Ecological Risk Screening Summary - Guadalupe Bass (Micropterus treculii)

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.

Micropterus treculii, Guadalupe Bass, is a fish native to streams originating in central Texas, including subbasins of the Brazos, Colorado, Guadalupe, and San Antonio rivers. M. treculii is a popular sportfish in Texas and has been intentionally stocked beyond its native range for conservation purposes. Hybridization with Smallmouth Bass (Micropterus dolomieu) has resulted in disappearance of pure M. treculii from parts of its native range. The History of Invasiveness for M. treculii is classified as Data Deficient. Although introductions have resulted in established populations in the Nueces River basin, any impacts or lack of impacts of these introductions has not been documented. The climate matching analysis for the contiguous United States indicates establishment concern for this species outside its native range. The highest climate matches were found in Texas where this species is native, extending through the Southern Plains and into portions of the Southeast and Southwest regions. The Certainty of Assessment for this ERSS is classified as Low because of the absence of information on any impacts of introduction or lack of impacts. The Overall Risk Assessment Category for M. treculii in the contiguous United States is Uncertain.