Comparative Study on the Reproductive Biology of Mullus surmuletus (Linnaeus, 1758) and Mullus barbatus (Linnaeus, 1758) along the Benghazi Coast, Eastern Libya (Mediterranean Sea)

Abstract

The purpose of this study was to examine the reproductive biology differences between Mullus barbatus and Mullus surmuletus along the coast of Benghazi, Eastern Libya (Mediterranean Sea). Sex ratio, gonadosomatic index (GSI), length at first sexual maturity and fecundity were among the important factors analyzed, along with comparisons to earlier research. From January to December 2022, samples were taken monthly from commercial trawl catches. The overall sex ratio was male-biased in both species (1:1.39 in M. surmuletus and 1:1.23 in M. barbatus). Males and females of M. surmuletus and M. barbatus were 12.9 cm and 13.2 cm, respectively, at 50% maturity. According to GSI values, M. barbatus spawned from late winter to early summer, while M. surmuletus spawned primarily in the spring. Despite interspecific variations, fecundity estimates in both species had a positive correlation with fish size. These results shed light on the reproductive tactics of two demersal species that are significant to the region's economy and show how environmental factors, such as climate change, may affect these species' ability to reproduce.