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526365 
Journal Article 
STOCKING DENSITY OF NILE TILAPIA (Oreochromis niloticus) FRY DURING SEX REVERSAL PHASE 
Tachibana, L; Leonardo, AFG; Correa, CF; Saes, LA 
2008 
34 
4 
483-488 
Portuguese 
This work aimed to evaluate Nile tilapia ( Oreochromis niloticus) fry of taiwanese strain at different stoking densities, during sex reversal phase. Experimental design was totally randomized with four treatments and three replicates in a period of 30 days. Fish with initial weight of 7.2 +/- 0,2 mg and total length of 8,2 +/- 0,5 mm were stocked at 1, 3, 5 and 7 fry L-1 in aquarium of 20L capacity with closed water recirculation system. Fish were feed 'ad libitum' five times daily with commercial ration (48% crude protein) containing 60mg of 17 alpha-metiltestosterna kg(-1). Data were submitted to variance analyses and means compared by Tukey's test with 5% of significance level. Means of final weight and length were 1.66; 0.73; 0.44; 0.37g and 4.47; 3.41; 2.86; 2.70 cm, respectively to 1, 3, 5 e 7 fry L-1. These results show that higher stoking densities lead to low fish growth. The variation coefficients of mass and length was 3.27; 1.88; 1.62; 1.29% and 9.68; 6.04; 5.61; 4.49%, respectively to 1, 3, 5 e 7 fry L-1. Survival, sex reversal efficiency and condition factor were not affected by stocking density. Higher stoking densities reduce growth rate and increase homogeneity of Nile tilapia fry. 
Recirculation system; stocking density; sex reversal; fry; growth