Reproductive Biology of Male European Hake (Merluccius merluccius) in Central Mediterranean Sea: An Overview from Macroscopic to Molecular Investigation

The vast majority of the world's commercial fish stocks are considered overfished.Among demersal species, in the Mediterranean Sea, the European hake (Merluccius merluccius) isexperiencing high fishing pressure, resulting in a critical overexploitation status. The reproductivepattern of the male sex is poorly investigated. In order to provide scientific advice for its sustainablemanagement, this study gave, for the first time in the Central Mediterranean Sea, an overview of thereproductive biology of male European hakes, by using a multidisciplinary approach. The sex ratiothroughout the three-year period and by length class showed that males dominated the populationfrom February to June and up to 24 cm, respectively. The reproduction occurred all year round witha seasonal peak in spring/summer. The macroscopic and histological sizes at first maturity were18.6 cm and 15.4 cm, respectively. The entire reproductive cycle was unequivocally identified byfive histological developmental stages of the testis. Finally, the molecular approach allowed us toinvestigate endocrine regulation from the onset of puberty to the adult lifecycle.