title: Disturbed flow in an aquatic environment may create a sensory refuge for aggregated prey.
abstract: Predators use olfactory cues moved within water and air to locate prey. Because prey aggregations may produce more cue and be easier to detect, predation could limit aggregation size. However, disturbance in the flow may diminish the reliability of odour as a prey cue, impeding predator foraging success and efficiency. We explore how different cue concentrations (as a proxy for prey group size) affect risk to prey by fish predators in disturbed (more turbulent or mixed) and non-disturbed (less mixed) flowing water. We find that increasing odour cue concentration increases predation risk and disturbing the flow reduces predation risk. At high cue concentration fish were able to locate the cue source in both disturbed and non-disturbed flow, but at medium concentrations, predators only located the cue source more often than expected by chance in non-disturbed flow. This suggests that objects disturbing flow provide a sensory refuge allowing prey to form larger groups, but that group sizes may be limited by level of disturbance to the flow.
authors.affiliation: Nesvik Marine Centre, Fiskaaling, Hvalvik, Faroe Islands; School of Biology, University of Leeds, Leeds, United Kingdom.
authors.forename: Asa
authors.initials: A
authors.lastname: Johannesen
authors.affiliation: School of Biology, University of Leeds , Leeds , United Kingdom.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Dunn
authors.affiliation: School of Environmental Sciences, University of Hull , Hull , United Kingdom.
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Morrell
keywords: Flow; Olfaction; Olfactory foraging; Predator-prey interaction; Prey aggregation; Stickleback