Ecological Risk Screening Summary - European Stream Valvata (Valvata piscinalis) - Uncertain Risk

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.

Valvata piscinalis, the European Stream Valvata, is a freshwater snail native to Europe, the Caucasus, western Siberia, and Central Asia. This species can reach up to 7mm in length and can tolerate a wide range of temperature and habitat conditions. It is a short-lived species that can spawn multiple times a year. The History of Invasiveness for Valvata piscinalis is Data Deficient. It has been documented as introduced to multiple locations in North America, primarily in the Great Lakes; however, no observed impacts of these introductions have been documented in the scientific literature. It is thought to have decreased native gastropod abundance in Oneida Lake, New York, but supporting documentation has not been published. V. piscinalis is regulated in Wisconsin. The climate matching analysis for the contiguous United States indicates establishment concern for this species. V. piscinalis has a high climate match with the contiguous United States, especially where it is established in the Great Lakes region and the Northeast, as well as in the Mid-Atlantic region. The Certainty of Assessment for this ERSS is classified as Low due to the lack of information on the impacts of introductions, which would inform the history of invasiveness. The Overall Risk Assessment Category for Valvata piscinalis in the contiguous United States is Uncertain.