This study investigated the selectivity of 90° turned meshes of 40 mm mesh size with 165 meshes around codend circumferences (40T1), 44 mm meshes size with 300 meshes around codend circumferences (44T1) and 44 mm mesh sizes with 150 meshes around codend circumferences (44T2). Experiments were carried out in the Kuşadası Bay of the Eastern Mediterranean, between 19 January and 29 March 2015 with commercial stern trawler. Selectivity data were collected using the covered codend method and analysed by means of a logistic equation with the maximum likelihood method. Individual hauls and mean selectivity parameter were estimated by using the CC2000 and EC-Modeller software, respectively. The mean 50% retention total length values (L50) and selection range (SR) were 12.7 cm and 2.3 cm for 40T1, 13.2 cm and 3.5 cm for 44T1 and 13.8 cm and 3.0 for 44T2, respectively. Significant differences were determined among the L50 values of the codends (between 40T1 and 44T2) (P<0.05). However, there are no statistical difference between the 40T1 and 44T1, 44T1 and 44T2 (P>0.05). On the other hand, L50 values of 40T1 and 44T1 are very close considered to the 13 cm length at first maturity size of the species.

Square mesh windows (SMWs) with 75 (75SMW; 37.5 mm bar length) and 90 mm (90SMW; 45 mm bar length) nominal mesh size were tested for determining size selectivity in dhow prawn fisheries of the Persian Gulf (Hormuzgan province). Fishing trials were conducted on the commercial fishing grounds of Hormuzgan province of the northern Persian Gulf by commercial dhow trawler. Covered codend methods were utilized for collecting data during October and November 2012. Totally 21 and 16 valid hauls were performed with 75SMW and 90SMW, respectively. The mean L 50 values of 75SMW 9 SMW . ± . .7 ± . Penaeus merguiensis) .9 ± . .9 ± .Jinga shrimp (Metapenaeus affinis) 8. ± . 8 9. ± . ork length for Indian ilisha (Ilisha melastoma), and 8. ± .8. ± . k ulphur goatfish (Upeneus sulphurous), respectively. This study clearly shows that there is not any notable different in size selectivity of square mesh windows with different mesh sizes for investigated species. Future studies on different by-catch reduction methods such as full square mesh codends or grids should improve size selectivity of the species and efforts to reduce by-catch in this fishing system.

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