Hydroacoustic and environmental data from autonomous underwater vehicle (AUV) in Lakes Superior and Michigan, 2022

This dataset contains hydroacoustic and environmental data collected by a long-range autonomous underwater vehicle (LRAUV) in U.S. waters of Lake Superior and Lake Michigan during August 2022. Data were collected to evaluate bias in fisheries hydroacoustic surveys associated with the surface acoustic dead zone (SADZ; 0–5 m depth), where near-surface fish often go undetected, leading to inaccuracies in fish abundance estimation. The LRAUV was equipped with upward- and downward-facing echosounders to quantify fish distributions across depth strata. Acoustic data were processed into 2-km horizontal intervals to estimate fish density, acoustic biomass (nautical area scattering coefficient), and the proportion of fish occurring within the SADZ. Differences between the 0–5 m and 5–10 m layers were calculated to assess near-surface bias. Environmental data (temperature, stratification metrics, and chlorophyll-a) were collected concurrently to support analyses of factors potentially influencing vertical fish distribution.