GILL NET SELECTIVITY FOR DIPLODUS-ANNULARIS AND MULLUS-SURMULETUS IN GREEK WATERS

The present study is the first concerning gill net selectivity in Gree k marine waters. Selectivity estimates were made for Diplodus annulari s and Mullus surmuletus. Sampling took place at 15 stations in the Sou th Euboikos Gulf in 1992 and 1993 with a chartered commercial small-sc ale fishing vessel. Samples were collected with gill nets of mesh size s (bar length) of 17, 19, 21 and 23 mm. Individual selection factors f or M. surmuletus and D. annularis ranged between 4.83 and 7.42 whereas the optimum selection lengths increased from 12.2 to 16.5 cm for M. s urmuletus and from 8.8 to 11.9 cm for D. annularis, for the 17 mm and 23 mm nets, respectively. Comparisons between the estimated optimum le ngths and the minimum legal landing sizes and between the length frequ ency distributions of the catches of D. annularis and M. surmuletus in gill nets and those in trawl nets are also presented.