Investigation of the Selectivity of Trammel Nets Used in Red Mullet (Mullus barbatus) Fishery in the Eastern Black Sea, Turkey

In the present study, the selectivity properties of trammel nets used in red mullet fishery by local fishermen were investigated. Trammel nets with five different mesh sizes (16, 17, 18, 20 and 22 mm bar length) in the inner panels and 100 mm mesh size in outer panel were used for fishing trial in the eastern Black Sea coast of Turkey between June 2010 and June 2011. Selectivity parameters for the target species Mullus barbatus, as well as Scorpaena porcus and Solea solea were estimated. Five different selectivity models (normal scale, normal location, gamma, log-normal and bi-modal) in the SELECT method were fitted to data sets. The bi-modal model gave the best fit for three species studied as it had the lowest deviance value. The optimum lengths for red mullet for the Bi-Modal model corresponding to 16, 17, 18, 20 and 22 mm mesh sizes were found as 15.49, 16.46, 17.42, 19.36 and 21.30 cm, respectively. The minimum mesh size of the trammel nets especially used in red mullet fishery must be 18 mm in order to protect fish stocks and to secure a profitable fisheries and optimum catch efficiency for the future.