Ecological Risk Screening Summary - Rainbow Smelt (Osmerus mordax)

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.

Osmerus mordax, the Rainbow Smelt, is a euryhaline fish that is native to Atlantic coastal areas and inland lakes of the United States and Canada. Osmerus mordax is commonly used as bait for fishing and is consumed by humans, and it has been introduced via stocking in many different areas of the United States as a forage fish. O. mordax has become established outside of its native range in both the United States and Canada. Although this species is utilized as a forage fish by game species in its nonnative environment, there have been negative impacts of its introduction, too. O. mordax alters food webs by preying on large-bodied zooplankton, and introduction of O. mordax has been linked to increased concentrations of bioaccumulating contaminants in native fish tissue. The History of Invasiveness for O. mordax is classified as High due to introduction and successful establishment outside its native range and substantial documentation showing the negative impacts of these introductions. The climate matching analysis for the contiguous United States indicates establishment concern for this species outside its native range, especially in the eastern and central United States around where the species is native or has established nonnative populations already. The Certainty of Assessment for this ERSS is classified as High due to there being sufficient information regarding the species distribution and history of invasiveness, including multiple, specific examples from scientifically defensible sources of the negative impacts this species has had where introduced. The Overall Risk Assessment Category for Osmerus mordax in the contiguous United States is High.