Mako reservoir which is situated on Zangmar River, located in western Azarbaijan province. It has an average area of 800 hectares. There isn't any fishing in Mako reservoir, and the purposes of construction were producing water supply for agriculture use and drinking water. The seasonal sampling were carried out in 5 stations by gillnet methods during 1998-1999. For catching the Capoeta capoeta, gillnet mesh size of 27mm was used. Capoeta capoeta was dominant species (90%) and Carassius aurata gibelio and rainbow trout had the lowest populations. Analysis on based Leslie and Delury methods showed that this reservoir has a range of 9.4-10.7 tons of Capoeta capoeta. By using Gulland method, the MSY estimated 4.5-4.8 tons.One year data collection and analyzing the data showed the average fork length were 23.9±4.3cm, mean weight of 162±68g and the mean age 2.6±0.68 years. Age composition showed that maximum and minimum frequency was in 3+ and 5+, respectively. Infinite length (L∞) and the growth coefficient (k) by using Walford formula computed 35.6 cm and 0.39 per year. Total mortality (Z) of this species determined 0.74. Natural and fishing mortality calculated 0.37 and 0.37, respectively.