fa aquaculture aquaculture پژوهشي Orginal research papers <p>This study was carried out to determine some biological characteristics including age, growth and somatic condition of <em>Carasobarbus luteus</em> and <em>Capoeta trutta </em>in the Turkish part of the Tigris River. The examined samples of <em>C. luteus</em> were distributed between II-IX years of age. The length-weigth relations of females and males were calculated as Log W =-4.7314 +3.0113 Log FL and Log W = -4.7631 +3.0263 Log FL respectively. &nbsp;Von Bertalanffy growth equations were estimated as Lt=40.09 [1-e^{-0.087036 (t+1.55004)}] for females and Lt=38.14 [1-e^{-0.080056 (t+2.34838)}] for males. The somatic condition was 1.9667 &plusmn; 0.1751 for females and 1.9967 &plusmn; 0.4205 for males. The observed samples of <em>C. trutta</em> were distributed between I-VI years of age. The length-weigth relationship of females and males were calculated as Log W = -4.6845 + 2.9303 Log FL, Log W = -4.7784 + 2.9746 Log FL, respectively. Von Bertalanffy growth equations were estimated as Lt=35.36 [1-e^{-0.082817 (t+4.82738)}] for females and Lt=28.82 [1-e^{-0.12380 (t+4.40235)}] for males. The somatic condition in female and male individuals were determined as; 1.4434 &plusmn; 0.1682 and 1.4722 &plusmn; 0.1984 respectively. Both species are economic fish in the Tigris River. Biological characteristics of the species determined in the present study, may contribute to a better understanding of the life cycle, thus providing useful data for its conservation and management.</p> Carasobarbus luteus, Capoeta trutta, Reproduction, Fecundity, Gonadosomatic index 170 187 http://jifro.ir/browse.php?a_code=A-10-600-62&slc_lang=fa&sid=1 S. Bilici serbestbilici@hotmail.com.tr 100319475328460019573 100319475328460019573 Yes T. Çiçek 100319475328460019574 100319475328460019574 No E. Ünlü 100319475328460019575 100319475328460019575 No