摘要：ABSTRACT This research was conducted to evaluate the performance of eel production at stocking density of 2 g/L, 3 g/L, and 4 g/L reared in recirculating system for 60 days. The experimental design used was completely randomized design. Fish were fed on sinking pellet given according to body weight. Collected data were survival, specific growth rate, biomass growth, feed convertion ratio, weight variance, blood profile, blood glucose, and cortisol levels.The results showed that the best performance was found in 4 g/L density with specific growth rate and biomass growth were 0.99±0.30 and 7.50±4.13 g/day, feed conversion ratio of 1.22±0.58, and weight variance of 21.72±3.60%. Stress responses parameters which consisted of cortisol and blood glucose levels showed no significant difference at 22.45± 8.59 nm/L and 31.92± 4.29 mg/dL, respectively. Blood profile in form of hemoglobin, hematocrit, red blood cell and differential leukocytes showed no significant differences except for the leukocyte parameters with the highest rate was achieved at the stocking density of 4 g/L (2.70±0.001x105 sel/mm3). In conclusion, the stocking density of 4 g/L produced the best physiological and production performance. Keywords: stocking density, growth, physiological response, eel, recirculation system ABSTRAK Penelitian ini bertujuan untuk mengevaluasi kinerja produksi dan respons fisiologis ikan sidat pada padat tebar 2 g/L, 3 g/L, dan 4 g/L dalam sistem resirkulasi selama 60 hari. Rancangan percobaan yang digunakan adalah rancangan acak lengkap. Pakan berupa pelet tenggelam diberikan sesuai bobot tubuh. Data yang diambil meliputi kelangsungan hidup, laju pertumbuhan spesifik, laju pertumbuhan biomassa, konversi pakan, koefisien keragaman bobot, gambaran darah, kadar glukosa darah, dan kadar kortisol. Hasil penelitian menunjukkan bahwa padat tebar berpengaruh nyata (P<0,05) terhadap laju pertumbuhan biomassa; pertumbuhan biomassa terbaik dicapai pada kepadatan 4 g/L dengan laju pertumbuhan spesifik dan laju pertumbuhan biomassa sebesar 0,99±0,30 dan 7,50±4,13, konversi pakan sebesar 1,22±0,58, dan koefisien keragaman sebesar 21,72±3,60%. Parameter respons stres yaitu kadar kortisol dan glukosa darah tidak menunjukkan perbedaan yang nyata, yaitu masing-masing sebesar 22,45±8,59 nm/L serta 31,92±4,29mg/dL. Gambaran darah berupa hemoglobin, hematokrit, jumlah sel darah merah dan diferensial leukosit tidak menunjukkan perbedaan yang nyata (P>0,05), kecuali pada parameter leukosit dengan nilai terbaik pada perlakuan 4 g/L (2,70±0,001 x105 sel/mm3). Hasil penelitian menunjukkan bahwa padat tebar 4 g/L menghasilkan kinerja fisiologis dan produksi terbaik. Kata kunci: padat tebar, pertumbuhan, respons fisiologis, ikan sidat, sistem resirkulasi
