Abstract
This study includes a preliminary study to predict the possible L50 selectivity parameter, which can be obtained for different mesh sizes used in bottom trawl fisheries, by using the morphological features of the Norwegian lobster (Nephrops norvegicus). The study was carried out in two stages as morphologically based works in the laboratory and then simulation studies in the computer-based. In the study, 20 Norwegian lobsters in various sizes, from the smallest to the largest (18-61 mm carapace length), were used to represent the population as much as possible. In laboratory studies, the carapace lengths and weights of these individuals were measured and the probability of escaping/passing from the mesh templates was tested. The data transmission to FISHSELECT software and also simulation process were done and isobar figures showing the L50 values of Norway lobster against mesh sizes and mesh openness degrees were produced. As result of the FISHSELECT simulation, it was determines as the best model ships for 133,745; R2= 0,810), CS2= 192,324; R2= 0,961) ve CS3 (184,590; R2= 0,948) As a result of FISHSELECT simulation, for 3 different body sections selected for Norway lobster , ship for CS1 and Flexellips 1 for CS2 and CS3 were determined as the most suitable models, respectively.