In this experiment of natural Atrina pectinata spat collection, the number of the pen shell spats settled on a collector were 4.2, 6.8, and 2.7 in the first, second, and third year, respectively. The highest number of pen shell spat settled on the collector was observed in August, and the shell length of juvenile pen shells grew up to 42.5 mm six months after setting. The relation between shell length (SL) and days (D) after setting could be expressed as; SL = 0.3854D ＋ 0.8423 (r2 = 0.9764). The spats developed the best in depth of 10-20 m. Spat collectors in mesh size of 1 x 2 mm were better for spats to survive than the ones in 1 x 1 mm. The most efficient material as substrate for the settlement of pen shell spat was a polyethylene monofilament in the spat collectors.