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Deterring the spread of invasive fishes is a challenge for managers, and bigheaded carp (including bighead and silver carp, Hypophthalmichthys spp.) are invasive fish that have spread throughout large portions of the Mississippi River basin and threaten to invade the Great Lakes' ecosystem. Studies have shown that elevated levels of carbon dioxide gas (CO2) have the ability to act as a nonphysical fish barrier, but little work has been done on the efficacy of CO2 to deter fish movement in flowing water. An annular swim flume was used to measure U-burst and sprint duration of the model species largemouth bass (Micropterus salmoides) across a range of pCO(2) levels (<400atm [ambient]; 10,000atm; 50,000atm; and 100,000atm). This species was tested as a proxy because of the likelihood of a similar CO2 response being produced, as well as constraints in obtaining and housing appropriately sized Asian carp. A significant decrease in U-burst swimming occurred when exposed to 100,000atm. No effects on sprint duration were detected. In both swimming tests, 15% of fish lost equilibrium when exposed to 50,000atm pCO(2), while 50% of fish lost equilibrium when exposed to 100,000atm. Together, results define target levels for managers to impede the spread of largemouth bass and potentially other invasive freshwater fishes, helping guide policy to conserve aquatic ecosystems.