The health status of hybrid grouper Epinephelus fuscoguttatus (♀) x E.lanceolatus (♂) cultured in floating-net cage at Kelapa Dua Island, Seribu Islands, Indonesia

This study aimed to identify the fish health status, based on the total erythrocytes (cells/mm3), total leukocytes (cells/mm3), hemoglobin level (g %), hematocrit, and histopathological profiles. This study was performed on February, 2021 – January, 2022. The study was located in floating-net cage of Kelapa Dua Island, Seribu Islands, Jakarta, Indonesia. Sampling was performed by a purposive-sampling method, environmental parameter measurements, containing temperature and salinity, clinical symptom observation in fish, total erythrocytes, leukocytes, hemoglobin, hematocrit, histopathological profiles of hybrid grouper liver and kidney, and existence of VNN virus. The observation results present the behavior changes in sick fish, namely whirling on the net cage surface, dead-sleeping or death-like condition below the net cage. Hybrid grouper has total erythrocytes of 1.36 x 106 – 5.13 x 106 cells/mm3, total leukocytes of 2.9 x 104 – 7.9 x 104 cells/mm3, hemoglobin level of 5.56 - 10.94 g %, and hematocrit of 13.31 - 24.78 %. From the histopathological observation, hepatocyte, necrosis, vacuolysis was occurred in liver and tubular, leukocyte infiltasi, nicrosis was occurred in kidney and with the highest prevalence of VNN at 20 – 80 %. Therefore, hybrid grouper is sick due to increased number of leukocytes at 5.13 x 106 cells/mm3 above the normal range, followed by decreased hemoglobin and hematocrit levels at 5.56 - 10.94 g % and 13.31 - 24.78 %, respectively, due to organ damage.       Keyword: must be written in not more than 5 words and alphabeticaly listed   ABSTRAK   Penelitian ini bertujuan untuk mengetahui status kesehatan ikan meliputi total eritrosit (sel/mm3), total leukosit (sel/mm3), kadar hemoglobin (gram %) dan hematokrit (%) dan gambaran histopatolgi. Penelitian ini dilaksanakan pada periode bulan Februari 2021 hingga Januari 2022. Lokasi penelitian pada keramba jaring apung (KJA) di Pulau Kelapa Dua Kepulauan Seribu. Metode pengambilan sampel ikan dilakukan secara purposive sampling, pengukuran parameter lingkungan perairan yaitu suhu dan salinitas, pengamatan gajala klinis ikan, perhitungan jumlah eritrosit, leukosit, kadar hemoglobin dan hematokrit serta gambaran histopatologi pada organ hati dan ginjal ikan kerapu cantang dan keberadaan virus VNN. Hasil pengamatan menunjukkan perubahan tingkah laku ikan sakit yaitu  berputar ke atas permukaan KJA, terjadi sleeping dead atau ikan berada di dasar seperti mati. Ikan kerapu cantang memiliki jumlah eritrosit 1.36 x 106 – 5.13 x 106 sel/mm3, leukosit 2.9 x 104 – 7.9 x 104 sel/mm3, hemoglobin 5.56 - 10.94 gr  %, dan hematokrit 13.31 - 24.78 %, hasil histopalogi ikan mengalami perubahan sel pada hati yaitu hepatosit, vakuolisasi, nekrosis dan ginjal mengalami perubahan infiltrasi leukosit, nicrosis, tubulus dan kehadiran virus VNN tertinggi berkisar 20 % - 80 %. Berdasarkan hasil penelitian tersebut maka dapat disimpulkan bahwa ikan kerapu cantang yang sakit karena jumlah leukosit meningkat 5.13 x 106 sel/mm3 melebihi kisaran normal, kadar hemoglobin menurun 5.56 - 10.94 % dan kadar hematokrit 13.31 - 24.78 % rendah dan terjadi kerusakan jaringan pada organ dalam ikan.   Kata kunci: Ikan Kerapu Cantang, Hematology, Histopatologi, Parameter Fisika dan Kimi