Stock Analysis, Critical Lengths and Exploitation Status of the Gilthead Seabream, Sparus aurata (Linnaeus, 1758) in the Mediterranean Sea off Alexandria, Egypt

The gilthead seabream Sparus aurata is a commercially significant fish species in the Egyptian Mediterranean fishing areas. The present study was directed to evaluate the stock status of S. aurata fishery from Alexandria fishing ground, Egypt. The data were collected from January to December 2022, and a total of 834 specimens were measured for length-weight and length-frequency distribution. The forked length (FL) ranged from 13.3 to 32.5cm, and the weight varied from 47.2 to 640.9g. Based on otolith readings, the growth and death rates were determined. The age composition of S. aurata comprises of six age groups from I to V plus age group zero. The length-weight relationship for combined sexes was W = 0.0225 L^2.96 (R² = 0.95) showing an isometric growth. The von Bertalanffy growth parameters were 𝐿∞ = 40.5cm, K = 0.236/ year, and t_ο = -0.47 year.  However, total mortality (Z), natural mortality (M) and fishing mortality (F) were 1.45, 0.55 and 0.90 year^-1, respectively. The exploitation ratio (E) was computed as 0.622, which is higher than the limit point (> 0.5) indicating that the stock of S. aurata is experiencing an overexploitation state. Critical lengths of this species were calculated giving that L_m was highly greater than L_c, forming  another evidence for the overfishing situation. It may be suggested that particular management actions should be taken to conserve the stock of this fishery at a sustainable level for the forthcoming generations.