Stock Expectations and Virtual Population Analysis of Three Mullets Species in the Shatt Al-Arab River, Iraq

Abstract

The research was conducted as many as 456 individuals of Planiliza abu, 500 individuals of P. klunzengeri and 600 individuals of P. subviridis. The purpose of this study was to analyze the frequency of fish lengths to determine stock expectations and analyze species population estimates using the VPA (Virtual Population Analysis) Method in the Shatt Al-Arab River from November 2015 to October 2016 using the FiSAT II program. The results showed that the growth patterns of the three species were negative allometric. The values of L∞ for the three species were 21.2, 27.0 and 29.3 cm, respectively. The rates of total mortality (Z), fishing (F), natural (M) and exploitation (E) for P. abu were 2.69, 1.09, 1.60 and 0.59, P. klunzengeri 2.49, 1.08, 1.41 and 0.57 and P. subviridis 1.51, 0.84, 0.68 and 0.45, respectively. The present exploitation rates (E) for all species are lower than the biological target reference points expressing a case of under-exploitation of the species. VPA showed that the maximum fishing mortality for the three species occurred in the mid-lengths, with maximum values at the length of 15 cm for P. abu and 17 cm for P. klunzengeri and P. subviridis. The mullets species catches have not met the criteria for good management (Lc50< Lm50), indicating that the fish may be vulnerable to capture before they mature. Accordingly, the present study proposes that the officials in fishery management can get more by yields through increasing the fishing activities on these species but must be matching the mesh sizes with the fishing recommendation to assure resource availability and sustainability.