This study was carried out to determine some biological parameters of carp populations introduced to the Kockopru Dam Lake on the Zilan River in Lake Van Basin and conducted between December 1999 and August 2001. Sampling was carried out monthly using hand nets and trammel nets. It was determined that carp become a sustainable population and is caught by fishermen. The maximum age was determined as VII; fork length as 61.7 cm and weight as 6002.6 g. Length-weight relationship was estimated as log W = -1.402+2.847 log L and age-length relationship was determined as Lt = 84.070 (1-e(-0.126(1+0.801))). It was also determined that male female ratio was 1:0.94 and maturity size was determined as more than 45 cm for female. Reproduction period was observed in June. It was also observed that commercial fishing could be a big threat for the future of the Kockopru Dam Lake population because of undersized catch.