A comparative study of sperm motility kinematics in six fish species of the subfamily Leuciscinae (Actinopterygii: Cypriniformes)

AIMS: A comparative study was conducted on the sperm motility kinematics of six species within the subfamily Leuciscinae, aiming to elucidate the potential relationship between variations in sperm motility parameters and both the water currents at their spawning grounds and their mating behaviour. METHODS: Computer-assisted sperm analysis (CASA) was performed to evaluate nine motility parameters. Water currents at the spawning grounds and mating behaviours were compiled based on literature data. KEY RESULTS: This study identified both similarities and differences in sperm motility characteristics. Differences in sperm motility kinematics primarily concerned velocity at activation and the total duration of movement. CONCLUSIONS: In rheophilic Leuciscinae spawners, such as the vimba bream and chub, a prolonged motility duration or lower sperm velocities were observed compared to still-water spawners. Still-water spawners, such as the territorial freshwater bream and the non-territorial white bream, which exhibits reported courtship tactics, showed intermediate sperm velocities. The roach and rudd, which display lek-like mating behaviour, presented the highest initial velocities. IMPLICATIONS: Further research is required to confirm that sperm traits in Leuciscinae are strongly shaped by environmental conditions and mating systems, as well as to provide detailed descriptions of the multi-faceted biological factors that underlie breeding success across different species.