GILL NET SELECTIVITY FOR 4 FISH SPECIES (MULLUS-BARBATUS, PAGELLUS-ERYTHRINUS, PAGELLUS-ACARNE AND SPICARA-FLEXUOSA) IN GREEK WATERS

In the present study, the size selectivity of gill nets for Mullus bar batus, Pagellus erythrinus, Pagellus acarne and Spicara flexuosa was e stimated from samples collected with nets of 17, 19, 21 and 23 mm mesh sizes (nominal bar length). Sampling was conducted at 15 stations in the South Euboikos Gulf (western Aegean Sea) in 1992 and 1993. The ind ividual selection factors ranged from 6.15 to 9.01 and the optimum sel ection lengths increased from 10.7 to 14.4 cm fork length (FL) for P. erythrinus, from 11.0 to 14.9 cm FL for P. acarne, from 13.3 to 17.9 c m FL for M. barbatus, and from 13.0 to 17.6 cm FL for S. flexuosa for the 17 and 23 mm gill nets, respectively. Comparisons between the esti mated optimum selection lengths and the minimum legal landing sizes an d sizes at 50% maturation as well as comparisons between the length fr equency distributions of the above mentioned species in gill net catch es with those in trawl catches are also presented and discussed.