Estimation of selectivity of gillnet and thermal net in use in the Bodrum peninsula

Estimation of Selectivity of Gillnet and Trammel net in Use in the Bodrum Peninsula In this study selectivity of gillnets of 40 mm mesh size which are widely used in the coastal fisheries, were studied for annular sea-bream (Diplodus annularis), round sardinella (Sardinella aurita), comber (Serranus cabrilla), bogue (Boops boops), axillary seabream (Pagellus acarne), striped red mullet (Mullus surmuletus), red mullet (Mullus barbatus), picarel {Spicara smarts) and chub mackerel (Scomber japonicus). Selectivity of trammel net of 80 mm mesh size was also investigated for common dentex (Dentex dentex). Selectivity parameters were estimated using Sechin model based on the measurements of maximum body girth and head girth. Optimum catch length and selection factor of gillnet of 40 mm mesh size were estimated as 12 cm and 3 for annular sea bream, 18 cm and 4.5 for round sardinella, 16 cm and 4 for comber, 16.4 cm and 4. 1 for bogue, 13.6 cm and 3.4 for axillary seabream, 16.5 cm and 4.2 for striped red mullet, 16.4 cm and 4.1 for red mullet, 15.2 cm and 3.8 for picarel, 19 cm and 4.75 for chub mackerel respectively. The optimum catch length and selection factor of trammel net of 80 mm mesh size were also as 28 cm and 7estimated for common dentex. Additionaly, relationship between fish length and maximum girth (Gmax) and head girth (Gc) for all fish species studied were also determined. Key Words: Selectivity, Gillnet, Trammel net, Bodrum Peninsula, Annular sea bream (Diplodus annularis), Round sardinella (Sardinella aurita), Comber (Serranus cabrilla), Bogue (Boops boops), Axillary seabream (Pagellus acarne), Striped red mullet (Mullus surmuletus), Red mullet (Mullus barbatus), Picarel (Spicara smaris), Chub mackerel (Scomber japonicus), Common dentex (Dentex dentex).