Marek Smejkal

I am interested reproductive strategies of asp (Leuciscus aspius) and potential impact of egg-feeding predators on their reproductive success. Since 2013, tagging campaigns are held each spring during asp spawning migration. So far, 2500 asp were individually tagged and their spawning behavior was recorded in every spawning season since 2015 by passive telemetry systems. Males of this species are protandric, meaning that they arrive earlier and leave the spawning ground later than females. I investigate whether males improve in their timing of reproduction over time; i.e. whether male reproductive success increase with male age and size. Another aspect of this model system is observed impact egg-feeding predators, especially bleak (Alburnus alburnus). Large shoals of bleak utilize asp spawning ground, where several hundred kilos of asp eggs are laid yearly. I try to untangle possible adaptations to this predation pressure such as nocturnal spawning pattern and predator avoidance.