The ghost fishing effects of bottom trammel nets, which drift on rocks in the bad weather conditions were investigated in regards of mortality of commercially important and endangered species in this study. Underwater experiments were performed in Yumurtalik, Iskenderun Bay between June 2013 and October 2013. Two panel experimental nets were used and data were gathered by underwater observation. During the study, 26 different species, belonging to 17 families, were caught in experimental nets. Teleost and crustaceans formed 98% of the captured individuals. The 24-hour catch rate of the experimental nets showed a rapid decline in the first few weeks and, by the 60th day, the decline was 80%. Afterwards, the decline slowly continued. No individual was caught in experimental nets after the 105th day. For this reason, the fishing life of the lost nets was assumed to be day 105. In the region, the mortality numbers of teleosts and crustaceans caused by bottom trammel nets lost by the entire fishing fleet were identified as 1291 (100 kg) and 6102 (990 kg) individuals, respectively. This mortality rate (0.55% for fish) can be considered to be insignificant in all fisheries, but the mortality rates of threatened species, such as Epinephelus marginatus and Chelonia mydas, were found to be noteworthy.