title: Escaping peril: perceived predation risk affects migratory propensity.
abstract: Although migratory plasticity is increasingly documented, the ecological drivers of plasticity are not well understood. Predation risk can influence migratory dynamics, but whether seasonal migrants can adjust their migratory behaviour according to perceived risk is unknown. We used electronic tags to record the migration of individual roach (Rutilus rutilus), a partially migratory fish, in the wild following exposure to manipulation of direct (predator presence/absence) and indirect (high/low roach density) perceived predation risk in experimental mesocosms. Following exposure, we released fish in their lake summer habitat and monitored individual migration to connected streams over an entire season. Individuals exposed to increased perceived direct predation risk (i.e. a live predator) showed a higher migratory propensity but no change in migratory timing, while indirect risk (i.e. roach density) affected timing but not propensity showing that elevated risk carried over to alter migratory behaviour in the wild. Our key finding demonstrates predator-driven migratory plasticity, highlighting the powerful role of predation risk for migratory decision-making and dynamics.
authors: Department of Biology, Aquatic Ecology Unit, Lund University, Ecology Building, Lund 223 62, Sweden kaj.hulthen@biol.lu.se.
authors: Kaj
authors: K
authors: Hulthén
authors: Department of Biology, Aquatic Ecology Unit, Lund University, Ecology Building, Lund 223 62, Sweden Ecology and Evolution Group, School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors: Ben B
authors: BB
authors: Chapman
authors: Department of Biology, Aquatic Ecology Unit, Lund University, Ecology Building, Lund 223 62, Sweden Department of Environmental and Life Sciences, Karlstad University, Karlstad 651 88, Sweden.
authors: P Anders
authors: PA
authors: Nilsson
authors: Department of Biology, Aquatic Ecology Unit, Lund University, Ecology Building, Lund 223 62, Sweden.
authors: Jerker
authors: J
authors: Vinterstare
authors: Department of Biology, Aquatic Ecology Unit, Lund University, Ecology Building, Lund 223 62, Sweden.
authors: Lars-Anders
authors: http://orcid.org/0000-0002-3035-1317
authors: LA
authors: Hansson
authors: National Institute of Aquatic Resources, Technical University of Denmark (DTU), Vejlsøvej 39, Silkeborg 8600, Denmark.
authors: Christian
authors: C
authors: Skov
authors: Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Center for Ecology, Evolution and Biogeochemistry, Kastanienbaum, Switzerland.
authors: Jakob
authors: J
authors: Brodersen
authors: National Institute of Aquatic Resources, Technical University of Denmark (DTU), Vejlsøvej 39, Silkeborg 8600, Denmark.
authors: Henrik
authors: H
authors: Baktoft
authors: Department of Biology, Aquatic Ecology Unit, Lund University, Ecology Building, Lund 223 62, Sweden.
authors: Christer
authors: C
authors: Brönmark
mesh_terms: D025041:Animal Migration; D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D017859:Esocidae; D011156:Population Density; D011157:Population Dynamics; D011235:Predatory Behavior; D012621:Seasons
keywords: animal migration; environmentally induced; facultative migration; mortality risk; predation