Catch and discard fish species of trawl fisheries in the Iskenderun Bay (North-eastern Mediterranean) with emphasis on lessepsian and chondricthyan species

Abstract

Fish species in catch and discard of trawl fisheries in and around Iskenderun Bay were examined within the fishing closure period and fishing period. The sampling was performed from May 2010 to January 2011 by a commercial trawl vessel. Chondricthyan species accounted for 51 % of discard catch biomass while Gymnura altavela and Dasyatis pastinaca were dominant in hauls. 27 lessepsian fish species were captured during the study, nine of them being target species for trawl fisheries. In total, 14 of the lessepsian fish species were determined as discard species. In both sampling periods, Equulites klunzingeri and Citharus linguatula contributed to discard fish catch dissimilarity among depth ranges (deeper and shallower than 60 m). E. klunzingeri showed high abundance in discard catch. There were no significant differences in the distribution of the discard fish biomass between the sampling periods (ANOVA test, p>0.05). However, depth range highlighted significant differences in discard fish catch composition (p<0.05). Among major commercial fish species of trawl fisheries, Mullus surmuletus and Sparus aurata were not separated as discard in any haul by fishermen. Any size of these two species was included in the commercial catch (Total length ranged from 61 to 721 mm).