Codends Selectivity for Bogue (Boops boops L., 1758) in the Eastern Mediterranean Demersal Trawl Fishery

Abstract

This study investigated the selectivity of 90 degrees 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 Kusadasi 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 (L-50) 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 L-50 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, L-50 values of 40T1 and 44T1 are very close considered to the 13 cm length at first maturity size of the species.