Habitat Classification of the St. Marys River Near the Soo Locks, Michigan

<jats:p>In June and October 2019, the US Army Corps of Engineers, Detroit District, collected over 130 linear miles (215+ km) of side-scan sonar data on the St. Marys River—from the northern lock region to the Lower Little Rapids—to map benthic habitats. In 2020, 56 bottom samples and 24 re-motely operated vehicle (ROV) videos were collected to validate the sonar data. Although mapping the same regions twice to assess seasonal variability was mostly unachievable due to environmental and operational factors, four regions were successfully repeated. Crucially, the dataset includes the newly restored Little Rapids and a previously unmapped area downstream of the main rapids. Results revealed abundant submerged aquatic vegetation across the St. Marys River, likely driven by a highly variable sediment matrix ranging from clay to boulders. These data will be invaluable for planning and assessing habitat diversity and health in this vital ecological system.</jats:p>