Species composition of cutlassfish (Trichiurus lepturus) trawl by catch in the fishing grounds of Hormozgan province, Northern Persian Gulf

Cutlassfish trawl fisheries have been used in the Persian Gulf, However, the species composition of the large volumes of by catch caught in this region is poorly known This study was conducted for estimation rates of by catch and species composition in the fishing grounds of Hormozgan province. The data on total species composition of 30 hauls from Kish vessels with the length of 47m and the width of 7.3m with 1200hp engine power operating off the fishing grounds of Hormozgan has been collected. From the estimated 1941.5 tonnes of bycatch taken annually in the fishing grounds of cutlass fish 45 species from 31 families were obtained which: 37 teleost species with 90 percent of the total biomass (1747.9t) from the main composition of the catches and followed by 9 elasmobranchs with 9.91 percent (192.5t) and 2 invertebrate with 0.1 percent (1.08t) of the biomass. The percentages of different groups of by catch and target catch (cutlass fish) were 67.75% cutlass fish, 17.81% commercial species, 10.58 small discards and 3.84 large discards. The examination of the by catch indicates the large impact on stocking density of commercial and non-commercial species in the fishing grounds of cutlass fish by cutlass fish