Multi-monofilament gillnet selectivity for Capoeta trutta (Heckel, 1843) in Keban Dam Lake

In this study, by benefiting from indirect estimation method developed by Holt (1963), multimonofilament gillnets with different mesh size used in fishing of Capoeta trutta (Heckel, 1843) that have selective properties were determined. Field studies were carried out between November 2011 and May 2012 in Pertek Region of Keban Dam Lake (Elazig-Turkey). In experiments, five pieces of gillnets with 35, 40, 45, 50 and 55 mm mesh sizes and 3 x 0.12 mm diameter multi-monofilament polyamide material were used. A total of 720 samples of Capoeta trutta were caught in 24 fishing attempts. It was determined that optimum catch length of Capoeta trutta caught by gillnets with 35, 40, 45, 50, and 55 mm mesh size as 28.57; 32.65; 36.73; 40.81 and 44.89 cm, respectively, common selectivity factor (SF) as 8.16 and common standard deviation (SD) as 3.51. Length at first maturity of female C. trutta (29.07 cm) was compared to the optimum selection lengths of gillnets with mesh sizes of 35, 40, 45, 50 and 55 mm. Results indicate that gillnets with mesh size of greater than or equal to 40 mm would be appropriate for catching C. trutta in the Keban Dam Lake. The use not of smaller mesh sizes are considered to be extremely important for the sustainable catching of C. trutta in Dam Lake