الفهرس 
Introduction and the Aim of WorkOnly 14 pages are availabe for public view
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Abstract
Cephalopoda is a major class of the phylum Mollusca; which includes several commercially and economically important species such as octopus, cuttlefish, and squid. Cephalopods fishery constitutes an important portion of the Gulf of Suez fisheries comprising " ~ "380 tons. The present study aimed to the assessment and the management of the most important squid species in the Gulf of Suez; the Indian squid Uroteuthis duvaucelii (D’Orbigny, 1835) for its development and for achieving sustainability. The study is based on monthly sampling from the landings of trawlers operating in the Gulf of Suez, during the fishing season 2017/2018. Investigation of population characteristics revealed that U. duvaucelii males grow to a larger size compared to females (maximum ML= 25.3 cm and 19.4 cm for males and females, respectively). Longevity was 2 years for both males and females using the modal progression analysis of Bhattacharya’s method. The overall sex ratio (M: F) was 1.7:1 showing the dominance of males over females during the study period. Females reach sexual maturity earlier than males (ML50% = 13.5 and 10 cm ML) for males and females, respectively. The gonado-somatic index values increased with the gonad maturation, having 2 beaks during spring and autumn. The spawning strategy in this species is iteroparous and spawns partially throughout the year. The length-weight relationship was W= 0.2067 ML 2.1345 and W= 0.1046 ML 2.4179 for males and females respectively. The estimated Von Bertalanffy growth parameters L∞, K were (26.8 cm, 1.2 / yr.), (19.9 cm, 1.3 / yr.) and (26.4 cm, 1 / yr.) for males, females, and combined sexes respectively. The instantaneous total (Z), natural (M), and fishing mortality (F) coefficients were (2.4, 2.4, 2.7 / yr.), (1.1, 1.2, 1.2 / yr.) and (1.3, 1.1, and 1.5 / yr.) for males, females and combined sex respectively. The estimated exploitation ratio (E = 0.54, 0.49, and 0.55 / yr. respectively), these values seem to be around the optimum level of exploitation (Eopt. = 0.50 / yr.). Stock assessment models [Y/R, Y’/R, and VPA] were applied for U. duvaucelii for determining the target reference points [Y/Rmax with the corresponding Fmax. and Y’/Rmax with the corresponding Emax], which are used as a guide for U. duvaucelii fishery management in the Gulf of Suez.