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....