en Stock assessment Stock assessment پژوهشي Orginal research papers Ribbonfish,&nbsp;<em>Trichiurus lepturus </em><em>(Linnaeus, 1758)</em>, is an important component of subsistence fisheries throughout its tropical and subtropical distribution. The catch rate of ribbonfish has increased seven-fold in a decade in the Persian Gulf and Oman Sea. We collected monthly biological samples from <em>T.<em>&nbsp;lepturus</em></em>, to estimate growth and mortality parameters, and identify species reproductive patterns. The annual instantaneous rate of fishing mortality (0.63 year^-1) was higher than the target (F_opt= 0.26 year^&minus;1) and limit (F_lim= 0.35 year^&minus;1) reference points, indicating that the ribbonfish stock is overexploited. The gonado-somatic index and monthly gonadal maturity stages of harvested fishes indicated that&nbsp;<em>T. lepturus</em>&nbsp;presents continuous reproductive activity throughout the year, peaking in the four months from March to June. The size at first maturity was estimated at 66.9 cm total length for females. The overall sex ratio differed significantly from the expected 0.5 with a larger proportion of females (&chi;2 = 203.10;&nbsp;<em>p</em>&nbsp;< 0.001).&nbsp; The current study provide important information that can facilitate management, conservation, and sustainable fishing of T. lepturus in the Persain Gulf. Life history traits, Reproduction, Trichurus lepturus, Fisheries, Persian Gulf 298 312 http://jifro.ir/browse.php?a_code=A-10-3412-3&slc_lang=en&sid=1 S.A. Taghavi Motlagh S-taghavimotlagh@hotmail.com 100319475328460039242 100319475328460039242 No Iranian Fisheries Science Research Institute, Agricultural Research, Education and Extension, Organization, Tehran, Iran. M. Ghodrati Shojaei mshojaei@modares.ac.ir 100319475328460039243 100319475328460039243 Yes Department of Marine Biology, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, 46414-356, Noor, Iran A. Vahabnezhad avn9400@gmail.com 100319475328460039244 100319475328460039244 No Iranian Fisheries Science Research Institute, Agricultural Research, Education and Extension, Organization, Tehran, Iran.