Gillnet selectivity for non target fish species caught by red mullet gillnets north Aegean Sea

The aim of this study is to determine the effects of red mullet gillnets that are commonly used in Turkish waters on the sustainability of non-target fish species. For this purpose, surveys were realized with 18 - 20 - 22 mm nominal bar length red mullet gillnets between December 2008 and May 2010 along the north Aegean Sea coasts (5-30 m). SELECT method was used with five different models (Normal location, normal scale, log-normal, gamma and bi-modal) for evaluating selectivity parameters of non-target fish species. Selectivity models were determined as bi-modal for Serranus scriba and Symphodus tinca, log normal for Scorpaena porcus and Spicara maena and gamma for Pagellus acarne. Optimum catch lengths and spread values and selectivity curves were given for 5 species. Results showed that use of a larger mesh size over the 22mm mesh is important for ensuring stock sustainability of the non-target fish species.