Ecological Risk Screening Summary - Serrasalmus marginatus (a piranha, no common name) - Uncertain Risk

Species that are considered uncertain risk need a more in-depth assessment beyond the Risk Summary to better define the species’ risk to U.S. environments.

Serrasalmus marginatus is a piranha species native to the Paraguay-Paraná River basin of South America. The colonization of the Upper Paraná River by S. marginatus following the construction of a dam is the only documented introduction of this species outside of its native range. In that case, introduction of S. marginatus correlated with a substantial population decline of native congener S. spilopleura. However, it was not clearly demonstrated that S. marginatus caused the decline in S. spilopleura; construction of the dam likely resulted in other changes to the habitat. S. marginatus has a medium climate match with the contiguous United States, with highest match occurring in peninsular Florida. Overall risk assessment category is uncertain.