Determination of some biological characters of rudd (Scardinius erythrophthalmus (Linnaeus, 1758)) in Omerli reservoir (Istanbul)

In this study, 317 rudd (Scardinius erythrophthalmus (Linnaeus, 1758)) individuals were captured between March 2005 - February 2007 from Ömerli Reservoir and some properties of their growth, reproduction and food were investigated. The age composition of rudd population varied between 0-VIII. II age group was the dominant group of the population. Females, males and unidentified individuals composed of the population as %54,26, %43,22 and %%2,2, respectively. The total length and weight of rudd varied from 6,8-29,0 cm and 3,4-392,7 g, respectively.Growth parameters of von Bertalanffy growth equations have been found as L? = 37,55 cm, W? = 819,23 g, k = 0,153, to = -1,389. Length-weight relation was estimated as W=0.0066L3.24 for all individuals. The reproduction activity of rudd in Omerli Reservoir occurred between May and July. Length at first maturity (L50) was 9,08 cm in males and 9,13 cm in females. Age at sexual maturity was found as age I. Average eggs number of age groups varied between 4679 (I) and 40651 (VIII).According to age groups, condition factor varied between 1,121-1,678 for females and 1,172-1,724 for males, respectively. Algea, macrophyta, zoobenthos, zooplankton, fish and insecta were found in the gut content of rudd.Keywords: Growth, Reproduction, Feeding, Rudd, Ömerli Reservoir.