One-year field study measures golden grey mullet reproduction and growth in

A one-year field study in Tunisia’s Bizerte Lagoon has mapped key reproductive and growth traits of the golden grey mullet (Chelon auratus) and found a clear October–December breeding window. Researchers sampled 576 fish monthly from January–December 2022 at Menzel Abderrahmane harbor using trammel nets with 26–60 mm diamond mesh. The catch included 290 females and 286 males, with no significant sex-ratio difference (χ² = 1.25, P > 0.05). Females reached 50% maturity at 23.46 ± 0.2 cm versus 22.5 ± 0.18 cm for males, and both sexes matured in their second year. Gonads began developing after August, and the gonadosomatic index peaked in October (9.5 ± 0.7 for females; 5.64 ± 0.58 for males). Absolute fecundity ranged from 115,000 to 500,000 oocytes (mean 256,867 ± 98,134). Growth was negative allometric, with a von Bertalanffy asymptote of 44.25 cm and a growth coefficient of 0.179 per year. Observed ages ran from one to six years, though the model estimated theoretical longevity around 15 years for females and 14.89 for males.