The investıgatıon of the selectivity of monofilament gill nets used in catch of Pike Perch (Sander lucioperca Bogustkaya and Naseka, 1996) in Seyhan Dam Lake

In this study, the gill nets used for pike perch (Sander lucioperca Bogustkaya & Naseka, 1996) which were 20, 22, 24 and 26 mm mesh size were investigated for their selectivity in Seyhan Dam Lake. The study was carried out between March 2008 and 2008 June in Seyhan Dam Lake. A prediction method developed by Holt (1963) was used for determining the selectivity parameters. At the end of the study, the optimum catch lengths found to be; 20.64, 22.70, 24.76 and 26.83 cm for 20, 22, 24, and 26 mm mesh size, respectively. Common selection factor and common standard deviation were calculated as 5.16 and 0.83 respectively. Lengths at first maturity of pike perch in Seyhan Dam Lake were compared with the gill nets (20, 22 and 24) used for fishing. Thus, it was determined that gill nets 20, 22 and 24 mm mesh size cause an over fishing on pike perch stock while 26 mm mesh size do not cause an over fishing.Key Words: Gill net selectivity, Optimum mesh size, Seyhan Dam, Pike Perch