A Study on the Age, Growth and Reproduction of Aspius vorax (Heckel, 1843) (Cyprinidae) in Ataturk Dam Lake (Euphrates River), Turkey

In this study, the age, growth and reproduction characteristics of Aspius vorax, which were caught from Ataturk Dam Lake (Euphrates River) between September 2007 and August 2008 were determined. The age composition of the specimens ranged between II and IX age groups. The observed sex ratio was 1:1.75 (females/males). The fork length and weight of the individuals that were examined ranged from 184 to 863 mm and from 54 g to 4,317 g, respectively. The relationship of fork length (L-F) and scale radius (S) was estimated as: L-F=-95.6669+172.254 S, (r(2) = 0.669). L-infinity values were calculated to be 158.36 cm for females and 218.47 for males. Length - weight relationships were Log W =-3.4242+2.4297 Log L-F; (r(2) =0.8686) for females, and Log W =-4.7247+2.9051 Log L-F (r(2) =0.9549) for males. Mean somatic condition of females and males were estimated as 1.069 and 1.062, respectively. The highest values of the somatic condition were determined in the November for females (K=1.23) and in the September and October (K=1.13) for males. Males matured during their third year of life in the studied samples, but due to lacking of young female specimens, the first maturity age for female was not determined. However, all those females examined at age 4 and over were seen to reach mature.