The U.S. Geological Survey, the U.S. Army Engineer Research and Development Center's Environmental Laboratory and partners use a 350-ton crane to install the underwater Acoustic Deterrent System weldment at Lock and Dam 19 on the Mississippi River in Keokuk, Iowa, Feb. 3, 2021. The weldment runs perpendicular to the lock's approach channel walls and is part of a study to understand how invasive Asian carp respond to acoustic signals. If the deterrent is effective at controlling upstream movement of Asian carp with limited effects on native species, this or similar technology could be deployed at other critical locations to help prevent the spread of the invasive fish.