Behavioural responses to con- and heterospecific alarm cues by an alien and a coexisting native fish

Abstract The monkey goby Neogobius fluviatilis is an invasive Ponto-Caspian fish that enters habitats of the native gudgeon Gobio gobio in European freshwaters, likely belonging to same prey guild. Their abilities detect and avoid predation have been poorly understood, although these traits may contribute competitive advantage drive invasion success goby. We tested intra- interspecific responses from sympatric populations damage-released alarm cues (skin extract) laboratory. Both species responded conspecific heterospecific cues, but their conspecifics were more diverse (changed social distancing among individuals, reduced vertical horizontal movement) than those elicited by heterospecifics only). Moreover, differed anti-predation behaviour: increased whilst decreased inter-individual distances only exhibited thigmotaxis mobility response cues. Interspecific differences show exhibit distant strategies. This might be associated with phylogenetic distance and/or higher differentiation ecological niches commonly assumed. Besides, our results suggest alien included exchange information local assemblages.