In the present study, the seasonal variations in demersal catch composition in Gülbahçe Bay were investigated by trawl sampling. Species identification of the samples was carried out at class, family and species levels. The results of this study were compared to those of previous studies carried out in the same area and it was concluded that red mullet, which is the dominant species of Gülbahçe Bay, has lost this characteristic because of overfishing and marine pollution. For this reason, fishing activities and the discharge of domestic waste waters should be strictly controlled.