The impacts of exotic species on ecosystem functions are still poorly known. Top-predatory fish, which are at the top of the food-chain are relevant models to study the impacts on freshwater ecosystems. Introductions of exotic top-predator fish can induce changes in the functioning of freshwater communities, that could be inferred by stable isotope analyses in lentic and lotic food-webs, using trophic positions and diet compositions of top-predators. Moreover, the otolith chemical signatures can discriminate freshwater fish stocks and help to reconstruction of the introduced fish life history. Our results provide new information about trophic ecology of top-predator fish, and this knowledge will be useful to design regional conservation plans.
