Nursery I: The effect of stocking density on the performance of glass eels, Anguilla bicolor in the biofloc system

Glass eels of Anguilla bicolor is an expensive and still abundant commodity in Laguna Segara Anakan, Central Java, Indonesia. However, the growth of glass eels to elver is still a problem because of high mortality in nursery I and II. The objective of the study was to evaluate the result of stocking density on the performance of glass eels in the biofloc system during nursery I. Glass eels were stocked at densities of 54.95, 109.89 and 164.84 fish/m3, respectively, with three replicate ponds for each density. Eels were fed a formulated pasta-diet containing 40% crude protein and , 4% crude lipid, 5% crude fiber, 11.5% ash and 12% moisture, respectively. The water quality were maintained at levels of for fish culture througout the experiements: water temperature was 27.1°C (ranged from 26.3 to 28.2°C), pH (7.6, ranged from 6.8 to 7.8) and DO (7.2 mg.L-1, ranged 6.9 to 7.5 mg.L-1). The results showed that the stocking density did not significantly affect the final weight, weight gain, AGR, SGR, FCR and survival, however this had a significant effect on the yield. The biofloc system was suitable for raising glass eels.