The introduction of exotic fish species (Largemouth bass: Micropterus salmoides, Northern pike: Esox lucius, Pumpkinseed: Lepomis gibbosus, Chameleon cichlid: Australoheros facetus, Eastern mosquitofish: Gambusia holbrooki, Zander: Sander lucioperca, Bleak: Alburnus alburnus) results in competition for food and space and predation on eggs, juveniles and adults of native species, such as the saramugo.
In addition, exotic species can also be disease vectors which can have unpredictable consequences on native species.
These threats become even more important during the summer, when the deepest parts of the rivers are at their shallowest.
The introduction of exotic species has frequently had negative and unpredictable results, and some species can even become pests, such as the Red swamp crayfish from Louisiana (Procambarus clarkii).
Lagoons are places where exotic species find good conditions to proliferate, and from where they disseminate through watercourses, competing with or even predating on native fish species.
