The investigations on the biology of Carasobarbus luteus, Capoeta trutta ve Garra variabilis species living in tigris river

In this study, some biological characteristics such as sex distribution, growth and growth rate of length and weight, condition factor, age and length of sexual maturity, egg production rate in species of Carasobarbus luteus (Heckel, 1843), Capoeta trutta (Heckel, 1843) and Garra variabilis (Heckel, 1843) which are commonly distributed around Bismil locality in Tigris River system. The examined samples of C. luteus were distributed between II-IX years age. The % 45 of the samples were female and % 55 of the samples were male and female-male rate was calculated as 1:1.22. mid-caudal length and weight of females variated between 103-271 mm and 22-354 g and between 103-200 mm and 20-182 g in males. The correlation of length-weigth between males and females were calculated as Log W = -4.7314 +3.0113 Log FL (r2 = 0.9274) P < 0.001, and Log W = -4.7631 +3.0263 Log FL (r2 = 0.9390) P < 0.001.The condition factor in female and male individuals were determined as; C = 1.52 ± 2.62, C = 1.51 ± 2.41 respectively. The von Bertalanffy correlation between age-length in female-male individuals was; Lt = 40.09 [1-e-0.087036 (t+1.55004)], Lt = 38.14 [1-e-0.080056 (t+2.34838)] respectively. It was determined that the reproduction period was between May and July. The water temperature at this period was between 21.4oC and 31oC. The egg number of captured samples varieted between 5266-78416 and egg diameter varieted between 0.24 mm (August 2012) and 1.45 (May 2013). The average GSI value of female and male C. luteus individuals varieted between 0.9 - 8.72 and 0.85 - 7.05 respectively. It was determined that Sexual maturity age and length for females were age III and 16.5 cm length and for males were age II and 21.2 cm length. The examined samples of C. trutta were distributed between I-VI years age. The % 68.3 of the samples were female and % 31.7 of the samples were male and female-male rate was calculated as 1:0.47. mid-caudal length and weight of females variated between 127-270 mm and 28-280 g and between 135-235 mm and 28-212 g in males. The correlation of length-weigth between males and females were calculated as Log W = -4.6845 + 2.9303 Log FL (r2 = 0.9142) P < 0.001, Log W = -4.7784 + 2.9746 Log FL (r2 = 0.8897) P < 0.001, respectively. The condition factor in female and male individuals were determined as; C = 1.47 ± 1.537, C = 1.334 ± 1.524 respectively. The von Bertalanffy correlation between age-length in female-male individuals was; Lt = 35.36 [1-e-0.082817 (t+4.82738)], Lt = 28.82 [1-e-0.12380 (t+4.40235)] respectively. It was determined that the reproduction period was between May and June. The water temperature at this period was between 21.4 oC and 31 oC. The egg number of captured samples varieted between 1730 ? 9227 and egg diameter varieted between 0.18 mm (October 2012) and 0.62 mm (June 2013). The average GSI value of female and male C. trutta individuals varieted between 0.7 - 2.95 and 0.9 - 14.5 respectively. It was determined that Sexual maturity age and length for females were age III and 18.2 cm length and for males were age II and 13.8 cm length. The examined samples of G. variabilis were distributed between II-VII years age. The % 85 of the samples were female and % 15 of the samples were male and female-male rate was calculated as 1:0.18. mid-caudal length and weight of females variated between 95-162 mm and 14-76 g and between 105-151 mm and 14-54 g in males. The correlation of length-weigth between males and females were calculated as Log W = -5.1080 + 3.15558 Log FL (r2 = 0.7489) P < 0.001, Log W = -4.8392 + 3.0153 Log FL (r2 = 0.6159) P < 0.001, respectively. The condition factor in female and male individuals were determined as; C = 1.17 ± 3.28, C = 1.02 ± 2.46 respectively. The von Bertalanffy correlation between age-length in female-male individuals was; Lt = 33.75 [1-e-0.04001 (t+7.34612)], Lt = 35.17[1-e-0.034345(t+21.6588)] respectively. It was determined that the reproduction period was between May and June. The water temperature at this period was between 21.4 oC and 31 oC. The egg number of captured samples varieted between 2877.7? 999.7 and egg diameter varieted between 0.29 mm (August 2012) and 1.75 mm (April 2013). The average GSI value of female and male G. variabilis individuals varieted between 2 - 27 and 0.9 - 12.5 respectively. It was determined that Sexual maturity age and length for females were age IV and 18.9 cm length and for males were age IV and 14.6 cm length.