The present study was the first attempt to evaluate the impact of dibutyl phthalate (DBP) and benzyl butyl phthalate (BBP) at concentrations of 100, 1000, and 10000 μg DBP dm-3 and 20, 200, and 2000 μg BBP dm-3 on the motility parameters of the sperm of European pikeperch, Sander lucioperca (L.), using computer assisted sperm analysis (CASA). The in vitro studies were conducted in the seminal plasma, which is the natural environment of the sperm, using two methods. The first was with the immediate activation of sperm movement in the presence of phthalates (0 h), while the second utilized phthalate incubation for 4, 24, and 48 h. It was confirmed that none of the compounds analyzed had a significant impact on the percentage of motile sperm (MOT), average path velocity (VAP), curvilinear velocity (VCL), straight line velocity (VSL), or amplitude of lateral sperm head displacement (ALH) (P > 0.05). It is plausible that in natural aquatic ecosystems, neither dibutyl phthalate nor benzyl butyl phthalate will affect motility of fish sperm at external fertilization event. It is necessary to track in vivo the impact these compounds have in concentrations similar to existing in the natural environment on the fish sperm quality.
