Ecological Risk Screening Summary - Thorn Sturgeon (Acipenser nudiventris) - 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.

Acipenser nudiventris, the Thorn Sturgeon, is a migratory species native to the Black, Azov, Caspian, and Aral Seas. It is listed as Critically Endangered by the IUCN, and it has been extirpated from much of its original native range. It has been intentionally introduced to China, but the status of this introduction is unknown. This species has a medium climate match with the contiguous United States, considering only freshwater habitats. Some A. nudiventris populations complete the life cycle in exclusively freshwater environments, while others spend part of the life cycle in a marine environment. RAMP (Sanders et al. 2018) was not developed for use in assessing climate match for marine species so the climate match in a marine environment cannot be assessed with an ERSS. Because of a lack of a demonstrated history of invasiveness, the certainty of this species’ risk assessment is low. The overall risk assessment category is therefore uncertain.