Ecological Risk Screening Summary - Bighead Carp (Hypophthalmichthys nobilis) - High Risk

Species that are considered high risk have a well-documented history of invasiveness in at least one location globally and are of establishment concern for the contiguous United States based on a climate matching analysis.

Hypophthalmichthys nobilis, Bighead Carp, is a freshwater fish native to lowland rivers of eastern China. This species is a planktivorous filter feeder. H. nobilis is used globally in aquaculture as a food fish and to improve water quality in culture ponds. Escape from aquaculture is one of the introduction pathways for this species, along with illegal stocking and release of contaminated grass carp stock. H. nobilis has become established outside its native range from Asia to Europe to the United States. It is listed as injurious by the U.S. Fish and Wildlife Service under the Lacey Act and is regulated in at least 40 U.S. States. The History of Invasiveness for Hypophthalmichthys nobilis is classified as High because of its ability to alter plankton community structure with cascading effects to fish communities. The climate matching analysis for the contiguous United States indicates Yes, there is establishment concern for this species outside of its already established range (the Mississippi River drainage and its major tributaries). The Certainty of Assessment for this ERSS is classified as Medium because much of the information available regarding impacts confounds the impacts from H. nobilis with impacts from other introduced fishes. The Overall Risk Assessment Category for Hypophthalmichthys nobilis in the contiguous United States is High.