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.
Stone Moroko (Pseudorasbora parva) is a species of cyprinid native to Pacific drainages in northeastern Asia. P. parva has been used commercially, as feed and bait, and in the ornamental trade. The history of invasiveness is high. The species was inadvertently and purposefully introduced, and then spread on its own, into various portions of Europe. It has been a contaminant of shipments of other species to Europe from Asia. P. parva competes for food with farmed fish species, feeds on juvenile stages of many locally valuable native fish species, and is a vector of infectious diseases (including Spherotecum destruens) that constitutes a serious threat to both native and farmed fishes. P. parva has been documented as a cause of or implicated in significant declines in native species in Europe. The climate match is high. There were very few areas of the contiguous United States that did not have medium or high matches. All states but two had high individual climate scores. The certainty of assessment is high. The overall risk assessment category is high.