bottom trawl selectivity parameters of four fish species from karataş coasts of turkey in northeastern mediterranean waters

the bottom trawl selectivity parameters (22mm cod-end mesh size) were determined for saurida undosquamis , mullus barbatus , upeneus pori , and pagellus erythrinus along karatas coasts of turkey in northeastern mediterranean waters during fishing season for the year 2002-2003. the lengths at first capture (l 50 ) values for s. undosquamis , m. barbatus , u. pori and p. erythrinus were 12.57, 9.27, 10.20 and 7.20cm, respectively. when lengths at first maturity of these species were taken into consideration, it was concluded that bottom trawl fisheries carried out in breeding areas creates a high fishing pressure (overfishing) on all species and enlarging the mesh size of the net is not enough to prevent the high fishing pressure on these species.