Abstract The ability to actively sample fish populations is a major advantage of hydroacoustic assessment. This technique does not affect fish behavior, and it typically produces more precise abundance estimates than do other gears. Thus, hydroacoustic surveys repeated on a closed population should produce similar fish density estimates. We sought to demonstrate this on inland waters using multiplexed side- and down-looking transducers and target-tracking enumeration methods. To test the repeatability of hydroacoustically derived fish density estimates, we conducted complete hydroacoustic surveys daily over three consecutive days on two Wyoming reservoirs, with a parallel transect design at one reservoir and a zigzag design at the other; this mimicked two designs commonly used during routine hydroacoustic surveys. These repeated surveys were performed on each reservoir monthly from April to September 2001. We used a Kruskal–Wallis test to detect significant differences in fish density estimates among repe...