PRACTICAL STUDIES ON THE USING OF RECIRCULATED GROUND WATER FOR MAXIMUM PRODUCTIVITY OF

AbstractHuge amounts of water are required for covering the expansion in land reclamation and intensive fish culture activities. To find a new sources of water, ground (well) water is considered as one of the most important sources, being used in many countries sThis study aimed to investigate the possibility of reusing the aquaculture effluent in the production of O. niloticus. As well as, how to maximize the productivity of tilapia that cultured under commercial practices of different intensification levels (40Three groups of concrete pond: Group I: used pure well (ground) water. Group II: used recirculated ground water. Group III: used mixture of pure well and recirculated ground water. All ponds were of the same area (100 m3 / ponds), at ones of the Arab FishPhysico-chemical characteristics of water: Temperature, (pH), ammonia, nitrite, Transparency, total hardness, salinity and dissolved oxygen in both of drainage and irrigation water during all seasons were significantly differed. Heavy metal in water: HeavPart one: Growth performance of O. niloticus during four production seasons: Total weight gain per fish (TWG/fish), TWG/pond and TWG/day): were decreased significantly (p<0.05) with each increase in stocking density under the three varieties of water. FeePart two: Stocking size experiment: Experimental period, rearing periods was increased with decreasing of the initial stocking size of O. niloticus . FCR, a strong inversely relationship between feed conversion ratio and initial stocking size. Survival ra