Multifilament Gillnet Selectivity for the Red Mullet (Mullus barbatus) in the Eastern Black Sea Coast of Turkey, Trabzon

The mesh selectivity of multifilament gillnets for red mullet (Mullus barbatus) was investigated using four different stretched mesh sizes (32, 36, 40 and 44 mm). Experimental fishing operations were carried out in Trabzon (Turkey) coasts of the Black Sea in springtime between 2002 and 2003. Selectivity on M. barbatus was assessed using the SELECT method, implemented in the PASGEAR software. Five different functional models; normal location, normal scale, gamma, log-normal and bi-model were used to fit the selectivity curve to the catch data. It was shown that the bi-model function was the hest to fit the data. For the selectivity curves oil the bi-model, the optimum lengths (100% retention probability for the 32, 36, 40 and 44 mill mesh sizes) were obtained as 14.24 cm, 16.02 cm, 17.8 cm, and 19.58 cm, respectively. Considering the minimum allowable landing size (13 cm) 36 mm was found the most adequate mesh for exploiting the red mullet as it evidenced more conservative approach towards fishing management.