Ecological Risk Screening Summary - Speckled Dace (Rhinichthys osculus) - Uncertain Risk

Rhinichthys osculus, the Speckled Dace, is a freshwater fish that is native to western North America from the Columbia River drainage in southern British Columbia, Canada to the Gila River in Arizona and portions of northern Sonora, Mexico. R. osculus is commonly found in rocky riffles, runs and pools of cool flowing water such as creeks, streams, and small to medium rivers. This species is intolerant to high temperatures and low oxygenated waters. They are often used as bait by anglers but not found in-trade during this assessment. R. osculus has been introduced to areas adjacent to its native range. R. osculus has been intentionally stocked outside its native range for scientific or management purposes. The History of Invasiveness for R. osculus is classified as Data Deficient due to minimal information regarding impacts of introduction. The climate matching analysis for the contiguous United States indicates establishment concern for this species outside its native range. High climate matches were found for the entire western United States, which includes this species’ native range, as well as the northern Great Lakes. The Certainty of Assessment for this ERSS is classified as Low due to lack of information regarding impacts of introduction and trade and the taxonomic complexity of the R. osculus species complex. The Overall Risk Assessment Category for Rhinichthys osculus in the contiguous United States is Uncertain.