THE EFFECTS OF DIFFERENT COD-END DESIGN ON BOTTOM TRAWL SELECTIVITY IN TURKISH FISHERIES OF THE AEGEAN SEA

The effect of different cod-end designs on bottom trawl selectivity wa s studied using the hooped cod-end cover method. The selectivities of three different cod-ends: standard, 15% shortened lastridge rope and n arrowed circumference (to 120 mesh from 150 mesh), were measured for r ed mullet (Mullus barbatus L., 1758) and annular sea bream (Diplodus a nnularis L., 1758) in Turkish territorial waters of the Aegean Sea in June and September 1994. Selection curves and selection parameters wer e calculated using a logistic model. 50% retention lengths and selecti on factors for red mullet were higher for the shortened lastridge rope case and narrow cod-end than the standard cod-end. There was no signi ficant difference for annular sea bream. This can be explained by the body shape differences of the two species. The effects of different co d-end designs on the selectivity are discussed. (C) 1997 Elsevier Scie nce B.V.