Intensive and size-selective harvesting is an evolutionary driver of life-history as well as individual behavioural traits. Yet, whether and to what degree harvesting modifies the collective behaviour and the circadian system of exploited species is largely unknown. I will present a multi-generation harvest selection experiment with zebrafish (Danio rerio) as a model species to understand the effects of size-selective harvesting on shoaling behaviour and the circadian system. The experimental system is based on a large-harvested (typical of most wild capture fisheries targeting larger size classes) and small-harvested (typical of specialized fisheries and gape-limited predators targeting smaller size classes) selection lines. I will first show the effects of size-selective harvesting on fish individual personality traits and possible repercussions in terms of mating behaviour and reproductive isolation. Then, I will document an overlooked evolutionary pathway through which size-selective mortality can affect group risk-taking behaviour and consequently the circadian system of fish both at behavioural and molecular level. Finally, I will present an elegant interdisciplinary approach by combining high resolution tracking with computational agent-based modelling and document a mechanism driving fisheries-induced evolution of collective behaviour and predict possible effects on natural and fishing mortality. Overall, I will provide new evidences on how size-selective harvesting can affect fisheries and trophic dynamics

Peer reviewed