Age and growth of large scale scraper (Capoeta aculeata) in the Gizehrud River, Tigris basin

The large scale barb, Capoeta aculeata is a little known species native to Iran. Its age and growth were studied in 377 specimens collected monthly from the Gizehrud River in Lorestan Province (Tigris basin) during May 2014–May 2015. Sex ratio was 1M:2.1F. The maximum age of both female and male specimens was 6+ years. The most common age group of both male and female fish was 4+. The fork length ranged from 12.2 to 20.8 cm (17.4 ± 1.2SD) and weight from 32 to 188 g (93.6 ± 21.8SD). The estimated length-weight relationship of male specimens was W = 0.0161FL3.012, (r2 = 0.82) and that of female specimens W = 0.0248FL2.87, (r2 = 0.79). This relationship showed that growth of both Capoeta aculeata sexes was isometric. The estimated von Bertalanffy growth model for males was Lt= 20.9[1-e-0.57(t+0.2)] and for females Lt = 20.3[1-e-0.56(t-0.8)]. The growth performance index was estimated at 5.4 and 5.5 for males and females, respectively, indicating a similar growth rate for both sexes.