Reproduction of the mediterranean killifish Aphanius fasciatus at different salinity conditions: Implications for conservation and management

Climate change is expected to significantly alter the distribution of fish organisms, particularly within vulnerable ecosystems like transitional water bodies. The anticipated rise in sea levels and extreme rainfall events could trigger coastal habitat salinisation or freshwater dilution, posing potential threats to resident species of European Community interest. In this study, we examine the impact of salinity fluctuations on the Mediterranean Killifish Aphanius fasciatus , a species listed in Annex II of the Habitat Directive. We employ a behavioural approach, analysing reproductive performance and courtship behaviours across a salinity range of 5–45 pss, both qualitatively and quantitatively. Results reveal the presence of the complete reproductive repertoire across all salinity treatments, including successful egg spawning, emphasising the significance of Mediterranean salt marshes in safeguarding local populations. • Extreme rainfall and habitat marinisation affect species distribution. • Reproductive performances and mating tactics might be threatened by salinity. • Aphanius fasciatus can court and spawn from oligohaline to hypersaline conditions. • Behavioural analysis is a powerful tool for assessing reproductive performance in a changing environment.