Experimental Examination of the Potential for Three Introduced Fish Species to Prey on Tadpoles of the Endangered Booroolong Frog, Litoria booroolongensis

Abstract

Abstract Over the past three decades the Booroolong Frog (Litoria booroolongensis) has declined across the majority of its range, with predation from introduced fish hypothesized as contributing to this decline. In this study we undertook an experiment in artificial enclosures to test the propensity for three introduced fish species (European Carp, Cyprinus carpio; Redfin Perch, Perca fluviatilis; and Mosquito Fish, Gambusia holbrooki) to prey on L. booroolongensis tadpoles. We manipulated the presence–absence of refuge habitat and alternative prey to examine how these two factors may affect tadpole predation risk. All three fish species consumed L. booroolongensis tadpoles, with juvenile C. carpio consuming nearly all tadpoles in all treatments. The provision of rocks within enclosures did not reduce the proportion of tadpoles consumed for any of the fish species examined; however, there was a reduction in the proportion of tadpoles consumed by P. fluviatilis and G. holbrooki when alternative prey were p...