Ecological Risk Screening Summary - California Roach (Hesperoleucus symmetricus)

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.

Hesperoleucus symmetricus, California Roach, is a freshwater fish that is native to central California and found in the upper Sacramento-San Joaquin River drainages. H. symmetricus is found in small and medium rivers, creeks, and headwaters with rocky bottoms. It may sometimes be used as a bait fish by anglers. No information was found indicating the presence of H. symmetricus in the aquarium trade. The History of Invasiveness for H. symmetricus is classified as Data Deficient due to record of an established population that is presumed to be introduced but a lack of impact information. The climate matching analysis for the contiguous United States indicates establishment concern for this species outside its native range. The climate matching analysis found high match in the Pacific Coast States, including the native range, and other areas of the Western Mountains. The Certainty of Assessment for this ERSS is classified as Low due to the recent taxonomic restructuring of the species complex to which H. symmetricus belongs; some information available on H. symmetricus may actually be relevant to one of the newly elevated species and not H. symmetricus sensu stricto. The Overall Risk Assessment Category for Hesperoleucus symmetricus in the contiguous United States is Uncertain.