Distribution extension of invader Palometa Serrasalmus maculatus (Kner, 1858) and first record of Pygocentrus nattereri (Kner, 1858) (Characiformes: Serrasalmidae) at the Patos Lagoon System, Rio Grande do Sul State, Brazil

This study documents the southern expansion of Serrasalmus maculatus and the first record of Pygocentrus nattereri in the central portion of Patos Lagoon, Brazil. Four individuals of S. maculatus were caught in the central and southern areas of the lagoon, whereas one sexually mature P. nattereri was found in its central region. Both species occur naturally in the Uruguay River basin and are considered allochthonous in the Patos Lagoon. Their presence in this lagoon could have been facilitated by artificial water channels associated with agricultural activities and exacerbated by high rainfall and river discharge, which are triggered by the El Niño phenomenon. Such predatory species pose a potential threat to local biodiversity due to their adaptable diets and the lagoon’s habitat diversity, which is potentially suitable for such invaders.

Keywords:
Invasive species; Biological invasions; Aquaculture; El Niño; Freshwater