Pemberian Nannochloropsis sp. dengan Kepadatan yang Berbeda pada Pemeliharaan Larva Kerapu Bebek (Cromileptes altivelis)
Humpback grouper hatchery has been successfully developed at small-scale farms. However one of the constraints in larval rearing is frequent mortality after addition of plankton Nannochloropsis sp. The mortality larval was due to improper addition (quality and quantity) of phytoplankton causing declines in water quality in larval rearing tank. This study attempted to determine the optimal addition of Nannochloropsis sp. as the green water and feed for rotifers. The treatment was the addition of Nannochloropsis sp. in various densities : A. Without Nannochloropsis sp.; B. Density of Nannochloropsis sp. 100,000 cells/mL; C. Density of Nannochloropsis sp. 300 000 cells/mL and D. Density of Nannochloropsis sp. 500 000 cells/mL. Results obtained in treatment D had an higher survival rate than that of other treatment (26.80%), followed by treatment C (19.50%), treatment B (14.20%) and treatment A (3.50%). Measurement of the total length on day 45 as growth indicator showed that the growth was similar in all treatments (2.47 to 2.53 cm).