EFFETS DE LA DENSITE DE STOCKAGE SUR LA CROISSANCE DES ALEVINS DE TILAPIA (OREOCHROMIS NILOTICUS L.) EN BASSINS DANS LE PERIMETRE AGRICOLE DE LAC KALLASSANE, SENEGAL

The study was carried out at Lake Kalassane to assess the effect of stocking density on the growth of tilapia fry in ponds. The tilapia fry used came from the Richard-Toll aquaculture station. The rearing equipment used consisted of six (06) concrete basins of 3m3 each. A completely randomized system with three (03) treatments (density 1= 330g/m3; density 2 250g/m3 and density 3 = 170g/m3) and two replicates was set up. Physico-chemical variables (temperature, pH and oxygen) were measured twice a day (09h and 16h) ; nitrate, nitrite and chlorine, once a week. Every fifteen (15) days, a control fishery was carried out to monitor the growth of the individuals and readjust their diet. Results show an average temperature of 22.30C, an average pH of 7.09 and an average dissolved oxygen value of 5.45mg/l. The average weight varied between 76.92g and 82.96g, the nutritional quotient between 2.23 and 2.3 and the growth rate between 30.61 g%.j-1 and 31.18 g%.j-1.The best survival rate was obtained with density1 (330g/m3). The results of this study show that the growth performance of the different treatments did not differ significantly. However, the density of 330g/m3 (treatment A) appears to be more favorable to tilapia (Oreochromis niloticus) rearing in the niayes zone.