In this study, the population structure and growth properties of Chalcalburnus mossulensis (Heckel, 1843) caught from Askale Region of River Karasu betwen February 1996 and January 1997 were examined. The age composition of population varied between I and VI ages, and the most abundant age group was the third age group (42.13%). The population was composed of 51.74% females and 48.26% males. The fork length and the body weights of males and females varied between 8.9-18.1 cm, 3.6-67.9 g and 8.5-18.5 cm, 5.1-79.5 g respectively. The specific and relative growth for length and weight were maximum in the second age. The age-length, age-weight (Von Bertalanffy equations) and length-weight relationships of males and females were calculated as L t = 20.41 (1-e -0.2485(t+1.47) ), L t = 21.59 (1-e -0.1978(t+2.13) ), W t = 80.77 (1-e -0.2485(t+1.47) ) 2.828 , W t = 103.63 (1-e -0.1978(t+2.13) ) 3.082 and LogW= -1.796+2.828LogFL (r=0.943), LogW= -2.097+3.082LogFL (r= 0.946) respectively. The mean condition factor of males and females were found as 1.023 and 1.047 respectively.

In this study, the population structure and growth properties of Chalcalburnus mossulensis (Heckel, 1843) caught from Askale Region of River Karasu betwen February 1996 and January 1997 were examined. The age composition of population varied between I and VI ages, and the most abundant age group was the third age group (42.13%). The population was composed of 51.74% females and 48.26% males. The fork length and the body weights of males and females varied between 8.9-18.1 cm, 3.6-67.9 g and 8.5-18.5 cm, 5.1-79.5 g respectively. The specific and relative growth for length and weight were maximum in the second age. The age-length, age-weight (Von Bertalanffy equations) and length-weight relationships of males and females were calculated as L t = 20.41 (1-e -0.2485(t+1.47) ), L t = 21.59 (1-e -0.1978(t+2.13) ), W t = 80.77 (1-e -0.2485(t+1.47) ) 2.828 , W t = 103.63 (1-e -0.1978(t+2.13) ) 3.082 and LogW= -1.796+2.828LogFL (r=0.943), LogW= -2.097+3.082LogFL (r= 0.946) respectively. The mean condition factor of males and females were found as 1.023 and 1.047 respectively.