Understanding the size selectivity based on fish morphology of striped red mullet (Mullus surmuletus) in bottom trawling

Striped red mullet (Mullus surmuletus) is one of the most important demersal species caught from our seas. Even it is not among in target species of bottom trawl operations, striped red mullet caught often and has high commercial value. In the aim of sustainable fishing targets, to develop suitable fishing gears for the target species is one of the most important goal of the scientists working in this field. It is important that to carry out fast and low cost selectivity studies for this need. For this reason in recent years, FISHSELECT like simulation based studies are giving positive results in the name of sustainable fisheries. In this study, sampled striped red mullets (Mullus surmuletus) was subject of morphological measurements, fall-through experiments and simulation phases. In the result of these minimum landing size, traditionally used meshes and mesh opening angles during towing considered as parameters. 40 mm, 44 mm, 50 mm diamond mesh and 40 mm square mesh bottom trawl models simulated and in order 9.87 cm, 10.75 cm, 12.19 cm and 12.3 cm 50% retention rates has been found. For different mesh sizes and opening angles design guides has been created. Although there not many bottom trawl selectivity studies about striped red mullet (Mullus surmuletus), previous study using FISHESELECT method about red mullet (Mullus barbatus) and compared these two studies by using their morphological similarities has given us positive results.