Dynamical parameters and relative yield per recruit of the Japanese anchovy Engraulis japonicus (Schlegel, 1846) in the Gulf of Suez, Red Sea, Egypt

F. Mehanna, Sahar; S. H. El-Sherbeny, Asaar; H. M. Ahmed, Mahmoud; B. El Kafrawy, Sameh; T. Khalil, Magdy

doi:10.21608/ejabf.2020.71123

Dynamical parameters and relative yield per recruit of the Japanese anchovy Engraulis japonicus (Schlegel, 1846) in the Gulf of Suez, Red Sea, Egypt

Document Type : Original Article

Authors

10.21608/ejabf.2020.71123

Abstract

Pelagic fishes, caught by purse seine in the Gulf of Suez, represent up to 65 % of the total annual fish production from the Gulf (GAFRD, 1999-2012), hence they contribute to a major fishery in Egypt. The most represented pelagic fish species in the purse seine catch are; anchovy, carangids, clupeids and scombrids. The population dynamical parameters of Japanese anchovy Engraulis japonicus are estimated based on 4086 specimen (3.1 – 10.4 cm TL), collected from the Gulf of Suez during the fishing season 2011/2012. The growth of this species is positive allometric based on the b-value of length weight relationship. From the length frequency distribution analysis, the population parameters were: asymptotic length L∞ = 12.27 cm TL, growth coefficient K = 0.66/y, total mortality Z = 2.58/y, natural mortality M = 1.00/y, fishing mortality F = 1.58, exploitation ratio E = 0.61/y, length at recruitment L_r = 3.1 cm TL, length at first capture L_c = 6.1 cm TL and length at first sexual maturity L_m = 5.9 cm TL. The high values of both F and E reflect the over exploitation situation. The relative yield per recruit Y’/R analysis shows that although the maximum Y’/R achieved at higher E (0.71) than the current one, the E value which will conserve 50% of the spawners is much lower (0.36). From the management point of view, the exploitation level of Japanese anchovy stock should be reduced by at least 30% to conserve and optimize its yield.

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