Population structure analysis of largehead hairtail fish (Trichiurus lepturus, Linnaeus 1758) in bottom trawl by-catch in Kolahi to Dargahan waters

Large-head hairtail, Trichiurus lepturus, is one of the commercial fish at the Persian Gulf and Oman Sea waters, which is exploited to export outside markets. To present population dynamics and characteristics of this species, the fish caught by trawling method were analyzed from Kolahi to Dargahan areas in Hormozgan province waters. The von Bertalanffy growth equation (VBGF) was fitted to length-frequency data (n =771) to obtain a VBGF with the following parameters: L∞, K, and t0 were 88.83 cm, 0.10, and -0.07, respectively. The estimated value of total mortality (Z) and natural mortality (M) were 0.44 and 0.28 (year-1), respectively. Also, fishing mortality (F) was recorded as 0.16 year-1. Exploitation rate, corresponding to the maximum relative yield per recruit (E) was 0.36, and this fish in the present study caught capacity. Recruitment pattern showing maximum added yang fishes in September. The present results have to be considered with caution for fisheries management purposes as fishing effort is still in increasing phase. Long-term monitoring is required. To better understand the T. lepturus population dynamic and its fishery framework in the study region.