kemudian diamati tingkat kelangsungan hidup, total bakteri, dan Vibrio spp. dalam media pemeliharaan. Penambahan dosis bioremediator berbeda tidak berpengaruh nyata terhadap tingkat kelangsungan hidup. Pada dosis 6 mL/m3 menunjukkan total bakteri terendah hingga akhir (H7) pemeliharaan dan menghambat pertumbuhan bakteri patogen seperti Vibrio spp. sebesar 140 CFU/mL. Benih yang dipelihara pada percobaan pertama dan kedua adalah ikan kerapu cantik berukuran panjang total rata-rata awal pemeliharaan 3,6±0,2 cm. Pakan yang diberikan berupa pelet komersial dengan kandungan protein 48 ̶ 55% secara at satiation. Parameter uji meliputi tingkat kelangsungan hidup, laju pertumbuhan mutlak panjang dan bobot, laju pertumbuhan spesifik panjang dan bobot, rasio konversi pakan, koefisien keragaman panjang dan bobot, hubungan panjang-bobot, kadar glukosa darah, total bakteri dan bakteri Vibrio spp. Parameter fisika kimia air terdiri dari suhu, salinitas, pH, oksigen terlarut (DO), amonia, dan nitrit. Paramater efisiensi bisnis berdasarkan produktivitas terdiri dari produktivitas faktor tunggal, produktivitas multi faktor, dan produktivitas total. Parameter efisiensi bisnis berdasarkan analisis usaha yang terdiri dari yaitu keuntungan, imbangan penerimaan dan biaya (R/C ratio), analisis titik impas (BEP), harga pokok produksi (HPP), serta analisis payback periode (PP). Hasil kinerja produksi percobaan pertama menunjukkan bahwa perlakuan RB mampu meningkatkan tingkat kelangsungan hidup dan laju pertumbuhan ikan kerapu cantik, serta menghasilkan rasio konversi pakan terendah yaitu sebesar 0,73±0,07. Sistem pendederan berbeda tidak berpengaruh nyata terhadap nilai koefisien keragaman panjang dan bobot. Hubungan panjang-bobot pada semua perlakuan menunjukkan hasil alometrik negatif. Kadar glukosa darah pada awal hingga akhir pemeliharaan untuk semua perlakuan berkisar 53 ̶ 76 mg/dL. Kisaran total bakteri tertinggi didapatkan pada perlakuan RB berkisar 330.000 ̶ 3.000.000 CFU/mL. Perlakuan RB menunjukkan total Vibrio spp. terendah berkisar 15 ̶ 2.580 CFU/mL. Fisika kimia air terbaik didapatkan pada perlakuan RB dengan salinitas yang lebih stabil sebesar 30 ̶ 35 g/L, dan mampu menghambat peningkatan amonia mencapai 0,0726 ̶ 1,8978 mg/L. Pada perlakuan SK menghasilkan nitrit terendah sebesar 0,0087 ̶ 0,5726 mg/L akibat pergantian air secara rutin. Produktivitas tenaga kerja, material, dan modal tertinggi didapatkan pada perlakuan RB sebesar 8,78±0,14, 1,78±0,04, dan 1,28±0,02 sedangkan untuk energi didapatkan pada perlakuan SK sebesar 34,94±0,25. Produktivitas multi faktor dan total tertinggi didapatkan pada perlakuan RB sebesar 0,45±0,02 dan 0,67±0,01. Pengembangan sistem resirkulasi dengan aplikasi bioremediasi mampu meningkatkan keuntungan sebesar 41,76% dan 8,81% lebih efisien dibandingkan perlakuan SK. Hasil kinerja produksi percobaan kedua menunjukkan bahwa perlakuan 1.000 ekor/m3 mampu meningkatkan tingkat kelangsungan hidup mencapai 94,7±1,1%, namun terjadi penurunan laju pertumbuhan ikan kerapu cantik dibandingkan dengan perlakuan 500 ekor/m3. Padat tebar hingga 1.000 ekor/m3 tidak berpengaruh nyata terhadap rasio konversi pakan serta koefisien keragaman panjang dan bobot. Hubungan panjang-bobot pada semua perlakuan menunjukkan hasil alometrik negatif. Kisaran kadar glukosa darah ikan kerapu, total bakteri, dan Vibrio spp. tertinggi didapatkan pada perlakuan 1.000 ekor/m3 yaitu 36 ̶ 73mg/dL, 11.000 ̶ 301.000 CFU/mL, dan 3.800 ̶ 6.320 CFU/mL. Hasil fisika kimia air menunjukkan bahwa padat tebar 1.000 ekor/m3 menurunkan nilai pH dan DO yaitu mencapai kisaran 6,8 ̶ 7,8 dan 4,30 ̶ 6,54 mg/L. Nilai amonia dan nitrit semakin meningkat pada padat tebar 1.000 ekor/m3 mencapai kisaran 0,9764 ̶ 3,4684 mg/L dan 0,5465 ̶ 3,4435 mg/L. Produktivitas tenaga kerja, material, energi, modal, multi faktor, dan total tertinggi didapatkan pada perlakuan 1.000 ekor/m3 sebesar 17,99±0,82, 1,78±0,07, 59,44±2,71, 2,62±0,12, 0,96±0,09, dan 0,98±0,04. Sistem resirkulasi dengan bioremediasi dapat meningkatkan padat tebar hingga 1.000 ekor/m3 serta meningkatkan keuntungan sebesar 164,44% dan 14,97% lebih efisien dibandingkan pada padat tebar 500 ekor/m3.

Nurseries for grouper (Epinephelus sp.) are generally carried out by spreading small seeds, high stocking density, and changing water regularly every day so that they are susceptible to fluctuations in water quality and decreased production performance. Grouper nursery with recirculation and bioremediation systems is expected to improve production performance by improving water quality at higher stocking densities. This study aims to analyze the efficiency of aquabusiness through system development and intensification of grouper nursery culture which was carried out in two experimental stages. The first experiment analyzed the effectiveness of three nursery systems: 1) conventional, 2) recirculating aquaculture system (RAS), and 3) RAS with bioremediation on grouper nursery production performance. The second experiment analyzed the effectiveness of increasing stocking density on the best system for aquabusiness efficiency. The experiment was conducted in two stages with 40 days each using a completely randomized design with three treatments and four replications. In the first experiment were studied each a stocking density 500 fish/m3 with the conventional systems without recirculation and without bioremediation (SK), recirculation systems without bioremediation (RAS), and recirculation and bioremediation (RB) systems. The results of the best rearing system from the first experiment were used as the basis for the second experiment with different density treatments, namely 500, 750, and 1,000 fish/m3. A concrete tank measuring 1 m × 2 m × 0.8 m filled with 1 m3 of seawater was used at each stage of the experiment. The filter in the recirculation system consists of synthetic foam (dacron), sand, zeolite, activated charcoal, and bioball. Water is pumped from the rearing tank into the filter at a rate of 1,600 L/hour. Water bioremediation was carried out with the addition of Lactobacillus casei and Saccharomyces cerevisiae. Preliminary tests were carried out before the study to determine the best dose of bioremediator in rearing water. The treatment was carried out by adding different doses of bioremediators, namely 3, 6, 9 and 12 mL/m3 and each dose was repeated 2 times. Cantik grouper size 3.2±0.3 cm was reared at a density of 500 fish/m3 and reared for 7 days, then observed the survival rate, total bacteria, and Vibrio spp. in the maintenance medium. The addition of different bioremediator doses did not significantly affect the survival rate. At a dose of 6 mL/m3 it showed the lowest total bacteria until the end (H7) of maintenance and inhibited the growth of pathogenic bacteria such as Vibrio spp. of 140 CFU/mL. The seeds kept in the first and second experiments were cantik grouper with an average initial length of 3.6±0.2 cm. The feed given is in the form of commercial pellets with a protein content of 48-55% at satiation. The test parameters included survival rate, absolute growth rate of length and weight, specific growth rate of length and weight, feed conversion ratio, coefficient of diversity in length and weight, length-weight relationship, blood glucose levels, total bacteria and Vibrio spp. Water quality parameters consist of temperature, salinity, pH, dissolved oxygen (DO), ammonia, and nitrite. Business efficiency parameters based on productivity consist of single factor productivity, multi factor productivity, and total productivity. Business efficiency parameters based on business analysis consist of profit, revenue and cost balance (R/C ratio), break-even point analysis (BEP), cost of goods manufactured (COGM), and payback period (PP) analysis. The results of the first experimental production performance showed that RB treatment was able to increase the survival rate and growth rate of cantik grouper, and resulted in the lowest feed conversion ratio of 0.73±0.07. Different rearing systems have no significant effect on the coefficient of variation in length and weight. The length-weight relationship in all treatments showed negative allometric results. Blood glucose levels at the beginning to the end of maintenance for all treatments ranged from 53 ̶ 76 mg/dL. The highest total bacterial range was found in the RB treatment ranging from 330,000 ̶ 3,000,000 CFU/mL. RB treatment showed total Vibrio spp. the lowest was 15 ̶ 2,580 CFU/mL. The best water quality was obtained in the RB treatment with a more stable salinity of 30 ̶ 35 g/L, and able to inhibit the increase in ammonia reaching 0.0726 ̶1.8978 mg/L. In the SK treatment, the lowest nitrite was 0.0087 ̶ 0.5726 mg/L due to regular water changes. The highest productivity of labor, materials, and capital was obtained in the RB treatment of 8.78±0.14, 1.78±0.04, and 1.28±0.02 while the energy was obtained in the SK treatment of 34.94±0.25. The highest multi-factor and total productivity were obtained in the RB treatment of 0.45±0.02 and 0.67±0.01. The development of a recirculation system with bioremediation applications was able to increase profits by 41.76% and 8.81% more efficiently than the SK treatment. The results of the production performance of the second experiment showed that the treatment of 1000 fish/m3 was able to increase the survival rate to 94.7±1.1%, but there was a decrease in the growth rate of cantik grouper compared to the treatment of 500 fish/m3. Stocking densities up to 1,000 fish/m3 did not significantly affect the feed conversion ratio and the coefficient of variation in length and weight. The length-weight relationship in all treatments showed negative allometric results. The range of blood glucose levels of grouper, total bacteria, and Vibrio spp. the highest was found in the treatment of 1000 fish/m3 ie 36 ̶ 73 mg/dL, 11,000 ̶ 301,000 CFU/mL, and 3,800 ̶ 6,320 CFU/mL. The water quality results showed that the stocking density of 1,000 fish/m3 decreased the pH and DO values, reaching the range of 6.8 ̶ 7.8 and 4.30 ̶ 6.54 mg/L. Ammonia and nitrite values increased at a stocking density of 1,000 fish/m3 reaching the range of 0.9764 ̶ 3.4684 mg/L and 0.5465 ̶ 3.4435 mg/L. The highest productivity of labor, material, energy, capital, multi-factor, and total was obtained in the treatment of 1,000 fish/m3 of 17.99±0.82, 1.78±0.07, 59.44±2.71, 2.62±0.12, 0.96±0.09, and 0.98±0.04. The recirculation system with bioremediation can be increased the stocking density up to 1000 fish/m3 and increased the profit by 164.44% and 14.97% more efficient than the stocking density of 500 fish/m3.