Knowledge and Management of Aquatic Ecosystems (BFPP-Connaissance et Gestion du Patrimoine Aquatique)
Abstract:Feeding success is a key factor for larval growth and survival, and is highly dependent on small-scale processes which occur during the predator-prey interaction. We studied the feeding mechanisms involved in the capture success of the European whitefish (Coregonus lavaretus) larvae using video recordings. The successful predatory sequence of this species consists of the following 5 events: encounter, pursuit (including fixation), strike, capture and ingestion. C. lavaretus larvae can exhibit an “S” shaped posture and always strikes on its prey from beyond. The mean fixation distance for wild larvae was 1.75 ± 0.71 mm and for reared larvae was 1.65 ± 0.76 mm. This distance was significantly different between failed and successful snaps, and seemed to be an important parameter to the capture success of C. lavaretus larvae. The analysis of the complexity in predator’s swimming path showed that more convoluted approaches are less likely to lead to a fruitful attack.