Species that are considered high risk have a well-documented history of invasiveness in at least one location globally, and a high or medium climate match to the contiguous United States.
The native range of Redear Sunfish (Lepomis microlophus) is in the southeastern United States. L. microlophus is used in environmental contaminant studies. L. microlophus feeds on mollusks and gastropods and has been introduced as a biocontrol for mollusks and gastropods with mixed results. The history of invasiveness for L. microlophus is high. L. microlophus has been introduced as a game fish in much of the rest of the United States. There are multiple documented instances of introductions of L. microlophus becoming established populations and the negative impacts that resulted. It has been known to reduce the population of other native Lepomis species. The climate match is very high across the whole contiguous United States. The certainty of assessment is high. The overall risk assessment category is high.