High-tech survey of Lake Michigan’s prey fish community helps with future decisions

The Department of Natural Resources is preparing to conduct its annual hydro-acoustic (sonar) and mid-water trawl survey of alewives and other prey fishes in Lake Michigan this month to determine the status of these key components of the Lake Michigan ecosystem.
The survey is conducted on board the DNR’s Survey Vessel (S/V) Steelhead, based out of Charlevoix, in conjunction with the U.S. Geological Survey’s (USGS) Great Lakes Science Center’s R/V Arcticus. The survey is done at night starting in mid-August and usually takes about three weeks to complete.
Once completed, estimates of total prey fish abundance are used by fisheries managers in balancing predator-prey dynamics. Managers adjust fish-stocking rates to keep alewife abundance in balance with lake productivity levels.
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