The efficacy of male's nest preparation and its effect on female's partner selection during semi-controlled reproduction in pikeperch (Sander lucioperca)

This study evaluated partner selection in pikeperch (Sander lucioperca) during seasonal nest spawning and its effect on reproduction efficiency. The experimental setup was based on the ability of the female to select pikeperch males of two sizes. After spawning, both empty and selected nests were photographed to evaluate male cleaning efficiency and egg distribution on the selected nests. After the completion of spawning, blood samples from all fish were taken to determine estradiol (females), testosterone, and 11-keto-testosterone (males) levels in blood plasma. The experiment lasted 24 days, during which 12 spawning events were recorded. Pikeperch females preferred a bigger male in 77% of recorded spawning events, as they have expressed more consistent cleaning efforts towards the spawning nest. All preferred males without the effect of their size exhibited better cleaning efforts towards the nest compared to non-preferred fish. It could be suggested that pikeperch females preferred males expressing better nest preparation. The parameters of egg distribution, egg clustering, and larvae production were not influenced by the male size, testosterone, 11-keto-testosterone, and estradiol levels in blood plasma. It indicates the importance of female partner selection in pikeperch for consistent reproduction output of formed spawning pairs. The present study has confirmed the variability of cleaning efforts within different sizes of males and the effective selective behaviour of females during natural reproduction.