Majallah-i ̒Ilmī-i Shīlāt-i Īrān (Jan 2018)
Fishery management based on relative yield-per-recruit model for the Largehead Hairtail (Trichiurus lepturus) stocks in the Persian Gulf and Oman Sea
Abstract
Among the several fish species commercially exploited at the Persian Gulf and Oman Sea waters, the Largehead hairtail, Trichiurus lepturus, stands as one of the most influential groups that have been recently exploited for export to outside markets. In the current study, we applied the Beverton and Holt's relative yield per recruit model to provide management guidance and determine the biological reference points (i.e. E0.5 and Emax) for T. lepturus stock in the coastal waters of Iran. The von Bertalanffy growth equation (VBGF) was fitted to length–frequency data (n =1309) to obtain a VBGF with the following parameters: L∞=111.3 cm total length; K=0.41 and t0= -0.28 years. The estimated value of total mortality (Z) based on length converted catch curve method was 1.11 year-1. Natural mortality (M) based on growth parameters was 0.67 year-1 while fishing mortality (F) was recorded as 0.44 year-1. Maximum exploitation rate (Emax), corresponding to the maximum relative yield per recruit was Emax = 0.62. The stock was not overexploited, since E < Emax. The present results have to be considered with caution to fisheries management purposes as fishing effort is still in increasing phase. The long-term monitoring is required to better understand the T. lepturus population dynamic and its fishery framework in the study region.
