Gill net selectivity for four 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 barbatus, Pagellus erythrinus, Pagellus acarne and Spicara flexuosa was estimated 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 individual selection factors ranged from 6.15 to 9.01 and the optimum selection 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 cm 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 estimated optimum selection lengths and the minimum legal landing sizes and sizes at 50% maturation as well as comparisons between the length frequency distributions of the above mentioned species in gill net catches with those in trawl catches are also presented and discussed.