Ecological Risk Screening Summary - Sacramento Blackfish (Orthodon microlepidotus)

Species that are considered uncertain risk need a more in-depth assessment beyond the Ecological Risk Screening Summary to better define the species’ risk to U.S. environments.

Orthodon microlepidotus, Sacramento Blackfish, is a freshwater fish that is native to the state of California in the United States. This species prefers a temperate climate with warm and turbid waters. It has been introduced in Nevada and outside its native range in California, both accidentally and deliberately. There are records of this species being harvested commercially, but no recent information was found on the size of the commercial fishery. The History of
Invasiveness for Orthodon microlepidotus is classified as Data Deficient due to knowledge of nonnative introductions resulting in established populations, but with a lack of data on impacts of these introductions. Effects on native fish and the plankton community have been suggested but no clear documentation of these impacts in wild populations was found. The climate matching analysis for the contiguous United States indicates Establishment Concern for this species outside its native range. The locations with the highest climate match extended west of the Rocky Mountains to the Pacific coast and included the native range of O. microlepidotus. The eastern United States had a generally low climate match. The Certainty of Assessment for this ERSS is classified as Low due a lack of information about negative impacts of this species. The Overall Risk Assessment Category for Orthodon microlepidotus in the contiguous United States is Uncertain.