FISHERY ASSESSMENT OF THE COMMON SILVER BIDDY GERRES OYENA FROM THE GULF OF SUEZ, RED SEA, EGYPT.

A. A. El Ganainy, Azza; H. M. Khouraiba, Hafez; M. Aly, Mervat; A. Osman, Menna Allah

doi:10.21608/ejabf.2020.100471

FISHERY ASSESSMENT OF THE COMMON SILVER BIDDY GERRES OYENA FROM THE GULF OF SUEZ, RED SEA, EGYPT.

Document Type : Original Article

Authors

10.21608/ejabf.2020.100471

Abstract

The common silver biddy Gerres oyena is one of the most commercial fish species in the Gulf of Suez. Some population parameters of the species were studied from samples collected from the trawl fishery in the Gulf of Suez during 2015-2017. Age determinations based on otolith readings showed that the growth of females is higher than that of males; where the maximum age attained by males was 4 years while that of females was 5 years. The von Bertalanffy growth equation was L_t = 20.2 (1 – e^{-0.267 (t + 3.281)}) for males and L_t = 22.831 (1 – e^{-0.210 (t + 1.940)}) for females. The fish grows allometrically (b = 3.1102 for both sexes combined) and relatively rapid, achieved about 40% of the growth during the first year of life. The total mortality rate "Z" was estimated as 1.08 year^-1. The natural mortality rate was found to be M =0.310 year^-1. The estimated current exploitation rate (E = 0.71) and the analysis of the relative yield per recruit indicate that the population of the silver biddy Gerres oyena in the Gulf of Suez is overexploited. The fishing effort must be reduced by about 30% of its current level; this can be achieved by reducing the number of fishing days or the number of trawling trips and changing the gear characteristics (mesh size) to catch larger fish to maintain the stock productivity and its sustainability.

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