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.
Piaractus mesopotamicus, Small-scaled Pacu, is a species of fish native to Argentina, Bolivia, Brazil, Paraguay, and Uruguay. This species is used in the aquarium trade and in aquaculture. It has been found Oregon and Florida, likely as a result of aquarium releases, although species identification has been challenging. These reported introductions seem to represent released specimens, not established populations. Without a confirmed established population outside its native range, the history of invasiveness for P. mesopotamicus is “Uncertain.” P. mesopotamicus has an overall medium climate match with the contiguous United States, with a high match in coastal areas of the Southeast. Because impacts of introductions of this species have not been studied, further information is needed to adequately assess the risk this species poses. Certainty of this assessment is low, and the overall risk assessment category is uncertain.
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Uncertain Risk
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