Age, growth and reproduction biology of the golden grey mullet, Chelon auratus (Risso, 1810) have been studied in the Istanbul Golden Horn area. Fish length ranged from 13.4–46.8 cm, and age from 1–10 years, respectively. The sex ratio (female:male) was 1:1.08. The length-weight relationship was estimated as W = 0.0127L2.89, W = 0.0099L2.97 and W = 0.0156L2.82 for both sexes combined, females and males, respectively. The von Bertalanffy growth equation parameters were: L∞ = 57.52 cm, K = 0.1 year−1, t0 = −2.24 year for pooled data. The gonadosomatic index (GSI) values indicated the major spawning period was between August and November, and the minor spawning peak between March and April. The highest GSI values were observed in September. The length and age of sexual maturity were estimated as 26.2 cm and 4 years for males and 24.1 cm and 3 years for females.
