Predator recognition and responses in the endangered Macquarie perch (Macquaria australasica)

Abstract

Macquarie perch, Macquaria austalasica, is an endangered species endemic to southern Australia whose distribution is highly fragmented and continues to decline. Key threatening processes include habitat destruction, dams and weirs, overfishing and interactions with introduced species. Here, we examined the responses of small and large Macquarie perch to two native predators and to the introduced redfin perch, Perca fluviatilis. Our results showed that Macquarie perch generally avoided large-bodied native predators but was attracted to small-bodied native predators. Responses to large and small redfin perch lay between these two extremes, suggesting that the Macquarie perch does treat these foreign fish as potential threats. Macquarie perch relied on both visual and chemical cues to identify predators, although its response tended to be stronger when exposed to visual cues. The results suggest that Macquarie perch has the capacity to recognise and respond to invasive species in a threat-sensitive manner, which has positive implications for the conservation management of the species.