Farklı tuzluluklardaki suların tilapia (Oreochromis niloticus L. 1758) balıklarının gelişimine etkileri

In this research study, effects of different salinity levels on the growth of 50 days post-hatching fry of Oreochromis niloticus was determined. The stocking rate in the aquaria was 80 L/15 fish. In the acclimatory phase fish were adapted to the salinities of 9 ppt, 18 ppt, 27 ppt and 36 ppt. Before adaptation initial mean weight and length were measured as 0.764±0.009 g and 3.708+0.066 cm respectively. Including the freshwater control group (salinity rate, 0 ppt) and the different salinity groups (9 ppt, 18ppt, 27 ppt, 36 ppt) for final mean weight and length in dublicate determinations of each group was found as follows, 5.590±0.605 g, 7.452+0.277 g, 7.913+0.172 g, 9.069±0.185 g, 7.030± 0.000 g and 6.894+0.254 cm, 7.618*0.110 cm, 7.439+0.126 cm, 7.811+0.066 cm, 7.160±0.000 cm respectively. Among the treatment groups the highest survival rate was observed in the freshwater control group with the percentage of 100% and the lowest in 36 ppt with the percentage of 66.667%. Specific growth rate remaind high in the salinity level of 27 ppt (3.300±0.027%/day) and low in the freshwater control group (2.619+0. 141%/day ). Mean daily weight gain ranged from 0. 1 1 1 ±0.003 (27ppt) to 0.064±0.008 g (freshwater). Feed conversion rate was found better than the others in the salinity of 18 ppt with the value of 3.221. Mean growth rate ranged from 8.306±0. 185 g to 4.81 1±0. 603 g in the salinity of 27 ppt and freshwater. At the 75th day of the trial, condition factor was determined as the highest 1.913+0.000 in the salinity of 36 ppt and the lowest 1.690± 0.01 1 in the freshwater group.

Key words : Tilapia, Oreochromis niloticus, salinity, breeding