The project’s goals are to enhance and/or develop new barriers using carbon dioxide to deter the range expansion of invasive bigheaded carp. These fish continue to migrate northward and present a danger to Minnesota’s aquatic habitat. The locks and dams on the Mississippi River present strategic bottlenecks where non physical deterrents can be deployed to prevent upstream carp migration. Acoustic deterrents have shown promise but are not completely effective. Two different strategies will be examined simultaneously to increase the effectiveness of acoustic deterrents by augmenting them with carbon dioxide. Bigheaded carp display strong aversion to the gas and, if successful, the combination of sound and carbon dioxide will increase the effectiveness of acoustic deterrents. The first objective will augment a bioacoustics bubble barrier by injecting carbon dioxide into the sound/bubble curtain. The second objective with use acoustic conditioning to train the fish to associate sound with carbon dioxide, which will prolong the fish’s aversion to broadband sound while simultaneously decreasing the frequency of carbon dioxide application. Both objectives are targeted to be deployed at the downstream lock gate at dams on the Mississippi River.