This study was conducted in Seyhan Dam lake between June 2007-2008. About 778 pikeperch (Sander lucioperca, Percidae) individuals were examined by means of monthly sampling and their spawning times and first sexual maturity lengths were determined. The findings obtained displayed that pikeperch in Seyhan Dam lake spawned after the month of February and the male and the female pikeperch reached the first maturity lengths of 256 mm TL (206 mm SL) and 264 mm TL (216 mm SL), respectively. Furthermore, the size selectivities of the pikeperch were estimated by using monofilament gillnets with mesh openings of 40, 44, 48 and 52 mm. For the estimation of size selectivity, the lowest deviation value was observed for the log-normal model among the selectivity curves drawn by using normal location, normal scale, log normal, gamma and bimodal distributions.