Age, Growth, Mortality and Reproductive Dynamics of the Red Mullet Mullus barbatus in the Delta Adjacent Waters, Mediterranean Sea, Egypt

The age and growth, reproductive biology, and mortality of the red mullet Mullus barbatus were addressed in the Delta adjacent area, the Mediterranean Sea, Egypt. Length frequency of 12 months from January to December 2020 was used to study the population dynamics of this species which is exploited by trawling. The examined samples were 522 (46.9%) males, 510 (45.8%) females and 81 (7.3%) unsexed. The growth pattern was determined as isometric for males and positive allometric for females. Fitting the von Bertalanffy growth model gave the following growth parameters: L∞=ˆ22.66 cm TL, K= 0.39 year^-1, t₀ = -1.02 year for males, L∞=ˆ23.75 cm TL, K= 0.39 year^-1, t₀= -0.97 year for females and L∞=ˆ24.22 cm TL, K = 0.34 year^-1, t₀ = -0.77 year for combined sexes. Based on the estimated total, natural and fishing mortality coefficients, the exploitation rate for males, females and pooled data were around 0.65. The estimated fishing mortality rate (1.35, 1.14 and 1.18 year^-1 for male, female and combined sexes, respectively) and exploitation rate (E = 0.65) obtained in this study indicate a high fishing pressure on the M. barbatus stock in the Egyptian Mediterranean waters. Monthly variation in both mean gonado-somatic index and maturity stages showed that this species breeds once a year from March to July for males and from February to June for females. From the analysis of the probability of capture, the length at first capture was estimated at 11.76 and 11.54cm for males and females, respectively, which was smaller than the length at first sexual maturity (12.29cm for males and 12.91cm for females). Thus, the red mullet species in the Delta adjacent area, the Mediterranean Sea is overexploited.