EFFECT OF DIFFERENT FEEDING LEVELS ON GROWTH PERFORMANCE AND POND PRODUCTIVITY OF THE NILE TILAPIA (ORECHROMIS NILOTICUS), THE GREY MULLET (MUGIL CEPHALUS) AND THE COMMON CARP (CYPRINUS CARPIO) STOCKED AT HIGHER RATES

This study was carried out to investigate the growth performance of Nile tilapia , Grey mullet and Common carp fish species stocked at higher rates and reared in earthen ponds as well as pond productivity as affected with different feeding levels. Eight earthen ponds were used; each of a total area of 8000 m2 represented four feeding levels (1,5 , 2.5 3 3.5 and 4.5 % of total biomass of fish) with two replicates for each feeding level . Fish species were stocked in each pond at densities of 48000 , 9000 and 3000 with an average initial weight of 25, 8 and 5 g for tilapia , mullet and carp species , respectively . The experiment was expanded for 8 months after start. Results obtained are summarized in the following:1- Final weight 9 weight gain , daily gain and SGR of the three tested species increased significantly with each increase in feeding levels tested.2- Total Fish production of the three tested species increased in almost. linear manner with each increase in feeding levels from 1.5 to 2.5 ; 3,5 or 4.5 % of the fish biomass.3-The highest net returns were obtained by the feeding rate 2,5 % followed in a decreasing order by 1.5 ; 3.5 and 4.5 % feeding rates respectively. Based on the obtained results it is recommeneded a feeding level of 2.5 % for tilapia , mullet and carp cultured together at higher rate in earthen ponds without supplemental aeration