Hydrographic surveys collected to monitor fish spawning reef placements, Detroit River, Michigan, June 23-24, 2015

The U.S. Geological Survey conducted hydrographic surveys from June 23-24, 2015, to monitor fish spawning substrate placements (reefs) in the Detroit River, Michigan. An interferrometric multibeam echosounder was used from the Great Lakes Science Center research vessel Mayfly to collect maps of river bottom topography in locations where spawning substrates have been placed. In addition, baseline topography was collected at locations where substrates were planned to be introduced. The Fighting Island reef had been constructed at the date of survey. Surveys were also conducted at prospective reef sites: Grassy Island, Fort Wayne and Upstream Belle Isle. This data release includes bathymetric surveys collected from June 23-24, 2015.