Reproductive biology of the golden grey mullet Liza aurata (Risso, 1810), in the Gulf of Gabes (central Mediterranean, Tunisia)

Abstract

In this study, some biological characteristics of the Golden grey mullet from the Gulf of Gabes (central Mediterranean, Tunisia) were examined; in particular, the gonado somatic index (GSI), hepato somatic index (HSI), condition factor (K), length at first sexual maturity (TL50) and fecundity (volumetric method) were calculated. The gonadosomatic index (GSI) indicated that the spawning season of the Golden grey mullet extends from October to December. The monthly variation of the hepato-somatic index (HSI) indicates that L. aurata saves lipid reserves in the liver. The length at first sexual maturity (TL50) was determined to be 23.73, 23.84 and 23.79 cm TL for female, male and combined sexes, respectively. In this study, the sex-ratio was unbalanced, with females dominating among large sized individuals (TL > 24.0 cm). Absolute fecundity, with a mean value of 286564, varied from a minimum of 210400 eggs for age 4+ to a maximum of 533600 for age 7+.