Study of some biological characteristics (Tiger tooth croacher, Silver pomfert, Yelow fin seabream, Hilsa shad, Indo-pacific king mackerel, Narrow-bared Spanish mackerel) in the coastal waters of the Persian Gulf

Abstract

The present study was carried out in the fishing landing center in khozestan using the commercial catch data. The data of total cutch of fishes and effort were prepared from the deputy of statistic office. Based on the pre data, the effort of gill-net fishery was being decreased from 1996 to 2000 and then had a trend to increase from 2001. The maximum and minimum of trap fishery of dhows ware observed 2005 and 1996 respectively. The maximum and minimum of total catch were observed in 2005 in Hilsha shad and Spanish mackerel with 4174.95 tones and 73.33 tones respectively. In this year the total catch of silvery pomfret and tiger tooth croaher species were recorded 323.6 tones and 1700.44 tons respectively. The growth parameters of Hilsha shad were estimated from 10071 specimens in Abadan and 4032 specimens of length frequencies from Hendijan, statistic program of t-test was used for the mean total length and the results showed the significantly different (p < 0.05) in the two areas during 12 months. The Von Bertalanffy growth parameters were estimated from the FISAT II and ELEFAN.The asymptotic length (L) was estimated using the Powell – Vetheral method in Abadan and Hendijan, 42.74 cm and 37.02 cm respectively. Growth coefficient or K for both areas were 0.77 and 0.71 per year respectively. The instantaneous rotes of total mortalities (Z) were estimated from length-converted catch curves and the values were at 2.55 year -1 for Abadan and 2.81 year -1 for Hendijan. The instantaneous rate of natural mortalities (M) and fishing mortalities (F) for both areas, Abadan and Hendijan were 0.75 year -1, 0.732 year -1 and 1.8 year -1, 2.078 year -1 respectively. The exploitation rates (E) for both populations were 0.7 year -1 in Abadan and 0.73 year -1 in Hendijan. However the optimum level of E should be 0.5 and the estimated valves of E is more than 0.5 and shows the pressure of fishing effort and overexploited on the population of this stock. The instantaneous rate of total mortalities of Tiger tooth croacker was 1.95 year -1 the instantaneous rate of natural mortality using Pauly empirical formula was estimated 0.7 year -1 and fishing mortality were 1.52 year -1. The exploitation rate for this species was calculated 0.62 year -1. The values of M and F for silvery pumfret were obtained 0.91 year -1 and 1.47 year -1 respectively. The exploitation rate was estimated 0.61 year -1.