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Abstract:

This study aimed to evaluate the effects of different methods to supply probiotics EM on the environment and varuna crabs survival rate in nursery. The zoea produced were stocked in 4m³ tanks at 160 ind/l, megalop at 40 ind/l. Artemia nauplii are also given at 5-10 ind/ml from zoea to megalop stage, 4 times/day. Water was replaced daily about 25%/time/3 days. Used artificial food (Lansy, Frippak): 4 times/day, 1g/10,000 larvae at the rate of 1:1. Probiotics are added at 3mg/l; 5mg/l; 7mg/l in seven day intervals. The results shown that TAN and Nitrite rate were the lowest in treatment EM 3mg/l/week and EM 7 mg/l/week, respectively. After 45 days of experiment, the highest survival rate (16,5±4,2%) was observed in direct supplemented treatment 3mg/l/week, which were significantly different from other treatments (p<0.05). Growth rates of varuna crabs in term of length gain also reached the highest values in direct supplemented EM 3mg/l/week method. This study contribute initial information for the effective procedure in seed nursing of varuna crabs.

Keywords: Varuna crab, Zoea, Megalop, nursing of varuna crab.