Age determination and growth rate of Capoeta trutta in Azad Dam Lake, Kurdistan Province, Iran

A total of 148 specimens of Capoeta trutta caught from Azad Dam Lake, Kurdistan Province, northwest of Iran were examined during 2015-2016 for assessing growth parameters. The total length (TL) and weight (W) of C. trutta ranged from 4.0 to 29.0 cm and 0.9 to 274.0 g,  average (± SD)  = 19.3 (± 4.0) cm and 80.3 (± 44.7) g, respectively. The length-weight regression was W = 0.0121 × TL2.9317 indicating isometric growth. The sex ratio (M:F) was 1:0.33, differed significantly from the expected 1:1 (P < 0.001). The von Bertalanffy growth parameters were estimated as L∞ = 29.6 mm, K = 0.33 yr-1, t0 = -0.57 yr. The instantaneous coefficient of natural mortality was estimated as 0.58 yr-1. The averaged condition factor (KF) was 1.00 ± 0.11, by significantly differences among seasons (P < 0.001). In the present study, the relative condition factor (Kn) of C. trutta were close to 1 suggesting the well-being condition of the fish in Azad Dam region.