---

This study was carried out to determine some biological characteristics including age, growth and somatic condition of Carasobarbus luteus and Capoeta trutta in the Turkish part of the Tigris River. The examined samples of C. luteus 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.  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 ± 0.1751 for females and 1.9967 ± 0.4205 for males. The observed samples of C. trutta 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 ± 0.1682 and 1.4722 ± 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.

---

Seasonal samplings were conducted over a year to study population dynamic of Carasobarbus luteus in Shadegan Wetland. Samples were collected from five sampling stations in Shadegan Wetland (Salmane, Rogabe, Khoroosi, Mahshahr and Atish) from April 2014 to March 2015. From total number of 1608 samples, 276 individuals were male and 1332 individuals were female. Length-weight relationship was W=0.013L^3.0124 (R²=0.92) for males; and W=0.0136L^3.0117 (R²=0.91) for females, showing an isometric growth pattern. Condition factor (K) was calculated to be 1.308±0.15 and 1.368±0.17 for the males and females, respectively, showing significant difference between the genders (p<0.05). Also, the results show that this species spawns in April-July with a long spawning period and sexual dormant period in autumn to early winter. Mean length at maturation was 161 and 174 mm for males and females specimens; whereas, weight of matured fish was 60 and 80 g for the males and females, respectively. Growth indices including L_∞, growth coefficient and t₀ were 305 and 301 mm, 0.67 and 0.55 per year and 0.23 and 0.29 for the males and females, respectively. Natural mortality, fishing mortality, total mortality, Munro Ф' and coefficient of exploitation were 1.22 and 1.02 per year, 1.61 and 1.45 per year, 2.83 and 2.47 per year, 2.79 and 2.72, and 0.57 and.59, respectively for the males and females.