Multiple records of aquatic alien and invasive species in diets of native predators in Singapore

We report for the first time the diversity of known aquatic alien species in the diets of four piscivorous predators in Singapore through a review of published and unpublished studies, and our empirical data. Of 15 aliens identified to the species level, 11 were fish, including the highly invasive tilapia (Oreochromis mossambicus [Peters, 1852]). Other alien species include the abundant red-eared slider (Trachemys scripta elegans [Wied-Neuweid, 1839]) and the American bullfrog (Lithobates catesbeiana [Shaw, 1802]). We hypothesize that the diversity of established alien species in Singapore’s aquatic habitats allows for novel ecological interactions, one of which is predation by native species. Our study provides preliminary evidence that alien and invasive species may benefit some native piscivores as a source of prey although it is not possible to infer relative composition of these alien species given our limited data. Future studies should investigate the ecological dynamics of these interactions, including the relative importance of these alien prey to diets and survival of predators.