Predator cues and environmental complexity shape the behaviour and life history of juvenile lobsters (Homarus...

Phenotypic plasticity is critical for animals to survive in our rapidly changing world, especially for species with low population densities. Standard hatchery procedures can assist some conservation programmes by producing large numbers of juveniles to be released into the wild. Yet we know surprisingly little about the impact that such standard, minimalistic hatchery settings have on the development of important behaviours and life-history traits of the animals. Here, we fill this gap by testing whether and how early-life exposure to different environmental conditions alters the development of ecologically relevant behaviours and life-history traits of the European lobster (Homarus gammarus)-one of the most harvested species in the Mediterranean. We used the progeny of wild-caught females and manipulated-in a full factorial design-the environmental complexity of the individual enclosures and the level of perceived predation risk. We repeatedly quantified key behaviours (activity, shelter use and aggressiveness) and life-history traits (carapace length and intermoult period) of individuals throughout their early development, capturing both mean and individual-level variation across treatments. Our results offer solid evidence that standard hatchery settings compromise the development of important behavioural and life-history traits of lobsters and even alter their behavioural plasticity-probably reducing the effectiveness of conservation programmes.